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Home My WebLink About; Olivenhain Road Widening/Realignment; Olivenhain Road Widening/Realignment; 1992-01-01FINAL ENVIRONMENTAL IMPACT REPORT FOR OLIVENHAIN ROAD WIDENING/REALIGNMENT AND FLOOD CONTROL PROJECT (SCH# 91011035) Prepared for: City of Encinitas Community Development Department 527 Encinitas Boulevard Encinitas, California 92024 (619) 944-5060 Prepared by: Brian F. Mooney Associates 9903-B Businesspark Avenue San Diego, California 92131 (619) 578-8964 January, 1992 TABLE OF CONTENTS Section Page USER'S GUIDE TO THE ENVIRONMENTAL IMPACT REPORT v SUMMARY S-l 1.0 INTRODUCTION 1-1 2.0 PROJECT DESCRIPTION II-l 2.1 Project Location II-l 2.2 Environmental Setting II-l 2.3 Proposed Project II-13 2.4 Environmental Review Study Areas 11-22 2.5 General Plan Designated Trail Alignment 11-22 2.6 Project Objectives H-26 2.7 Agency Approvals Required 11-27 3.0 ENVIRONMENTAL ANALYSIS HI-1 3.1 Biological Resources III-l 3.2 Cultural Resources 111-21 3.3 Geologic Hazards 111-26 3.4 Traffic/Circulation 111-31 3.5 General Plan Compatibility 111-49 3.6 Traffic Noise 111-55 3.7 Paleontological Resources 111-66 3.8 Hydrology /Water Quality 111-68 3.9 Community Character/Visual Resource 111-75 3.10 Public Services/Utilities 111-90 4.0 GROWTH INDUCEMENT IV-1 5.0 CUMULATIVE IMPACTS V-l 6.0 ALTERNATIVES TO THE PROPOSED PROJECT VI-1 7.0 EFFECTS FOUND NOT TO BE SIGNIFICANT VIM 8.0 THE RELATIONSHIP BETWEEN LOCAL SHORT-TERM USES OF MAN'S ENVIRONMENT AND THE MAINTENANCE AND ENHANCEMENT OF LONG-TERM PRODUCTIVITY VIII-1 TABLE OF CONTENTS (Continued) Section Page 9.0 ANY SIGNIFICANT IRREVERSIBLE ENVIRONMENTAL CHANGES WHICH WOULD BE INVOLVED IN THE PROPOSED ACTION SHOULD IT BE IMPLEMENTED IX-1 10.0 MITIGATION MONITORING PROGRAM X-l 11.0 REFERENCES, PERSONS AND AGENCIES CONSULTED XM 12.0 CERTIFICATION XIM APPENDICES (Bound Separately) 1. Environmental Impact Assessment Form for Olivenhain Road Interim Expansion to Four Lanes (Fay Round and Associates) 2. Notice of Preparation (City of Encinitas) 3. Comments Received During Notice of Preparation Review Period 4. Drainage Study for Encinitas Creek (Dr. Chang) 5. Biological Resources Technical Report (BFMA) 6. Cultural Resources Technical Report (BFMA) 7. Soil and Geologic Reconnaissance Technical Report (GEOCON) 8. El Camino Real/Olivenhain Road Intersection Capacity Utilization (ICU) Analyses (City of Carlsbad and City of Encinitas) 9. Existing Traffic Volumes for El Camino Real between Olivenhain Road and Levante Street (JHK & Associates), Intersection Capacity Utilization Standards and Relationship to Levels of Service (Highway Capacity Manual), and Intersection Warrants (AASHTO and Highway Design Manual) 10. Acoustical Analysis Technical Report (BFMA) 11. Paleontological Assessment Technical Report (RMW Paleo Associates) 12. Hydrology, Hydraulics, and Water Quality Technical Report (Nolte and Associates) 13. Letters of and Responses to Public and Other Agency Comments LIST OF FIGURES Number Title Page 2.1-1 Regional Location Map II-2 2.1-2 Vicinity Map II-3 2.2-1 Topography at Western End of Project Route II-4 2.2-2 Topography at Eastern End of Project Route II-5 2.2-3 Residential Land Uses Along the Project Route II-7 2.2-4a Encinitas Creek 100-Year Floodway/Floodplain Limits Adjacent to Olivenhain Road (Western Segment) II-9 2.2-4b Encinitas Creek 100-Year Floodway/Floodplain Limits Adjacent to Olivenhain Road (Eastern Segment) 11-10 2.2-5 Encinitas Creek 100-Year Floodway/Floodplain Limits Adjacent to La Costa Avenue/El Camino Real Intersection 11-11 2.3-1 Proposed Olivenhain Road Alignment #2 11-14 2.3-2 Proposed Olivenhain Road Cross-Sections 11-15 2.3-3 Proposed Floodwater Detention Dike 11-18 2.3-4 Alternative Flood Control Berm Designs at La Costa Ave/El Camino Real 11-20 2.3-5 Conceptual Cross-Section of Proposed Flood Control Berm at La Costa Ave/El Camino Real 11-21 2.4-1 Alternative Alignments Study Area 11-23 2.4-2 Proposed Dike and Future Detention Basin "D" Study Area 11-24 2.4-3 Alternative Flood Control Berms Study Area 11-25 3.1-1 Biological Resources Map - Olivenhain Road III-2 3.1-2 Biological Resources Map - Detention Basin III-3 3.1-3 Biological Resources Map - La Costa Avenue III-4 3.1-4 Olivenhain Road Biological Impacts Map III-9 3.1-5 Detention Basin Biological Impacts Map III-12 3.1-6a La Costa Avenue Alternative 1 III-14 3.1-6b La Costa Avenue Alternative 2 III-15 3.1-7a Proposed Revegetation Sites - Olivenhain Road 111-18 3.1-7b Proposed Revegetation Site - La Costa Avenue 111-19 3.3-1 Existing Soils at Western End of Project Route 111-27 3.3-2 Existing Soils at Eastern End of Project Route 111-28 3.5-1 City of Encinitas Circulation Plan 111-50 3.5-2 City of Carlsbad Circulation Plan 111-52 3.5-3 Comparison of Street Design Guidelines 111-54 3.6-1 Measured Existing Noise Levels 111-56 3.6-2 Calculated Existing Noise Levels - Western Road Segment 111-57 3.6-3 Calculated Existing Noise Levels - Eastern Road Segment 111-58 3.6-4 Future Noise Levels - Western Segment 111-61 3.6-5 Future Noise Levels - Eastern Segment 111-62 3.8-1 Locations of Detention Basins within the Project Vicinity 111-69 3.9-1 Visual Resource Sensitivity Map 111-76 in LIST OF FIGURES (Continued) Number Title 3.9-2 Natural Resource Sensitivity Map 3.9-3 Vantage Point Locations 3.9-4 Vantage Point 1 3.9-5 Vantage Point 2 3.9-6 Vantage Point 3 3.9-7 Vantage Point 4 3.9-8 Vantage Point 5 3.9-9 Vantage Point 6 3.9-10 Vantage Point 7 3.9-11 "Worst Case" Thompson Property Grading 3.10-1 Major Utility Easements within the Project Vicinity 5.0-1 Planned Development in Project Vicinity 6.2-1 Alternative #1: Southern Alignment 6.2-2 Alternative #3: Northern Alignment 6.2-3 Alternative #4: Existing Two-Lane Alignment Page 111-77 111-78 111-79 111-80 111-81 111-82 111-83 111-84 111-85 111-87 111-91 V-2 VI-2 VI-5 VI-7 LIST OF TABLES Number Title 3.1-1 Summary of Impacts to Vegetative Habitats Within the La Costa Avenue Flood Control Project Area 3.4-1 Primary Roadways and Key Intersections in the Project Vicinity 3.4-2 Roadway Definitions by Classification 3.4-3 Standards for Roadway Levels of Service 3.4-4 Roadway Capacity Standards 3.4-5 Summary of Existing Roadway Levels of Service Within the Project Vicinity 3.4-6 Intersection Capacity Guidelines for Functional Design 3.4-7 Summary of Existing Intersection Levels of Service Within the Project Vicinity 3.8-1 Water Quality Standards for Encinitas Creek and Batiquitos Lagoon 3.8-2 Batiquitos Lagoon Water Quality 6.2-1 Summary of Impacts to Vegetative Habitats within the Olivenhain Road Project Area 10.0-1 Mitigation Monitoring Checklist Page III-13 IH-34 111-35 111-36 111-37 111-39 111-40 111-41 HI-70 111-71 VI-4 X-3 IV USER'S GUIDE TO THE ENVIRONMENTAL IMPACT REPORT The California Environmental Quality Act (CEQA) of 1970 requires the preparation of an Environmental Impact Report (EIR), or other environmental analysis, for any project which may have a significant effect on the environment The purpose of an EIR is to identify such effects, to identify alternatives to the project, and to indicate the manner in which those significant effects can be mitigated or avoided. EIRs must be organized and written in such a manner that they will be meaningful and useful to both decision-makers and the public. When an EIR is required, it must be considered by every public agency prior to its approval or disapproval of a project The Lead Agency has the responsibility for determining whether an EIR or a Negative Declaration would be required for a project The City of Encinitas is the Lead Agency for oils project and has determined that an EIR is required. EIRs must contain discussions of specific topics as outlined by the lead agency, as well as specific topics outlined in guidelines for the implementation of CEQA prepared by the State Secretary for Resources. Such guidelines are periodically updated to comply with changes in CEQA and court interpretations. This report follows the most recent guidelines and amendments to CEQA. Chapter 1.0 of this document introduces the project, and Chapter 2.0 includes a discussion about the location, environmental setting, and description of the proposed project as well as the objectives and agency approvals required. Chapter 3.0 is a description of the Environmental Analysis which examines the issues identified by the City of Encinitas as having potentially significant environmental effects. These issues are biological resources, cultural resources, geologic hazards, traffic/circulation, General Plan compatibility, traffic noise, paleontological resources, hydrology/water quality, community character/visual resource, and public services/utilities. Chapters 4.0 through 10.0 address the specific topics required by CEQA and include: Growth Inducement; Cumulative Impacts; Alternatives To The Proposed Project; Effects Found Not To Be Significant; The Relationship Between Local Short-Tenn Uses of Man's Environment and the Enhancement of Long-Term Productivity; Any Significant Irreversible Environmental Changes Which Would be Involved in the Proposed Action Should it be Implemented; and a Mitigation Monitoring Checklist The Alternatives Section includes a discussion of the No Project Alternative, Alternative Alignments, Road Widening Alternative, and Grade-Separated Intersection Alternative. This Draft EIR will be made available for review by the public and public agencies for 45 days. The Encinitas City Council will consider the Final EIR, certify it as complete and in compliance with CEQA, and must consider it in approving or disapproving the project Public input is encouraged at any scheduled hearings for the project and EIR. In the final review of the project, environmental considerations, as well as economic and social factors, will be weighed to determine the most appropriate course of action. SUMMARY PROJECT DESCRIPTION The proposed project involves three aspects: widening and realignment of a portion of Olivenhain Road between El Camino Real and Rancho Santa Fe Road; construction of a floodwater detention dike just to the south of this road; and construction of a flood control berm at the intersection of La Costa Avenue and El Camino Real. Existing and proposed rights-of-way for Olivenhain Road are within the corporate boundaries of both the cities of Encinitas and Carlsbad, in northern San Diego County. The future floodwater detention basin "D" would be located in the Encinitas Creek floodplain, just west of Rancho Santa Fe Road, hi the City of Carlsbad. The La Costa Avenue/El Camino Real intersection flood control berm would be situated along the City of Carlsbad/County of San Diego boundary, just south of Batiquitos Lagoon. ENVIRONMENTAL ISSUES The following environmental issues analyzed in this EIR, and briefly summarized below, have been found not to be significantly impacted by the proposed project: cultural resources, geologic hazards, traffic/circulation, General Plan compatibility, paleontological resources, and hydrology/water quality. Potentially significant environmental impacts have been identified for the remaining issues evaluated herein, but can be mitigated to below a level of significance through implementation of mitigation measures. These issues include biological resources, traffic noise, community character/visual resource, and public services/utilities. Additional environmental issues were evaluated during an initial Environmental Impact Assessment, and were determined by the City of Encinitas not to be impacted by the proposed project These issues, which were not included in this EIR analysis, are: air quality, natural resources utilization, land use compatibility, light and glare, hazardous waste generation and disposal, housing demand, recreational uses, and agricultural conversion. Biological Impacts. The proposed project would directly impact sensitive wetland habitats including southern willow scrub, coastal freshwater marsh, coastal salt marsh, and disturbed wetland scrub, as well as upland habitats including southern mixed chaparral, eucalyptus woodland, ruderal vegetation, and disturbed land. The impact to coastal salt marsh is considered significant Impacts to southern willow scrub and freshwater marsh habitats are considered cumulatively significant due to their limited range. The impact to ruderal vegetation may include losses of the sensitive sand aster. A slight increase in roadway runoff volumes due to increased asphalt surface area for the widened road, which may include residuals of oil and grease, could significantly impact Encinitas Creek aquatic wildlife. Significant noise levels from construction equipment operation and future traffic along Olivenhain Road may disrupt sensitive songbird (i.e., willow flycatcher and least Bell's vireo) mating and foraging activities in adjacent riparian habitat S-l Mitigation. The Alternative #2 Olivenhain Road design and the Alternative #1 flood control benn design at La Costa Avenue/El Camino Real intersection are recommended as the least m environmentally damaging alternatives. A U.S. Army Corps of Engineers Pre-Discharge Notification and a California Department of Fish and Game 1601 Streamcourse Alteration Agreement shall be prepared and approved prior to the approval of final roadway improvement «* plans. All mapped sensitive habitats to be disturbed shall be revegetated at the appropriate replacement ratios and within ecologically appropriate areas on-site. All proposed habitat restoration sites shall be monitored by a qualified biologist during plant installation and for a 4* five-year period thereafter. Prior to construction of the proposed flood control benn at La Costa Avenue/El Camino Real intersection, the coastal salt marsh vegetation and top soil layer to be *" impacted shall be salvaged, and then tilled into the soil of the prepared salt marsh revegetation 1* site. jjf Proposed roadway construction for the portion of the project route between the SDG&E easement ** and the western Willow Creek subdivision boundary shall occur outside the months of March _ through July in order to avoid potentially significant noise impacts to sensitive breeding songbirds. In order to avoid incremental water pollution impacts from oil and gas residuals into „. the Encinitas Creek watershed, appropriate runoff protection facilities shall be installed south of Olivenhain Road.«w — Cultural Resources tttf Impacts. No cultural resources are located within the proposed construction easements delineated <•* for the three study areas; therefore, no adverse direct impacts to these resources would occur as a result of project implementation. m Mitigation. Because two archaeological sites exist adjacent to the project study areas, all construction activities shall be restricted to within the limits of proposed construction easements, * as delineated by visible flagging/staking. ** m Geologic Hazards m Impacts. There are no soil or geologic conditions present within the three study areas which m would preclude project implementation. The presence of undocumented fill soils and compressible alluvium, however, would require removal and recompaction of all loose soils prior *» to construction. Stabilization replacement fills would be required for the proposed 32-foot high, fi 2:1 cut slope along the north side of the road segment to be realigned. The presence of shallow groundwater at this location would limit the depth of remedial grading to just above the •*• groundwater level. Placement of a geotextile fabric and coarse aggregate blanket would be ggf required over the exposed cut soils prior to compaction of fill and paving. Construction dewatering, particularly adjacent to El Camino Real, would also be required. * m Mitigation. Prior to the approval of final roadway improvement plans, a detailed soils and geologic investigation addressing the approved alignment shall be performed. All proposed "* roadway improvement and grading plans within existing utility easements on-site shall be M S-2 reviewed and approved by the Public Works Departments of the cities of Encinitas and Carlsbad prior to final approval. All manufactured cut/fill slopes shall be planted with erosion-resistant groundcover vegetation, and watered by a well-designed and maintained irrigation system. A Landscape and Irrigation Plan for all graded slopes shall be approved by the Public Works Departments of the cities of Encinitas and Carlsbad prior to approval of final roadway improvement plans. Landscaping and irrigation of all manufactured slopes, per approved plans, shall be installed as soon as practical after grading in order to reduce erosion potential on exposed slopes. Traffic/Circulation Impacts. The proposed project would improve existing traffic congestion which presently occurs along Olivenhain Road to acceptable levels of service. It would also result in acceptable levels of service at primary street segments and key intersections in the project area under build-out (Year 2010) traffic conditions, except for El Camino Real and Rancho Santa Fe Road south of Olivenhain Road. Some temporary traffic delays may be experienced along Olivenhain Road and its intersections with El Camino Real and Rancho Santa Fe Road during the construction period. Mitigation. Closure of Olivenhain Road to through traffic shall not be permitted during its proposed widening and realignment, unless other detour options, such as Calle Barcelona between El Camino Real and Rancho Santa Fe Road (if it is allowed to be completed prior to project implementation), are identified which would be acceptable to die City Engineers of Encinitas and Carlsbad. A Traffic Control/Detour Plan for the proposed project shall be approved by the cities of Encinitas and Carlsbad Planning and Engineering Departments prior to approval of final roadway improvement plans. Approval of such a Plan would eliminate temporary traffic delays otherwise caused by detouring, thereby maintaining existing traffic/circulation patterns within the project area. During the construction period, the road shall be re-striped to allow one lane in each direction for use by public and emergency vehicle traffic. The existing traffic signal at the Olivenhain Road/El Camino Real intersection shall be switched to the flashing red mode during construction equipment operation. Future improvements to El Camino Real and Rancho Santa Fe Road segments in the vicinity of the proposed project will be required prior to build-out year traffic forecasts to ensure compliance with the City of Encinitas General Plan Circulation Element Finally, in response to comments recieved from County Department of Public Works during the Public Review Period, the following mitigation measures shall also be included as required conditions of project approval: 1) Construct the Olivenhain Road/El Camino Real intersection at right angles; 2) Determine appropriate right-of-way widths and distances required for relinquishment of access rights; 3) Provide adequate sight distance; and 4) Provide the appropriate number of left-turn lanes at the Olivenhain Road/El Camino Real intersection. S-3 General Plan Compatibility Impacts. The proposed Alignment #2 would result in minor deviations from General Plan roadway design criteria established by the cities of Encinitas and Carlsbad for the construction of a Prime Arterial; however, the respective Circulation Elements contain provisions for variation in design. In particular, the descriptions of width and other facilities are offered as non-exclusive alternatives which allow for such minor variations in roadway design. Consequently, the proposed project is determined to be in substantial conformance with the General Plan Circulation Element standards for a Prime Arterial roadway. Mitigation. No mitigation measures are required. Traffic Noise Impacts. An increase in future traffic volumes along the widened Olivenhain Road would result in increased traffic noise levels at existing residences fronting the proposed project route on both sides of the road. Construction equipment operation may also result in short-term noise impacts to these residences. Significant construction noise levels may also impact sensitive breeding bird species that use the Encinitas Creek riparian area adjacent to the south side of the proposed road. Most of the proposed road construction would take place at the western end of the project route. Since no residential land uses occur in this area, construction noise would primarily impact biological habitat Mitigation. Future traffic noise impacts to residences fronting the south side of the project route shall be mitigated via proposed extension of existing noise attenuation walls. The feasibility of extending existing walls for the purpose of future traffic noise attenuation along the rear yards of residences fronting the north side of Olivenhain Road shall be internally evaluated by the cities of Encinitas and Carlsbad, in accordance with Policy 1.1 of the Encinitas General Plan Noise Element If found to be feasible, any proposed wall extensions shall be of sufficient height and uniform building material consistent with existing structures so as to reduce noise to exterior and ground floor receptors, but may not significantly reduce noise to second floor receptors. Proposed roadway construction for the portion of the project route between the SDG&E easement and the western Willow Creek subdivision boundary shall occur outside the months of March through July in order to avoid potentially significant noise impacts to sensitive breeding songbirds. Paleontological Resources Impacts. The Santiago Formation occurs in all three project study areas, and contains significant fossils as evidenced by their abundance and high potential for discovery in the immediate project vicinity. Quaternary age marine terrace and alluvial deposits found in the study areas are also considered significant, but have a low potential of fossil occurrence in the Carlsbad area. S-4 facilitate evaluation and, if necessary, salvage. Due to the small nature of some fossils, it may be necessary to collect matrix samples for processing through fine mesh screens. Any fossils collected shall be prepared to the point of identification and properly curated before they are donated to their final repository. All fossils collected shall be donated to a public, non-profit institution with a research interest in the materials, such as the San Diego Natural History Museum. Hydrology/Water Quality Impacts. The proposed project is not expected to create significant water quality impacts within the project areas or downstream watersheds, such as Batiquitos Lagoon. Temporary increases in turbidity and/or total suspended solids may occur within Encinitas Creek during the construction phase of the project, but no surface or groundwater impacts are expected. Due to anticipated increases in future traffic volumes and paved surface area, slight increases in grease and oil residuals runoff may be encountered. Sediment transport is expected to decrease due to the increased paved area and the addition of floodwater detention basin "D." Mitigation. Debris fences and screens shall be stationed downstream from proposed grading, but outside the Encinitas Creek 100-year floodplain limits and associated sensitive wetland habitat boundaries. Any temporary dams shall be constructed from material such as clean gravel which would cause little or no siltation. Except as shown on approved plans, no riprap, rock or other impermeable materials shall be discharged into Encinitas Creek. Any temporary fills shall be constructed of nonerodible materials and shall be removed immediately upon completion of the work. When road construction operations are completed, any excess materials or debris shall be removed from the work areas. Bridge plans for the El Camino Real bridge just south of Olivenhain Road intersection indicate that riprap protection is in place approximately 20 feet upstream and downstream of the bridge, but is currently silted over. Prior to road construction, the status and condition of this riprap shall be inspected to determine if it is still providing adequate protection against scour from erosive velocities on the upstream side of the El Camino Real bridge. Community Character/Visual Quality Impacts. Proposed roadway cut slopes along the north side of the realigned road would result in significant visual impacts to northbound traffic along El Camino Real, south of its intersection with Olivenhain Road, and to existing residential land uses south of the project route. Adverse visual impacts to the Thompson residence on the south side of the proposed realignment would result from placement of a fill slope/retaining wall approximately 12 feet away to support the widened road segment at this location. No visual impacts would occur from proposed construction of detention basin "D" dike or the flood control berm at the La Costa Avenue/El Camino Real intersection. S-5 *"* Mitigation. Mitigation for visual/landform modification impacts associated with proposed m roadway grading shall include scarification of the cut face by the use of a serrated blade or other methods to create pockets where planted vegetation could better take hold. Where possible, all manufactured slopes shall undulate, with rounding of the tops and toes of the slopes to better *• blend them into the surrounding terrain. A detailed Landscape and Irrigation Plan for all manufactured slopes shall be approved by the cities of Encinitas and Carlsbad Planning and ^ Engineering Departments. All plans shall be submitted for review and approval by the respective <* cities' Landscape Architects. Prior to final "as-built" approval of grading plans, representatives from the Public Works Departments of both cities shall inspect landscape installation to ensure "" conformance with the requirements of this EIR and relevant Grading Permits. Additionally, them project Landscape Architect shall certify by letter to these departments that the landscape installation conforms to these requirements. m Rather than constructing a retaining wall or fill slope adjacent to the Thompson residence, one ^ of the following two alternative mitigation measures shall be implemented during road construction in order to reduce adverse visual impacts to below a level of significance: 1) Two,— six-foot high vegetated crib walls shall be installed adjacent to this property, with a three-foot — wide planting area between them; or 2) Two, six-foot high slump-block retaining walls, similar in color and appearance as the existing four-foot wall fronting the Willow Creek/Bridgewater M subdivision to the west, shall be installed. In addition, a four-foot high slump-block wall shall M be installed at the southern ROW edge, at the top of the slope. This wall shall match and tie into the existing aforementioned block wall to the west. Three-foot wide planting areas shall also be established between each wall. Construction of either alternative shall meet commonly-accepted a. engineering practices. Vegetation and irrigation associated with either alternative shall be specified by the homeowner, but shall not be unreasonably demanded. . Public Utilities Impacts. Relocation of existing utility lines within the western segment of Olivenhain Road to <«• be realigned would not be required as long as these lines remain within the proposed ROW of •m the new road alignment; there is no major excavation required for the new roadway cut; and no new facilities connections are proposed. If relocation is required, these facilities would remain «* in service until new lines have been relocated and tested. As long as standard construction m procedures for utility line relocation are followed, no impacts or interruptions to existing service in the project area arc anticipated. Existing gas and electric facilities within the 150-foot wide ** SDG&E easement that crosses Olivenhain Road near El Camino Real would be lowered to * accommodate the new profile of the proposed road realignment Potential impacts resulting from these relocations could include accidental damage to lines during construction and/or public m safety impacts from personnel working too close to the lines. The proposed project may significantly impact law enforcement, fire protection, and paramedic emergency response time to the Olivenhain Road project area, particularly during peak-hour m commuter periods, should bottlenecks, traffic delays, or detours occur at existing neighborhood a access points and transition routes during the construction phase. " S-6 Mitigation. To ensure that public services in the project area are not impacted, specifications shall be placed in the construction documents that would provide for temporary service connections in the event of anticipated interruptions to water, sewer, gas, electric, telephone, or television lines. The cities of Encinitas and Carlsbad shall coordinate final approval of roadway improvement plans with the respective utility companies and agencies to ensure non-interference with existing public facilities. Furthermore, SDG&E requires that certain standards be followed while working in or around gas transmission facilities. Finally, the County Sheriffs Department and local fire departments shall be provided copies of the approved Traffic Control/Detour Plan for the proposed project Receipt of such Plans would provide these agencies information regarding the variables which could potentially affect emergency response mode and time to the project area during proposed road construction. With this information, these agencies could develop alternate routes or other methods to ensure that emergency response to the project area is not significantly impacted during project construction. S-7 <*k 1.0 INTRODUCTION -* This draft Environmental Impact Report (EIR) is an informational document intended for use by — the Qty of Encinitas (hereinafter referred to as the "Qty"), any Federal, State or local jurisdictional agencies, and the public. As such, it provides a detailed review and analysis of the <** potential environmental impacts that could result from the proposed Olivenhain Road widening, m realignment, and flood control project, as identified by the City during an Environmental Initial Study (EIS) for the project (Appendix 1). The proposed project is located generally east of El <w Camino Real, south of La Costa Avenue, west of Rancho Santa Fe Road, and north of Encinitas — Boulevard, in the Qty of Encinitas. «r Based on the results of the EIS, the City has determined that an EIR is required for the proposed g* project The environmental analysis contained herein is based on the Olivenhain Road Route Adoption Report prepared by Project Design Consultants (August 16,1990, revised February 26, *> 1991). This EIR has been prepared in conformance with Qty environmental review guidelines m and procedures. This document also complies with all criteria, standards, and procedures of the Quifornia Environmental Quality Act (OiQA) of 1970 (Public Resources Code 21000 et sea.), ** and State EIR Guidelines (Administrative Code 15000 et seq.X m The Qty will use this EIR for environmental review of discretionary actions required for approval of the proposed project This EIR identifies environmental constraints, analyzes **"* program alternatives, and recommends site-specific mitigation measures. The first volume of this »• document provides detailed impact analyses and specific mitigation recommendations that can be used to assess potential environmental impacts associated with proposed road and flood ** control improvements. The second volume contains the technical studies, background data, and ** research material used to support these environmental findings. m A Notice of Preparation (NOP) for the proposed project was sent to the State Clearinghouse on *t January 3, 1991 (Appendix 2). Appendix 3 contains public and agency comments received — during the NOP review period. M 2.0 PROJECT DESCRIPTION 2.1 Project Location The proposed project involves widening/realignment of a portion of the existing Olivenhain Road between El Camino Real and Rancho Santa Fe Road, construction of a floodwater detention dike just to the south of this road, and construction of a flood control berm at the intersection of La Costa Avenue and El Camino Real Existing and proposed rights-of-way for Olivenhain Road are within the corporate boundaries of both the cities of Encinitas and Carlsbad, in northern San Diego County (Figure 2.1-1). An east-west, two-lane road which connects El Camino Real with Rancho Santa Fe Road; it is approximately one mile in length (Figure 2.1-2). East of the proposed dike, a future floodwater detention basin "D" would be located within City of Carlsbad boundaries, in the Encinitas Creek floodplain just west of Rancho Santa Fe Road. Figure 2.1-2 also shows the proposed location of a flood control berm at the La Costa Avenue/El Camino Real intersection, situated along the City of Carlsbad/County of San Diego boundary, just south of Batiquitos Lagoon. Regional access to these project areas is provided by Interstate 5 (1-5) to the west 2.2 Environmental Setting 2.2.1 Topography 2.2.1.1 Existing Olivenhain Road Project Route The existing Olivenhain Road alignment is within an east-west trending valley which contains Encinitas Creek. It is mainly oriented on south-sloping terrain, with topography on the north side of the road sloping upward. A fairly steep hill occurs at the northwestern end of the project route extending eastward from El Camino Real for a distance of approximately 1,300 feet (Figure 2.2- 1). Elevations in this area range between 87 feet above mean sea level (AMSL) along the northern edge of the paved roadway to 175 feet AMSL at the top of the hill, approximately 750 feet to the north. Manufactured slopes separating existing residential development from the northern roadway edge increase in height from 5-10 feet at the western boundary of the Rancho del Ponderosa subdivision to 15-20 feet at the eastern boundary of the Santa Fe Ridge subdivision near the Olivenhain Road/Rancho Santa Fe Road intersection. Topography on the south side of Olivenhain Road is relatively level where it abuts the Encinitas Creek floodplain at its western end. The terrain on this side of the road begins to gradually slope downward at a vacant lot on the westernmost boundary of the Willow Creek subdivision, approximately 1,550 feet east of El Camino Real. Continuing east past an existing day care center and welding shop, steep, manufactured slopes in excess of 20 feet in height occur below the roadway edge, behind a four- to five-foot high retaining wall along this subdivision. East of the Thompson residence, the natural slope on the south side of Olivenhain Road begins to level again until it flattens out at an agricultural feed store located on Rancho Santa Fe Road (Figure 2.2-2). H-l Lpucadia' Project Site T3 CO o 0 Encinitas O Q> \Cardiff-by-the-Sea (Cardiff) Solana Beach N i 0 2 3 Miles Ollvenhain Road Alignment Regional Location Map bricin f mooncp Figure 2.1-1 SOURCE: U.S.G.S. 30' x 60' Quad Map ( Oceanside )E1R Future Detention Basin "D Potential 100-Year Flood Ponding Area N Ollvenhaln Road Alignment Vicinity Map 1000' 2000' bricin F mooncv a. dtslgn A «wlronm»nlal studies Figure 2.1-2 SOURCE: U.S.G.S. 7.5' Quad Map (Encinitas & Rancho Santa Fe) ii i 1 it i i t i it 11 ft i t * i i • i it i i tiff it ii • i Approximate Limits - Riparian Habitat 0 100' 200' bricin Fmooney litudto Rancho del Ponderosa Subdivision Boundary^^±11 OHvenhaln Road_ Willow Creek Subdivision Boundary OHvenhaln Road Alignment Existing Topography at Western End of Project Route Figure 2.2-1 EIR i i ii i it 11 t i « * tit* t i t i i i 11 t i t i iti i it Existing Tack & Feed Store Thompson Residence Approximate Limit* - Riparian Habitat briqn fjriponay Olivenhain Road Alignment Existing Topography at Eastern End of Project Route Figure 2.2-2 m m 2.2.1.2 Future Detention Basin "D" Project Area «H «• Topography at the future floodwater detention basin "D" is relatively flat due to its location within the 100-year floodplain of Encinitas Creek (see Figure 2.2-2). * 2.2.1.3 La Costa Avenue/El Camino Real Intersection Project Area The proposed flood control berm would be constructed atop a manufactured roadway slope at them southwest comer of this intersection. The existing slope inclination in this area is at a 2:1 ratio. "" 2.2.2 Vegetation m 2.2.2.1 Existing Olivenhain Road Project Route The steep slope area on the north side of the existing Olivenhain Road alignment, at its western m end, has generally been cleared of native vegetation. This area is dominated by ruderal plant _ species such as non-native grasses and Russian thistle. Further to the north, among the knolls east of El Camino Real, are patches of native coastal sage scrub vegetation. Still at the western «* end of the project route, Encinitas Creek is on the south side of Olivenhain Road, extending east mf and west of El Camino Real Vegetation in this area is characterized by dense stands of willows, giant reed, laurel sumac, coyote bush, and buckwheat Beginning at approximately 2,000 feet «• east of El Camino Real, the creek is channelized for an approximate 2,500-foot distance, within m the Willow Creek/Bridgewater subdivision (Figure 2.2-3). «» 2.2.2.2 Future Detention Basin "D" Project Area 4» Between the eastern Thompson property/Bridgewater subdivision boundaries and Rancho Santa ~ Fe Road, Encinitas Creek continues within its natural drainage course. It is in this area that the M proposed dike and future floodwater detention basin "D" would be located (see Figure 2.2-2). Vegetation within this reach of the creek is dominated by marsh habitat, densely covered with "* pickleweed, cattails, and other riparian plants. A vacant plot of land occurs to the north of this » reach of the creek. It is bounded to the west by the Thompson property, to the north by Olivenhain Road, and to the east by a construction/grading storage yard. This area appears to m have been cultivated in the distant past since it supports little native vegetation. Existing "• vegetation composition on this lot consists of sparse clumps of non-native grasses and Russian thistle. The area south of the creek at this location has recently been plowed and disked in *" preparation for planting. It also contains disturbed and ruderal plant species. 0 2.233 La Costa Avenue/El Camino Real Intersection Project Area "* A disturbed area exists at the southwest corner of the La Costa Avenue/El Camino Real H intersection, site of the proposed flood control berm. Extending further west from this intersection, along the south side of La Costa Avenue, existing vegetation transitions from disturbed, ruderal plant species, such as mustard and Indian sweet clover, to marsh and willow „ scrub species such as cattail, bulrush, spiny rush, and arroyo willow. n-6 I (! n n i c r 1 C Santa FjeRidg '\ Arroyo La Costa j 0)! Map No. 8363 lOi Units Existing Olivenhain Road Jignrr^^••i^cs venhain_Roa Approximate Limits -Riparian Habitat " 255-040-06 , \ oi-.\\ 10.51 Acres255-024-01 *•«.!ia6S Acres "^il Approximate Limits - Riparian Habitat ry N 0 200' 400' brion F mooncv planning, design & environmental studies Olivenhain Road Alignment Residential Land Uses along the Project Route 2.23 Hydrology 2.23.1 Existing Olivenhain Road Project Route The 100-year floodplain of Encinitas Creek occurs south of the existing Olivenhain Road alignment (Figures 2.2-4a and 2.2-4b). These figures show the 1982 floodway/floodplain limits, as mapped by the County of San Diego, and current 100-year floodplain limits obtained from the Encinitas Creek Drainage Study (Dr. Chang, 1991). It should be noted that the current 100-year floodplain limits shown on these figures are only approximate, and are based on computed reduced stormwater discharges. The current floodplain limits take into account several upstream detention basins either in place (detention basins "A" and "B") or under construction (detention basin "C"). Please refer to Section 3.8 of this EIR for a discussion of, and graphic showing, the geographic relationship between these detention basins. According to Figures 2.2-4a and b, the Encinitas Creek floodplain (with detention basins "A", "B", and "C" in place) ranges in width between 200 and 550 feet at the western end of the project route, and between 270 and 400 feet at the eastern end. These 100-year floodplain limits are restricted to a 50- to 200-foot width along an approximate 2,500-foot long channel that traverses the Willow Creek/Bridgewater subdivision, midway between El Camino Real and Rancho Santa Fe Road. This channel is mainly earthen except for a small (three-foot wide by one-foot deep) concrete low-flow drainage swale (pilot ditch) at the bottom. The earthen side embankments for this channel vary from 2:1 to 3:1 slope. 2.2.3.2 Future Detention Basin "D" Project Area Future construction of floodwater detention basin "D" would occur within the 1982 County floodway limits mapped between the Thompson property/Bridgewater subdivision boundaries and Rancho Santa Fe Road (see Figure 2.2-4b). Until then, however, proposed construction of the detention basin dike is expected to contain 100-year storm flows within the natural topography along both sides of the creek channel at this location (Rowson, 1991). 2.23.3 La Costa Avenue/El Camino Real Intersection Project Area Figure 2.2-5 shows current 100-year floodway/floodplain limits for Encinitas Creek in the vicinity of this intersection. According to this figure, the width of the 100-year floodway along the south side of La Costa Avenue extends west from this intersection for a distance of approximately 400 feet 2.2.4 Geology Geologically, all proposed project areas extend across Eocene nonmarine soils (USDA, 1985). More specifically, these areas are underlain by the Torrey and Delmar Formations. These formations are known to be fossiliferous; the Delmar Formation in particular is known to contain rich molluscan assemblages. H-8 it it ———— 1982 Floodway * «» 1990 Floodplain (per Dr. Chang Mapping) —'—""* 1982 Floodplain (per County Mapping) CHANNEL CAPACITY.COMPUTED DISCHARGES brian f mooncv '"""(©dOcafegS) I. dmlgn t environmental studm Ollvenha/n Road Alignment Enclnltas Creek 100-Year Floodway/Floodplain Limits adjacent to Ollvenhaln Road SOURCE: Dr. Chang Figure 2.2-4a EH I i I i t i t i t i I I i t I l i i t l t J • i • i i I I I I I I 1 t i t i ——— 1982 Floodway ...•—- 1990 Floodplain (per Dr. Chang Mapping) •—<—••••" 1982 Floodplain (per County Mapping) * J ' '•"•$' A / L• ^ \ I / "iv '• /' *;VI // ./' Olivenhain Road ~X 1 City of Encinitas PEAK WATER r.O CFS STORAGE* ENCINITAS200' 400' bricin F mooncv litudtes Olivenhain Road Alignment Enc/n/tas Creek 100-Year Floodway/Floodplaln Limits adjacent to Olivenhain Road Figure 2.2-4b ^ SOURCE: Dr. Chang EIR County Floodplairv CountyFloodway Ollvenhaln Road Alignment I brian F moonay Enclnltas Creek 100-Year Floodway/Floodplaln Limits Adjacent to La Costa Ave./EI Camlno Real Figure 2.2-5 I Source: Dr. Chang 2.2.5 Public Utilities/Infrastructure Existing public facilities along the existing Olivenhain Road alignment include overhead electric transmission lines and underground gas and oil lines within a 150-foot San Diego Gas and Electric (SDG&E) easement This northwest-southeast trending easement crosses the western portion of the project route, approximately 600 feet east of the Olivenhain Road/El Camino Real intersection. A gas regulator station is also located within this easement just south of Olivenhain Road. Underground electric transmission, gas main, sewer main, and telephone duct facilities occur within the existing road alignment Existing water lines are located along Olivenhain Road and at the El Camino Real intersection. Finally, an underground television conduit crosses Olivenhain Road at Amargosa Drive. 2.2.6 2.2.6.1 Existing Olivenhain Road Project Route Zoning on either side of the existing Olivenhain Road alignment is designated by three separate jurisdictions: the Cities of Encinitas and Carlsbad, and the County of San Diego. The City of Encinitas zoning designations adjacent to the south side of Olivenhain Road, from east to west are "Residential-8" (R-8) and "Ecological Resource/Open Space/Parks" (P). Future construction of floodwater detention basin "D" and proposed construction of the detention basin dike would occur in the area zoned R-8 by the Dry of Encinitas. The City of Carlsbad zoning designations adjacent to the north side of Olivenhain Road, from east to west are "Planned Community" (P- C), "Public Utility" (P-U), and "Limited Control" (L-Q. The triangular-shaped Olivenhain Municipal Water District (OMWD) office facilities located just west of Rancho Santa Fe Road and south of Olivenhain Road is zoned for "Office" (O) uses by the City of Carlsbad. Finally, the property on the west side of the Olivenhain Road/El Camino Real intersection is zoned "Agricultural Cropland" (A-C), "Specific Plan Area" (SPA 2.8), and "Impact Sensitive" (24) by the County of San Diego. 2.2.6.2 La Costa Avenue/El Camino Real Intersection Project Area Most of the proposed flood control berm at the southwest corner of this intersection would occur in an area zoned P-C by the City of Carlsbad. The western leg of this proposed berm would be in an area designated A-C by the County of San Diego zoning. 2.2.7 Surroundln2 Land Uses 2.2.7.1 Existing Olivenhain Road Project Route Existing land uses along the project route generally reflect the underlying zoning. Most of the existing Olivenhain Road alignment is bounded by residential development (see Figure 2.2-3). Although single-family residences occur on both sides of the road, a day care center, welding shop, agricultural feed lot, Olivenhain Municipal Water District (OMWD) offices, and the Encinitas Creek floodplain/designated open space are also found on the south side. Most residential structures are located approximately 100 feet from the road centerline, and are separated from the paved roadway edge by manufactured slopes and/or retaining walls. H-12 2.2.7.2 La Costa Avenue/El Camino Real Intersection Project Area A modified barn structure used as a sales and marketing office for the nearby Aviara development is located approximately 200 feet south of the proposed flood control improvements at this intersection. A commercial shopping center is located at the southeast comer, a gas station is located at the northeast corner, and the Batiquitos Lagoon Ecological Preserve is located at the northwest comer of this intersection. 23 Proposed Project The proposed project involves the widening and realignment of a 1,200-foot segment of Olivenhain Road extending east from El Camino Real; re-striping of the remaining 4,100-foot road segment from the western boundary of the Rancho del Ponderosa subdivision to Rancho Santa Fe Road; construction of a floodwater detention dike to the south of this road; and construction of a flood control berm at the La Costa Avenue/El Camino Real intersection. The proposed improvements are discussed below. 2.3.1 Proposed Oiivenhain Road Improvements The Circulation Elements of both the Encinitas and Carlsbad General Plans classify Olivenhain Road between El Camino Real and Rancho Santa Fe Road as a six-lane prime arterial. Four alternative alignments are proposed to accommodate this six-lane facility, with Alignment #2 being the preferred alternative for the City of Encinitas (Figure 2.3-1). For the purpose of this analysis, the following description of Alignment #2 is provided. A detailed description and comparison between the other three road alignments is given in the "Alternatives" Section of this EIR. Proposed Alignment #2 would widen the existing road to six travel lanes, with a bike lane, sidewalk, and curb/gutter on each side of a central median. Two cross-section widths are proposed to accommodate these improvements (Figure 2.3-2). The four-lane road segment fronting the Rancho del Ponderosa and Santa Fe Ridge subdivisions would primarily be re-striped within the existing 107-foot right-of-way (ROW), and the existing two-lane road segment west of the Rancho del Ponderosa subdivision to El Camino Real would be widened and realigned, based on the City of Carlsbad's 126-foot ROW standard. 2.3.1.1 Proposed Restrioing of Existing Road Segment (107-Foot ROW) The 107-foot ROW cross-section would be re-striped to provide a total 87-foot paved width between curbs including six, 12-foot travel lanes; a five-foot median; two, five-foot bike lanes; and two, 10-foot landscaped parkways with 5-foot sidewalks within each parkway. The distance between curbs would be increased at intersections to 90 feet by reducing the width of the existing sidewalk on the north side of the road to seven feet Striping at intersections would provide six, 11-foot travel lanes; a 10-foot left-turn pocket; a 4-foot median; and two, 5-foot bike lanes. Provision of a six-lane facility within the existing 107-foot ROW eliminates the need for additional ROW acquisition from property owners within the Rancho del Ponderosa and Santa Fe Ridge subdivisions. It also avoids costly relocation of existing retaining walls and utilities along these frontages. n-13 I i I 1 I i t l t i I i i i i 1 I i I l • 1 t 1 I I • I I i I I • 1 i i • i Legend Proposed 126' Right-of-Way ( Preferred Alternative No. 2 ) o D Alignment No. 2 Centerline OHvenhain Road Existing Alignment Centerline Approximate Limits - Riparian Habitat Future Leucadia Boulevard i 0 100' 200'\ bricin f moonev OHvenhain Road Alignment Proposed Alignment No. 2 Figure 2.3-1 ER SOUTH \ NORTH 10' 87* 5' L 12' •Bike Lane 12' __^^H^ 12' _^ 5' F^ 12', ma^—i 12' •^^^•M 12' Bike- Lane "" — — 5' ) t 10' •MTZ^ 6 LANES THROUGH TRAFFIC SOUTH NORTH 7' mr^^^M ^90' 5' I 11' -Bike Lane 11>.11' ^^^I^^IB 1 10' Turn Lane mm^mmt 4'11' - 11' ^•^•^^^MK 11' Bike- Lane 5' J > 10' m^*rm& SOUTH NORTH \ 101 r 2tf - 5' B^e Lane 53' 12*i 12' - 1C < 9' 11 tf L 9' 3* 1 12' •1BHH 53' 12' ^•^•^B_i 20' 5*Bike Lane ^j •v 101 i^RR -Ret. Wall Where Req'd 6 LANES THROUGH TRAFFIC bricin F mooncv Ollvenhaln Road Alignment Future Roadway Cross-Sections Figure 2.3-2 Source: Project Design Consultants EIR Although this portion of Olivenhain Road would primarily be re-striped, some road widening and grading will be required in isolated, unimproved pockets along its southern edge. In particular, proposed grading adjacent to the Thompson property could involve the placement of fill for approximately 70 feet from the southern edge of the existing road (see Section 3.9.2 of this EIR for more information on this "Worst Case" grading scenario). This could result in the toe of a 2:1 fill slope being placed approximately 12 feet from the existing Thompson residence. Additional roadway improvements along the eastern portion of the project route are proposed just west of the Olivenhain Road/Rancho Santa Fe Road intersection. Specifically, approval will be required from the City of Carlsbad to re-construct the existing curve leading up to this intersection, which currently has a 1,200-foot centerline radius. Either a super-elevated cross- section or reduced traffic speed, or both, will be required at this curve. Other improvements are proposed at the Olivenhain Road/Rancho Santa Fe Road intersection. These include widening the southerly extension of Rancho Santa Fe Road to a four-lane major arterial, as identified in the City of Carlsbad General Plan, for a distance of approximately 700 feet from this intersection. At this point, the proposed four-lane facility would transition to its existing two-lane configuration continuing to the south. These intersection improvements will require additional ROW acquisition from the OMWD parcel to the west An existing right-turn lane onto northbound Rancho Santa Fe Road and an intersection bypass from eastbound Olivenhain Road to southbound Rancho Santa Fe Road, just south of the OMWD offices, would also be abandoned. The ROW to be vacated from removal of this two-lane bypass road could be exchanged to offset the additional ROW required on OMWD property for the intersection improvements discussed above. 2.3.1.2 Proposed Widening/Realignment of New Road Segment (126-Foot ROW) The 126-foot ROW cross-section would be a newly-constructed road between the western Rancho del Ponderosa subdivision boundary and El Camino Real. This road would provide a total 106- foot paved width between curbs including four, 12-foot travel lanes; two, 15-foot travel lanes; an 18-foot raised median; two, five-foot bike lanes; and two, 10-foot landscaped parkways with 5-foot sidewalks within each parkway. At intersections, the raised median would be reduced to an eight-foot width to accommodate a 10-foot left-turn pocket This proposed road segment would also be realigned as shown on Figure 2.3-1. The existing, 1,200-foot segment of Olivenhain Road to be realigned would be broken up, and the asphalt pieces ground for use as base or fill material. Proposed Alignment #2 would not cross Encinitas Creek; therefore, bridge construction over the creek will not be required. This alignment may also avoid saturated ground areas which would otherwise require stabilization. Approximately 60,000 cubic yards of cut are required to construct Alignment #2, creating a maximum slope height of 35 feet on the north side of the road which would require buttressing. A 30-inch gas main and two fuel mains which occur within an SDG&E easement along die existing Olivenhain Road alignment would be relocated. For the proposed realignment, the City would need to acquire additional ROW from two parcels of land west of the Rancho del Ponderosa subdivision, and owned by Northern Western Pacific Railroad Company and Fieldstone/La Costa Associates. According to the project engineer, a 50-foot wide H-16 construction zone will be required on the downslope side of this realignment, while 15 feet will be required on the cut slope side, for equipment movement (Wonseski, 1991). 2.32 Proposed Flood Control Improvements 2.3.2.1 Proposed Floodwater Detention Dike/Spillway The selected site of the proposed floodwater detention dike and spillway is located south of Olivenhain Road and approximately 1,200 feet west of Rancho Santa Fe Road (Figure 2.3-3). The proposed dike and spillway would be constructed at the downstream outlet of this reach of Encinitas Creek, along the eastern Thompson property/Bridgewater subdivision boundaries. The hydrologic design for these flood control improvements are described in the Drainage Study for Encinitas Creek (Chang, 1991 [Appendix 4]). According to this report, the spillway configuration would consist of a broad-crested weir with sloped upstream and downstream faces and rounded corners. The spillway crest elevation would be at 106 feet AMSL. The 100-year flood would be routed through this spillway at a maximum outflow discharge rate of 753 cubic feet per second (cfs). A 36-inch diameter RCP drain pipe would be installed below the spillway opening to allow normal flows past the dike. The dimensions of the proposed floodwater detention dike would be 60 feet wide by 660 feet long. The width of this dike may be designed to allow future vehicle access from Olivenhain Road into the Wiegand property to the south. The maximum top-elevation of the dike would be 115 feet AMSL, transitioning down to 112 feet AMSL above the spillway. The side slopes for this earthen dike would be constructed at a 2:1 ratio of inclination. According to the project engineer, a 50-foot wide construction easement/work area will be required from the toe of slopes of the proposed dike, on all sides, for equipment/personnel movement (Wonseski, 1991). This construction easement may be reduced in width in order to avoid impacts to planned OMWD facilities (see below) should they be constructed prior to the proposed dike. Although not proposed as part of this project, future construction of the side embankments for detention basin "D" from Rancho Santa Fe Road to the proposed dike would most likely accompany grading and development of the OMWD and Weigand properties on which they would be located. The width of this basin would generally coincide with the 100-year (1982) floodway limits. Please refer to Appendix 4 for discussion of the hydrologic design of detention basin "D". The Wiegand property engineers have given preliminary indication that future construction of the southern embankment would maintain a variable-width building setback, to a Tuaxinmtri of 100 feet from the edge of mapped wetland habitat in this area. This setback would be comprised of a maximum 50-foot wide biological buffer and a maximum 50-foot wide planning buffer. The City of Carlsbad could require that this maximum 100-foot wide setback zone be placed in a dedicated open space easement as a condition of approval for any future development on the Wiegand property. The planned expansion of OMWD facilities to the north of Encinitas Creek may require that a portion of the northern embankment for detention basin "D" be redesigned to the south of the 100-year floodway. According to a conceptual site plan provided by OMWD during the Public Review period (Appendix 13), an approximate 300-foot segment of this future embankment and a small area designated as wetland ecotone adjacent to Rancho Santa Fe Road is shown within proposed developable area (designated by cross-hatch). A future parking lot or greenbelt is planned at this location. Planning efforts for future construction of the detention basin "D" H-17 K5KK TO £NCIMTA& CRttK DRAINAGE UHlBttfOK PEAK WA7CKSUKFACE fLfVATION EAST OF KANCHO SANTA K m PTUAL PLAN OF DETENTION BASIN 'D 198Z FLOOD WAY LINE Proposed Dike and Fill Banks PEAK WATER SURFACE ELEVATION' 110.08 PEAK STORAGE -83.6 AC-FT. 100 YEAR flLf 753.0 CFS PKOPOSCD PROPOSED WOKKAK£A Olivenhaln Road Alignment bnan F moonav Proposed Floodwater Detention Dike planning, design & environmental studies Source: Dr. Chang embankment in this area should be coordinated between OMWD and the City of Carlsbad in order to avoid or, if infeasible from an engineering standpoint, to minimize potential direct impacts to sensitive wetlands. Except for this small area of potential impact, future OMWD facilities and the remainder of the northern embankment would not result in additional impacts to adjacent wetlands as long as the embankment is constructed along the 100-year floodway as designated by the 1982 County FEMA maps. In this case, future development on the OMWD property would maintain a variable-width building setback from the edge of mapped wetland habitat The OMWD would be amenable to planting and maintaining appropriate native vegetation compatible with adjacent wetland species within the area between the 100-year floodway and designated wetland limits, in order to provide a "screening effect" from sensitive biological habitat along Encinitas Creek. This landscaped zone would serve to separate future OMWD facilities from mapped wetland habitat, and also provide a desirable aesthetic effect 2.3.2.2 Proposed Flood Control Berm at La Costa Avenue/El Camino Real Intersection Two alternative designs have been provided by the project engineer for proposed construction of this earthen berm (Figure 2.3-4). Alternative #1 involves the construction of a "U-shaped" berm, extending west from the La Costa Avenue/El Camino Real intersection for a distance of approximately 450 feet along the south side of La Costa Avenue. The eastern leg of this berm would extend along the west side of El Camino Real for a distance of approximately 150 feet south of the intersection. The western leg of the proposed berm would extend south of La Costa Avenue for a distance of approximately 250 feet Alternative #2 would involve the construction of an "L-shaped" berm, extending west from the La Costa Avenue/El Camino Real intersection for a distance of approximately 2,000 feet along the south side of La Costa Avenue. The eastern leg of this berm would extend along the west side of El Camino Real for a distance of approximately 150 feet south of the intersection. Proposed construction of Alternative #2 berm would require extension of two, existing box culverts beneath La Costa Avenue. According to the conceptual cross-section for the proposed flood control berm (Figure 2.3-5), the top-elevation would be at 21 feet AMSL; the top-width would be approximately five feet, extending between one to four feet above the adjoining roadway surface elevation; and the side slope would be at a 2:1 ratio of inclination. Proposed construction of either berm would require relocation of an existing, 18-inch diameter RCP stormdrain within the southern ROW edge of La Costa Avenue. According to the project engineer, a 15-foot wide construction easement will be required from the toe of slope of die proposed berm for equipment and personnel movement (Wonseski, 1991). It should be noted that this proposed berm is not required as a result of any direct impacts to the Encinitas Creek drainage or 100-year floodplain due to the planned wideningAealignment of Olivenhain Road. Rather, it would be constructed as a required condition of approval for development projects within the Zones 11 and 12 drainage basins, including the planned Arroyo/La Costa (CT 88-3) tentative map development, in the City of Carlsbad. Although the timing of construction for the La Costa Avenue/El Camino Real flood control berm would not correspond with that of the currently proposed widening/realignment of H-19 Alternative 1 bricin F mooncv planning, design & environmental studies Alternative 2 UKUSBM VW. U0>&0-?(m3) BAflQUITOS LAGOON vmoc. Ofto'KCP25S-12Z-25 msr.Boxcutmr PROPOSEDwmttstw ZS5-KZ-Z4 Olivenhaln Road Alignment Alternative Flood Control Berm Designs Figure 2.3-4 0 Source: PDC I i t I I i 1 i I I I l I 1 I i t l I I I i t i i. * *. a TO- 10- LA COSTA AVENUE KOADWAY K/W I K>30 40 70 80 brian F moonav OHvenhaln Road Alignment Conceptual Cross-Section of Proposed Flood Control Berm Figure 2.3-5 SOURCE: Project Design Consultants Olivenhain Road, the City has determined that environmental analysis of this project feature should be conducted at this time, and the results delineated herein. 2.4 Environmental Review Study Areas Figures 2.4-1 through 2.4-3 show the specific study area boundaries for the three project areas covered in this EIR. The alternative alignments study area (Figure 2.4-1) encompasses the proposed Alignment #2, as well as Alternative Alignments #1, #3, and #4 (please refer to the "Alternatives" Section of this EIR). Figure 2.4-2 shows the area encompassed by the future detention basin "D" (as delineated by the 1982 100-year floodway limits) and the proposed detention basin "D" dike/construction easement Finally, the two alternative designs for the proposed flood control berm at La Costa Avenue/El Camino Real intersection are encompassed within the study area boundaries shown on Figure 2.4-3. The extent of field surveys and associated environmental analysis contained in this document were focused in these three project study areas. Due to the linear nature of the proposed flood control berm adjacent to La Costa Avenue, significantly more area to the south of this roadway (approximately 600 feet) was included in the field surveys, but not counted in existing acreage calculations. 2.5 General Plan Designated Trail Alignment The City of Encinitas General Plan designates a hiking/equestrian trail along the south side of Olivenhain Road. This future trail segment is part of a planned regional trail system extending easterly through the Willow Creek/Bridgewater subdivision, and connecting with designated trails within the County of San Diego and City of Carlsbad on the west side of El Camino Real According to preliminary information provided by the City, this future trail segment would extend from the east, adjacent to the improved Encinitas Creek flood control channel which bisects the Willow Creek/Bridgewater subdivision. Continuing west from the westernmost boundary of this subdivision, the trail would follow the natural drainage course of the creek (approximately 250 feet south of the paved edge of the realigned road) for a short distance, then it would turn northwest paralleling Olivenhain Road. The trail would cross El Camino Real and meet with the future City of Carlsbad trail extending northerly, along the west side of the Green Valley riparian corridor. From the Olivenhain Road/El Camino Real intersection, the trail would also proceed west along the north side of the future Leucadia Boulevard extension. The future trail shall be designated within a 20-foot wide trail easement For the portion adjacent to the realigned Olivenhain Road, this easement shall extend southerly from the paved roadway edge. A 10-foot wide trail shall be constructed within this easement with a 10-foot buffer separating it from the roadway for public safety purposes. The future trail alignment between the Willow Creek/Bridgewater subdivision boundary and El Camino Real would occur within the proposed Home Depot Specific Plan area south of the project route. An EIR is currently being prepared for this project It is anticipated that the primary environmental issues associated with the future trail alignment to be analyzed in that EIR include: n-22 11 ii II II ti II II li 11 I* I* •lf Existing Alignment Rancho del Ponderosa Subdivision Boundary Willow Creek Subdivision Boundary brian dMlgn A MvlrannMntal ttudte* Ollvenhaln Road Alignment Alternative Alignments Study Area Figure 2.4-1 1. 1 1 i t i I I I i I 1 I I I i I \ I 1 i i I 1 i J t j i j t Existing Tack & Feed Store Thompson Residence brian f moonav 4d iludtei Ollvenhaln Road Alignment Proposed Dike and Future Detention Basin "D" Study Area Figure 2.4-2 i i i i i i i i i i i I i I i i i i i i a t i i. La Costa Avenue 100' 200' Ollvenhain Road Alignment La Costa Avenue Alternative Flood Control Berms Study Area bricin f mooncv Figure 2.4-3 EIR • Possible additional impacts to sensitive wetland habitat within the Encinitas Creek floodplain. Additional area beyond the road right-of-way could be potentially impacted by proposed construction and future use of this trail Any additional impacts to wetlands within this reach of Encinitas Creek floodplain will require mitigation (at the appropriate replacement ratios) in the form of "in-kind" habitat restoration on-site. Depending upon the extent of this impact, however, off-site mitigation area may be required • Design feasibility and potential public safety impacts for the El Camino Real crossing. An important component of this analysis will involve necessary requirements for the construction of a specially-designed trail crossing of El Camino Real including, but not limited to, appropriate signage, modified crossing signal with raised pedestrian control buttons, and non-slip "textured" pavement in the crossing zone. • Maintenance of connections to existing trails and/or to the planned regional trail system designated by the General Plans of the cities of Encinitas and Carlsbad, and the County of San Diego. 2.6 Project Objectives Currently, Olivenhain Road carries an estimated 20,599 vehicles per day (JHK and Associates, 1990). Traffic congestion presently occurs along this road segment for a distance east of its intersection with El Camino Real due to limited road width which causes a back-up for vehicular turning movements onto El Camino Real. With General Plan build-out traffic volumes estimated to be 48,000 average daily nips along this road segment, congestion at the Olivenhain Road/El Camino Real intersection will intensify. To reduce traffic congestion at this intersection, the proposed project would add more travel and turning lanes, as well as bike lanes and sidewalks to provide safe passage for bicyclists and pedestrians. The project also proposes to realign an approximate 1,200-foot segment at the west end of Olivenhain Road, where it connects with El Camino Real, in order to expedite westbound traffic flow. Additional road width would be required for these proposed improvements. These improvements are also a necessary component in achieving regional traffic circulation goals, as envisioned by the San Diego Association of Governments (SANDAG) Mid-County Transportation Study and City of Encinitas General Plan Circulation Element Both of these documents envision a regional traffic scenario for the project area in which necessary roadway improvements are implemented to facilitate east-to-west traffic flow. This traffic scenario emphasizes commuter transition routes from the local street network within residential-designated inland areas, such as Olivenhain and San Marcos, onto east-west Prime Arterials to eventually reach north-south business destinations via Interstate 5. The proposed project's eventual connection with future Leucadia Boulevard represents an important link within this regional traffic scheme, in conformance with the City's General Plan. H-26 Proposed flood control improvements would reduce property damage and traffic complications which have resulted from past flooding within the project area. These improvements would eliminate periodic flooding problems at the Olivenhain Road/El Camino Real intersection, and reduce existing flooding impacts entering the project area from offsite locations. 2.7 Agency Approvals Required As die project proposes the placement of fill and associated disruption of less than one acre of wetland habitats within the 100-year floodplain of Encinitas Creek, a U.S. Army Corps of Engineers Pre-discharge Notification will be required. The proposed project will also require a 1601 Streambed Alteration Agreement with the California Department of Fish and Game (CDFG). The discretionary action necessary to implement the proposed project consists of the approval of funding and contract documents by the Encinitas City Council n-27 3.0 ENVIRONMENTAL ANALYSIS 3.1 BIOLOGICAL RESOURCES The following discussion is based on biological resources surveys conducted for the three project study areas (see Figures 2.4-1 to 2.4*3) by staff biologists from Brian F. Mooney Associates (BFMA). The complete technical biology report is provided as Appendix 5 of this EIR. 3.1.1 Existing Conditions 3.1.1.1 Vegetation The three project study areas support a complex wetland mosaic of coastal freshwater marsh, coastal salt marsh, southern willow scrub, wetland ecotone, disturbed wetland scrub, and baccharis scrub, as well as southern mixed chaparral and disturbed upland habitats. These vegetation types are illustrated on Figures 3.1-1 through 3.1-3. As requested by the California Coastal Commission (CCQ during the Notice of Preparation (NOP) review period for this project, the eastern boundary of the Coastal Zone Planning Area has been mapped on Figure 3.1- 1 as the inland extent of the El Camino Real right-of-way (ROW). The existing vegetation patterns are die result of natural hydrology, encroachment by development into the Encinitas Creek and Green Valley floodplains, and urban runoff. The encroachments include fill for a tack and feed store just west of Rancho Santa Fe Road, the Willow Creek subdivision located west of the proposed floodwater detention dike, and roadway fills for Rancho Santa Fe Road, Olivenhain Road, La Costa Avenue, and El Camino Real. The most abundant wetland habitat type found within the three study areas is coastal freshwater marsh, which covers a total of approximately 6.49 acres. This habitat type is located within Encinitas Creek south of the existing Olivenhain Road alignment, and south of La Costa Avenue. Freshwater marsh species include salt marsh fleabane, great marsh evening primrose, and southwestern spiny rush. Soft flag is the dominant marsh species within Encinitas Creek, covering 95% of this habitat Tule cattail is the dominant marsh species south of La Costa Avenue. Coastal salt marsh encompasses approximately 4.64 total acres within the study area of the future detention basin "D". This habitat is dominated by woody glasswort Many of these plants appear desiccated, however, with a few dried salt beds scattered among them. Alkali-heath and sweet fennel are also included in this habitat type. The proposed La Costa Avenue/El Camino Real flood control berm study area supports salty susan, as well as a dense stand of southwestern spiny rush. Southern willow scrub occurs in scattered locations south of the existing Olivenhain Road alignment and La Costa Avenue, constituting approximately 2.43 total acres within these two study areas. Arroyo willow is the main arboreal element of this habitat, with shrubby willows, mule fat, soft flag, and southwestern spiny rush comprising the understory. m-i till liiililiiifi I i I 1 I I I 1 I i Legend Dist Disturbed DWS Disturbed Wetland Scrub FWM Freshwater Marsh Rud Ruderal SWS Southern Willow Scrub E Wetland Ecotone loo- CSM Coastal Salt Marsh SMC Southern Mixed Chaparral Willow Flycatcher Downy Woodpecker oiivenhaln Road Coastal Zone Planning Area , , ( Eastern Boundary) > ^Oiivenhaln Road Alignment Western Project Route Biological Resources Map 100' 200' 100-Year Roodplain (with Detention Basins A.B.C) bf Ian mO ttudM 10o-YearFloodplain AD/_ ( with Detention Basins A.B.C.D )Figure 3.1-1 EIR ti I i ti i f ii i **' ft i ii it ii § • „ Legend CSM Southern Coastal\ wnfl Salt Marsh Existing «st Disturbed Tack & Feed Store DWS Disturbed Wetland Scrub E Ecotone OMWD \ \ FWM Freshwater Marsh Rud Ruderal SWS Southern Willow Scrub Sand Aster Spiny Rush oone?§§) g. dMlgn * »o»lroom«otal atudtos Ollvenhaln Road Alignment Future Detention Basin "D" Biological Resources Map Figure 3.1-2 it ii is i * a i i i ; i till i i f I • I * * * 4 Southwestern Spiny Rush Area La Costa Avenue N 100' 2001 bricin F mooncv planning, design & •nvironmenlal studies LEGEND BS Baccharis Scrub GSM Coastal Salt Marsh DCSS Disturbed Coastal Sage Scrub DIST Disturbed EUC Eucalyptus Woodland SWS Southern Willow Scrub Ollvenhaln Road Alignment La Costa Avenue Biological Resources Map Figure 3.1-3••• EIR Wetland ecotone exists south of the existing Olivenhain Road alignment as a coastal salt marsh/disturbed riparian scrub mixture. This habitat type covers a total of approximately 1.23 acres within the alternative alignments and future detention basin "D" study areas. Marsh species consist of woody glasswort, alkali-heath, and salt marsh fleabane, while coastal goldenbush and Russian thistle constitute the disturbed scrub element This ecotone occurs adjacent to the southern roadway edge in the eastern portion of the project route and further south of the road at the western end. Species composition of disturbed wetland scrub (approximately 1.89 acres) varies to the south of the existing Olivenhain Road alignment At the eastern end of the project route, within the future detention basin "D" study area, widely spaced individuals of coastal goldenbush and coyote bush are interspersed between non-native species such as castor-bean, cheeseweed, and Australian saltbush. Along the central portion of the project route, this habitat is dominated by coastal goldenbush with patches of bare ground and red brome between the shrubs. At the western end of the project route, within the alternative alignments study area, this plant community is dominated by broom baccharis with marsh elements such as great marsh evening primrose, woody glasswort, and salt marsh fleabane. The baccharis scrub habitat consists of a solid stand (0.06 acre) of coyote bush. Southern mixed chaparral occurs north of the existing Olivenhain Road alignment, extending approximately 0.54 acre into the alternative alignments study area. Vegetation in this area is dense, at about one to two meters in height Dominant species in this habitat type include chamise, scrub oak, toyon, and mission manzanita. This habitat type occurs on steep slopes in excess of 25% gradient to the north of the alternative alignments study area. As shown on Figure 3.1-1, the extent of southern mixed chaparral on steep slopes within the Coastal Zone boundary which is encompassed by this study area is minuscule, occurring only a few feet east of El Camino Real. Disturbed areas consist of the tack and feed store just west of Rancho Santa Fe Road, eucalyptus woodlands, and areas of ruderal vegetation with non-native species such as Russian thistle, Australian saltbush, mustard, soft chess, and red brome. Existing fill slopes south of the La Costa Avenue/El Camino Real intersection also contain non-native species such as Indian sweet clover, white stem fUaree, and gazania. The area south of the future detention basin "D" has recently been cultivated, including some areas that previously supported coastal salt marsh habitat A total of approximately 7.75 acres of disturbed land and 7.16 acres of ruderal vegetation occurs within the three project study areas. Approximately 73 plant species were observed within the three project study areas, 34 (46 percent) of which are non-natives (Table 1 of Appendix 5). This high percentage of non-native species reflects die disturbed nature of most of the Olivenhain Road project route. Some of the summer herbaceous species were not in evidence at the time of year when the biological field surveys were conducted, and, therefore, this should not be considered a complete list of plant species for the three project study areas. m-5 3.1.1.2 Zoology One reptile species, side-blotched lizard, was observed in a ruderal area (Jennings, 1983), and an amphibian species, bullfrog, was observed in a pond in freshwater marsh habitat within the three project study areas. Thirty-five bird species were also observed within these study areas (Table 2 of Appendix 5). All may breed on-site except for the migrants, yellow-rumped warbler, white-crowned sparrow, red-tailed hawk, red-shouldered hawk, California towhee, and great blue heron, whose nesting habitats are located off-site. Evidence of five mammal species were observed in ruderal or disturbed wetland scrub habitats within the three project study areas, and include coyote, rabbit, woodrat, skunk, mule deer, and California ground squirrel (Jones et al., 1982). 3.1.1.3 Sensitive Species Plant and animal species are considered sensitive if they are listed as such by Federal or State agencies, or by one or more conservation groups. 3.1.13.1 Sensitive Plants One sensitive plant species was observed and identified within the three project study areas, and another sensitive species was observed, although its variety was not determined. Southwestern spiny rush was detected in freshwater marsh and southern willow scrub habitats. This plant is listed as a sensitive species by the California Native Plant Society (CNPS, List 4). The survey also revealed a sand aster in a ruderal area west of the tack and feed store, which could have been either Del Mar mesa sand aster or San Diego sand aster. Its variety is difficult to identify, however, because sand asters flower in the summer (June to September). Del Mar mesa sand aster is on CNPS List IB, and is a candidate for federal listing. San Diego sand aster is on CNPS List 4. 3.1.1.3.2 Sensitive Animals Two sensitive bird species were observed within or near the three project study areas, and three more may also occur. The two bird species observed are downy woodpecker and willow flycatcher. A variety of other migratory riparian song birds may forage in the southern willow scrub habitat, including the least Bell's vireo, yellow warbler, and yellow-breasted chat. A pair of downy woodpeckers and two fledglings were observed west of the Olivenhain Road/El Camino Real intersection. Downy woodpeckers are typically found in this type of extensive mature riparian habitat, and are considered "Declining" by Everett (1979). Willow flycatchers were seen in southern willow scrub habitat within Encinitas Creek south of the existing Olivenhain Road alignment, and also west of El Camino Real, but no breeding activity was observed. This species is a candidate for State listing as "Endangered"; a Federal sensitive species; is on the Audubon Society's "Blue List" (Tate, 1986); and Everett (1979) determined it to be "Declining". The least Bell's vireo is a State- and Federally-listed "Endangered" species. Last seen in the project vicinity in 1982, within the Green Valley riparian corridor west of El Camino Real, it has not been sighted since, despite numerous directed surveys. This obligate riparian habitat, m-6 migratory song bird requires woodland vegetation to carry out its life cycle. All reproductive activities, from pair formation to fledgling of young, occur in well-defined territories; usually willow-dominated riparian vegetation with a dense understory. Yellow warbler is a "Species of Special Concern" (CDFG, 1990); is on the Audubon Society's 4 "Blue List" (Tate, 1986); and is also considered a "Declining" species (Everett, 1979). Yellow warblers may forage within southern willow scrub or disturbed wetland scrub habitats within the three project study areas. Yellow-breasted chat is a "Species of Special Concern" (CDFG, 1990); * is considered "Declining" (Everett, 1979); and is rarely seen as a migrant in either spring or fall Similar to the yellow warbler, the yellow-breasted chat may also forage within the project study areas. 4 m 3.1.1.4 Sensitive Habitats * Sensitive habitats are those which are considered rare within the region, are rapidly declining, » or support sensitive plants or animals. Southern willow scrub, coastal freshwater and salt marshes, and wetland ecotone, all of which occur within the three project study areas, are considered sensitive habitats. In addition, southern mixed chaparral is considered a sensitive m habitat by the CCC if it occurs on steep slopes in excess of 25% gradient within the Coastal m Zone boundary. «• Southern willow scrub and other wetlands are regarded as sensitive and valuable resources due m to their ability to support a diversity of wildlife species. Proximity to water, interface between a variety of habitat types, and vertical stratification of foliage are factors which contribute to the *» richness and productivity of wetlands. While a few wildlife species are restricted entirely to „. wetlands for all of their life requirements, many more are dependent on these habitats for necessities such as food, cover, or breeding. Numerous other species also make extensive use *"* of these habitats even though they may not be entirely dependent upon them. In southern California, riparian areas by their nature are limited, and in San Diego County they *" are extremely limited. Somewhere between 0.2% (5,000 acres) and 0.5% (13,000 acres) of the m County's total land area of 2.7 million acres (Wheeler and Fancher, 1984) consists of wetland habitat Riparian habitat is also one of the fastest disappearing habitats in the County. Each of ** the wetland habitats within the three project study areas (Le., freshwater marsh, coastal salt 0 marsh, and wetland ecotone) are considered sensitive in San Diego County. This is due to their limited area, diminishing acreages, and sensitive flora and fauna that depend on these habitats. ** Coastal freshwater marsh and coastal salt marsh on-site are also sensitive because they support m a sensitive plant species, southwestern spiny rush. "" 3.1.1.5 Habitat Evaluation •L ^ Habitat values on-site vary due to differing levels of disturbance. Urbanization and disturbances from grading are the primary sources for reduced habitat values on-site. Disturbed areas are "* often of significant value, however, to certain animal species, such as large mammals and birds « of prey because they provide foraging opportunities. But, the lack of evidence of significant small mammal and reptile populations during field observations indicates a probable low habitat value for the disturbed uplands found in the project study areas. Due to inadequate vegetative — cover, these disturbed areas provide little wildlife value as foraging habitat for birds of prey. wr m-7 The disturbed wetland scrub habitat within the three project study areas is relatively sparse and contains non-native species. These characteristics attract fewer native animals. In contrast to the previously mentioned disturbances, the natural resilience of riparian systems positively affects the habitat value of the disturbed wetland scrub. The wetland ecotone on-site is also valuable as edge habitat The southern willow scrub habitat south of the existing Olivenhain Road alignment is of medium value to wildlife due to its sparseness and relatively limited coverage. Used as foraging habitat by various birds and animals, it is probably not suitable for nesting by the least Bell's vireo. The southern willow scrub habitat south of La Costa Avenue, except for a small stand adjacent to the road, is dense, mature, and of relatively high value to wildlife. This area is affected by significant traffic noise levels from La Costa Avenue, however, which lowers its habitat value. Southern mixed chaparral north of the existing Olivenhain Road alignment has limited habitat value due to "edge effects", or disturbances from adjacent developed areas. Furthermore, future impacts to this habitat are anticipated from the approved Arroyo La Costa development at this location. Its relatively undisturbed and dense condition, however, presently increases its habitat value. Finally, since the extent of this habitat within the Coastal Zone, which is defined by the CCC as the inland edge of the El Camino Real ROW, is restricted to a narrow strip east of the paved roadway edge, habitat quality in this area is degraded by traffic noise and related "edge effects" due to its proximity to the road. Coastal salt and freshwater marsh habitats on-site are of relatively high wildlife value. During the February field survey, coastal salt marsh plants south of Olivenhain Road were in a dessicated state due to drought conditions, but may have recovered from the March rains. The coastal salt marsh habitat south of La Costa Avenue appears to be healthier, possibly due to some degree of tidal flushing from Batiquitos Lagoon. 3.1.2 Impacts Impacts to vegetative habitats within the three project study areas are discussed below as direct, construction-related and indirect, construction/traffic noise-related. 3.1.2.1 Olivenhain Road Expansion^^••^^^MMM«^«BSS»«M«PMMBwBI««MM«» 3.1.2.1.1 Proposed Roadway Alignment and Construction Easement The proposed Alignment #2 would directly impact approximately 0.04 acres of southern willow scrub, 0.33 acre of southern mixed chaparral, 4.7 acres of ruderal vegetation, and 0.40 acre of disturbed land (Figure 3.1-4). The impact to southern willow scrub is considered cumulatively significant due to this habitat's limited range. The construction easement for this road (i.e., 50 feet wide from the southern roadway edge and 15 feet on the north) would temporarily impact an additional 0.21 acre of southern willow scrub, 0.14 acre of coastal freshwater marsh, 0.21 acre of southern mixed chaparral, 0.04 acre of disturbed wetland scrub, 0.69 acre of ruderal vegetation, and 0.16 acre of disturbed land. Impacts from this easement to southern willow scrub and freshwater marsh are considered cumulatively significant The impact to disturbed wetland scrub is not considered significant because of its low wildlife value due to the presence of a high percentage of non-native species. m-8 I i I 1 I I I I t i • I II If Itti i# NOTE: Northernmost Limit of Proposed Construction Easement • to be Determined by Limits of Remedial Grading Legend Dist Disturbed DWS Disturbed Wetland Scrub FWM Freshwater Marsh Rud Ruderal SWS Southern Willow Scrub E Wetland Ecotone CSM Coastal Salt Marsh SMC Southern Mixed Chaparral (wf) Willow Flycatcher Downy Woodpecker Construction Easement Roadway Cut Slopes OHvenhaln Road Coastal ZonePlanning Area ( Eastern Boundary)ExistingAlignment 100-Year Roodplam (with Detention Basins A.B.C) FWM OHvenhaln Road Alignment100' 200' Proposed Alignment #2 Biological Impacts MapbflaJ\fjriponev 100_YearFl0odp,a5n ( with Detention Basins A.B.C.D )Figure 3.1-4 EIR 3.1.2.1.2 Sedimentation and Roadway Runoff .•** , Proposed roadway construction would include the placement of a silt fence along the southern edge of the 50-foot wide construction easement, and a siltation basin along the northern roadway edge near existing culverts in order to prevent downstream sedimentation. Detention basins A ., and B would also detain most of the upstream sedimentation that would normally flow into the 4 project area (Ruth, 1991). Slight increases in oil and grease runoff from increased paved surface area and vehicular traffic along the widened road segment are anticipated, and would be « considered a significant cumulative impact to sensitive aquatic microbiota associated with the m Encinitas Creek watershed. The widening of Olivenhain Road would also slightly increase stonndrain runoff volumes into this reach of Encinitas Creek due to an eight-acre increase in m impermeable (Le., paved) surface area contributing to this drainage basin. This would result in m an increase of the 100-year peak discharge from 361 cubic feet per second (cfs) to 368 cfs (Ruth, 1991), which is not regarded as significant. «M m 3.12.13 Roadway Construction and Traffic Noise **> Significant noise levels generated by heavy construction equipment operation and increased traffic an along the improved Olivenhain Road may further disrupt foraging and mating activities of sensitive songbirds that could use the southern willow scrub habitat within Encinitas Creek to thew south. Noise levels in excess of 89 decibels (dB) have been recorded at 50 feet from the point- Mi source for a general mix of operating construction equipment (Kurtz, 1991). These noise levels generally decrease by 6 dB for every doubling of distance from the point-source. With Encinitas "" Creek riparian habitat located between one and 300 feet south of the proposed construction • easement for Alternative #2 alignment, construction noise levels would significantly impact sensitive songbird species that may use this area (e.g., willow flycatcher). ** From existing information on the sensitivity of songbirds to traffic noise (Le., the proximity of breeding territories to major roads or highways), acceptable noise disturbance levels have been *" found to be within the 50-60 dB range (SANDAG, 1988; Mock, 1989). The U.S. Fish and m Wildlife Service (USFWS) uses 61 dB(A) L^, as its standard noise threshold for impacts to m sensitive bird species, such as the least Bell's vireo (Rieger, 1990). The current 61 dB(A) L^ noise contour already encompasses most of the riparian area south of Olivenhain Road. ^ The proposed project would result in shifting this existing noise contour approximately 110-120 feet further to the south (see Section 3.6.2 of this EIR), resulting in additional impacts of approximately 1.64 acres to southern willow scrub habitat Most of this noise impact, however, m would be attributed to increases in future traffic volumes along El Camino Real Thus, m incremental noise impacts to sensitive songbirds due to increased traffic volumes along the unproved Olivenhain Road would not be regarded as significant in comparison to the amount of — habitat currently being affected. m-io 3.1.2.2 Proposed Detention Basin "D" Dike Construction of the proposed dike would directly impact approximately 0.16 acre of coastal freshwater marsh, 0.19 acre of disturbed wetland scrub, and 0.89 acre of ruderal vegetation (Figure 3.1-5). The impact to freshwater marsh would be regarded as cumulatively significant The projected loss of disturbed wetland scrub would not be considered significant due to its disturbed nature. Impacts to ruderal vegetation may include losses of the sensitive sand aster. The 50-foot wide construction easement required to construct the dike would result in additional temporary impacts of 0.17 acre of disturbed wetland scrub and 2.14 acre of ruderal vegetation. The temporary impact to disturbed wetland scrub from this easement is not considered significant, but impacts to the area mapped as ruderal vegetation cannot be ascertained until the variety of sand aster on-site is determined. Although not proposed as part of this project, there is a potential that future construction of the southern embankment for detention basin "D", concurrent with future development of the Wiegand property, could result in additional significant impacts to wetland habitats mapped in this area. It has been brought to our attention, however, that the property owner would be willing to designate a minimum 100-foot buffer from the toe of any future fill slope for the basin embankment in order to preserve wetland habitat values on-site. 3.1.2.3 Proposed La Costa Avenue Flood Control Berm According to Table 3.1-1, the Alternative #1 berm design would directly impact approximately 0.08 acre of southern willow scrub, 0.04 acre of coastal salt marsh, and 0.31 acre of ruderal vegetation (Figure 3.1-6a). Impacts to southern willow scrub and coastal salt marsh are considered cumulatively significant The 15-foot wide construction easement required for the Alternative #1 berm would temporarily impact an additional 0.08 acre of southern willow scrub, 0.04 acre of coastal salt marsh, 0.03 acre of baccharis scrub, 0.03 acre of eucalyptus woodland, and 0.20 acre of ruderal vegetation. Temporary impacts to willow scrub and salt marsh from this easement are regarded as cumulatively significant. The Alternative #2 berm design would directly impact approximately 0.19 acre of southern willow scrub, 1.19 acres of coastal salt marsh, 0.01 acre of eucalyptus woodland, and 0.59 acre of ruderal vegetation (Figure 3.1-6b). The impact to coastal salt marsh is considered significant, while the impact to southern willow scrub is considered cumulatively significant The 15-foot wide construction easement for the Alternative #2 berm would temporarily impact an additional 0.09 acre of southern willow scrub, 0.33 acre of coastal salt marsh, 0.03 acre of eucalyptus woodland, and 0.26 acre of ruderal vegetation. Temporary impacts to southern willow scrub and salt marsh wetland habitats from this easement are considered significant 3.1.2.4 Sensitive Plants Construction of the proposed detention basin "D" dike could potentially impact the Del Mar sand aster if it is determined to be present during a summer survey. San Diego marsh elder may also be present in the freshwater marsh habitat at this location. Approximately 1.19 acres of habitat P 1* 1 l f 1 i i I i t i I I t i t i I i I I ft I t i I 1 1i k 4 i Legend Southern Coastal Salt Marsh Dist Disturbed DW3 Disturbed Wetland Scrub E Ecotone FWM Freshwater Marsh Rud Ruderal SWS Southern Willow Scrub s») Sand Aster sg Spiny RushProposed Dike Construction Easement Rud 1990 Ftoodplaki (per Dr. Chang) N 100' 200' 0, dwlgn t mvkoniMnW atudto* Rud Ollvenhaln Road Alignment Proposed Detention Basin "D" Dike Biological Impacts Map Figure 3.1-5 t i f i i li I it it t i m §E %t i TABLE 3.1-1 SUMMARY OF IMPACTS TO VEGETATIVE HABITATS WITHIN THE LA COSTA AVENUE FLOOD CONTROL PROJECT AREA Habitat Type Southern willow scrub Coastal salt marsh Baccharis scrub Eucalyptus woodland Ruderal Total Alternative #1 Berm Construction Easement 0.08 0.08 0.04 0.04 0.03 0.03 0.31 0.20 Alternative #2 Berm Construction Easement 0.19 0.09 1.19 0.33 0.43 0.35 0.01 0.59 1.98 0.03 0.26 0.71 m-is titititiiiiitlifi k * 100' 200' bf ion fmooncv planKWiMiesign S environmental studies LEQENB BS Baccharis Scrub CSM Coastal Salt Marsh DCSS Disturbed Coastal Sage Scrub DIST Disturbed EUC Eucalyptus Woodland SWS Southern Willow Scrub Alternative #1 Berm Design Construction Easement Ollvenhaln Road Alignment La Costa Avenue Biological Impacts Map for Alternative 1 Flood Control Berm Figure 3.1-6a E« I i 1 1 I i i m i 11 i i Southwestern Spiny Rush Area Fresh \ Water \Marsh \ brian F moonav—""- BS Baccharis Scrub GSM Coastal Salt Marsh DCSS Disturbed Coastal Sage Scrub DIST Disturbed EDO Eucalyptus Woodland SWS Southern Willow Scrub mmi& Construction Easement Alternative »2 Berm Design Olivenhaln Road Alignment La Costa Avenue Biological Impacts Map for Alternative 2 Flood Control Berm Figure 3.1-6b TaST that contains the southwestern spiny rush would be directly impacted by the Alternative #2 flood control berm design at the La Costa Avenue/El Camino Real intersection. This would be considered a significant impact 3.1.2.5 Sensitive Animals •1 ^ The willow flycatcher and downy woodpecker would be impacted by the projected loss of southern willow scrub habitats within the project study areas. This is regarded as a significant ••» cumulative impact due to the precipitous decline of this habitat type in the region. lh*tt 3.1.2.6 Off-Site Impacts I'd* IM- Olivenhain Road may connect with future Leucadia Boulevard alignment west of the El Camino Real intersection. Southern willow scrub and freshwater marsh habitats occur along the Green 1« Valley riparian area west of El Camino Real, and would be impacted by this future alignment i* Preliminary design of future Leucadia Boulevard at this intersection indicates that approximately 0.12 acre of freshwater marsh and 0.05 acre of southern willow scrub habitats could be impacted. •"*• This would be considered a significant cumulative impact to these two wetland habitat types. m During a 100-year flood, the salt-grass pasture east of Rancho Santa Fe Road could be inundated "" with water behind future detention basin "D". Approximately four acres in this area may be m flooded; however, this would not be considered a significant impact to the disturbed wetland habitat which occurs here.•m «• Locations of staging areas for construction of the proposed road and detention basin dike are not known at this time; therefore, impacts cannot be assessed.«• if No impacts to biological resources in the Olivenhain Road project area would occur from required detouring for this project because at least one existing or proposed traffic lane will be "" maintained for circulation during project construction. The potential for biological impacts in m the project area would further be reduced should alternate detour options be used during proposed m road construction, such as Calle Barcelona between El Camino Real and Rancho Santa Fe Road (if it is allowed to be completed prior to project implementation). *, 3.L3 Mitigation The Alternative #2 Olivenhain Road design and the Alternative #1 flood control berm design at «(i La Costa Avenue/El Camino Real intersection are recommended as the least environmentally m damaging alternatives in terms of potentially significant impacts to biological resources within these project study areas. Specific measures to further mitigate identified impacts to biological *« resources associated with project implementation are provided below. 3.13.1. A U.S. Army Corps of Engineers Pre-Discharge Notification and a California """ Department of Fish and Game (CDFG) 1601 Streamcourse Alteration Agreement shall be m prepared and approved prior to the approval of final roadway improvement plans. Included in * m-16 the 1601 Agreement would be the required revegetation of sensitive wetland habitats to be directly impacted by the proposed project (see Attachment 1 of Appendix 5). According to the Conceptual Wetland Restoration Plan presented in Appendix 5, southern willow scrub habitat impacts shall be replaced at a 3:1 ratio and the impacted marsh habitats at a 1:1 ratio. This translates to a total of approximately 0.36 acre of southern willow scrub and 0.04 acre of coastal salt marsh to be revegetated on-site. Figure 3.1-7a shows the disturbed areas along Encinitas Creek floodplain, within the area of the future detention basin "D", that are ecologically appropriate for "in-kind" wetland habitat restoration. Figure 3.1-7b shows an alternative location for coastal salt marsh revegetation south of La Costa Avenue, based on a higher probability of success for restoration of this habitat at this location. This is due to its proximity to thriving marsh habitat which may benefit from increased tidal action from the nearby Batiquitos Lagoon. A pie-application meeting at both sites with resource agency personnel is recommended in order to ascertain the preferred location for coastal salt marsh revegetation. Given the complex hydrology and salinity which resulted in the mosaic of wetland types, creation of these various habitats may be difficult Please refer to Attachment 1, Appendix 5, for detailed specifications regarding the Conceptual Wetland Restoration Plan required for this project. 3.13.2. Prior to construction of the proposed flood control benn at La Costa Avenue/El Camino Real intersection, the coastal salt marsh vegetation and top soil layer to be impacted shall be salvaged, and then tilled into the soil of the prepared salt marsh revegetation site. Marshes and southern willow scrub habitats within proposed construction easements shall be protected by laying geotextile and then covering the cloth with soil. The soil overcovering shall be imported from adjacent areas to be disturbed. Any willows which occur within the construction easements shall be cut down to just above the height of the soil surface layer. These cut materials shall be mulched and laid on the surface of the prepared willow scrub revegetation site. Prior to construction and placement of geotextile, the outer limits of all construction easements shall be flagged with fluorescent tape to prevent additional wetland impacts from accidental encroachments. The soil within the construction easements shall be retained to avoid sedimentation. Soil samples shall be taken prior to and after construction to determine the level of compaction in these easements. If the soil is compacted, it shall be loosened by hand raking. 3.13.4. All construction easements shall be surveyed by a qualified biologist during the spring after project implementation to determine if the habitats in these areas are regenerating on their own. If the biologist determines that these areas are not adequately regenerating on their own, additional plantings of the affected habitat types, at the appropriate replacement ratios (3:1 for southern willow scrub and 1:1 for the marshes), shall be installed at the proposed revegetation sites shown on Figures 3.1-7a and 3.1-7b. These are in addition to plantings required for direct impacts. m-17 |/ X //^Proposed Dike Construction Easement I IS J f , X -*•-" ' « ^**fc. . **.**. *^ »•! !_-!._!.1982 100-Year Floodplain er County) Proposed Dike Marsh Revegetation Alternative 1 Site LEGEND • Southern Willow Scrubwm Revegetation Site CSM Southern Coastal Salt Marsh Dist Disturbed - DWS Disturbed Wetland Scrub FWM Freshwater Marsh Rud Ruderal 50' 100' 1990 100-Year Floodplain^- ^j (per Dr. Chang) Ollvenhaln Road Alignment Proposed Revegetation Sites Within Future Detention Basin "D" bricin F mooncv g. design & environmental studies Figure 3.1-7a I i 11 II II t I 1*1* lit! II ft I fc I t I , Southwestern Spiny Rush Area Fresh WaterMarshBatiquitos Lagoon La Costa Avenue Coastal SaltMarsh Revegetation Alternative 2He N LEGEND o 100' 200- BS Baccharis Scrub CSM Coastal Salt Marsh DCSS Disturbed Coastal Sage Scrubbrian f mponc v DIST Disturbed " EUC Eucalyptus Woodland SWS Southern Willow Scrub Ollvenhain Road Alignment La Costa Avenue Alternative Coastal Salt Marsh Revegetation Site NJUV/X/N^S %^JU-^-JU\^N^.Jl ptarirang. design & wwlrorunental studies Figure 3.7-76 EH 3.13.5. All rcvegetation areas shall be monitored by a qualified biologist proficient at horticultural sampling techniques for at least a five-year period to evaluate the initial success of plant establishment, and direct maintenance activities. All rcvegetation activities shall also be monitored during plant installation to ensure that substitute plant species are not incorrectly used for the given ecological context 3.1.3.6. In order to avoid incremental water pollution impacts to Encinitas Creek aquatic microbiota from oil and gas residuals runoff from the widened roadway surface, a permanent oil catchment basin or native grass-lined drainage swale/retention basin shall be installed on the south side of Olivenhain Road. 3.13.7. The construction period for the portion of the project route between the SDG&E easement and the western Willow Creek subdivision boundary shall not occur within the months of March through July in order to avoid potentially significant construction noise impacts to sensitive breeding song birds. m-io 33 CULTURAL RESOURCES The following discussion is based on cultural resources surveys conducted for the three project study areas (see Figures 2.4-1 to 2.4-3) by staff archaeologists from Brian F. Mooney Associates (BFMA). The complete technical report is provided as Appendix 6 of this EIR. Prior to field surveys, record searches from the San Diego Museum of Man and the South Coastal Information Center (SQQ at San Diego State University were reviewed for the project study areas. 3.2.1 Existing Conditions 3.2.1.1 Background Research A review of site records indicates that 58 prehistoric sites and one historic site had previously been recorded within a one-half mile radius from the project study areas. Most of the prehistoric sites consist of light surface scatters of flaked and/or ground lithic artifacts, and many contain light to moderate scatters of shell. A few sites have extensive midden deposits with relatively high concentrations of lithic artifacts, and some exhibit traces of hearths. The sites which have been recorded in the immediate vicinity of the three project study areas are described below. 3.2.1.1.1 Alternative Road Alignments Study Area A portion of one recorded prehistoric site appears to possibly exist within the alternative alignments study area. Specifically, site SDi-4872 (W-982) has been described as existing on the northeast comer of the Olivenhain Road and El Camino Real intersection. This site was first recorded by R. Kaldenberg in 1976, who noted the presence of scrapers, flakes, choppers, chopping tools, cores, and thermally fractured cobbles located on the southwest slope of a knoll approximately 300 feet northeast of this intersection. Described as a possible yucca processing site, the artifact assemblage was not diagnostic of a particular cultural affiliation. In 1989, a cultural resource study was conducted by ERC Environmental and Energy Services Company for the same alternative alignments study area. The intensive survey relocated SDi- 4872 in the location described by Kaldenberg, and artifacts from this site were also observed within about 30 feet of the existing Olivenhain Road alignment An area extending approximately 75 feet north from the roadway edge, and for some 600 feet between El Camino Real on the west and a dirt road about 600 feet to the east, was tested to evaluate the significance of this portion of the site. The testing program included a surface collection and excavation of five shovel test pits. Four artifacts were recovered from the surface and one shovel test pit yielded a single flake. It was concluded that the materials in the test area had washed downslope from the main portion of the site, and that "the majority of the site appears to be surface in nature as described by Kaldenberg (1976)" (Gallegos and Pigniolo, 1989). It was recommended that no mitigation or further archaeological study would be necessary if direct and indirect impacts associated with the proposed road widening were confined to a strip 75 feet north of the existing road alignment m-21 A second site recorded in this study area is W-4318. Situated on a terrace overlooking Encinitas Creek about 450 feet north of the existing Olivenhain Road alignment, this prehistoric site, interpreted to be affiliated with the La Jolla Complex, was found and subsequently tested by B. Smith (Smith, 1990). Consisting of a sparse, dispersed scatter of lithics, fourteen artifacts were recovered from the surface including three flakes, two debitage, two metate fragments, one mano, one scraper plane, and five scrapers. No shell or other cultural materials were observed. Twenty-five shovel test pits and a one-meter-square unit were excavated, but no subsurface ' materials were recovered. This site is not considered to be significant « A third site recorded near the alternative alignments study area is SDi-11027. Situated on a terrace south of Encinitas Creek and east of El Camino Real, the site was described by T. Van ,« Bueren in 1988 as consisting of a light scatter of shell, fire-affected rock, two manos, several cores, and debitage. The site is situated approximately 650 feet south of the existing Olivenhain Road alignment »m iwf The only other site recorded within the immediate vicinity of the alternative alignments study area is SDi-4400 (W-921, and possibly also W-48). Situated on a mesa overlooking the existing •"•* Olivenhain Road to its south, this site was located by R. Kaldenberg in 1976, tested by RECON m in 1982, and tested again by S. Apple and R. Olmo in 1983. Consisting of a surface scatter of flaked and groundstone artifacts, this site location is now a residential development and could •• not be relocated in 1989 (Gallegos and Pigniolo, 1989). m 3.2.1.L2 Future Floodwater Detention Basin "D" Study Area MI The only site recorded in the immediate vicinity of the future detention basin "D" and proposed dike study area is SDi-2734 (W-49-E). Situated approximately 150 feet south of this future ** detention basin and abutting the west side of Rancho Santa Fe Road, this site was described by *• Malcolm Rogers as a W. Diegueno site consisting of one acre within the L. Scon Ranch. Rogers reported that Mr. Scott possessed a collection from this site, including an intrusive Cahuilla arrow ** straightener. m A single site has been recorded in the immediate vicinity of the potential 100-year flood ponding "* area located to the east of future detention basin "D". Situated on a knoll north of the Encinitas Creek river bottom and east of Rancho Santa Fe Road, site SDi-11,267 (W-48-A) was reported by M. Rogers to be a campsite utilized by San Dieguito, Littoral (i.e., Archaic), and Yuman (Le., Late Prehistoric) peoples. The site exhibited flaked tools, considerable groundstone tools, * ceramics, shell, and hearth stones. Rogers described the site as having been disturbed and eroded due to a long history of bean fanning. SDi-11,267 was investigated in 1989 by G. T. Gross, M. Robbins-Wade, and T. Brown Sampson, who described it as a sparse shell and lithic scatter * spread over a wide area. The observed artifacts included one mano, one San Dieguito-like M scraper, one flake, and one hammer. m-22 3.2.1.13 La Costa Avenue/El Camino Real Flood Control Berm Study Area A review of previous research disclosed that a site, SDi-6868, had been identified in the immediate vicinity of the proposed flood control berm study area at the southwest corner of La Costa Avenue and El Camino Real intersection. First recorded in 1979 by Gary Stickel, shell, fire-affected rock, some pottery sherds, and possibly some grey midden were observed A subsequent investigation of SDi-6868 by RECON in 1989 indicated traces of the site despite the fact that the area had become badly overgrown. Several small scatters of shell were located during the field survey, but damage to this site from past agricultural operations appeared to be extensive. Both Stickel (1979) and Davis and Hector (1989) concluded that a testing program would be necessary to determine the extent, depth, age, complexity, level of disturbance, and significance of this site. If such testing revealed a significant subsurface component, mitigation in the form of open space preservation or data recovery would be recommended. 3.2.1.2 Field Survey Methods An intensive on-foot examination of all three project study areas listed above was conducted by Mr. John Cook and Dr. Michael Baksh of BFMA on February 1, and June 3, 1991. A survey interval of 30 to 60 feet was maintained throughout all undeveloped portions of the project areas, except for areas of poor accessibility and low surface visibility. Special attention was also given to the locations of previously recorded sites and other areas considered to have the potential for site occurrence. Survey of the future detention basin "D" study area was generally restricted to either side of Encinitas Creek. The potential 100-year floodwater ponding area east of this detention basin offered excellent visibility. No artifact collections were made, nor was any subsurface testing conducted as part of this study. 3.2.1.3 Results The results of the archaeological surveys were negative in that no significant cultural resources were identified in all three project study areas. 3.2.1.3.1 Alternative Alignments Study Area No cultural resources were found within the areas proposed for widening and realignment of the existing Olivenhain Road. The northeast comer of Olivenhain Road/El Camino Real intersection was the focus of special attention, but no artifacts from site SDi-4872 were located in this area. More importantly, an area within about 100 feet from the roadway edge has been graded since the archaeological test reported by Gallegos and Pigniola (1989). This grading has likely not destroyed any significant resources and, in any case, none were observed. Site SDi-4872 was relocated to the area described by Kaldenberg (i.e., about 300 feet north of the existing Olivenhain Road alignment), and appears to be in the condition more recently described by Gallegos and Pigniola (1989). Artifacts observed to be eroding down the hill in the direction of Olivenhain Road included a mano, hammerstone, and numerous flakes, but these materials are out of the project area. m-23 In general, the areas directly adjacent to both sides of Olivenhain Road between El Camino Real and the Willow Creek/Rancho del Ponderosa subdivisions have been heavily impacted. On the north side of the road, an area below and east of the north-south high-voltage transmission lines has been cleared of brush and recently graded. This area has generally sustained heavy vehicular traffic. On the south side, the area between Olivenhain Road and Encinitas Creek has been graded in the distant past and currently contains numerous large chunks of asphalt and cement In addition, a gas plant, gas lines, and an east-west electrical line have been constructed along * the south side of the road at its western end. <•«* No effort was made to relocate site W-4318, which is situated about 450 feet north of the '* existing Olivenhain Road alignment In any case, the site was tested by B. Smith and found not ,* to be significant (Smith, 1990). Similarly, no effort was made to relocate site SDi-11027, which is about 650 feet south of Olivenhain Road. Finally, no effort was made to locate SDi-4400, '" which is in a developed area outside the alternative alignments study area. <«• 3.2.1.3.2 Future Floodwater Detention Basin "D" Study Area \m —————————————— *» No sites were found in the area encompassed by the future detention basin "D". Although sites m are not likely to be located in marshy areas that are regularly inundated, it must be noted that this wetland and its dense riparian vegetation prevented a thorough examination of the study area. <** Although site SDi-2734 is described as existing near the southeastern border of this area, no m cultural materials were observed. — No cultural resources were found in the creek bottom indicated as a 100-year flood ponding area m to the east of detention basin "D", but site SDi-11,267 was relocated on a knoll north of this area. A mano, granitic metate fragment, and cobble hammerstone were observed on this knoll. No "* artifacts were found within about 60 feet of this area. MM 3.2.1.3.3 La Costa Avenue/El Camino Real Flood Control Berm Study Area «M> With the exception of site SDi-6868, no cultural resources were found in the vicinity of the areas proposed for a flood control berm under either Alternative #1 or #2 designs (see Figure 2.3-4).m The only evidence observed of SDi-6868 was very light scatters of shell along a north-south ** trending dirt road traversing the study area. A few of the relatively cleared areas on either side of this dirt road also exhibited extremely light shell deposits. Although the site was originally *"" mapped as extending north to La Costa Avenue, no shell or prehistoric cultural remains werem observed within 50 feet of the roadway edge. No lithics, ceramics, or other artifacts described by Stickel in 1979 were observed in this area, but dense vegetation prevented a thorough surface examination of the site. 4* „ 3.2.2 Impacts ** No cultural resources are located within areas proposed for the widening and realignment of . Olivenhain Road; within the area encompassed by proposed construction of floodwater detention basin "D" dike, the future detention basin, and corresponding 100-year flood ponding area east m-24 of Rancho Santa Fe Road; and within the area proposed for the construction of a flood control berm at La Costa Avenue/El Camino Real intersection. No adverse direct impacts would therefore result from implementation of these three aspects of the proposed project 3.23 Mitigation Measures It is unlikely that indirect impacts would occur to sites located in the vicinity of the three project study areas. In an effort to minimize possible risks, however 3.2.3.1. Unlike SDi-6868, SDi-4872 is located at such a distance from proposed roadway construction areas that direct or indirect impacts to it are considered remote. Nevertheless, any proposed road construction activities conducted in the northeast corner of Olivenhain Road/El Camino Real intersection shall be restricted to within a maximum distance of 50 feet from the edge of grading for the preferred alignment, so as not to threaten damage to SDi-4872. Prior to any road construction in this area, SDi-4872 site boundary shall be flagged by a certified archaeologist and identified to construction crews as environmentally sensitive. 3.23.2. All activities related to proposed construction of detention basin "D" dike or improvements to Rancho Santa Fe Road at the Olivenhain Road intersection shall be restricted to an area within SO feet of the current Rancho Santa Fe Road ROW (by the use of flagging and/or temporary signage daring the construction period), so as not to risk indirect impacts to SDi-11267. Since this site is located approximately 60 feet north of the proposed dike, and about 120 feet east of Rancho Santa Fe Road, it would not be directly impacted either by proposed flood control or road construction activities in these two areas. 3.233. The Alternative #1 flood control berm at La Costa Avenue/El Camino Real intersection is recommended in terms of a preferred design alternative because it would not impact SDi- 6868; however, if the Alternative #2 berm design is selected, a certified archaeological monitor shall be retained to periodically monitor the construction area to ensure that no impacts occur to this site, since its northern boundary had originally been mapped up to the southern roadway edge of La Costa Avenue. m-25 3.3 GEOLOGIC HAZARDS The following discussion provides geologic substructure and soils information for the areas encompassed by the alternative road alignments and future floodwater detention basin "D". General physical characteristics of on-site soils are described and evaluated below as to their 1 suitability for the intended uses. This section is based on information obtained from a geology study performed in February, 1991, by Geocon, Inc. The complete technical report is included as Appendix 7 of this EIR. H> 33.1 Existing Conditions, .f( ^^HM^AM^H^taHMM^M^M^BI^MM •*• 33.1.1 Geology Two geological formations are found within the project vicinity: the Eocene-aged Delmar ** Formation and the Torrey Sandstone. The Delmar Formation generally consists of relatively „„, dense, brown to olive-green sandstones, siltstones, and claystones. Geologic processes have shifted this formation in such a manner that it slopes two to five degrees to the opposite direction *** in which grading is proposed. Weathering has created remolded clay seams between the layers. »* H Portions of the project site are capped by Torrey Sandstone which consists of dense, light tan sandstone underlain by the Delmar Formation. Contact between the two formations at the — western portion of the site was noted at an approximate elevation of 115 feet above mean sea m level (AMSL). 3.3.1.2 Soils M Three surficial soil types were encountered during field investigations conducted on-site. These - surficial soil types consist of alluvium, slopewash, and undocumented fill. Figures 3.3-1 and 3.3- m 2 show the locations of these soil types within the project areas. Characteristics of each soil type are briefly listed below.•• *• Alluvial soils occur within the drainage bottoms at the eastern and western portions of the project site. Alluvial deposits typically consist of silty to clayey sands to sandy clays. Depths of alluvium at the western end of the Olivenhain Road project area are approximately 30 to 50 feet - The depth of alluvium in the area of the future detention basin "D" is approximately 25 feet This soil type has been classified as moderately to highly compressible. " Slopewash soils are found adjacent to and beneath the western portion of the project site, and generally consist of loose to stiff brown and dark brown sandy clays and clayey sands. The depth of these soils is estimated to be between two and seven feet• m Undocumented fills are found mostly beneath and adjacent to the western portion of the Olivenhain Road project area. Some fills were also found at the eastern portion. Fill depths range from two to eight feet, and cap the formational alluvium and slopewash soils described - above. * m-26 i I t i i i E i i I l i i f i i 1 1 I I l i I I 1 1 I I i i Legend Proposed 126' Right-of-Way ( Preferred Alternative No. 2 ) Qudf Undocumented Fill Qsw Slopewash Qal Alluvium Proposed Alignment *2 'J* Torrey Sandstonei , >_ -Id Delmar Formation Approx. Location of .Geologic Contact N Existing Olivenhain \ Road Alignment brian F moonc v )(§XSD(3](s@S) I. d**ign twMlroATMntil itudtas Ollvenhaln Road Alignment Existing Soils Map Western End of Project Route Figure 3.3-1 EIR , , ( , I , I I I I I I I I I I I I I I I I I I I I 1 I I < * * * ' * ' ' ' LEGEND Qudf Undocumented Fill Tt Torrey Sandstone Qal Alluvium mm mm Approx. Location ofGeologic Contact Proposed Dike Construction Easement ° Jbrian f moona v Ktudto* 0 100' 200' Qudf Olvenhaln Road Alignment Existing Soils Map Eastern End of Project Route Figure 3.3-2 Elfl 3.3.1.3 Seismicitv Although the project site is not located on any known active fault, it is located approximately five miles east of the Rose Canyon Fault zone. This fault zone is currently the subject of research to determine its potential for seismic activity. A fault zone is classified as active if displacement of sediments younger than 11,000 years has been observed. The results of ongoing research indicate that movement has occurred along the Rose Canyon Fault during the Holocene Epoch. This fault has been classified as active in the downtown San Diego and La Jolla areas. The California Division of Mines and Geology is currently acting to include this fault within an Alquist-Priolo Special Studies Zone. Other active faults in die region include the Elsinore Fault zone and the San Jacinto Fault zone which lie approximately 27 and SI miles to the northeast, respectively. In the event of a major earthquake in the southern California region, the project site could be subjected to severe ground shaking. 33.1.4 Groundwater Groundwater was previously encountered in subsurface excavations at various depths within alluvial and formational soils on-site. Groundwater, or seepage, at the site may vary as a result of seasonal fluctuation and irrigation. Perched water conditions are likely to exist near the surface, within the major east-west alluvial-filled valley. This potential, shallow groundwater condition may require special consideration to reduce construction difficulties. 33.2 Impacts There are no soil or geologic conditions present on-site that would preclude the proposed widening and realignment of the relevant portion of Olivenhain Road. The presence of undocumented fill soils, compressible alluvium, and shallow groundwater, however, will require special consideration where development is planned. Impacts to geology of the site can be divided into two different areas: the eastern portion of the existing road alignment, which is planned for widening mainly through restriping, and the area encompassed by the proposed detention basin dike; and the western portion of the project route, which is planned for road widening and realignment 3.3.2.1 Eastern Portion of Project Site: Proposed Road Widening/Detention Basin Dike Proposed road widening and grading adjacent to the Thompson Property will require removal and recompaction of loose surficial soils, which may include existing fill soils. The area of the proposed detention basin dike will require remedial grading in the form of removal and recompaction of the near surface, loose alluvial soils and any existing undocumented fill soils. It is anticipated that proposed fill slopes for this dike would be constructed at inclinations of 2:1, or less. It should be noted that this same recommendation applies to future construction of the side embankments of detention basin "D", although not proposed as part of this project ffl-29 3.3.2.2 Western Portion of Project Site; Proposed Road Widening and Realignment Project implementation will require remedial grading of the existing undocumented fill soils, fonnational soils with adverse bedding, and slopewash/alluvial soils at the western portion of the project site. The alternative alignments located south of the existing road, are predominantly underlain by alluvial soils. Partial removal and recompaction of these alluvial soils will be required and construction dewatering will probably be necessary. The alternative alignments located north of the existing road will require stabilization fills for slopes cut in Delmar Fonnational soils containing adverse bedding. This is because the two- to five-degree slope at this location makes an unstable base for a roadway without proper grading. Partial removal and recompaction of the alluvial soils that exist in this area will also be necessary. Any undocumented fills encountered within the western portion of the project site will require removal and recompaction. Proposed construction for the preferred Alignment #2 will require removal and recompaction of existing fill soils, slopewash and alluvium. Construction will also require a stabilization replacement fill for the proposed 32-foot high, 2:1 cut slope located within adverse bedding of the Delmar Formation. The presence of shallow groundwater at this location will limit the depth of remedial grading to just above the groundwater level. It should be anticipated that "in situ" treatment of the alluvium (i.e., placement of a geotextile fabric and coarse aggregate blanket) will be required over the exposed cut soils prior to compaction of fill and pavement Construction dewatering, particularly adjacent to El Camino Real, will likely be required. 3.3.3 Mitigation The following measures shall be incorporated into the proposed project in order to mitigate potentially significant geologic hazards identified herein: 3.33.1. Prior to the approval of final roadway improvement plans, a detailed soils and geologic investigation addressing the proposed Alignment #2 shall be performed. 3.3.3.2. All proposed roadway improvement and grading plans within existing utility easements on-site shall be reviewed and approved by the Public Works Departments of the cities of Encinitas and Carlsbad prior to final approval 333.3. All manufactured fill slopes shall be planted with erosion-resistant groundcover vegetation, and watered by a well-designed and maintained irrigation system. A landscape plan and irrigation system for all graded slopes shall be reviewed and approved by the Public Works Departments of the cities of Encinitas and Carlsbad prior to approval of final roadway improvement plans. Landscaping and irrigation for all manufactured slopes, per approved plans, shall be installed as soon as practical after grading in order to reduce erosion potential on exposed slopes. m-30 3.4 TRAFFIC/CIRCULATION The following discussion summarizes various traffic studies conducted within the Olivenhain Road project area. In particular, baseline traffic data is derived from the General Plan Circulationv Elements of both the Cities of Encinitas and Carlsbad; a General Plan traffic analysis conducted by Austin-Foust Associates, Inc. (1988) for the City of Encinitas; and traffic studies conducted by ASL Consulting Engineers (1988) and Weston Pringle & Associates (1990) for the Arroyo/La ' Costa Master Plan EIR in the City of Carlsbad Olivenhain Road/El Camino Real intersection , analyses (Appendix 8) conducted by the Cities of Carlsbad (JHK & Associates, 1990) and Encinitas (Willdan and Associates, 1991) are also summarized below. * 3.4.1 Existing Conditions 3.4.1.1 Primary Street Segments m 3.4.1.1.1 Olivenhain Road <n» Designated as a six-lane Prime Arterial in both the Encinitas and Carlsbad General Plans, the «* existing Olivenhain Road alignment is divided into a four-lane segment from Rancho Santa Fe Road to the westernmost boundary of the Rancho del Ponderosa subdivision (Carlsbad Tract Nos. ** 8363, 8362, and 8145), and a two-lane unimproved segment from this subdivision boundary to * El Camino Real The north side of this road from the Rancho Santa Fe Road intersection westerly along the frontage of the Santa Fe Ridge subdivision (Carlsbad Tract No. 11018) to the "* eastern boundary of the Rancho del Ponderosa subdivision includes two travel lanes, a bike lane, ** curb/gutter, and sidewalk. The south side of this road segment consists of two travel lanes with an unimproved shoulder. An unimproved median varies in width along this approximate 85-foot "* paved road segment, between Rancho Santa Fe Road and the eastern boundary of Rancho del— Ponderosa subdivision, within a 107-foot wide right-of-way (ROW). "" Continuing west along the frontages of Rancho del Ponderosa subdivision to the north andm Willow Creek/Bridgewater (Encinitas Tract No. 4579-1) subdivision to the south, to the eastern m boundary of the approved Arroyo/La Costa (Carlsbad Tentative Map No. 88-3) subdivision, the Olivenhain Road ROW is a uniform 107-foot width. This road segment consists of two "" eastbound and two westbound lanes separated by a striped median which allows for left-turn m pockets into the adjacent developments. Improved bike lanes, curbs/gutters, and sidewalks also occur along both sides of this road segment Two isolated areas along the south side of this road "* segment have not been improved to these conditions, nor has ROW been dedicated m Westerly of the Rancho del Ponderosa and Willow Creek subdivision boundaries to El Camino W Real, Olivenhain Road transitions to a two-lane road with a pavement width of 35 feet and unimproved shoulders, within a 60-foot wide ROW. Traffic speeds in both directions along Olivenhain Road are 35 miles per hour (mph) for the two-lane road segment, and 45 mph for the four-lane segment m-31 3.4.1.1.2 El Camino Real El Camino Real is a designated Prime Arterial in both the Encinitas and Carlsbad General Plans. Between Garden View Road and Levante Street, this road segment consists of two travel lanes in each direction, a striped median, and berms on both sides. The ROW width for this road segment is 108 feet south of Olivenhain Road and 90 feet to the north. Traffic speeds in both directions along El Camino Real are 50 mph. 3.4.1.13 Rancho Santa Fe Road Rancho Santa Fe Road is designated as a Prime Arterial north of Olivenhain Road, in both the Encinitas and Carlsbad General Plans. South of this intersection, it is designated as a Local Street/Augmented Facility by the City of Encinitas, and Secondary Arterial by the City of Carlsbad. Between Olivenhain Road and Calle Barcelona, this road segment consists of three travel lanes in each direction, a raised median, and improved curb/gutter and sidewalks in some locations along both roadway edges. The ROW width for this road segment varies between 107 and 120 feet Between Olivenhain Road and Avenida La Posta, this road segment consists of two travel lanes and unimproved shoulders, within a 60-foot wide ROW. Posted traffic speeds along this road segment are 35 mph south of Olivenhain Road, and 50 mph to the north. 3.4.1.2 Key Intersections 3.4.1.2.1 Olivenhain Road/El Camino Real This is a signalized "T" intersection with four travel lanes and a striped median along El Camino Real. The northbound El Camino Real approach to this intersection contains two through lanes and one right-turn lane. The southbound approach contains two through lanes and one left-turn lane. Olivenhain Road approaches this intersection from the east as an unimproved roadway skewed approximately 32 degrees parallel with Encinitas Creek, which crosses under El Camino Real directly to the south. This westbound approach contains one right-turn lane and one left- turn lane. 3.4.1.2.2 Olivenhain Road/Rancho Santa Fe Road Olivenhain Road approaches this signalized four-way intersection as a four-lane road with variable width median. The eastbound approach contains two through lanes and one left-turn pocket Rancho Santa Fe Road continues northeast as a six-lane Prime Arterial, and to the south as an unimproved, two-lane road. Northbound Rancho Santa Fe Road contains one through/left- turn lane and a free right-turn lane, and the southbound approach contains two through lanes onto Olivenhain Road, one left-turn lane, and one right-turn pocket Camino Alvaro enters this intersection from the northwest as a two-lane, 40-foot wide Collector Street with improved median, curb/gutters, and sidewalks on both sides, within a 60-foot wide ROW. Its southbound approach contains one through/left-turn/right-turn lane. m-32 An intersection bypass road extends from eastbound Olivenhain Road, along the southern edge of the triangular-shaped Olivenhain Municipal Water District (OMWD) parcel, for a distance of approximately 1,000 feet This two-lane bypass allows left turns onto southbound Rancho Santa Fe Road south of its intersection with Olivenhain Road, although left turns are also allowed at this intersection. 3.4.13 Daily Traffic Volumes Existing traffic volumes for Olivenhain Road are estimated at 20,599 vehicles per day, based on 24-hour counts performed by JHK & Associates in July, 1990. Existing traffic volumes for El Camino Real south of Olivenhain Road are estimated at 33,222 average daily trips (ADT), based on 24-hour counts performed by the City of Encinitas in November, 1989 (Villegas, 1991). Existing traffic volumes for El Camino Real north of Olivenhain Road are estimated at 18,249 ADT, based on 24-hour counts performed by JHK & Associates in July, 1990 (Attachment A of Appendix 9). Existing traffic volumes for Rancho Santa Fe Road, south of Olivenhain Road are estimated at 10,500 ADT, based on 24-hour counts performed by the City of Encinitas in 1988 (Guarnes, 1991). Existing traffic volumes for Rancho Santa Fe Road between Olivenhain Road and Calle Barcelona are estimated at 18,900 ADT, based on 24-hour counts performed by the City of Carlsbad on March 4,1990 (Gale, 1991). 3.4.13.1 Street Segment Operations Roadway capacity is a term used to describe the number of vehicles that can be reasonably accommodated on a facility of a certain classification (e.g., six-lane Prime Arterial, four-lane Major Arterial, etc.). Roadway capacity values for various road classifications have been empirically derived and are widely publicized in transportation literature. This general method of analysis uses the ratio of two-way ADT to roadway capacity, resulting in a volume-to-capacity (V/C) ratio for each road. This value is largely dependent on the number of cross streets and side streets, and their relative traffic volumes. For example, the design capacity of a six-lane Prime Arterial is 51,200 ADT according to City of Encinitas standards. If the roadway segment carries 40,000 ADT, the V/C ratio would be 0.78. Values greater than 1.00 indicate that traffic volumes exceed street segment capacities. The V/C ratio is associated with the level of service (LOS) provided to motorists. LOS is the measure of a roadway's ability to handle traffic loads. The LOS is expressed by an alpha designation, with LOS F (unstable traffic flows) assigned a numeric value of 1.00 and LOS A (stable traffic flows) assigned a "zero" value. According to both the Encinitas General Plan and Carlsbad Growth Management Plan criteria, any roadway which carries traffic volumes in excess of LOS D exceeds the capacity standard defined as being acceptable within each City's respective circulation system. Please refer to Tables 3.4-1 to 3.4-4 .for representative ADT capacities and LOS assignments for various roadway classifications within the project vicinity, as identified by the General Plan Circulation Elements of the cities of Encinitas and Carlsbad. m-33 TABLE 3.4-1 PRIMARY ROADWAYS AND KEY INTERSECTIONS IN THE PROJECT VICINITY Primary Roadways 1-5 La Costa Avenue: From 1-5 to El Camino Real From El Camino Real to Rancho Santa Fe Road El Camino Real Rancho Santa Fe Road Olivenhain Road Calle Barcelona1 Leucadia Boulevard1 Classification Interstate Freeway Major Arterial Secondary Arterial Prime Arterial Prime Arterial Prime Arterial Secondary Arterial Major Arterial Kev Intersections; La Costa Avenue and El Camino Real El Camino Real and Levante Street El Camino Real and Calle Barcelona . El Camino Real and Olivenhain Road Rancho Santa Fe Road and Calle Barcelona Rancho Santa Fe Road and Olivenhain Road/Camino Alvaro Olivenhain Road and Los Pinos Drive Olivenhain Road and Amargosa Drive Source: City of Carlsbad Circulation Element 1 These are planned facilities only partially constructed, and not presently open to through traffic. m-34 TABLE 3.4-2 ROADWAY DEFINITIONS BY CLASSIFICATION LOCAL STREETS: Provide vehicular, pedestrian, and bicycle access to property abutting the public right-of-way and enable such traffic to be distributed to collector and arterial streets. COLLECTOR STREETS: Serve as the connecting link for traffic between local streets and secondary and major arterials. SECONDARY ARTERIALS: Carry traffic from collector streets to and from larger arterials or freeways. MAJOR ARTERIALS: Provide for the movement of traffic within and through the City. Major arterials have two moving lanes in each direction and a median divider. Driveway access from private property is prohibited. PRIME ARTERIALS: Carry large volumes of traffic within and through the City. Prime arterials have three moving lanes of traffic in each direction and a median divider. Driveway access is prohibited. Source: City of Carlsbad Standard Design Criteria, 1987. ffl-35 TABLE 3.4-3 STANDARDS FOR ROADWAY LEVELS OF SERVICE Nominal Range of Volume to Level of Service Capacity Ratio A Low Volumes; primarily free flow operations. Density is low 0.00-0.60 and vehicle can freely maneuver within the traffic stream. Drivers can maintain then* desired speeds with little or no delay. B Stable flow with potential for some restriction of operation speeds 0.61-0.70 due to traffic conditions. Maneuvering is only slightly restricted. The stopped delays are not bothersome and drivers are not subject to appreciable tension. C Stable operations, however the ability to maneuver is more restricted 0.71-0.80 by the increase in traffic volumes. Relatively satisfactory operating speeds prevail but adverse signed coordination or longer queues cause delays. D Approaching unstable traffic flow where small increases in volume 0.81-0.90 could cause substantial delays. Most drivers are restricted in their ability to maneuver and their selection of travel speeds. Comfort and convenience are low but tolerable. E Operations characterized by significant approach delays and 0.91-1.00 average travel speeds of one-half to one-third the free flow speed. How is unstable and potential for stoppages of brief duration. High signal density, extensive queuing, or signal progression/timing are the typical causes of the delays. F Forced flow operations with high approach delays at critical 1.00+ signalized intersections. Speeds are reduced substantially and stoppages may occur for short or long periods of time because of downstream congestion. Source: Highway Capacity Manual. Special Report 209, Transportation Research Board, 1985. m-36 ' * •a TABLE 3.4-4 ROADWAY CAPACITY STANDARDS Facility Type Freeway Prime Arterial Prime Arterial-Augmented Major Roadway Major Roadway-Augmented Collector Roadway Local Roadway Local Roadway-Augmented Number of Lanes 6 8 10 6 6 4 4+ 4 2 2+ ADT Capacity1 LOSC 108,000 145,000 175,000 46,000 53,000 28,200 36,300 26,000 11,200 16,000 LOSD 120,000 160,000 195,000 51,200 60,000 31,600 41,000 29,200 12,600 18,000 LOSE 135,000 175,000 215,000 57,000 66,000 35,200 45,400 32,400 14,000 20,000 Source: City of Encinitas Circulation Element 1 Capacity means the maximum volume for the stated level of service. m-37 According to Table 3.4-5, Olivenhain Road currently operates at an unacceptable level of service (LOS F, V/OL07). It should be noted that Olivenhain Road currently operates at an acceptable LOS based on peak-hour monitoring data. A peak-hour analysis is utilized to more accurately assess the LOS of a given street segment approaching failure. Thus, according to the City of Carlsbad's Mid-Year Growth Management Monitoring Report (A.B. 11425; November 5,1991), Olivenhain Road meets the City's adopted performance standards under existing conditions. An LOS F based on the V/C ratio (General Plan-level) analysis will, nevertheless, be used to evaluate/characterize "Worst Case" traffic impacts for this road segment under existing conditions. The segment of El Camino Real between Garden View Road and Olivenhain Road currently operates at LOS A (V/O0.54). The segment of El Camino Real between Olivenhain Road and Levante Street currently operates at LOS A (V/C-0.24), according to Attachment A of Appendix 9. The segment of Rancho Santa Fe Road between Olivenhain Road and Calle Barcelona also operates at LOS A (V/C=0.26), as does the segment between Olivenhain Road and Avenida La Posta (V/O0.42). 3.4.1.3.2 Key Intersection Operations Roadway capacity is generally limited by the ability to move vehicles through intersections. An intersection V/C ratio is the primary consideration in assessing traffic-related impacts. These impacts are determined using the Intersection Capacity Utilization (ICU) method of analysis. The ICU method results in a numeric value representing the amount of time delay experienced at an intersection based on a given number of traffic lanes. As with street segment operations, ICU values exceeding 1.00 indicates that travel demand exceeds the intersection capacity. ICU values are also correlated with LOS, in that LOS F (arrival of vehicles exceeds intersection capacity, resulting in unacceptable traffic delays) is assigned a numeric value of 1.00 and LOS A (optimal intersection operating conditions with little or no delay to motorists) is assigned a "zero" value. The ICU is usually calculated for both A.M. and P.M. peak hour conditions. According to the both Encinitas General Plan and Carlsbad Growth Management Plan criteria, roadways which carry traffic volumes resulting in an LOS E at any intersection exceeds the capacity standard defined as being acceptable within each City's respective circulation system. Please refer to Attachment B of Appendix 9 and Table 3.4-6 for a detailed explanation of the ICU analysis and description of corresponding LOS assignments. According to Table 3.4-7 the Olivenhain Road/El Camino Real intersection currently operates at LOS C (ICU=0.81) in the A.M. peak hour and LOS D (ICU=0.89) in the P.M. peak hour. The Olivenhain Road/Rancho Santa Fe Road intersection is currently operating at LOS A (ICU=0.59) in the A.M. peak hour and LOS B (ICU=0.69) in the P.M. peak hour (Gale, 1991). Therefore, the two key intersections in the project vicinity meet both the cities of Encinitas and Carlsbad performance standards for acceptable levels of service under existing conditions. m-38 m TABLE 3.4-5 SUMMARY OF EXISTING ROADWAY LEVELS OF SERVICE WITHIN THE PROJECT VICINITY Road Segments 1-5: La Costa Avenue: I-S to El Camino Real El Camino Real to Rancho Santa Fe Road El Camino Real: South of La Costa Avenue North of Olivenhain Road South of Olivenhain Road Rancho Santa Fe Road: North of Olivenhain Road South of Olivenhain Road Olivenhain Road: East of El Camino Real Calle Barcelona: Non-Existent Leucadia Boulevard: Non-Existent Volume to Capacity Ratio (VIC) Not tested 1.07 Level of Service (LOS) 1.02 0.83 0.58 0.52 0.54 0.26 0.42 F1 D A A A A A 1 According to the City of Carlsbad's Mid-Year Growth Management Monitoring Report (A.B. 11425; November 5,1991), however, this road segment currently operates at an acceptable LOS based on a peak-hour analysis. Source: City of Carlsbad Circulation Element m-39 TABLE 3.4-6 INTERSECTION CAPACITY GUIDELINES FOR FUNCTIONAL DESIGN 24-HOUR SERVICE VOLUME (LEVEL OF SERVICE D), VEHICLES PER DAY (V/D)1 FOR FACILITY UNDER CONSIDERATION Faculty * Under Consideration 4-lane Arterial 6-lane Arterial 8-lane Arterial One-way 4-lane One-way 5-lane One-way 6-lane Intersecting Streets Two-way/Two-way Two-way/One-way One-way/One-way Grade Separation 80,000 (1.0? 90,000 (1.0) 120,000 (1.0) 85.0004 (1.0) 81.0004 (1.0) 97.0004 (1.0) Local (Stop) 54.000 (.90) 81.000 (.90) 103,000 (.90) 82,000 (.95) 77,000 (.95) 92,000 (.95) Minor Major Collector 4-bne 4-lane (Signal) (Signal) (Signal) 45.000 (.75) 68.000 (.75) 90.000 (.75) 40,000 (.75) 63.000 (.75) 92,000 (.75) Total Number of Intersecting Through Lanes 8 to 10 12to 14 16 8 11 to 10 to 14 40,000 (.70) 63.000 (.70) 90.000 (.75) 46.000 (.70) 57.000 (.70) 68.000 (.70) Sum of G/C1 .90 .80 .70 .95 .90 21.000 (.45) 50.000 (.65) 60.000 (35) 33,000 (30) 41.000 (30) 49,000 (30) 0 to 12 1.00 1 V/D = 1,930 vehicles per lane per hour of green; V/D (one-way) = 1,620 vehicles per lane per hour 2 All arterials are assumed to have at least one left turn lane at intersections, plus other exclusive turn ' Figure in parenthesis is green/cycle (G/C) ratio assumed. 4 Also equilibrated to expressway operation of 4, 5, or 8 lanes in one direction of flow. 1 1 1 I 1 » 1 f 1 * 1 1 I * 1 ra-40 i i i i r 6-lane (Signal) 21.000 (35) 38.000 (.40) 54,000 (.45) 27,000 (.40) 28,000 (35) 34,000 (35) One-way 8-lane 4-bute (Signal) (Signal) 15,000 (.25) 32,000 (35) 42,000 (35) 20,000 (30) 24.000 (30) 29,000 (30) of green, lanes as necessary. The lanes I I I f 1 P 27,000 MS) 50,000 (.65) 72.000 (.80) 33,000 (30) 40,000 (30) 63,000 (35) indicated are 1 f One-way One-way 5-lane 6-lane (Signal) (Signal) 27,000 (.45) 50.000 (.60) 72.000 (.60) 33,080 (30) 41.000 (.50) 49.000 (30) through lanes. 1 1 1 27,000 (45) 50,000 (.60) 72,000 (.60) 28,000 (30) 41,000 (30) 49,000 (30) f 9 * 1 TABLE 3.4-7 SUMMARY OF EXISTING INTERSECTION LEVELS OF SERVICE WITHIN THE PROJECT VICINITY Intersections Intersection Capacity Utilization (ICU) A.M. Peak Hour (LOS) PM. Peak Hour (LOS) El Camino Real and La Costa Avenue1 0.61 El Camino Real and Olivenhain Road1 0.81 El Camino Real and Garden View Road1 0.77 La Costa Avenue and El Camino Real2 0.84(D) El Camino Real and Levante Street2 0.43(A) El Camino Real and Calle Barcelona2 Non-Exist El Camino Real and Olivenhain Road2 0.72(C) Rancho Santa Fe Road and Calle Barcelona2 0.35(A) Rancho Santa Fe Road and Olivenhain O.S3(A) Road/Camino Alvaro2 Olivenhain Road and Los Finos Drive2 0.60(A) Olivenhain Road and Amargosa Drive2 0.64(B) 0.75 0.89 0.77 0.80(C) 0.54(A) Non-Exist 0.80(D) 0.38(A) 0.62(B) 0.70(B) 0.70(B) Note: These are standard condition calculations. Actual intersection capacity ratios may be affected by special conditions and circumstances (e.g., adjacent intersections being located very close to one another). 1 Source: City of Encinitas Circulation Element 2 Source: City of Carlsbad Circulation Element m-41 3.4.2 Future/Build-Out Conditions 3.4.2.1 Primary Street Segments 3.4.2.1.1 Olivenhain Road The Circulation Element of the City of Encinitas General Plan forecasts build-out (Year 2010) traffic volumes on Olivenhain Road between El Camino Real and Rancho Santa Fe Road to be 48,000 ADT. The Carlsbad and County of San Diego General Plan Circulation Elements forecast build-out traffic volumes of 39,000 ADT and 22,000 ADT, respectively, for this road segment The SANDAG Mid-County Transportation Model forecasts build-out traffic volumes long this road segment to be 39,500 ADT (Attachment Bl of Appendix 8). This model assumes build-out of all adopted land uses and circulation networks west of Interstate 5, south of State Route 78, and north of State Route 56. The model also assumes the North City Sphere Study Concept #4 for the future urban area (in the Qty of San Diego) and a region-wide 40% "drive alone" rate for home-to-work trips. Although the SANDAG forecast is more recent, the Encinitas General Plan figure is used herein as a "Worst Case" analysis. Therefore, based on a "Worst Case" ADT of 48,000, this road segment would operate at LOS D with proposed roadway improvements in place (see Table 3.4-4). It should be noted that an LOS C would be achieved for this improved road segment using the Carlsbad General Plan build-out traffic forecasts. Thus, for either scenario, the improved Olivenhain Road would operate at an acceptable LOS under build-out conditions, in conformance with both the cities of Encinitas General Plan and Carlsbad Growth Management Plan performance standards. 3.4.2.1.2 El Camino Real The Circulation Element of the Gty of Encinitas General Plan forecasts build-out traffic volumes on El Camino Real south of Olivenhain Road to be 55,000 ADT. The Carlsbad and County of San Diego General Plan Circulation Elements forecast build-out traffic volumes of 54,000 ADT and 40,000 ADT, respectively, for this road segment The SANDAG Mid-County Transportation Model forecasts build-out traffic volumes along this road segment to be 53,100 ADT (Attachment Bl of Appendix 8). Although the SANDAG forecast is more recent the Encinitas General Plan figure is used herein as a "Worst Case" analysis. Therefore, based on a "Worst Case" ADT of 55,000, this road segment would operate at LOS E with proposed roadway improvements in place (see Table 3.4-4). It should be noted that this segment of El Camino Real south of Olivenhain Road is within both the County of San Diego and City of Encinitas, and therefore has no relationship to the Gty of Carlsbad's Growth Management Plan. 3.4.2.13 Rancho Santa Fe Road The Circulation Element of the City of Encinitas General Plan forecasts build-out traffic volumes on Rancho Santa Fe Road to be 22,000 ADT south of Olivenhain Road, and 46,000 ADT to the north. The Carlsbad General Plan Circulation Element forecasts build-out traffic volumes for this m-42 road segment of 25,100 ADT to the south, and 24,900 ADT to the north of the Olivenhain Road intersection (Gale, 1991). Based on the Encinitas General Plan, LOS F would be experienced along Rancho Santa Fe Road south of Olivenhain Road (see Table 3.4-4). Based on the Carlsbad General Plan build-out traffic forecasts, however, LOS C would be experienced to the north; thereby, meeting Growth Management Plan performance standards. 3.4.2.1.4 Leucadia Boulevard The City of Encinitas General Plan Circulation Element designates the continuation of Olivenhain Road west of the El Camino Real intersection as the future Leucadia Boulevard extension, an ultimate four-lane Major Arterial "Scenic Roadway" within an 85-foot ROW traversing the County of San Diego's "Ecke Agricultural Preserve" to connect with 1-5 to the west The County's General Plan Circulation Element calls for Olivenhain Road to continue west of El Camino Real as a Major Road through the "Ecke Sphere" to tie into Leucadia Boulevard. This future alignment would be within the City of Encinitas sphere of influence. The General Plan lists specific goals and policies related to this future "Scenic Roadway". For example, Policies 5.1 and 5.2 call for the adoption of a Specific Plan by the City of Encinitas for the unincorporated sphere area through which this road would pass, and annexation of this area to the City. Policy 5.3 also lists several general design and improvement standards to be developed and adopted for this road, subject to review and approval by a Leucadia Boulevard Task Force. One of these standards states that the "connection of Leucadia Boulevard to Olivenhain Road shall bridge over Encinitas Creek rather than use pipes or culverts to minimize impacts to the drainage area." The Circulation Element of the City of Encinitas General Plan forecasts build-out traffic volumes on future Leucadia Boulevard extension just west of El Camino Real to be 31,000 ADT. The County of San Diego General Plan Circulation Element forecasts build-out traffic volumes of 28,000 ADT for this road segment The SANDAG Mid-County Transportation Model forecasts build-out traffic volumes along this road segment to be 27,600 ADT (Attachment Bl of Appendix 8). Although the SANDAG forecast is more recent the Encinitas General Plan figure is used herein as a "Worst Case" analysis. Therefore, based on a "Worst Case" ADT of 31,000, this road segment would operate at an LOS D with proposed roadway improvements in place (see Table 3.4-4). 3.43.2 Key Intersections 3.43.2.1 Olivenhain Road/El Camino Real Based on an ICU analysis conducted by Austin-Pouts Associates, Inc. (1988) for the City of Encinitas General Plan traffic study, the Olivenhain Road/El Camino Real intersection would operate at LOS D in the A.M. (ICU=0.81) and P.M. (ICU=0.89) peak hours at build-out (post- Year 2010) traffic conditions (Attachment B6 of Appendix 8). This would be considered an acceptable level of service which would not warrant additional intersection improvements. The m-43 County of San Diego Department of Planning and Land Use (DPLU), however, expressed concerns in a comment letter (February, 1991) received during the Notice of Preparation (NOP) review period for the project, that future traffic volumes at this intersection may exceed the capacity of an at-grade intersection, thereby requiring a grade separation. Then: concerns were based on SANDAG's Mid-County Transportation Model forecast traffic volumes of 86,500 ADT, with 8,650 peak-hour trips, at this intersection. Grade separations are warranted when an intersection reaches LOS F, and no other measures are feasible. This is stated in A Policy on Geometric Design of Highways and Streets (AASHTO, 1990) and Caltrans' Highway Design Manual (1987), excerpts of which are included in Attachments C-D of Appendix 9. In response to DPLU's concerns, peak-hour turning movements and ICU calculations were conducted at this intersection for build-out conditions by the cities of Carlsbad (Attachment A of Appendix 8) and Encinitas (Attachment B of Appendix 8). The City of Carlsbad ICU analysis assumed three through lanes in each direction along Olivenhain Road, and used saturation flow rates of 2,000 vehicles per hour for through lanes and 1,800 vehicles per hour for turn lanes. Based on these assumptions, the City of Carlsbad projected a build-out LOS D during both the A.M. (ICU=0.84) and P.M. (ICU=0.87) peak hours; thereby, meeting Growth Management Plan performance standards for this intersection. The City of Encinitas ICU analysis relied on turning movement counts obtained from the SANDAG Mid-County Transportation Model. This analysis assumed saturation flow rates of 1,700 vehicles per hour for through lanes and 1,500 vehicles per hour for turn lanes. A 0.10 clearance was also added to account for vehicular flow rates through yellow lights. The lane assumptions used to calculate build-out LOS at this intersection were as follows: 1. Northbound El Camino Real = two left-, two through, and one through/right-turn lanes. 2. Southbound El Camino Real = two left-, two through, and one through/right-turn lanes. 3. Eastbound future Leucadia Boulevard = two left-, one through, and one through/right-turn lanes. 4. Westbound Olivenhain Road = two left-, two through, and one right-turn lanes. Based on these assumptions, the City of Encinitas projected a build-out LOS D during both the A.M. (ICU=0.89) and PJM. (ICU=0.88) peak hours at this intersection (Attachment B2 of Appendix 8). This is consistent with LOS calculations performed by Austin-Foust Associates (Attachment B6 of Appendix 8) for post-Year 2010 conditions with the City's adopted Circulation Element m-44 3.43.2.2 Olivenhain Road/Rancho Santa Fe Road Based on an ICU analysis conducted by JHK & Associates (1990), the Olivenhain Road/Rancho Santa Fe intersection would operate at LOS C in the A.M. (ICU=0.72) and P.M. (ICU=0.77) peak hours at build-out (Year 2010) traffic conditions (Gale, 1991). This would be considered an acceptable level of service which would not warrant additional intersection improvements; thereby, conforming to both the cities of Encinitas General Plan and Carlsbad Growth Management Plan performance standards. 3.4.4 Impacts 3.4.4.1 Primary Street Segments and Key Intersections The proposed Olivenhain Road Alignment #2 would improve existing traffic congestion and poor levels of service (i.e., LOS F) currently experienced along this roadway segment to acceptable levels of service. The proposed improvements would also maintain existing, acceptable levels of service for El Camino Real north and south of Olivenhain Road; Rancho Santa Fe Road north and south of Olivenhain Road; the Olivenhain Road/El Camino Real intersection; and the Olivenhain Road/Rancho Santa Fe Road intersection. The proposed project would result in acceptable levels of service at all of the above-mentioned street segments and key intersections under build-out (Year 2010) traffic conditions, except for the portions of El Camino Real (LOS E) and Rancho Santa Fe Road (LOS F) both south of Olivenhain Road. As previously noted, these road segments would operate at acceptable LOS under build-out conditions as designated by the City of Carlsbad General Plan Circulation Element Therefore, they have no relationship to non-attainment of Carlsbad's Growth Management Plan criteria. The proposed Alignment #2 would maintain a through route consistent with the County of San Diego's Route Location Study for the future extension of Leucadia Boulevard, between El Camino Real and the current eastern terminus of Leucadia Boulevard. Any improvements at the Olivenhain Road/El Camino Real intersection required for the proposed project would be coordinated with the County of San Diego Traffic Engineering Department Construction of a bridge over Encinitas Creek, as stated under Policy 5.3 of the City of Encinitas General Plan Circulation Element, would require raising the Olivenhain Road/El Camino Real intersection, as well as a portion of El Camino Real north and south of this intersection. Please refer to Section 6.0 of this EIR for a complete discussion of this alternative roadway design. Because biological impacts to sensitive wetland habitats and species within this drainage area have been minimized by the proposed design, a bridge is no longer required at this location. 3.4.4.2 Traffic Detouring Some temporary traffic delays may be experienced along Olivenhain Road and its intersections with El Camino Real and Rancho Santa Fe Road during the construction period for the proposed project In addition, the City of Carlsbad Planning Department expressed concern in a comment m-45 letter (Februaiy 4, 1991) received during the NOP review period regarding potential impacts to access points into and out of the existing OMWD facilities southwest of the Olivenhain Road/Rancho Santa Fe Road intersection during proposed road construction. The City also expressed concern over future access to the approved Arroyo/La Costa (CT 88-3) tentative map development to the north of the proposed realignment Finally, the City Planning Department is concerned that proposed road construction may result in traffic safety impacts to pedestrians and bicyclists that use Olivenhain Road. With implementation of a Traffic Control/Detour Plan, as delineated in Section 3.4.5 below, the temporary traffic delays caused by detouring during proposed road construction would not have a significant impact to existing traffic/circulation patterns within the project area. In addition, with implementation of these measures, proposed roadway improvements are not expected to block existing access points along the construction route, particularly access into and out of the existing OMWD facilities. With respect to maintenance of future access to the planned Arroyo/La Costa development, necessary intersection improvements shall be installed at this future access road intersection with Olivenhain Road, in accordance with the conditions of approval for CT 88-3, to ensure a safe and adequate operational level of service. Finally, the potential impacts to pedestrians and bicyclists along Olivenhain Road during construction of proposed improvements would not be considered significant as long as appropriate measures are included in the Traffic Control/Detour Plan (see Section 3.4.5.4. below) to ensure their safety. 3.4.5 Mitigation 3.4.5.1. The following roadway improvements are listed either as a condition of approval for the Arroyo/La Costa (CT 88-3) tentative map (City of Carlsbad, 1990), or as a recommended mitigation measure in the certified FJR (City of Carlsbad, 1990) for that project, in order to mitigate projected deficiencies in levels of service along El Camino Real: 3.4.5.1.1. El Camino Real shall be improved to a half street width of 63 feet from Olivenhain Road to Levante Street, including full width landscaped median. The developer/owner may be eligible for partial reimbursement from the adjacent property owners on the west half width of the median. A reimbursement agreement must be approved by the City of Carlsbad prior to approval of the final map for this phase. 3.4.5.1.2. Upon construction of the future Leucadia Boulevard extension (between El Camino Real and the existing eastern terminus of Leucadia Boulevard), El Camino Real from Olivenhain Road to Calle Barcelona shall be widened to six lanes. Neither the proponents of the Arroyo/La Costa project nor property owners within the City of Carlsbad Local Facilities Management Plan (LFMP) Zones 11 and 12 are responsible for funding the construction of this future roadway extension. If this road extension is not constructed by the Year 2000, however, the segment of El Camino Real identified above shall be widened by the Year 2010 (build-out). ra-46 3.4.5.2. The following is intended as a future action to be carried out by the City of Encinitas, according to the General Plan Circulation Element, in order to mitigate projected deficiencies in levels of service for Rancho Santa Fe Road south of Olivenhain Road: To improve traffic flow and reduce side friction, Rancho Santa Fe Road from Olivenhain Road to Avenida La Posta shall be augmented by either 1) signalizing the Avenida La Posta intersection; 2) adding additional lanes at the Olivenhain Road intersection; and/or 3) adding a central median along this road segment to allow turning movements, thereby restricting access to the extent possible. Augmentation of this Local Street segment shall occur prior to build-out Year 2010, but not as part of this proposed project As such, neither the proponent of the Arroyo/La Costa project nor property owners within the City of Carlsbad LFMP Zones 1 1 and 12 are responsible for funding these future roadway improvements. 3.4.53. The Contractor shall submit for approval a Traffic Control/Detour Plan prepared by a Registered Traffic Engineer, as directed by the Senior Traffic Engineers of the Cities of Encinitas and Carlsbad, which shall conform to the following provisions: 3.4.5.3.1. Closure of Olivenhain Road to through traffic shall not be permitted during its proposed construction and widening, unless other detour operations are identified which would be acceptable to the Gty Engineers of both Encinitas and Carlsbad. For example, traffic during the construction period could be temporarily re-routed to calle Barcelona if this planned roadway were constructed prior to proposed widening/realignment of Olivenhain Road. 3.4.5.3.2. One lane shall be available in each direction for use by public traffic. Prior to commencement of road construction, the City shall re-stripe Olivenhain Road to provide a of one, 15-foot wide traffic lane in each direction. Any lane closures shall conform to provisions of the standard specifications. The lane or lanes to be closed shall be approved by the City Engineer. The use of reflective traffic delineators to direct traffic away from excavations shall be considered as a lane closure. 3.4.53.3. In conjunction with re-striping, the existing traffic signal at die Olivenhain Road/El Camino Real intersection shall be switched to the flashing red mode during construction equipment operation. 3.4.53.4. The Contractor shall maintain a 50-foot minimum working area/construction zone along the southerly edge of the proposed Alignment #2. This construction easement shall provide for a width of IS feet beyond the area required for grading along the northerly edge of the proposed alignment (see Figure 3.4-1). 3.4.53.5. Standard construction barricades equipped with flashing lights shall be placed in the southern easement area at 25-foot minimum spacing adjacent to excavations. Every eighth barricade shall be equipped with standard signage. Sheeting for these signs shall be high-density (encapsulated lens). Barricade lights shall be required to burn only during hours of darkness. m-47 3.4.5.3.6. In any excavated section at which the Contractor is unable to maintain the afore- mentioned work areas, the excavation shall be protected by standard railing at the close of the working day. The south edge of the railing shall be a minimum of 12 feet from the centerline striping. Each end of the railing shall be flared away from the adjacent travel lanes at approximately 20 degrees. All railing shall be equipped with two-way clear reflectors at a minimum 24-foot spacing. 3.4.5.3.7. The Contractor shall maintain access to Amargosa Drive, Los Pinos Circle, and all private driveways on both sides of Olivenhain Road. 3.4.5.3.8. At the start of the construction period, the Contractor shall install signage per standard specifications and as shown on the Detour Plan. All signs shall be mounted on 4-inch by 4-inch wooden posts at standard height, and shall be constructed of high-intensity (encapsulated lens) sheeting. 3.4.5.3.9. The Contractor shall also abate dust nuisance by cleaning or sweeping, and sprinkling with water or other means as necessary. The use of water resulting in mud on public streets shall not be permitted as a substitute for cleaning, sweeping, or other methods. 3.4.5.4. In response to comments received from the County of San Diego, Department of Public Works, during the Public Review Period for this project, the following mitigation measures shall be included as conditions of project approval, to be implemented during project construction and shown on final roadway improvement plans: 3.4.5.4.1. Construct the Olivenhain Road/El Camino Real intersection at right angles. 3.4.5.4.2. Determine appropriate ROW widths and distances required for relinquishment of access rights in order to implement the proposed project. 3.4.5.4.3. Provide adequate sight distance. 3.4.5.3.4. Provide an alignment for Olivenhain Road (i.e., the proposed Alignment #2) such that it would be compatible with the future alignment of the planned Leucadia Boulevard extension west of El Camino Real. 3.4.5.4.5. Provide the appropriate number of left-turn lanes to allow left-turning movements from El Camino Real to Olivenhain Road, and vice versa. m-48 3.5 GENERAL PLAN COMPATIBILITY The proposed project boundaries fall within three different jurisdictions: City of Encinitas, City of Carlsbad, and County of San Diego. The relevant portions of the General Plan Circulation Elements for each jurisdiction is described under Section 3.5.1 below. Section 3.5.2 analyses the proposed project's conformance with these various Plans. 3.5.1 Existing Conditions 3.5.1.1 City of Encinitas The City of Encinitas lies just south of Olivenhain Road. Property lying within the City of Encinitas and adjacent to Olivenhain Road includes land that is designated as residential (5.01- 8.00 units/acre), and land that is designated as an ecological resource. The City of Encinitas Circulation Element designates Olivenhain Road as a six-lane Prime Arterial, divided into three travel lanes in each direction by a median (Figure 3.5-1). Direct driveway access to and from this roadway is restricted. The desirable goal for every classified street section is that it carry the designed volume of traffic at the desired level of service. The improved Olivenhain Road would connect with the future Leucadia Boulevard extension, which is planned west of El Camino Real to link with the existing segment of Leucadia Boulevard near Interstate 5 (1-5). This linkage provides an important component to facilitate east-west traffic flow from several North County inland communities, such as Olivenhain and San Marcos, to north and south business destinations via 1-5. The City of Encinitas also mandates full design and improvement plans for the entire length of Leucadia Boulevard (existing and planned road segments) between 1-5 and Olivenhain Road. This road shall be a "Scenic Roadway" completed and adopted by the City, subject to the following Circulation Element guidelines: The City shall form the Leucadia Boulevard Task Force to be composed of residents of Leucadia. The Task Force will participate with City staff in developing design standards for Leucadia Boulevard east of 1-5. Comments by residents of New Encinitas will be considered in the design of the northeast link of Leucadia Boulevard. Design may include full landscape/street-scape design, bicycle and pedestrian facilities, recreational trails, and intersection improvements where desired. Where facilities cannot be accommodated within the right-of-way, additional easements may be required. The design of the Leucadia Boulevard extension may include broad landscaped medians and/or parkways which may be integrated with pedestrian facilities. Buffers such as earth berms, vegetation, broad parkways and other landscape features may be provided to protect adjacent land uses from undesirable effects of traffic, noise, pollution, and light along Leucadia Boulevard. The extension of Leucadia Boulevard across the bluff facing Green Valley shall be aligned and developed so as to minimize grading impacts to the bluff along Green Valley. m-49 E 0 D I I e r B i ri u U L 0 N Project Site Major ro n Pljin MitK it*•" " —P °™ ™ *. *=M«J * t w \»QUF^ ItT«?fI5 B«n?ho Santa F« *««n v >v. •PJTM July 13—J99O 61 M43B»». «Ifectlve N £*r ; Planning DeptI for «tatua" 200' 400' bricin F mooncvi— __ - O f^^ 3» planning, design & environmental studies Freeway Prime Arterial C6 LanesD Major (4 Lanes) mini Augmented Facility Collector (4 Lanes] Local Street (2 Lanes] Limited Facility Interchange Reconstruction NOTE: Leucadia Blvd. between Interstate 5 and El Camino Real designated as 'Scenic Roadway' with 85 foot right-of-way CROW] Olivenhain Road Alignment City of Encinitas Circulation Plan Source: City of Encinitas General Plan Figure 3.5-1 Wildlife corridors across the alignment of Leucadia Boulevard at the Green Valley bluff and elsewhere as warranted shall be provided to facilitate wildlife passage and provide continuous areas of habitat The connection of Leucadia Boulevard to Olivenhain Road shall bridge over Encinitas Creek rather than use pipes or culverts to minimize impacts to the drainage area. With street design, detailed noise impact analysis shall be provided to identify where 4 noise walls or other attenuation measures may be required. Such analysis shall assume ultimate "build-out" traffic volumes. The installation of noise walls/other measures shall be provided prior to or in conjunction with street improvementi .„ Where it is necessary or desirable to construct retaining or noise-attenuation walls along the Leucadia Boulevard corridor, they shall be constructed with natural-looking materials "* and generously landscaped with vines, trees, and shrubbery, reflecting local community «, character. The design and improvement of Leucadia Boulevard may be considered as a two lane •m highway and Stage n providing additional lanes and improvements as needed to M accommodate ultimate projected traffic. *m A maximum of four through-travel lanes shall be designed and improved. The additional m right-of-way for physical or visual mitigation shall not be used for through-lanes. *• A high priority shall be given to implement these standards in areas where 126 feet of m right-of-way presently exists. "~ No truck routes shall be permitted along Leucadia Boulevard from 1-5 to Sidonia Street ton The City will consider purchasing any land within the right-of-way when it is offered for """ sale along Leucadia Boulevard from 1-5 to Sidonia Street *BP 3.5.U Citv of Carlsbad *M *» The City of Carlsbad lies just north of Olivenhain Road. Property lying within the City of Carlsbad and adjacent to Olivenhain Road includes land that is designated low-medium "" residential (0-4 dwelling units/acre), and land that is designated for public utilities. The City of *" Carlsbad Circulation Element designates Olivenhain Road as a six-lane Prime Arterial (Figure 3.5-2). A Prime Arterial is designed to carry large volumes of traffic within and through the city. "" Prime Arterials have three moving lanes of traffic in each direction and a median divider. Direct m driveway access is prohibited on a Prime Arterial. The estimated number of average daily trips m on a Prime Arterial is 40,000 or more. The Circulation Element of the City of Carlsbad mandates the design of streets in such a way that the number of intersections and other m conflicting traffic movements are minimized. The City of Carlsbad supports the maintenance of m, the future Leucadia Boulevard extension eastward to El Camino Real. m-si 8UENA VISTA LAGOON AGUA HEOIONOA LAGOON PACIFIC OCEAN , CAftLSSAD CITY LIMITS AVCNIOA CNCINAS MAKCOS BATIOUIT03 LAGOON CITY OF CARLSBAD CIRCULATION PLAN RAILROAD 1 FREEWAY PRIME ARTERIAL MAJOR ARTERIAL SECONDARY ARTERIAL COLLECTOR STREET No Scale bricin F mooney Ollvenhain Road Alignment City of Carlsbad Circulation Plan Figure 3.5-2 Source: City of Carlsbad General Plan ER 3.5.2.3 County of San Diego The Circulation Element of the County of San Diego General Plan designates Olivenhain Road as a four-lane Major Road (one-half width equals 56 feet), and El Camino Real (SF 1411) as a six-lane Prime Arterial (one-half width equals 68 feet) with bike lanes. Specific design criteria '" for Major Roads include an 18-foot wide median, 24 feet of paved travel lanes, 10 feet of paved , bike lanes, an 8-foot wide shoulder, a 10-foot wide parkway strip, an 82-foot wide roadbed, and 112-foot wide right-of-way (ROW). , The property through which the future Leucadia Boulevard extension would occur is designated as Agricultural Cropland and is pan of what is known as the "Ecke sphere". A portion of the Batiquitos Lagoon Resource Conservation Area extends into the Ecke sphere. The Ecke sphere , remains an important part of the open space and drainage system that feeds into Batiquitos 4 Lagoon. The Ecke sphere has a Specific Planning Area designation over it, allowing a density of 2.8 dwelling units per acre. Agricultural lands not approved for future development hi this ••* area are to be preserved under the appropriate restrictions as a condition of development In the m event that all development cannot be accomodated within the low-lying areas of the Ecke sphere, additional holdings, especially those distinct from the mesa-top agricultural areas, may be «* considered for development provided that it be clustered, that it provide a logical and viable m neighborhood, and that it contribute to the establishment of a stable limit to urban development. ** 3.5.2 Impacts m The proposed Alignment #2 would follow a more northerly route from the existing alignment to *"* an intersection with El Camino Real. This proposed alignment meets all of the design criteria «• for a Prime Arterial, as established by the City of Encinitas, except that the existing road segment to be re-striped (107-foot wide ROW) will not conform to the ultimate 120-130 foot wide ROW **" requirement In addition, the proposed project does not meet all of the City of Carlsbad's design *- criteria for a Prime Arterial route. Centerline radii would be 1,600 feet and not the 2,400 feet as per standard. The centerline intersection of Olivenhain Road with El Camino Real would be skewed approximately 3 degrees, rather than perpendicular. Design speed for this alignment "" would be 50 miles per hour, instead of 60 as per standard. The Circulation Elements for the ^ cities of Encinitas and Carlsbad, however, state that variation in design is expected and that the descriptions of width and facilities are offered as non-exclusive alternatives. A comparison of the roadway design guidelines for each jurisdiction is included as Figure 3.5-3. These diagrams are presented as guides to what is reasonable, or desirable, not as inflexible rules. It is therefore determined that the minor inconsistencies between the proposed project and the relevant General Plan design standards for this roadway would not represent a significant deviation from the ultimate configuration required to improve traffic flow and safety through this area. 3.53 Mitigation * Because the proposed project is determined to be in substantial conformance with the roadway design guidelines mandated by the relevant General Plan Circulation Elements, no mitigation measures are required. m-53 ' R/W >0' Id IZ1 ,2.' .2.' Prime ArterialCity of Encinitas 17.' .2' N brian F moonay B. design A tnvlronm«nt»l studtes Pr/me Arterial City of Carlsbad 102.' e/W Major Road County of San Diego Olivenhain Road Alignment Comparison of Street Design Guidelines Figure 3.5-3 Source: Project Design Consultants BR 3.6 TRAFFIC NOISE The following section is based on a noise study conducted by James Kurtz of Brian F. Mooney Associates (BFMA) and summarizes an acoustical analysis prepared for the Olivenhain Road project route, of which the complete technical report is provided as Appendix 10 of this EIR. 3.6.1 Existing Conditions The principal noise source for most of the project area is Olivenhain Road traffic. At the western end of this road, the traffic noise from El Camino Real is an additional major source. There are no other significant noise sources in the project area. Existing traffic volumes on Olivenhain Road are estimated at 20,599 vehicles per day (JHK & Associates, 1990). Traffic speed was estimated during field visits made in February and March 1991. The speeds in both directions of this road are 35 miles per hour (mph) for the two-lane segment, and 45 mph for the four-lane segment. The traffic mix, estimated from observations and counts in February and April 1991, is 95 percent autos, 3 percent medium trucks, and 2 percent heavy trucks (95/3/2). It was noted that most of the heavy trucks using Olivenhain Road are trash disposal trucks; the road is a principal route to and from a landfill site to the east The trash truck traffic occurs mostly in the morning hours. During the late afternoon hours, there are very few heavy trucks. Existing traffic volumes on El Camino Real south of Olivenhain Road are estimated at 33,222 average daily trips (ADT), based on November 1989 counts performed by the City of Encinitas (Villegas, 1991). Speed is estimated at 50 mph; traffic mix at 93/4/3. Existing traffic noise levels were measured at the specific (point) locations shown on Figure 3.6- 1. The results of these noise measurements are shown on this figure. Except where noted, these values represent the noise level for the outside or ground floor receptor. In the City of Encinitas, and most other jurisdictions, the exterior receptor is calculated at five feet above the ground level. In the City of Carlsbad, the exterior/ground floor receptor is set at a height of six feet, in accordance with Planning Department Administrative Policy No. 17. For source-receptor geometries which include noise barriers, the higher receptor will usually have a higher noise level, and will require a higher barrier to achieve a level equivalent that of the five-foot high receptor. The results of traffic noise level calculations are shown at selected points and as noise contours in Figures 3.6-2 and 3.6-3, and are described as 24-hour average noise levels (L^. This community noise level scale takes into account human sensitivity to noise at night, when ambient noise levels are normally less. A "penalty" of 5 dB is added to noise levels occurring between the hours of 10KX) p.m. and 7:00 a.m. A similar community noise level scale, CNEL (Community Noise Equivalent Level), adds a 3 dB penalty to noise levels occurring between the m-55 \ X // 255-O31-03 -1.95 Acres ) N 0 200' 400' bricin F mooncv studies LEGEND © Point Location * - 7 MARCH 91 [9] Point Location * - 23 APRIL 91 (AM) 12*. Point Location * - 23 APRIL 91 (PM) 52 Noise Level, Decibels, L^ Ollvenhain Road Alignment Measured Existing Noise Levels Figure 3.6-1 EIR i i I i i i I * t li 11 i A> I 4 i i N Map No. Unit iT—-\\\ - '•\ \\ •. ...: '*•••••• AJpr of Rirfarian Habitat 255-024-01 •x 13.65 Acres 100' 2001 LEGEND Olivenhain Road Alignment Calculated Existing Noise Levels -Western Road Segment bricin F mooncv g. dolgn t cnvlrontiMnt*) studta .65-Noise Level Contours, Decibels. Ldn I I i I i i I f i I I i 4 I 1 t t i I i Rancho Del Ponderosa N 200' 40O1 brIan f rnooncv . dMfen tcnvkoniTMntal •tudtet LEGEND • 65— .60 Noise Level Contours. Decibels. Ldn Noise Level Point Locations. Decibels. Ldn Ollvenhaln Road Alignment Calculated Existing Noise Levels -Eastern Road Segment Figure 3.6-3 E1R evening hours of 7:00 p.m. to 10:00 p.m., in addition to a 10 dB nighttime hour adjustment The unit of measure for the measured values in Figure 3.6-1 is L.,, the average noise level for the period of measurement The measured noise levels should not be directly compared with calculated noise levels because the traffic volumes and mixes for the two situations are different, as well as are the units of t measure. The relative differences between noise levels at various point locations, on the other hand, can be compared. This comparison is a means of verifying the model calculations, and is used to confirm and adjust absorption and shielding parameters in the model. i«*»For existing traffic volumes, average noise levels at the edge of the right-of-way (ROW) in the » widened part of Olivenhain Road (eastern road segment) are 72 dB L^. Existing traffic noise M levels in the rear yards of homes on the north side of this road segment range from 56 to 62 dB Lfe. On the south side of this road segment, noise levels in the residential areas range from 55 to 60 dB I,*,. Noise levels at second-story receptors on the north side of this road segment are ,M 3-5 dB higher than ground floor noise levels, and range from 60 to 67 dB L^. Noise levels at the second floor elevations of two-story homes are generally higher due to less noise attenuation ~ by the existing walls. Mf Existing traffic noise levels at 50 feet from the centerline of the two-lane western segment of * Olivenhain Road, without the influence of vehicle noise from El Camino Real, is 70 dB L^. m Existing traffic noise levels at the El Camino Real ROW, south of Olivenhain Road, is 76 db L^. ~ 3.6.1.1 City of Encinitas Noise Guidelines ^ The following policies, which are stated in the Noise Element of the City of Encinitas General "" Plan, are applicable to the assessment of project-related traffic noise impacts:<*• ^ Policy 1.1: If a project would increase the traffic noise level by more than 5 dB and the resulting Lfe would be over 55 dB, then mitigation measures must be evaluated. If the ** project, or action, would increase traffic noise levels by 3 dB or more and the resulting ^ noise would exceed 60 dB in outdoor use areas in residential development, noise mitigation must be similarly evaluated. «. Policy 1.6: Include noise mitigation measures in the design of new roadway projects. Policy 1.7: Apply Title 24 of the California Administrative Code, associated with noise *• insulation standards, to single-family dwellings. «*Policy 2.1: Any project which would be located in a normally unacceptable noise * exposure area, based on the Land Use Compatibility Guidelines, shall require an m acoustical analysis. Noise mitigation in the future shall be incorporated in the project as needed. m-59 The City of Encinitas Noise Ordinance limits the hours of construction to 7:00 a.m. and 7:00 p.m., Monday through Saturday. No construction is allowed on Sundays or holidays. No construction equipment is allowed to be operated that would cause noise levels at a developed residential property to be in excess of 75 dB for more than eight hours. 3.6.1.2 City of Carlsbad Noise Guidelines The Noise Element of the City of Carlsbad General Plan is in the process of being updated and amended. The current governing document is Planning Department Administrative Policy No. 17, which is applicable to proposed new residential projects of five or more dwelling units. The City of Carlsbad has no current policy document relating to the assessment of impact and mitigation measures from projects which increase vehicle noise levels to existing sensitive receptors. 3.6.2 Impacts 3.6.2.1 Traffic Noise The Circulation Element of the City of Encinitas General Plan forecasts future traffic volumes on Olivenhain Road and El Camino Real, south of Olivenhain Road, to be 48,000 ADT and 55,000 ADT, respectively. These values are used for analysis of future traffic noise impacts. The General Plan designates both roads as Prime Arterials, with speeds of 45 mph on Olivenhain Road and 50 mph on El Camino Real. This indicates an increase in traffic speed for only the westerly end of Olivenhain Road. Although both roads would have six lanes, the increase in traffic volumes would result in levels of service D or E, which implies speeds less than the design speed or allowable speed. Traffic mixes along this road segment would are assumed to be the same as that of existing conditions. The western segment of Olivenhain Road would experience increases in both traffic volumes and speed, resulting in vehicle noise increases of about 6 dB at the ROW edge. Increases in traffic volumes along El Camino Real would also increase vehicle noise levels at the ROW edge by 2 dB (Figure 3.6-4). Projected increases in future traffic volumes along the eastern section of Olivenhain Road would increase traffic noise levels along this segment by about 4 dB, or 76 dB L^ (Figure 3.6-5). Within the Willow Creek/Bridgewater subdivision, on the south side of this road segment, noise levels would increase to 58-64 dB L^. Noise levels on the north side of this road segment, within the Rancho del Ponderosa and Santa Fe Ridge subdivisions, would increase to 64-66 dB Lfe. Noise levels at elevated, second-story receptors along this road segment would also increase, ranging from 65 to 70 dB L^ in the Rancho del Ponderosa and Santa Fe Ridge subdivisions. m-60 t i • i II ic I * till it i i i i i 04 J-14 Acres 255-040-06 10.51 Acres 255-024-01^*0 * ia65 Ac brian f mooncv 5 .dMlgn *«nv • *- x Ollvenhaln Road Alignment Future Noise Levels - Western Segment (Proposed Alignment 6 1001 2001 Figure 3.6-4 li i $ ft i i > i i t » t j t f i i i l i i I i i i Rancho Del Ponderosa Map No. 8362 N 200' 400' brian f mponc v B. dMlgn I wwlronnMntal ttudlm Ollvenhaln Road Alignment Future Noise Levels - Eastern Segment Figure 3.6-5 EIR 3.6.2.2 Construction Noise Proposed construction activities associated with road widening and realignment would also generate noise. The principal noise source from construction equipment such as bulldozers, backhoes, graders, trucks and pavers are diesel engines. Compressors or impact tools, such as jackhammers, if used, may also emit significant noise levels. A commonly accepted value for construction site noise is 89 dB L^, measured at 50 feet from the noise source. This noise would decrease at a rate of about 6 dB per doubling of distance. Thus, construction noise levels would be 83 dB L^ at 100 feet, and 75 dB L^ at 250 feet from the edge of the proposed 50-foot wide construction easement on the south side of Alignment #2, and from the edge of the 15-foot wide easement on the north side of grading required for the proposed road. This construction noise would be intermittent, which is typical of such activities. Most of the proposed construction activities would take place at the western end of the project route. At present, there are no residential land uses directly adjacent to that section of the roadway. 3.6.2.3 Existing Residential Areas Within the City of Encinitas Future traffic noise levels in the Willow Creek subdivision would range from 60 to 61 dB L^, an increase of 4 dB over the existing condition. The 60 dB threshold value established by General Plan Policy 1.1 (for noise level increases between 3 and 5 dB) would be slightly exceeded for properties at the western end of this subdivision. Future traffic noise levels in the Bridgewater subdivision would range from 60 to 61 dB L^, with existing noise level increases of 1-3 dB. But, these noise level increases would not exceed the standards of Policy 1.1. Proposed road widening adjacent to the Thompson property, just east of the Bridgewater subdivision, would result in moving the roadway closer to this existing residence, with the provision of a 12-foot high slope or retaining wall. Future noise levels at this property, however, would not change. The existing and future calculated noise level will remain at 68 dB L^. Proposed grading in this area would provide shielding to offset anticipated increases in vehicle noise generation. 3.6.2.4 Existing Residential Areas Within the Citv of Carlsbad Because there is no City standard governing noise impacts for existing homes from proposed road projects, Encinitas General Plan Policy 1.1 is used to evaluate future traffic noise impacts in the Rancho del Ponderosa and Santa Fe Ridge subdivision areas. Future traffic noise levels in these areas would range from 62 to 66 dB L^, which represents increases of 4 dB. Thus, all of these properties would experience noise increases which exceed the standards of Policy 1.1. It should be noted, however, that projected traffic noise levels ranging between 62 to 66 dB L^ would be within acceptable noise level limits (i.e., 65 dB L^ established by other jurisdictions, such as the City of San Diego. Therefore, some flexibility as to strict application of Policy 1.1 standards is permitted, subject to approval by the City Planning Director, for such situations as presented by the proposed project m-63 Future traffic noise levels at the second floor of homes within in the Rancho del Ponderosa and Santa Fe Ridge subdivision areas may exceed the 45 dB L^ standard for interior noise established by Title 24 of the California Administrative Code. Noise levels outside the second floor windows would range from 65 to 70 dB L^. If these homes have mechanical ventilation which allows comfortable occupancy with the windows closed, and if the windows provide a good seal, then the noise attenuation characteristics are probably adequate to avoid a significant impact 3.6.2.5 Encinitas Creek Riparian Area The undeveloped property south of proposed Alignment #2, between El Camino Real and the Willow Creek subdivision, contains riparian vegetation. Some species of sensitive breeding birds have been observed in this area or may use this area in the future, and may therefore be disturbed by noise levels in excess of 61 dB L^. There is also a potential for construction noise impacts to sensitive breeding bird species in this riparian area. Please refer to Section 3.1.2.1.3 of this EIR for detailed analysis regarding potentially significant noise impacts to this adjacent "noise sensitive" biological habitat south of Olivenhain Road. 3.6.2.6 Other "Noise Sensitive" Areas Within the Project Vicinity Future traffic noise levels at the Olivenhain Municipal Water District (OMWD) property at the eastern end of Olivenhain Road, west of Rancho Santa Fe Road, would increase by 4 dB, from an existing 69 to 73 dB L&. Most of the OMWD buildings in this area are windowless, however, so the noise increases would not be noticeable. Any interior areas with windows, nevertheless, may experience some noise impacts. Portions of the approved Arroyo La Costa development north of Olivenhain Road and west of the Rancho del Ponderosa subdivision would be subject to potentially significant noise impacts from increased traffic volumes and speeds along the adjacent widened road segment There is also a potential for short-term construction noise impacts from heavy construction equipment operations within 250 feet of residential receptors. This may occur at the eastern end of project route, which is about 250 feet from the southwest comer of Rancho del Ponderosa, and adjacent to the Thompson property. A violation of the City of Encinitas Noise Ordinance at these locations is very unlikely, however, because normal road construction operations do not generate high noise levels in one location for extended periods. It should be noted that most of the noise impacts described above may be attributed to anticipated increases in traffic volumes in the project area, independent of the proposed project, with the remainder of these impacts attributed directly to the project As build-out commences, future traffic analyses for new developments in the area may provide additional information that could be used for a more accurate quantitative differention between project versus non-project traffic volume increases, and the corresponding increases in traffic noise levels. m-64 3.63 Mitigation Measures 3.63.1. Prior to road construction, the wall at the west end of Lot 39 of the Willow Creek subdivision shall be extended southward for a distance of 30 feet, and the height of this wall shall be raised to six feet The wall adjacent to the entire southern edge of Olivenhain Road, and extending down Amargosa Drive, shall also be increased in height from six to seven feet This mitigation measure would reduce future traffic noise impacts to existing residential areas adjacent to the south side of Olivenhain Road to below a level of significance, in conformance with the thresholds established in City of Encinitas General Plan Policy 1.1. 3.63.2. As stipulated by Policy 1.1 of the Encinitas General Plan Noise Element, the Engineering and Planning departments of the cities of Encinitas and Carlsbad shall internally evaluate the feasibility and practicability of a range of applicable noise mitigation measures intended to reduce future traffic noise impacts to existing residences within the Rancho del Ponderosa and Santa Fe Ridge subdivisions, adjacent to the northern edge of Olivenhain Road. This evaluation shall include, at a minimum, the possibility of extending existing walls along the rear yards of these homes. If found to be feasible, any proposed wall extensions shall be constructed of solid materials, abutted directly to the existing structures. The wall materials may be masonry, wood, or a transparent material, such as glass or plexiglass. Wooden walls should be at least 3/4 inch thick; glass or plexiglass should be at least 3/8 inch thick. It should be noted that any potential (future) wall extensions intended to reduce traffic noise to exterior and ground floor receptors may not significantly reduce noise levels to second floor receptors. 3.633. The following is listed either as a condition of approval for the Arroyo/La Costa (CT 88-3) tentative map (City of Carlsbad, 1990), or as a recommended mitigation measure in the certified EIR (City of Carlsbad, 1990) for that project: In order to mitigate potentially significant impacts to portions of the approved Arroyo/La Costa development resulting from future traffic noise levels along Olivenhain Road which would exceed the City of Carlsbad's 60 CNEL exterior noise standard, noise barriers shall be installed at the top of the slope in this area, to the satisfaction of the City Engineer. Second-story balconies could require additional mitigation, however, which would be determined when detailed site plans and architectural drawings are submitted for review and approval. m-65 3.7 PALEONTOLOGY The following discussion is based on a paleontological assessment conducted in January, 1991 by RMW Paleo Associates. The complete technical report is included as Appendix 11 of this EIR. 3.7.1 Existing Conditions Two types of geologic formations are present within the three project study areas. These formations document some of the major geologic events that have shaped the physical environment of northern San Diego County. These formations are: Eocene age rocks of the Santiago Formation and Quaternary age marine terrace and alluvial deposits. Marine and non-marine Eocene age rocks of the Santiago Formation are the oldest rocks to be found in the study areas. These rocks are 35 to 54 million years old. A large amount of terrestrial vertebrate and invertebrate fossils have been recovered from Santiago Formation areas in various nearby North County locations. All of these fossils have been recovered entirely from exposures created by grading activities. Quaternary age alluvium, which is the other type of geologic formation found in the project vicinity, forms a thin covering over the floor of the Green Valley west of El Camino Real. Scattered exposures of Quaternary age marine deposits may be present in the study areas. Some quaternary deposits may be as old as 1.8 million years but are generally considered to be less than 10,000 years old. Because of their relatively young geologic age, these deposits are unlikely to contain significant fossils. Fossils of Ice Age animals have been discovered in Quaternary age alluvium deposits in San Diego County, however. During a walkover survey of the project study areas, invertebrate fossils were observed at seven locations. All of these fossils are from the Eocene age Santiago Formation. Quaternary age marine deposits have produced fossil invertebrates at localities to the west of the study areas. No fossils were discovered in the Quaternary age alluvium or marine deposits within or near the study areas. 3.7.2 Impacts The Santiago Formation contains significant fossils in the Carlsbad area. These fossils represent a significant paleontological resource. There is a high potential for their discovery during proposed road construction due to the abundance of fossils in the immediate vicinity of the study area. Project implementation would involve grading activities that may expose fossils in this Formation. Potential destruction of any fossils from the Santiago Formation due to future road grading would result in a significant impact on the region's paleontological resources, because these fossils can provide information on the age of the Santiago Formation and the diversity of life in southern California during the Middle Eocene. m-66 The Quaternary age marine terrace and alluvial deposits within the three study areas have a low potential for the discovery of fossils because of the absence of fossils in these deposits in the „ project vicinity. Discovery of fossils in these deposits would provide information on the age of marine terrace deposits and alluvium within the project vicinity. The destruction of fossils from these deposits would represent an adverse impact on the region's paleontological resources. w Although Quaternary age deposits have a low potential for the discovery of fossils, it is recommended that the entire area be considered as having a high potential when implementing - mitigation measures. This recommendation is based on the fact that Quaternary age deposits are — located above the Santiago Formation, and form a layer of varying thickness over this Formation. Because of this, grading activities may expose the "fossil rich" Santiago Formation at varying •*» rates, depending on the thickness of the Quaternary layer above it Therefore, it is desirable to m have ample mitigation measures being carried out over all three study areas. *" 3.73 Mitigation m The following mitigation measures would reduce the proposed project's adverse impacts to the *• region's paleontological resources to an acceptable level These mitigation measures have proven v successful in protecting paleontological resources, while allowing the timely completion of other ^ projects in southern California. •» 3.7J.I. During proposed road construction, a qualified paleontologist shall be retained to perform periodic inspections of excavations and, if necessary, salvage exposed fossils. The *"" frequency of inspections shall depend on the rate of excavation, the materials being excavated, «** and the abundance of fossils. In areas of high potential, monitoring shall be full-time, initially. **" 3.73.2. The paleontologist shall be allowed to divert or re-direct grading in the area of an *** exposed fossil to facilitate evaluation and, if necessary, salvage. * 3.733. Due to the small nature of some fossils in the study areas, it may be necessary to collect '** matrix samples for processing through fine mesh screens. 3.73.4. Any fossils collected shall be prepared to the point of identification and properly curated *" before they are donated to their final repository. taw! 3.73.5. All fossils collected shall be donated to a public, non-profit institution with a research interest in the materials, such as the San Diego Natural History Museum. m-67 3.8 WATER QUALITY/HYDROLOGY A water quality and hydraulic analysis for the proposed project was conducted by Nolle and Associates in February, 1991. The following section provides a summary of their technical report, which is attached as Appendix 12. Although this study focused on the proposed Alignment #2, any impacts from the alternative alignments were also analyzed. 3.8.1 Existing Conditions 3.8.1.1 Water Quality Encinitas Creek borders the alternative alignments study area to the south. This creek has a drainage basin of approximately 7.3 square miles and empties into Batiquitos Lagoon to the north. This drainage basin makes up 14% of the total Batiquitos Lagoon watershed. Impacts to the Creek may, therefore, directly affect the Lagoon. The proposed project would affect a 0.6 square mile sub-basin of the Encinitas Creek drainage basin. To date, no surface water quality tests have been performed for Encinitas Creek. Batiquitos Lagoon enters the Pacific Ocean between the City of Carlsbad and the Encinitas community of Leucadia. The lagoon waters are extremely shallow (6 to 12 inches in depth). Except after major storm flooding, the Lagoon is blocked from tidal exchange by a naturally- created beach berm just west of Pacific Coast Highway. During summer months, evaporation rates exceed freshwater inflows, resulting in decreased water level and increased salinity of the Lagoon. The Regional Water Quality Control Board (RWQCB) maintains water quality standards for Encinitas Creek and Batiquitos Lagoon (Table 3.8-1). RWQCB performed routine water quality sampling in Batiquitos Lagoon monthly from January 1979 through December 1982. Water samples were analyzed for the following contents: total phosphate, orthophosphate, nitrite, ammonia, total organic nitrogen, total dissolved residue, turbidity, conductivity, total suspended solids, volatile suspended sediment, and settleable residue. Table 3.8-2 shows the nutrient values of the Lagoon water. The water quality test results varied with season and year. Because of the variability in results, it is not possible to determine the impact that the project would have on water quality of the Lagoon. Although no test borings have been performed to determine the depth or quality of groundwater within the three project study areas, there have been groundwater tests performed on other proximally located coastal plains. It can be assumed, therefore, that the groundwater in the study areas would be similar in chemical composition to these other areas. Groundwater occurring in the coastal plains is generally high in sodium chloride and has a high concentration of total dissolved solids (TDS) that range from 500 to 5,000 mg/L The poor chemical quality of groundwater in the area can be attributed to brackish waters that exist in Batiquitos Lagoon. Groundwater does not appear to be a significant source of water for the Lagoon, however, due to a surface layer of silty clay soil that prevents large amounts of lagoon water from percolating into the subsoil. m-68 t i 1 I I t I i 1 i i r i i i f i f i i t t 4 i i i 1 i i § t i I i i I t N Approved \\ Detention Basin 'C'—^VT- 0 1000' 2000' brian F mooncp ital stodtes Existing Detention Basin 'A1 5"o> 8Q Future Detention Basin 'D1 Existing -Detention Basin 'B' \\ Ollvenhaln Road Alignment Locations of Detention Basins Within the Project Vicinity Figure 3.8-1 TABLE 3.8-1 WATER QUALITY STANDARDS FOR ENCINITAS CREEK AND BATIQUrTOS LAGOON CONSTITUENT* INLAND SURFACE WATER GROUNDWATER Total Dissolved Solids 500 1000 Chlorides 250 400 % Sodium 60 60 Sulfates 250 500 Nitrates — 10 Iron 0.3 0.3 Manganese 0.05 0.05 Methylene Blue 0.5 0.5 Active Substances (MBAS) Boron 0.50 0.50 Odor None None Turbidity (JTU) 20 5 Color (Units) 20 15 Fluoride 1.0 1.0 Concentrations not to be exceeded more than 10% of the time during any one year period (mg/l or as noted). Source: San Diego Regional Water Quality Control Board III-70 TABLE 3.8-2 BATIQUITOS LAGOON WATER QUALITY (January 1979 to December 1982) Constituent Total Phosphates (mg/1) Total Inorganic Nitrogen (mg/1) Total Organic Nitrogen (mg/1) Chlorophyll-a (g/1) Salinity (ppt) Turbidity (jTU) Eastern Basin Summer Winter 0.50 0.36 Western Basin Summer Winte 0.34 0.23 1.58 4.22 12.00 18.6 26 3.99 2.01 4.30 15.8 60 0.85 2.42 5.30 31.8 10 1.47 2.00 5.10 24.8 29 Source: San Diego Regional Water Quality Control Board (RWQCB) Currently, there are no significant erosion problems occurring within the study areas. Agricultural activity within the Encinitas Creek watershed contributes to some erosive soil loss, however. The existing sediment load for Encinitas Creek was previously estimated by CH2M Hill to be 12,940 tons of fines (silts and clays) per year and 6,295 tons of sands per year. In order to provide flood attenuation and lower the sediment load carried by Encinitas Creek, the construction of detention basin "D" dike has been proposed (see Figure 2.3-3). 3.8.1.2 Hydrologic/Hydraulic Regime In the past, a 1,500-foot segment of Olivenhain Road easterly of its intersection with El Camino Real has been inundated by the 100-year peak discharge of Encinitas Creek prior to the construction of detention basins "A" and "B". A drainage study performed by Dr. Howard Chang m-71 in September, 1990 (Appendix 4) was used as the base document to evaluate hydrologic impacts of the proposed project. In this report, a HEC-1 flood hydrography study was conducted in order to determine the hydrological conditions in the Encinitas Creek watershed based upon ultimate development of the area. The 100-year peak discharges computed from the HEC-1 analysis were used as input to the HEC-2 water surface profiles model in order to determine the 100-year floodplain for Encinitas Creek. Within the Olivenhain Road study area, the 100-year peak discharge for the local area draining into Encinitas Creek is 361 cubic feet per second (cfs), as compared to a 100-year peak discharge 01 4,725 cfs for the entire Encinitas Creek watershed. The computation of these flows assumed that no detention facilities were constructed. Two detention basins are currently in place within the Encinitas Creek watershed: "A" and "B". They are located approximately 2,600 and 500 feet, respectively, upstream of Rancho Santa Fe Road. Detention basin "C" is approved and soon to be constructed. Figure 3.8-1 shows the locations of these detention basins, as well as the future detention basin "D". With detention basins "A", "B", and "C" in place, the 100-year peak discharge for the entire basin is computed to be 3,450 cfs. With detention basins "A", "B", "C", and "D" in place, the total 100-year peak discharge is computed to be 2,926 cfs. The 100-year peak discharge which contributes directly to the Olivenhain Road study area remains constant throughout all conditions, since its drainage basin is downstream of detention basin "D". 3.8.2 Impacts 3.8.2.1 Water Quality The proposed project is not expected to create significant water quality impacts within Encinitas Creek or the downstream Batiquitos Lagoon. There could be a temporary increase in turbidity and/or total suspended solids (TSS) during the construction phase of the project, but no surface or groundwater impacts to any of the components listed in Table 3.8-1 are expected. Due to the increase in traffic and asphalt surface area, slight increases in grease and oil residuals runoff may be expected. Sediment transport is expected to decrease due to the increased paved area. Finally, a slight increase in turbidity may also accompany proposed construction of the detention basin "D" dike. 3.8.2.2 Hydrologic/Hydraulic Analyses Proposed widening of Olivenhain Road to a six-lane facility would not significantly impact the 100- year floodplain of Encinitas Creek. A slight increase in runoff volumes to Encinitas Creek would occur, however, due to an eight-acre increase in the impervious area. But, this equates to an increase of only 0.01 square miles, or approximately 2% of the entire drainage area of the Creek. Proposed construction of the detention basin "D" dike would further reduce the 100-year floodplain, as compared to existing floodplain limits with detention basins "A" and "B" already in place. It would also increase flood velocities at the upstream side of the bridge at El Camino Real from 1 to 6 feet per second (fps). 111-72 Proposed construction of the detention basin "D" dike would also result in some positive impacts on the Encinitas Creek drainage basin. The 100-year peak discharge would be reduced from 3,450 to 2,926 cfs, which narrows the 100-year floodplain for Encinitas Creek downstream. In addition, the culverts beneath the bridge at El Camino Real would convey the 100-year peak discharge without inundating this intersection. Among many possible sites for the future construction of detention basin "D", the proposed site is the most effective for flood discharge attenuation in the Olivenhain Road project area. 3.83 Mitigation 3.83.L In order to protect the surface and groundwater quality of the area, the following mitigation measures are recommended: 3.83.1.1. Debris fences and screens shall be stationed downstream from areas where grading activities are occurring, but outside the sensitive wetland habitats mapped for this reach of Encinitas Creek (see Figure 3.1-1). 3.83.1.2. Any temporary dam shall only be constructed of material such as clean gravel which will cause little or no siltation. 3.83.13. Except as shown on approved plans, no riprap, rock or other impermeable materials shall be discharged into Encinitas Creek. 3.83.1.4. Any temporary fills shall be constructed of non-erodible materials and shall be removed immediately upon completion of the work. 3.83.1.5. Except as required to move existing vegetation and earth to construct this project; and except for those materials and measures used in the construction of this project; no debris, soil, silt, sand, bark, slash, sawdust, rubbish, cement or concrete or washings thereof, oil or petroleum products, or associated activity of whatever nature shall be allowed to enter into or be placed where it may be washed by rainfall or runoff into Encinitas Creek. 3.83.1.6. Any vegetation removed for initial construction shall be replaced at designated locations (see Figures 3.1-7a and 3.1-75) with comparable species, and at replacement ratios set forth by the relevant resource agencies (see Conceptual Revegetation Plan, Attachment 1 of Appendix 5, for required specifications). 3.83.1.7. At completion of construction operations, any excess materials or debris shall be removed from the work areas. m-73 3.83.2. In addition to the above measures, a Report of Waste Discharge (RWD) shall be filed with the RWQCB for the waste discharge requirements of this project Monitoring and reporting of water quality may be necessary as part of the waste discharge requirements. This would allow for the identification of water quality trends, and the separation of Olivenhain Road impacts from upstream impacts. 3.833 Bridge plans for the El Camino Real bridge just south of Olivenhain Road intersection indicate that riprap protection is in place approximately 20 feet upstream and downstream of the bridge, but is currently silted over. Prior to road construction, the status and condition of this riprap shall be inspected to determine if it is still providing adequate protection against scour from erosive velocities on the upstream side of the El Camino Real bridge. Provided the riprap is still in place and providing adequate erosion protection, no other forms of mitigation shall be required to protect the bridge piers and abutments from local scour. If the existing riprap is not providing adequate erosion protection, a detailed hydraulic analysis shall be conducted prior to approval of final roadway improvement plans to determine additional mitigation measures necessary to protect the bridge. m-74 3.9 COMMUNITY CHARACTER/VISUAL RESOURCE 3.9.1 Existing Conditions The community character surrounding the alternative alignments study area is semi-rural with some mixed land uses that include commercial, public and residential. Rural areas within the project vicinity are being replaced with newer residential units on smaller lots. Larger tracts of land are being developed, leaving small portions of land unimproved. The community character of the area is changing from that of a rural community to a new "bedroom" community. This change in community character is due to an increase in new development on previously undeveloped land. A street tree theme, consisting of planted pine and eucalyptus, exists within the developed portions of the Olivenhain Road study area. This theme is implemented through landscape plans required by the cities of Encinitas and Carlsbad. The north side of the street is landscaped more densely than die south side. A noise wall extends along the southern edge of the road right-of- way (ROW). The undeveloped land surrounding the intersection of Olivenhain Road and El Camino Real consists of disturbed sage scrub and riparian vegetation communities. The City of Encintas General Plan identifies El Camino Real and the future extension of Leucadia Boulevard to the west as "Scenic Highways". The area surrounding the intersection of Olivenhain Road and El Camino Real is designated by the General Plan as a "Scenic View Corridor". This Corridor begins at Garden View Road and continues north to La Costa Avenue (Figure 3.9-1), and has significant aesthetic and visual resources. The Resource Management Technical Report of the Encintas General Plan designates this area as a "High Sensitivity Area", and is considered ecologically significant by biologists and naturalists (Figure 3.9-2) due in part to the extensive riparian woodland along the Encintas Creek floodplain. El Camino Real parallels the east side of this riparian woodland northward to Batiquitos Lagoon. Figure 3.9-3 is a map of the project vicinity showing the photo vantage points. The Olivenhain Road project study area is most visible to those traveling north on El Camino Real. The study area becomes visible at approximately one-half mile south of the existing road alignment, as one approaches the intersection of El Camino Real and Olivenhain Road (Figures 3.9-4 and 3.9-5). Residences located on the tops of bluffs to the south and west of the study area have clear views of the existing alignment and its intersection with El Camino Real (Figures 3.9-6 and 3.9-7). Residences along Scott Place and Starflower Road to the south of the study area have downward views of Olivenhain Road, as shown on Figure 3.9-8. The Thompson residence is a single-story home situated approximately 12 feet below and 80 feet away from the existing roadbed. Elevations rise to meet the road elevation on both sides of this property. Existing plant material on the road bank adjacent to this residence consists of a mixture of ornamental shrubs and native species which partially screen views of Olivenhain Road (Figures 3.9-9 and 3.9-10). m-75 scala In lot Scenic View Corridor I Significant Viewshed [ Scenic Highway Vista Point Ollvenhaln Road Alignment Visual Resource Sensitivity Map brian F moonev g, design ft snvlronTnental studtes Figure 3.9-1 Source: Encinitas General Plan EIR Batiquitos Lagoon NOTE: Detailed identification of in« presence ol sensitive resources will be assessedat me lime ol development proposals 10 determine precise locations. Ollvenhaln Road Alignment Natural Resource Sensitivity Map bricin f mooncro Figure 3.9-2 Source: Encinitas General Plan . / '• <<;r\, \ ) ^\\N OLIVENHAIN ROAD :| (Existing Alignment) N 500' 1000' bricin F moonay I. design » enviroriTwntal studies Ollvenhaln Road Alignment Vantage Point Locations Figure 3.9-3 SOURCE: U.S.G.S. 7.5' Quad Map (Encinitas & Rancho Santa Fe)E1R •*- i- x^>S *- c I pa o*wl^ilMSf ECC 2£«•- o 2 "=fl| fo !^oo rj- 5 4" 00I I ; O) CO £ , £ 5C:^§ Eo**• 4»«(0(00> £ O2 I OO-I CM f s; >V oo in« | to « 0) 1.2 lgi O tOC=3 C.^•S1 :©« ' X^\o> jja c c oS OtC 6> Q. i. 00 Oi 1 cc UJ .53•ScI co Oz .£ oo 3.9.2 Impacts Implementation of the proposed project would impact the visual character of the surrounding area to a varying degree, depending on the location of the observer. The proposed Alignment #2 would entail roughly 57,500 cubic yards of excavation, creating a 2:1 cut slope of approximately 32 feet in height on the northern side of the road. This cut slope would be considered a significant visual impact to Vantage Points 1-5 (see photo-modifications on Figures 3.9-4 to 3.9- 8). A crib wall of approximately six to eight feet in height may also be required at the southeast corner of the Olivenhain Road/El Camino Real intersection, but would not be considered a significant visual impact to these vantage point locations, if vegetated. Two alternative road improvement designs are proposed adjacent to the Thompson parcel, both of which would be considered adverse visual impacts to this residence. One alternative design is to construct a 2:1 fill slope, with the toe of slope approximately twelve feet away from the residence (Figure 3.9-11). The other alternative is to construct a twelve-foot high retaining wall at the edge of the southern road ROW, which would be approximately 35 feet from the residence. Additionally, a four-foot high chain link fence would be constructed atop either the slope or wall for public safety purposes. The Thompson driveway would be reconstructed at a 15.7% slope from the ROW edge down to meet the existing property grade. The alternative fill slope design would be more visually impactive than the alternative retaining wall design at the Thompson property; therefore, the fill slope will be used as a "Worst Case" analysis in assessing visual impacts to this residence. Proposed construction of the detention basin "D" dike within Encintas Creek floodplain near the eastern end of the alternative alignments study area would not be seen from either existing residential development to the west or motorists along Rancho Santa Fe Road to the east due to intervening topography, vegetation, and elevation differential. 3.93 Mitigation 3.93.1. Mitigation for significant visual impacts associated with proposed roadway grading shall consist of special grading and landscaping techniques described below. Detailed Landscape and Irrigation Plans for all manufactured slopes shall be prepared in accordance with the cities of Encintas and Carlsbad landscape design guidelines. These Plans shall be prepared by a Registered Landscape Architect who is licensed to practice in the State of California. These Plans shall be based on final Grading Plans to be approved by the cities of Encinitas and Carlsbad Departments of Public Works, and shall be submitted to the Citys' Landscape Architect for approval. Prior to final "as-built" approval of Grading and Landscape/Irrigation Plans, the Public Works Departments of both cities shall inspect landscape installation for conformance to the requirements of this EIR and the grading permit Additionally, the contracting Landscape Architect shall certify by letter to the cities' Planning and Engineering Departments that the landscape installation conforms to these requirements. m-86 Plan View EXISTING SOLfTHeeNlX EDCaE. J^ HOU5E 110- MBOiAN Cross Section PROPOSED ±12- HOUS* TO-roe OP SLOPE. Olivenha/n Road Alignment 'Worst Case" Grading Alternative for the Thompson Property bricin fmponev Figure 3.9-11 ER The following measures shall be included as key components of the approved Landscape and Irrigation Plans required for all manufactured slopes: 3.93.1.1. Final Grading and Landscape Plans for all proposed cut and fill slopes shall portray techniques that enhance plant establishment and ensure long-term viability. This may include scarification of the cut face by the use of a serrated blade or other methods to create pockets in the cut face where bushes and trees could better take hold. All manufactured slopes shall undulate, including rounding of the tops and toes of the slopes to better blend them into the surrounding terrain. 3.93.1.2. The final Landscape Plan shall provide functioning habitat which is self-maintaining. Drought-tolerant vegetation shall be used to decrease water consumption, as well as provide biological and visual compatibility. Rather than hydroseed treatment alone, increased planting densities for container-grown shrubs and trees shall be used on all slopes over 20 feet high. Selection of plant material in the upper or lower 10 feet of all slopes over 20 feet in height shall utilize plants in such a way that visual continuity is achieved. 3.93.13. Final Irrigation Plans shall include the use of a drip irrigation system for container- grown plants, where appropriate, particularly on slopes over 20 feet high. The Plan shall avoid over-reliance on impact heads, such as rainbirds, which could saturate the slope, waste water, and erode the soil. The slope irrigation system shall be maintained and operated until plant material has established an adequate root system, whereby supplemental irrigation is no longer required for plant survival. Implementation of the above mitigation measures, along with a monitoring program (to be discussed below), would reduce the visual impacts of proposed cut/fill slopes to below a level of significance. 3.93.2 As opposed to the proposed construction of a retaining wall or fill slope as discussed above, one of the following two alternative mitigation measures shall be implemented during road construction in order to reduce adverse visual impacts to the Thompson residence to below a level of significance: 3.93.2.1. A vegetated crib wall shall be installed adjacent to this property. This crib wall shall be designed in two, six-foot high sections, with a three-foot wide planting area between them. Construction of this crib wall shall meet commonly-accepted engineering practices. The wall itself shall also be vegetated and irrigated as specified by the homeowner, but shall not be unreasonably demanded. 3.93.2.2. Two slump-block retaining walls, similar in color and appearance as the existing four- foot high wall fronting the Willow Creek/Bridgewater subdivision to the west, shall be installed adjacent to this property. These walls shall be six feet in height, with a three-foot wide planting area between them. In addition, a four-foot high slump-block wall shall be installed at the southern ROW edge, at the top of the slope, with a three-foot wide planting area between it and the first retaining wall. This wall shall match and tie into the existing aforementioned block wall m-88 to the west Construction of these walls would enable the Thompsons to retain slightly more front yard than the proposed and alternative plans; provide the Thompsons a greater degree of safety with respect to possible automobile accidents, than the proposed plans; and possibly minimize traffic noise to a greater extent than the proposed and alternative plans. Landscaping and irrigation shall also be installed within the planting areas fronting each wall using appropriate groundcovers, vines, shrubs, and/or trees, as specified by the homeowner, but not unreasonably demanded. 3.9.3.2.3. In addition to the two alternative plans above, any manufactured slopes created on the Thompson property as a result of the proposed project shall be vegetated and irrigated. 3.93.3. A monitoring program shall be implemented to ensure the success of landscaped plant material on proposed cut and fill slopes along the realignment of Olivenhain Road. The goal of the monitoring effort is to ensure 80 percent vegetative cover by the end of five years. The Monitoring Plan shall implement the following measures in order to meet this goal. Within the first year, the contracting Landscape Architect shall survey all landscaped areas. All dead plants shall be replaced with like kind. Any hydroseeded areas not establishing shall be re-hydroseeded. The cause of the failure (i.e., irrigation, soil, cover, etc.) shall be determined and repaired prior to re-landscaping the area. A second survey shall be conducted by the Landscape Architect during Fall of the same year to determine plant viability. If more than 20 percent of the container stock have not survived, the dead material shall be replaced with the same type and size as originally planted. This replanting shall be accomplished during the winter months. Letter reports shall be submitted to the cities of Encintas and Carlsbad Planning Departments after each site visit to document the progress of the Landscape Plan. The above measures shall be incorporated into final project plans and specifications, which shall be reviewed by the respective Planning Departments prior to approval by the Cities' Engineers. Implementation of the above measures shall be the responsibility of the grading and landscape contractors, and are subject to approval by the cities of Encintas and Carlsbad Planning and Engineering Departments. m-89 3.10 PUBLIC SERVICES/UTILITIES The following information is derived primarily from the comment letters received from the various agencies listed below during the Notice of Preparation (NOP) review period for the proposed project 3.10.1 Existing Conditions 3.10.1.1 Water Service The Olivenhain Municipal Water District (OMWD) maintains a 12-inch diameter major water distribution main along the south side of Olivenhain Road in the vicinity of its intersection with El Camino Real. This 12-inch water main connects with a 12-inch diameter water main in El Camino Real. Water service along Olivenhain Road is provided by service laterals which tie into this transmission main. Water mains are generally located four feet below the ground surface unless there are conflicts with other utilities (Fontanesi, 1991). 3.10.1.2 Sewer Service The Leucadia County Water District provides sewer service to the Olivenhain Road project area. Facilities along the existing road alignment include an 18-inch diameter sewer main, which runs below the roadway centerline from El Camino Real to the westernmost Rancho del Ponderosa subdivision boundary, and four sewer manholes. This 18-inch sewer main connects with 12- and 18-inch diameter sewer mains in El Camino Real to the west, at a depth of about six to ten feet (Roehl, 1991). 3.10.1.3 Gas and Electric Service San Diego Gas and Electric provides service to the project area via a 150-foot wide right-of-way (ROW) easement crossing Olivenhain Road at a distance of approximately 500-600 feet east of its intersection with El Camino Real (Figure 3.10-1), and gas/electric lines along Olivenhain Road. Major facilities within the 150-foot ROW include 138 kilovolt (kV) and 230 kV overhead electric transmission lines, a 30-inch diameter gas transmission main (800 psi), and a 10-inch diameter oil line (595 psi) belonging to San Diego Pipeline Company. A gas regulator station also occurs within this easement, approximately 50 feet south of the paved edge of the existing road and about 20 feet west of the eastern ROW edge. Overhead 12 kV electric lines and an underground four-inch diameter gas main (400 psi) occur within Olivenhain Road. The electrical lines along Olivenhain Road connect with overhead 12 kV lines along El Camino Real to the west The four-inch gas main within Olivenhain Road feeds into the gas regulator station south of the road m-90 So. Cal. Gas 12.75 inches 0 20001 4000' bricin F mooncy planning, design & environmental studies I38KV & 230KV ProjectRoute ^ /* -138KV & 230KV * f— Utility Easement High Pressure Distribution^0 Transmission Mair 30 inches10 jnches Encinit Substationi ^_ Mln.. 1\ "69KV- IllllII^IIII _ S20' Easement^ fligh Pressure Distribution inches 69KV 138KV, & 230KV9 Transmission..Main 30 inchesSo. Cal. Gas 12.75 inches Gas Facility Electric Facility Ol/venhain Road Alignment Major Utility Easements Within the Project Vicinity Figure 3.10-1 Source: City of Encinitas General Plan 3.10.1.4 Telephone Service Pacific Bell provides telephone service to the project area via a series of underground ducts and connecting conduits within the Olivenhain Road ROW. In particular, twelve, four-inch diameter ducts occur within the southern ROW edge along the 1,200-foot road segment proposed for realignment, at a depth of about 24 to 30 inches (Buchanan, 1991). These telephone ducts within Olivenhain Road connect with thirteen, four-inch diameter ducts along the eastern ROW edge of El Camino Real. 3.10.1.5 Cable Television Service Daniels Cablevision Communications Center provides cable television service to the project area via a two and one-half inch diameter underground conduit crossing Olivenhain Road along the east side of Amargosa Drive. This conduit is buried approximately 24 inches deep beneath the eastern edge of the road ROW. 3.10.1.6 Police Protection The Olivenhain Road project area is served by both the County of San Diego Sheriffs Department and City of Carlsbad Police Department The City of Encinitas contracts with the Sheriffs Department for law enforcement services. The Encinitas Sheriffs Substation is located at 175 Norm El Camino Real, Encinitas, and serves the entire North County coastal area south of the City of Carlsbad (Hendrickson, 1991). Residential areas south of Olivenhain Road are included in Beat 223, which is bounded by El Camino Real on the west, Olivenhain Road on the north, Rancho Santa Fe Road/El Camino del None/Carlsbad City limits on the east, and Encinitas Boulevard on the south (Schultze, 1991). Average response time for this Beat during the Fiscal Year July 1, 1989 to June 30, 1990 was approximately 10 minutes for priority calls, and IS minutes for non-priority calls. The City of Carlsbad Police Department is located at 2560 Orion Way, Carlsbad. Residential areas north of Olivenhain Road are included in Beat 46, which is bounded by El Camino Real on the west, Alga Road on the north, Rancho Santa Fe Road on the east, and Olivenhain Road on the south (Diamond, 1991). Average response time for this Beat during the Fiscal Year July 1, 1990 to June 10, 1991 was approximately seven minutes for priority calls. 3.10.1.7 Fire Protection/Paramedic Service The cities of Encinitas and Carlsbad Fire Departments provide fire protection and paramedic services to the Olivenhain Road project area. The nearest stations to the area are located at 2011 Village Park Way (Encinitas Station #4) at the comer of Mountain Vista Road, Carlsbad Station #2 on El Camino Real north of La Costa Avenue, and Carlsbad Station #6 near the Rancho Santa Fe Road/Via Estancia intersection (LaMarsh, 1991). According to the City of Encinitas Fire Department, response times for emergency vehicles from these stations to existing residential areas north and south of Olivenhain Road are plotted by the San Diego Association of Governments (SANDAG). Response times and routes from the various stations are given below, m-92 and are based on the "SANDAG Travel Time Study" and response time route maps for the area (Salvati, 1991). Encinitas Station #4: Five to nine minutes via Mountain Vista Road west to El Camino Real north to Olivenhain Road east Carlsbad Station #2: Five to nine minutes via El Camino Real south to Olivenhain Road east Carlsbad Station #6: Four to seven minutes via Rancho Santa Fe Road south to Olivenhain Road west 3.10.2 Impacts 3.10.2.1 Water Service Impacts to the existing 12-inch diameter water transmission line at Olivenhain Road and El Camino Real cannot be fully assessed at this time given the conceptual/schematic plans depicting the proposed intersection improvements. 3.10.2.2 Sewer Service Relocation of an 18-inch diameter sewer main within the western segment of Olivenhain Road would not be required as long as this line remains within the proposed ROW of the new road alignment; there is no major excavation required for the new roadway cut; and no new facilities connections are proposed. If relocation is required, approximately 1,200 linear feet of this line within the existing road segment to be realigned would be moved to follow the new road alignment The existing sewer facility would remain in service, however, until the new line has been relocated and tested. As long as standard construction procedures for utility line relocation are followed, no impacts or interruptions to existing service in the project area are anticipated. 3.10.2.3 Gas and Electric Service Approximately 350 linear feet of the gas transmission main and oil line which occur within the ISO-foot wide SDG&E easement that crosses Olivenhain Road near El Camino Real may be lowered to accommodate the new profile of the proposed road realignment The gas regulator station on the south side of Olivenhain Road would not require relocation because it would remain just outside the 50-foot wide construction easement to the south of the proposed Alignment #2. Electric and gas facilities within the existing 1,200-foot segment of Olivenhain Road to be realigned may be relocated to follow the new road alignment This may involve the relocation of approximately 1,600 linear feet of an overhead 12 kV electric line and 700 linear feet of underground gas main. m-93 These existing gas and electric facilities would remain in service until all new lines have been relocated, spliced, tested, and in working order. As long as standard construction procedures for utility line relocation are followed, no impacts or interruptions to existing service in the project area are anticipated. Other potential impacts from required utility line relocations, however, could include accidental damage to lines caused by construction or relocation activities and/or public safety impacts from personnel working too close to the lines. In addition, the City of Carlsbad Planning Department commented during the NOP review period that proposed relocation of the regional (30-inch diameter) gas transmission main which crosses Olivenhain Road could impact riparian habitat within Encinitas Creek floodplain south of the road. As shown on Figure 3.1-1, however, ruderal vegetation is mapped within the area proposed for relocation; therefore, no wetland impacts are anticipated from required lowering of this portion of the regional gas main. 3.10.2.4 Telephone Service Relocation of underground telephone lines and manholes along the southern edge of the western segment of Olivenhain Road would not be required as long as there is no major excavation required for the new roadway cut or the new alignment does not result in the existing manholes located within travel lanes. If relocation is required, the telephone facilities along the existing 1,200-foot road segment to be realigned would be moved to within the new alignment New telephone ducts would be relocated to a position behind the ultimate curbline of the proposed Alignment #2, if possible, as the roadbed nears final grade. The existing facilities would remain in service until all new cables have been relocated to their final position, spliced, tested, and in working order. Safe access into the relocated manholes would be maintained by placing them in an area near the edge of the ROW for the realigned road. No impacts or interruptions to existing telephone service in the project area are anticipated as long as the above methods for relocation are followed. 3.10.2.5 Cable Television Service Impacts to the existing television cable conduit which crosses Olivenhain Road along Amargosa Drive are not anticipated because roadway grading and widening is not proposed at this road segment; therefore, relocation of this line is not required. 3.10.2.6 Police Protection The San Diego County Sheriffs Department, Encinitas Substation, commented during the NOP review period that the proposed project would have a noticeable impact on traffic flow, particularly during peak-hour commuter periods, from existing neighborhood access points and transition routes in the project vicinity during the construction phase. This may significantly impact law enforcement response time to the affected areas. m-94 3.10.2.7 Fire Protection/Paramedic Service The proposed project may significantly impact fire protection and paramedic emergency response time to the Olivenhain Road project area, particularly during peak-hour commuter periods, should bottlenecks, traffic delays, or detours occur at existing neighborhood access points and transition routes during the construction phase. 3.103 Mitigation 3.10 J.I. To ensure that public services in the project area are not impacted, specifications shall be placed in die construction documents that would provide for temporary service connections in the event of anticipated interruptions to water, sewer, gas, electric, telephone, or television lines. Any service interruptions from lines that need to be relocated shall be avoided by installing temporary connections during the time period when permanent relocations of these lines are under construction. This work shall occur under close coordination between the contractor and the appropriate utility company representatives. Furthermore, the cities of Encinitas and Carlsbad shall coordinate final approval of roadway improvement plans with the respective utility companies and agencies listed above to ensure non-interference with existing public faculties. 3.103.2. Grading plans showing proposed changes in elevation over any portion of the existing potable water lines located within the project area shall be evaluated by OMWD staff and consulting engineers prior to approval of final project design. Prior to commencement of construction, all project drawings and improvement plans shall be submitted to OMWD for review of proposed cuts, fills, and changes in traffic loading. Any reconstruction or relocation of existing water transmission facilities that does become necessary shall require appropriate advance planning and logistics coordination with OMWD to avoid impacts or interruptions of service to existing customers in the project area. 3.1033. SDG&E requires that certain standards be followed while working hi or around gas transmission facilities. The following SDG&E measures, which would mitigate potentially significant impacts to public safety and avoid accidental damage to on-site gas transmission facilities, shall become conditions of project approval: 3.1033.1. Maintain a muiitnmn 18-inch vertical separation between any proposed underground utility and existing SDG&E facilities. 3.1033.2. Maintain at least three feet of soil cover over the on-site gas mains at all times. 3.10333. Notify SDG&E prior to commencement of construction activities in the vicinity of the on-site gas mains so that stand-by personnel may be dispatched to the construction site to monitor these activities. 3.1033.4. Maintain vehicle access to the SDG&E ROW, both north and south of the proposed road construction area at all times. m-95 3.103.3.5. No temporary or permanent structures shall be installed within the SDG&E ROW without prior written approval from its Gas Engineering Department 3.103.3.6. SDG&E's Gas Engineering Department shall review and approve all roadway improvement plans prior to final approval by the cities of Encinitas and Carlsbad. 3.103.4. The County of San Diego Sheriffs Department, Encinitas Substation, shall be provided with a copy of the approved Traffic Control/Detour Plan for the proposed road construction period (see 'Traffic/Circulation" mitigation section of this EIR). Concurrent with the provision of this Plan, the Sheriff's Department shall be provided with full disclosure of all the variables potentially affecting law enforcement response mode and time for the project area during the proposed road construction period, such as projected timing phases, levels of service, signage, and detours, as enumerated in this EIR. 3.103.5. The Encinitas and Carlsbad Fire Departments shall be provided with a copy of the approved Traffic Control/Detour Plan for the proposed project (see mitigation measures in "Traffic/Circulation" Section of this EIR) for distribution to the relevant Fire Stations serving the project area. m-96 4.0 GROWTH INDUCEMENT Growth inducement refers to the factors associated with a proposed project which may have the potential to stimulate growth in an area. Generally, growth-inducing factors are those which promote the extension of access roads and/or public services, such as water, sewer, or schools, to an area which has been reserved in long-range planning for non-urban land uses until some time in the distant future. The currently proposed Olivenhain Road improvements would not extend access roads to an area reserved from development; however, it may facilitate accelerated development in the area. As previously discussed, Olivenhain Road is already experiencing traffic congestion and this situation is expected to worsen as future traffic flows increase. The addition of four travel lanes and a 10-foot wide left turn pocket at the Olivenhain Road/El Camino Real intersection is intended to alleviate congestion and mitigate the need for further widening of the roadway. Although Olivenhain Road is adjacent to the Encinitas Creek floodplain, current land uses to the south are fairly intensive. Proposed construction of detention basin "D" dike would decrease the remainder of the undisturbed areas from the 100-year floodplain, but this is not expected to result in unplanned growth because much of these undeveloped areas are designated as an "Ecological Reserve" by the City of Encinitas General Plan and Zoning maps. IV-1 5.0 CUMULATIVE IMPACTS Although the individual effects of the proposed project may be considered insignificant when analyzed separately, if considered together with other projects presently occurring in the area or reasonably anticipated to occur, cumulative effects may prove to be significant As required by CEQA, this section analyzes identified impacts of the proposed project in conjunction with other projects in the vicinity (Figure 5.0-1). Specifically, the following projects are included in this cumulative impact analysis: 5.1 Kev Projects in the Area 5.1.1 Home Depot Specific Plan The Home Depot Specific Plan site is located on the southeastern quadrant of the intersection of Olivenhain Road and El Camino Real, within the Encinitas corporate boundaries. The site consists of approximately 51 acres east of El Camino Real, and includes Encinitas Creek and lowland areas within the 100-year floodplain. The Conceptual Plan proposes to develop 37 of the 51 acres for light industrial, light retail, office, open space, and residential uses. This project is constrained by several environmental factors including the presence of wetlands, sensitive plant species, and the possibility of flooding due to an inadequate flood control system. 5.1.2 Arroyo La Costa Master Plan The Arroyo La Costa project site is located on the northeastern quadrant of the intersection of Olivenhain Road and El Camino Real, in the City of Carlsbad. This approved project proposes a low-density residential development on approximately 477 acres, including 1,076 dwelling units, a recreation building, and open space. The approved Master Plan also allows for construction of a community sports complex, elementary school, and junior high school. 5.13 The Shellev Property Development The Wooley Annexation project entailed an approved EIR for the annexation of a portion of County of San Diego land to the City of Carlsbad. Development of this property was not proposed in the EIR, however, only the annexation of developable land was addressed. The recently proposed Shelley Development is situated on a portion of the Wooley Annexation property, and consists of approximately 115 acres in the City of Carlsbad, south of the Olivenhain Road/Rancho Santa Fe Road intersection. This project proposes a low-density residential development comprised of approximately 256 dwelling units, with open space areas. 5 J Impact Analysis The following cumulative impact analysis addresses each environmental issue in the order they appear in the Environmental Analysis Section of this EIR. The projects listed above have been included in the following analysis. V-l 22 23 27*26 Shelley Development*«? Home Depot Specific N No Scale bricin F mooney g. design A environmental studies Olivenhain Road Alignment Planned Development In Project Vicinity Figure 5.0-1 EIR 5.2.1 Biological Resources Cumulative impacts with respect to biology would be the net loss of habitats that support sensitive plants and animals. The proposed project's contribution to the cumulative loss of habitats supporting sensitive species in the region include projected impacts to grasslands, chaparral, and wetlands. No net loss of wetland habitats are allowed by the governmental resource agencies; however, implementation of the Conceptual Wetland Restoration Plan, as proposed in the "Biological Resources" Section of this EIR, would mitigate the project's cumulatively significant impacts to these habitat types to a level of insignificance. 5.2.2 Cultural Resources No significant cultural or archaeological sites are located within the three study areas; therefore, the proposed project would not contribute to cumulative impacts to archaeology in the vicinity. Geologic Hazards All project-related impacts to soils shall be mitigated; therefore, no cumulative impacts to geology in the project area would occur. The proposed project, along with others in the area, would represent an increase in urbanization in an area prone to seismic events. As long as they are all constructed according to California Building Code standards, cumulative impacts resulting from seismic events would be minimized. 5.2.4 Traffic Circulation The proposed project would alleviate traffic congestion in the area. Although the projected increase in traffic from other projects would result in cumulative traffic impacts in the project area, Olivenhain Road is designated by both the cities of Encinitas and Carlsbad as a six-lane Prime Arterial to accommodate these increased volumes. 5.2.5 General Plan Compatibility Since the proposed project would conform to the roadway design guidelines for a Prime Arterial, as established by the General Plan Circulation Elements of the cities of Encinitas and Carlsbad, as well as the County of San Diego, no cumulative traffic impacts would occur. 5.2.6 Traffic Noise Increased future traffic volumes along the widened Olivenhain Road would contribute to cumulative traffic noise impacts in the project area. These cumulative noise impacts would be mitigated for single-story structures and the first floor of two-story structures through the proposed extension of existing noise attenuation walls along the road. These barriers would only be high enough to shield traffic noise from first story elevations. Thus, the projected increase in traffic noise to the second floor of two-story structures along the improved Olivenhain Road would be considered a significant and immitigable cumulative impact V-3 5.2.7 Paleontological Resources Proposed road grading would not result in significant cumulative impacts to paleontological resources found near the three project study areas, as long as these activities are restricted to within proposed construction easements. 5.2.8 Water Quality/Hydrology The proposed improvements to Olivenhain Road would result in a slight increase in runoff volumes into Encinitas Creek and Batiquitos Lagoon downstream of the project area, due to an increase in impervious surface area. Although the incremental contribution from the project to live stream discharge affecting Batiquitos Lagoon is not considered significant, when added to the combined runoff volumes from other projects in the area, long-term water quality degradation would occur to this watershed. 5.2.9 Community Character/Visual Resource Proposed improvements for Olivenhain Road would contribute to the significant alteration of the rural community character. This change would be regarded as a cumulatively significant, immitigable impact to the rural character of the area. Development plans for the Arroyo/La Costa project show fill slopes on the north side of Olivenhain Road in excess of 25 feet in height The proposed Alignment #2 would also affect Lots 24 through 29 of this development by encroaching into the fill slope for mis area, thereby, necessitating the redesign or removal of these lots. Any reimbursement of costs associated with the required redesign or possible loss of these approved lots, shall be coordinated between the cities of Encinitas and Carlsbad. The Home Depot preliminary development plans show that fill would be placed within portions of the Encinitas Creek floodplain in order to expand the developable area. This would add to the cumulative visual impacts in the area. Finally, fill from the future Wiegand development would be required to create the side embankments of the future detention basin "D", but no preliminary development plans are available at this time to assess the visual impacts from grading at this location. 5.2.10 Public Services/Utilities Required lowering or relocation of the regional, 30-inch diameter gas transmission main located within the 150-foot SDG&E easement which crosses Olivenhain Road may result in significant cumulative impacts to existing gas service, if road construction were to cause a service interruption or accidental damage to this line. This potentially significant cumulative impact would be mitigated, however, by establishing temporary service connections during relocation or in the event of emergency breakage (within 24 hours). V-4 6.0 ALTERNATIVES TO THE PROPOSED PROJECT In order to more fully evaluate proposed projects, CEQA mandates that alternatives to their implementation be discussed. These alternatives should focus on the elimination of identified, significant, adverse environmental effects or on the reduction of these effects to a level of insignificance. The evaluation of these alternatives is necessary even if they impede to some degree the attainment of project objectives, or would be more costly. Four alternatives to the proposed project are addressed below. They consist of those reasonable alternatives which would achieve the primary objectives of the proposed action: to expedite traffic flow and reduce flooding along Olivenhain Road. These alternatives were developed with a focus on eliminating identified, significant environmental effects, minimi/ing these effects to a level of insignificance, and responding to input from policy makers and public agencies. In accordance with CEQA requirements, the "No Project" alternative, "Alternative Alignments" option, "Grade-Separated Intersection" alternative, and "Alternative Road Widening" options are herein addressed. Each of these alternatives are briefly discussed below, followed by a brief analysis of the major environmental impacts associated with their implementation. 6.1 No Project 6.1.1 Description The existing Olivenhain Road alignment would not be widened to its ultimate six-lane configuration, nor would the proposed flood control improvements be implemented. 6.1.2 Environmental Impacts The "No Project" alternative would result in the reduction of several environmental impacts associated with the proposed project, including impacts to biology, cultural resources, geology, visual quality, paleontology, and hydrology. Implementation of this alternative, however, would result in severe traffic congestion and flooding impacts along Olivenhain Road and at the El Camino Real intersection in the future. 6.2 Alternative Alignments 6.2.1 Alignment #1: Southern Alignment 6.2.1.1 Description This alignment would extend almost due west from the Willow Creek subdivision boundary, crossing Encinitas Creek and intersecting roughly perpendicularly with El Camino Real (Figure 6.2-1). In conformance with the City of Carlsbad design speed criteria, this alternative would require right-of-way (ROW) acquisition west of Rancho del Ponderosa subdivision, the majority of which exists within three parcels of land. VI-1 I i I i f i i i f i l i i i i f i i I i ' ii ii ! i if it ti i i sS^fS:-^ w?))' <W-v^^^>±j Cvv/r'^^K' WP^ZSiS&JtMCEMt'iQS' I S >» s.'r".^ i- Existing Alignment .! Proposed Alignment *i I bricin f mooncv Ollvenhaln Road Alignment Alternative #1: Southern Alignment Figure 6.2-1 SOURCE: Project Design Consultants 6.2.1.2 Environmental Impacts Implementation of this alternative alignment would require the construction of a bridge over sensitive riparian vegetation associated with Encinitas Creek. A majority of this wetland vegetation would be spanned by the proposed bridge, but as shown on Table 6.2-1, alternative Alignment #1 would directly impact approximately 1.38 acres of southern willow scrub, 0.26 acre of coastal freshwater marsh, 0.27 acre of disturbed wetland scrub, 1.46 acres of ruderal vegetation, and 1.00 acre of disturbed area. Impacts to southern willow scrub and coastal freshwater marsh are considered cumulatively significant. The impact to disturbed wetland scrub is not considered significant because of its low wildlife value due to the presence of a high percentage of non-native species. Each alternative alignment would require a 50-foot construction easement from the southernmost roadway edge. In addition, Alignment #1 would require a 50-foot construction easement from its northern roadway edge, and Alignments #2, #3, and #4 would require 15-foot construction easements from their northern roadway cuts. The construction easement for alternative Alignment #1 would result in temporary impacts to an additional 0.82 acre of southern willow scrub, 0.28 acre of coastal freshwater marsh, 0.41 acre of disturbed wetland scrub, 12% acres of ruderal vegetation, and 0.08 acre of disturbed land. Impacts from this easement to southern willow scrub and freshwater marsh are considered cumulatively significant, while the impact to disturbed wetland scrub is not considered significant Remedial grading and ground stabilization may be required under the roadway in order to minimize potential soils settlement The gas regulator station located south of the existing alignment would be impacted by alternative Alignment #1. This facility may need to be relocated further to the south along the existing 30-inch gas main, if a conflict is determined during final design. Approximately 14,500 cubic yards of fill would be required to raise the elevation of the roadbed for this alternative alignment from Rancho del Ponderosa subdivision to just east of El Carnino Real In addition, a maximum slope height of nine feet would be created. The construction of this bridge and associated fill slopes would contrast to the surrounding riparian vegetation, resulting in significant visual impacts. 6.22 Alignment #3: Northern Alignment 622.1 Description The alignment would follow a more northerly route than the existing road to an intersection with El Camino Real (Figure 6.2-2). This alternative would not meet all of the City of Carlsbad's design criteria for a Prime Arterial route. Centerline radii would be 1,800 feet, as opposed to 2,400 feet, which is standard. The centerline horizontal curve would begin at the centerline of El Camino Real, instead of 100 feet beyond the rear of the curb return, as per standard. The centerline intersection of Olivenhain Road with El Camino Real would be at a 7 degree skew, and not at the recommended right angle. The design speed would be 55 miles per hour (mph), instead of 60 mph, as per standard. Implementation of this alternative would require ROW acquisition west of Rancho del Ponderosa subdivision, the majority of which consists of land from two parcels. VI-3 TABLE 6.2-1 SUMMARY OF IMPACTS TO VEGETATIVE HABITATS WITHIN THE OLIVENH AIN ROAD PROJECT AREA Alternative Proposed Alternative Alternative Alignment #1 Alignment #2 Alignment #3 Alignment #4 netoitinn Badn »n" Construction Construction Road Easement Road Easement Habitat Type Southern willow scrub 138 0.82 0.04 0.21 Coastal salt marsh — — — — Coastal freshwater marsh 0.26 028 — 0.14 Southern mixed chaparral — — 0.33 0.21 Disturbed wetland scrub 0.27 0.41 — 0.04 Wetland ecotone — — — — Ruderal 1-46 1.28 4.7 0.69 Disturbed 1-00 0.08 0.40 0.16 Subtotal 437 2.87 5.47 1.45 Total 7.24 6.92 Construction Construction Construction Road Easement Road Easement Dike Easement 0.25 035 035 035 — — — — 0.08 0.19 0.16 — 0.04 0.11 0.04 — 0.19 0.04 030 0.19 0.17 — _.. — — — 4.41 0.75 3.80 1.00 0.89 2.14 Q_29 4.95 1.41 430 1.89 134 231 6.36 6.18 3.55 r i VI-4 » » * « II * 1 f I 11 II » I If II if e l i i I i I i i i I i I i 1 i i i I i i 1 i i I i l I i j N W^&t!'UM!A^dfc*fi&-: Existing Alignment f\»^-/ V~ -2I ( ,'"-r~ i v--s/lii > r»»—•/. I ' I '»-»^>~- Proposed Alignment «-)v ^^Ji I im?£Si!^^ No Scale brlqn f mpona v Olivenhaln Road Alignment Alternative if 3: Northern Alignment Figure 6.2-2 SOURCE: Project Design Consultants 6.2.2.2 Environmental Impacts Alternative Alignment #3 would directly impact approximately 0.25 acre of southern willow scrub, 4.41 acres of ruderal vegetation, and 0.29 acre of disturbed land. The impact to southern willow scrub is regarded as cumulatively significant An additional 0.35 acre of southern willow scrub, 0.08 acre of coastal freshwater marsh, 0.04 acre of southern mixed chaparral, 0.19 acre of disturbed wetland scrub, and 0.75 of ruderal vegetation would be temporarily impacted by the construction easement for alternative Alignment #3. Temporary impacts to southern willow scrub 4 and freshwater marsh from this easement are considered cumulatively significant, while the impact to disturbed wetland scrub is not considered significant ' Alternative Alignment #3 may avoid saturated ground areas which may require stabilization. ..„ Approximately 50,000 cubic yards of excavation would be required to construct this alignment, creating a cut slope of 25 feet on the north side of the road which may require buttressing. This "* cut slope would represent a significant visual impact The 30-inch gas main and fuel line located „„ within the 150-foot wide SDG&E easement would need to be relocated to accommodate the required road profile. Traffic delays and detouring required to accommodate the bridge/intersection phasing may result in significant traffic impacts during the construction period. ..* The construction of a crib wall six to eight feet in height may be required on the south side of M Olivenhain Road, east of El Camino Real, to avoid direct impacts to wetlands in this area; however, significant visual impacts may result from this crib wall if it is not vegetated. «• m 6.23 Alignment #4: Existing Two-Lane Alignment 6.23.1 Description tt» This alignment would follow the existing Olivenhain Road for most of its route (Figure 6.2-3), but would fail to meet many of the design criteria established by the City of Carlsbad for a Prime Arterial. The centerline radii would be 1,400, not 2,400 feet as per standard. The centerline intersection of Olivenhain Road with El Camino Real would be at a 23 degree skew, as opposed to the recommended right angle. Normally, public agencies would allow a maximum of 10 » degree skew at an intersection. The design speed would be 55 mph, instead of 60 mph as per standard. Implementation of this alternative would require ROW acquisition west of Rancho del Ponderosa subdivision, the majority of which consists of land from two parcels. m 6.23.2 Environmental Impacts«t* - Alternative Alignment #4 would directly impact approximately 0.35 acre of southern willow scrub, 0.04 acre of disturbed wetland scrub, 0.11 acre of southern mixed chaparral, and 3.8 acres of ruderal vegetation. The impact to southern willow scrub is considered cumulatively " significant The impact to disturbed wetland scrub is not considered significant Disturbance within the construction easement for alternative Alignment #4 would temporarily impact approximately 0.35 acre of southern willow scrub, 0.19 acre of freshwater marsh, 0.04 acre of " southern mixed chaparral, 0.30 acre of disturbed wetland scrub, and 1.00 acre of ruderal vegeta- VI-6 N Existing Alignment ;—;-. r '••"•*-'- - • *\\'\* ._ ™ - ' / ^\\\ Proposed Alignment i^^^^^lt-^^))/ Vf P ~^£r /=*'^Sir«* ^v,'O^-rv^> ^^7;' /--';- - ^-r T%&*.• '^-^Kff^K\' < r^^i -^ -'/v --ft? :^'No Scale bricinjF rnooncv placwing, design A wwlronmental »tuc«»« Ollvenhaln Road Alignment Alternative 94: Existing 2-Lane Alignment Figure 6.2-3 SOURCE: Project Design Consultants tion. Temporary impacts to southern willow scrub and freshwater marsh from this easement would be regarded as cumulatively significant, while the impact to disturbed wetland scrub is not considered significant. Roughly 12,000 cubic yards of excavation for this alignment would require the creation of a maximum cut slope of approximately 25 feet on the north side of the road, which may require buttressing. As with Alternative Alignments #2 and #3, a significant visual impact could result depending on the type of soil material encountered when excavating. For example, because rock slopes do not vegetate easily, significant visual impacts would occur if the excavation is in solid rock. The existing 30-inch gas main and fuel line located within the ISO-foot wide SDG&E easement that crosses Olivenhain Road would need to be relocated to accommodate the required alignment profile. 6.3 Alternative Road Widening Option 6.3.1. Description This alternative involves the widening of another existing or proposed road, as opposed to Olivenhain Road. Several roads were considered. The widening of Mountain Vista Drive to the south was considered, but rejected because this road only provides access to the community of Olivenhain. The future Melrose Drive connection to the east was also considered as an alternative. This road would run in a north/south direction from the San Marcos landfill to Del Dios Highway. If this road were widened, its subsequent increased use would not significantly alleviate east/west traffic congestion in the project area. Improvement of east/west traffic flow is a primary goal of the proposed project; therefore, the Melrose Drive connection would not meet this objective. The planned extension of Leucadia Boulevard west of El Camino Real was also considered as an alternative road widening option. SANDAG's traffic projections state that the primary purpose of this planned road extension would be to route traffic eastward to Interstate 15. The main purpose of the proposed project, however, is to provide westward flow towards Interstate 5. For this reason, the future Leucadia Boulevard extension is not an appropriate alternative route. 6.3.2 Environmental Impacts Environmental impacts associated with widening of any of the alternative roads discussed above, would need to be analyzed via CEQA-mandated environmental review guidelines and procedures within the affected jurisdictions. 6.4. Grade-Separated Intersection Alternative 6.4.1 Description This alternative would involve raising the intersection at El Camino Real and Olivenhain Road. Olivenhain Road would still be widened. According to intersection capacity utilization analyses conducted by the cities of Encinitas and Carlsbad (Appendix 8), this intersection would provide acceptable levels of service under buildout conditions. Therefore, construction of a grade- separated intersection is not warranted (please refer to Section 3.4.3.2.1 of this EIR for a detailed discussion of grade separation warrants for this intersection). VI-8 6.4.2 Environmental Impacts Implementation of this alternative would result in increased biological impacts over what is proposed. This alternative would impact an additional 0.41 acre of freshwater marsh, 0.14 acre of disturbed wetland scrub, 02 acre of southern mixed chaparral, 4.14 acres of ruderal vegetation, and 1.0 acre of southern willow scrub. An increase in traffic impacts can also be expected due to the increased construction period and traffic detouring. An increase in impacts to public facilities relocations and possible service interruptions can also be expected. In summary, more environmental impacts would occur from this alternative than from the proposed project due to the larger area to be affected. VI-9 7.0 EFFECTS FOUND NOT TO BE SIGNIFICANT The following environmental issues analyzed in this EIR have been found not to be significantly impacted by the proposed project: cultural resources, geologic hazards, traffic/circulation, General Plan compatibility, paleontological resources, and hydrology/water quality. Potentially significant environmental impacts have been identified with the remaining issues evaluated in this EIR, but can be mitigated to a level of insignificance through implementation of the measures outlined herein. These issues include biological resources, traffic noise, community character/visual resource, and public services/utilities. Additional environmental issues evaluated during an initial Environmental Impact Assessment conducted by Fay Round and Associates (1989 [Appendix 1]) were determined by the City of Encinitas not to be impacted by the proposed project and, therefore, were not included in this EIR analysis. These issues are: air quality, natural resources utilization, land use compatibility, light and glare, hazardous waste generation and disposal, housing demand, recreational uses, and agricultural conversion. .'in* Mr vn-i 8.0 THE RELATIONSHIP BETWEEN LOCAL SHORT-TERM USES OF MAN'S ENVIRONMENT AND THE MAINTENANCE AND ENHANCEMENT OF LONG- TERM PRODUCTIVITY This section addresses the long-term effects of the proposed project on the environment and impacts that narrow the range of beneficial uses of the environment or pose long-term risks to health and safety. Implementation of the proposed project would have a negative effect on the long-term productivity of the physical environment This effect primarily relates to the conversion of existing undeveloped land to roadway and flood control improvements. Short-term use of the property as open space appears limited, however, as these areas are within designated right-of-ways, set aside by the General Plans of Encinitas and Carlsbad for street and flood control improvements. The long-term productive use resulting from implementation of the proposed project would be die accommodation of increased traffic capability within a region with rapidly increasing population. vm-i 9.0 ANY IRREVERSIBLE ENVIRONMENTAL CHANGES WHICH WOULD BE INVOLVED IN THE PROPOSED ACTION SHOULD IT BE IMPLEMENTED Significant, irreversible changes that would be involved in the proposed project include the conversion of vacant property to urban facilities. Although this change is irreversible, all significant impacts identified in this EIR could be mitigated to a level of insignificance through the implementation of proposed design measures, guidelines, and environmental management conditions. DC-1 10.0 MITIGATION MONITORING CHECKLIST Mitigation measures which would reduce or eliminate potential environmental impacts of the proposed project have been identified in this document The cities of Encinitas and Carlsbad are required to implement adopted mitigation measures. In order to ensure compliance, the following Mitigation Monitoring Program and checklist has been formulated. The Mitigation Monitoring Program is intended to be administered by the Departments of Planning (DP), Public Works (DPW), and Code Compliance (CC) of the cities of Encinitas and Carlsbad. These Departments, augmented by possible contracts personnel, shall be responsible for enforcement of the zoning regulations. It is further intended that funds for administering the Mitigation Monitoring Program be provided on a full-cost recovery basis by the two cities. Certifications of Compliance required by other agencies, such as Caltrans, County of San Diego, California Department of Fish and Game, U.S. Fish and Wildlife Service, and San Diego Regional Water Quality Control Board shall be secured by the City of Encinitas Planning Department. No authorization to commence any activity on-site shall be granted except with the concurrence of the respective cities' Departments. The following checklist is intended to be used by personnel from the above-listed Departments, as the appointed monitoring entities. Information contained within the checklist clearly identifies the mitigation measure, delineates the monitoring schedule and defines the conditions required to verify compliance. Following is an explanation of the six columns which constitute the checklist Column 1 Mitigation Measure; An inventory of each mitigation measure is provided, with a brief description. Column 2 Type: Each mitigation measure is classified as either Project Design (PD) Mitigation, Ongoing Mitigation (OM), or Cumulative Mitigation (CM) based upon the following definitions: • Project Design Mitigation - mitigation which has been incorporated into the project design (e.g., acoustical barriers, road improvements); • On-going Mitigation - mitigation associated with a project over a period of time (e.g., dust control, landscape maintenance); • Cumulative Mitigation - mitigation which requires monitoring over a greater period of time (e.g., progressive reclamation of mining site). Monitor Identifies the agency or department which is responsible to determine compliance with the mitigation measure and to inform the City of Encinitas Community Development Department (CDD) regarding compliance. X-l Column 4 Schedule; As scheduling is dependent upon the progression of the overall project, specific dates are not used within the "Schedule" column. Instead, scheduling describes a logical succession of events (e.g., prior to occupancy, annual) and, if necessary, delineates a follow-up program. Column 5 Reporting Requirements: The status of on-going and cumulative mitigation measures is to be documented in letter report after each visit. The monitor can quickly determine whether a mitigation measure has been completed by referring to this column. Upon satisfaction of the reporting requirement listed in this column, the mitigation measure is considered complete. Where the "Schedule" column indicates annual or other on-going mitigation measures, verification of compliance may not occur until completion of the project Information provided within progress reports will be helpful in the development of future mitigation programs. This Mitigation Monitoring Program is to be adopted by the Lead and Responsible agencies upon formulation of Findings, in order to comply with the requirements set forth by Assembly Bill 3180 (Public Resources Code Section 21081.6). X-2 TABLE 104-1 Mitigation Type MITIGATION MONITORING CHECKLIST Monitor Conceptual Revegetttion Plan Implementation (Southern Willow Scrub) a. Weed Control CM Qualified Biologift Qualified Horticultnranst Landscape Contractor CitieiDP/DPW b. Replacement Planting (bated on the Mowing CM success criteria) (1) Quantitative Assessments: (a) Belt and line-interoept1 inrveyi to record shrub and ground cover deniitiei; tree and ihrub heighu; percent canopy cover for trees; and % throb and ground cover. Revegetttion goal at the end of five yean is: 40 - 60% combined tree canopy cover 30 - 50% shrub canopy cover 2-9% herbaceous cover 3-9% open ground (b) Quadrat? surveys to record survivorship; crown cover; tree density and species composition; diameter at breast height (dbh) and foliage volume density (2) Qualitative Assessments CM Monthly for the firrt 3 months, then quarterly thereafter Send-annually (in late September and arid- February) with in-kind replacement between November and January of < as follows: achgn First year: replacement planting if greater than 15% mortality for any species Second year replacement planting if greater than 15% mortality for any species and/or less than 50% coverage Third yean replacement planting if greater than 15% mortality for any species and/or less man 60% coverage Fourth yean repl less man 70% coverage planting if Fifth year replacement planting if less than 80% coverage. Consultation with resource agencies if less than 80% coverage Monthly for the first year after installation Quarterly letter reports from Consulting Biologist toCStyCDD Quarterly letter reports from Consulting Biologist to City CDD Annual letter reports from Consulting Biologist to U.S. Army Corps of Engineers. U.S. Fish & Wildlife Service. U.S. Environmental Protection Agency, and California DepL Fish tt Game, and City CDD Quarterly letter reports from Consulting Biologist to City CDD 1 Six, meter-wide belt transects with central line transects shall be randomly established and permanently located within southern willow scrub. Avifaunal surveys shall also be conducted along the bell transects to record bird species present and any breeding activities taking place on-site. The presence of macroinvertebrates and mamm.l. ihall also be recorded. 1 Quadrats shall be randomly established and permanently located within southern willow scrub, placed in a north-south direction across the revegetation site and covering at least 10% of the site. Permanent photodocnmentation stations shall also be established within the quadrats to visually document vegetational changes and community development » 1 9 1 if f|f 1 Pi I I X-3 I 1 1 ff il fi fi r i r * i i t i i i i J t i i i i i I I i i i I 1 l i Mitigation Measure TABLE 100-1 (conttencd) MITIGATION MONTTORING CHECKLIST Type Monitor 5. 7. Conceptual Revegetation Plan Implemenutica CM (Coastal Sail Marsh? a. Salvage salt manh vegeUtion and toptofl, till into soil of prepared tab marsh revegetation rile Lay geotejttile over nunhei and tootfaem wfflow OM scrub habitat* wilhin construction casements a. Salvage cut wfllowi within construction easement!; mulch and lay on surface of prepared willow scrub revegetatica site b. Hag outer limits of all construction easements c. Take soil samples in aH construction easements d. Survey natural plant regeneration within aH construction easements4 Install permanent oil catchment or native grass-lined PD drainage swale/retention basin south of improved road Flag SDi-4872 site boundary; restrict construction OM easement to within SO feet from northern road edge Flag SDi-11267 site boundary Periodically monitor the construction easement area in the vicinity of SDi-68685 OM Qualified Biologist Qualified Horticultnralist Landscape Contractor Cities DP/DPW Qualified Biologist Qualified HorticultaraHst Cities DP/DPW Certified Land Surveyor Certified Soils Engineer Construction Supervisor Cities DP/DPW Certified Archaeologist OM Certified Archaeologist Certified Archaeologist Quarterly at 0.3.6,9.12, IS. 18. and 24 Prior to construction of flood control berm Prior to construction of improvements Prior to conjtruction/placeraent of geotextile Prior to construction/placement of geotextile Prior to/after construction/placement of geotextile During the Spring after project implementation During road construction Prior to construction of improvements Prior to construction of improvements During construction of improvements Quarterly letter reports from Consulting Biologist toCityCDD Letter report from Consulting Biologist to City CDD after completion of salvage operation I fttff report from Consulting Biologist to City CDD after Letter report from Consulting Biologist to City CDD prior to placement of geotextile letter report from Consulting Biologist to City CDD at completion of survey Letter report from Construction Supervisor to City CDD at completion of improvements Ivffttcr report from Consulting Archaeologist to City CDD at completion of flagging Letter report from Consulting Archaeologist to City CDD at completion of flagging Letter report from Consulting Archaeologist to City CDD at completion of flagging One square meter quadrats for herbaceous species, and threc-by-three meter quadrats for shrubby species randomly established and permanently located to record height, percent cover, above-ground biomass, and species composition. If the biologist determines mat these areas are not adequately regenerating on their own, additional plantings of the affected habitat types, at the appropriate replacement ratios (3:1 for southern willow scrub and 1:1 for the marshes), shall be installed at the designated revegetation sites. All revegetation activities shall be monitored during plant installation to ensure mat substitute plant species are not incorrectly used for the given ecological context This mitigation measure shall be implemented only if the Alternative #2 flood control berm design at La Costa Avenue/H Camino Real intersection is chosen. X-4 Mitigation Measure TABLE HUM (conttBiMd) MITIGATION MONITORING CHECKLIST Type Monitor Schedule Reporting Requirements 8. 9. 10. 11. 12. 13. Perform detailed soils and geologic inveitigation for approved road design Review final road improvement/grading plant within existing utility < Review final landscape/irrigation plans for all manufactured slopes OM OM OM Improve El Camino Real from Olivenhain Road to CM Calle Barcelona to six lanes7 Augment Rancho Santa Fe Road from Olivenhain CM Road to Avenida La Poita by the following: a. Signalize the Avenida La Posta intersection b. Add lanes at die Olivenhain Road intersection c. Add central median to allow turning movements Prepare a Traffic Control/Detour Plan with the OM following provisions: a. Re-stripe Olivenhain Road to provide one, 15- foot wide traffic lane in each direction b. Switch traffic signal at Olivenhain Road/El Camino Real intersection to flashing ted mode c. Maintain 50-foot construction zone from scum- em road edge, and 15 feet from northern edge d. Place construction barricades with flashing lights in easement areas at 25-foot minimum spacing Certified Soils Engineer Certified Soils Engineer Cities DP/DPW Certified Soils Engineer Cities DP/DPW Cities DP/DPW Cities DP/DPW Prior to approval of final road improvement plans Letter report from Consulting Soils Engineer to City CDD prior to road constmctkn Prior to approval of final road improvement plans Letter report from Consulting Soils Engineer to Cuy CDD prior to road construction Prior to approval of final road improvement plans Letter report from Cnmnrring Sous Engineer to City CDD prior to road construction Prior to build-out Year 2010 Prior to build-out Year 2010 No letter report required No letter report required Registered Traffic Engineer Prior to approval of final road improvement plans Letter report from Consulting Construction Supervisor Traffic Engineer to City CDD f i ' Landscaping and irrigation for all manufactured roadway slopes, per approved plans, shall be installed as soon as practical after grading in order to reduce erosion potential on exposed slopes.7 This mitigation measure shall be implemented only if the future Leucadia Boulevard extension (between El Camino Real and the existing eastern terminus of LfnctnH« Boulevard) is not constructed by the Year 2000. ii f i f~i i i if fi fi iv f i* 1 fill f i f i §1 l i f i i i i i l i i i i I i i i i l l i t i i l I i I l i i I 1 ! Mitigation Measure TABLE 104-1 (coMttaaed) MITIGATION MONITORING CHECKLIST Type Monitor Schedule Reporting Requir 14. 15. 16. e. Install tailing, with two-way dear reflecton, at dose of working day at 12 feet from cemerline striping, and minimum 24-foot spacing f . Maintain access to Amargosa Drive, Lot Pinoi Circle, and all private driveways on both sides of Olivenhain Road g. Install rignage per ttandaid specifications h. Institute dust abatement measures', a* necessary In response to comments rccicved from County PD DPW during the Public Review Period, the following mitigation measures shall also be included as required conditions of project approval, and shown on final roadway improvement plans: a. Construct the Olivenhain Road/El Canrino Real intersection at right angles b. Determine appropriate right-of-way widths and distances required for relinqoiihment of access rights c. Provide adequate sight ^i d. Provide the appropriate number of left-turn lanes at the Olivenhain Road/El Camino Real intersection Adherence to Noise Ordinance: limit daily const- PD ruction noise and activities to less than 75 dB averaged over an eight-hour period, between 7:00 sum. and 7:00 pan., Monday through Saturday (no construction allowed on Sundays and holidays) Extend wall at west end of Lot 39 of Willow Creek subdivision southward for a distance of 30 feet, and the height to six feet PD Cities DP/DPW County DPW Registered Traffic Engineer Construction Supervisor During project construction Letter report from Construction Supervisor to City CDD at completion of improvements Cities DP/DPW Code Compliance Officer Construction Supervisor Cities DP/DPW During project grading and construction Prior to road construction Monthly letter report from Cities' DPW during grading/ construction of facilities, or upon violation Letter report from Construction Supervisor to City CDD at completion of improvements Adherence to County of San Diego Air Pollution Control District (APCD) mandatory dust control requirements and Cities' performance standards involves dewatering of construction areas to reduce fugitive dost generation during project grading. X-6 Mitigation Measure TABLE 10.0-1 (continued) MITIGATION MONITORING CHECKLIST Type Monitor Reporting Requtrcmeabi 17. 18. 19. 20. 21. Extend wall adjacent to southern edge of Olivenhain Road to teven feet in height Conduct feasibility study/b ritoringat PD PD Cooftiuction Supervisor Cities DP/DPW Prior to toad oomtmction residences within Rancbo del Ponderosa and Santa Fe Ridge subdivision north of improved toad. Extend height of existing walls along rear yards of these homes, if practical Install acoustical attenuation barrier at the top of manufactured slope of the approved Arroyo/La Costa development adjacent to northern edge of Olivenhain Road Registered Acoustical Engineer After project implementation Cities DP/DPW Letter report from Construction Supervisor to City CDD at completion of impove CM City of Carlsbad DP/DPW During future development of this phase of the planned Arroyo/La Costa project Paleontological monitoring of on-rite excavations' OM Qualified Paleontologist Construct the following erosion/sfltation control improvements: a. Debris fences and screens shall be installed downstream from areas of grading, but outside sensitive wetland habitats b. Any temporary dam shall onty be buflt from material such as dean gravel which will cause Mule orno sutation c. Temporary fills shall be constructed of non- erodible materials and shall be removed immediately upon completion of work PD Construction Supervisor OM Cities DP/DPW During project grading Prior to and during project grading Letter report from Consulting Acoustical Engineer to City CDD at completion of traffic noise monitoring. Pursuant to monitoring leouiie- ments of the City of Carlsbad Planning and Engineering Departments, or as stipulated by the certified EIR for this approved project Letter report from Consulting Paleontologist to City CDD at completion of monitoring Letter report from Construction Supervisor to City CDD at completion of improvements Frequency of inspections shall depend on the rate of excavation, the materials being excavated, and the abundance of fossils. In areas of high potential, monitoring shall be full- time, initially. The paleontologist shall be allowed to divert or re-direct grading in the area of an exposed fossil to facilitate evaluation and, if necessary, salvage. Any fossils collected shall be prepared to the point of identification and property curated before they are donated to their final repository. All collected fossils shall be donated to a public, non- profit institution with a research interest in the materials, such as the San Diego Natural History Museum. I 1 X-7 I * t * t fl f i f i 9 1 I I i l i I 1 I i i I i i i § ] TABLE lOjO-1 (conttaiied) MITIGATION MONITORING CHECKLIST Mitigation Measure Type Monitor Schedule Reporting Requirements 22. Adhere to die fallowing erofton/ifltttion OM Consttuction Supervisor Prior to and during project grading Letter report from Cowtiuction ; control measures: Cities DP/DPW Supervisor to City CDD at ! completion of improvements • a. No riprap, rock, or other impetmeable materials i shall be discharged into Endnitai Creek, except 1 as shown on approved plans ; b. When any dam (artificial obttroction) is being constructed. BiniTtninftiP, or placed in operation, sufficient water shall at all times be allowed to pass downstream to n»«fcitMn fish life below dam c. Except as required to move existing vegetation, dredge, and earth to construct this project; and except for those materials and measures used in the construction of this project; no debris, sou, silt, sand, bark, slash, sawdust, rubbish, cement or concrete, or washings thereof, ofl or petroleum • products, or associated activity of whatever nature shall be allowed to enter into or be placed where it may be washed by rainfall or runoff into ; Encinitas Creek 1 d. At completion of construction operations, any i excess materials or debris shall be removed ' from the wotk areas e. Any vegetation removed for initial construction shall be replaced with planted material at desig- nated locations, and appropriate replacement ratios 23. Pile Report of Waste Discharge (RWD) with CM Water Quality Specialist After project implementation No further letter report required San Diego RWQCB, per NPDES Permit requirements Cities DP/DPW 24. Inspect condition of riprap10 on upstream side of OM Certified HydrauKc Engineer Prior to road construction Letter report from Consulting El Camino Real bridge Cities DP/DPW Hydrologist to City CDD at 10 Provided this riprap is still in place and offering adequate erosion protection, no other forms of mitigation shall be required to protect the bridge piers and abutments from local scour. If the existing riprap is not providing adequate erosion protection, a detailed hydnutic analysis shau be conducted pirn to determine additional mitigation measures necessary to protect die bridge. completion of inspection X-8 Mitigation Measure TABLE 104-1 (coBtfBMd) MITIGATION MONITORING CHECKLIST Tjpe Monitor Schedule Reporting Requirements 25. Prepare detailed landscape/irrigation plant for «U PD manufactured dopes, with die following key OM components: a. Create pockets in cot facet where vegetation could better take hold by tcarifying dope* with termed blade to create 18-inch benchet b. Undulate, and round the top* and toes of dopes to better blend them into surrounding terrain c. Plant dopes with drought-tolerant vegetation to decrease water consumption, and provide biological and visual compatibility d. Increase planting densities for container shrubs and trees on aU dopes over 20 feet high e. Install drip irrigation system11 for container plants on slopes over 20 feet high f . Install two-tiered vegetated crib wall, or three- tiered slump-block retaining wall adjacent to Thompson property g. Implement monitoring program to ensure 80% CM vegetative cover of landscaped plant material on manufactured dopes at end of five yean, based on the following criteria: (1) If more than 20% of container stock have not survived within each year, dead material shall be replaced with same type and size as originally planted (2) Any hydioseeded areas not establishing shall be re-hydroseeded Registered Landscape Architect Prior to final "as-built" approval of grading Cities' Landscape Architect and landscape/inigation plans Qualified Hofticuloinlist Landscape Contractor CilieiDP/DPW During and immediately after plant installation, and during the Fall of each year, thereafter Letter report from Consulting Landscape Contractor to City CDD at completion of land- scape installation Annual letter report from Consulting Biologist to City CDD at completion of each survey * i r i PI 11 The Irrigation Plan shall avoid over-reliance on impact heads, such as lainbiids, which could saturate slopes, waste water, and erode the soil The slope irrigation system shall be maintained and operated until plant material has established an adequate root system, whereby supplemental irrigation is no longer required for plant survival X-9if fi f i r i fi ft fi ri r i fi fi fi fi r i r * 1 'i i i i i i i i i i i t MttlgafloB Measure TABLE 10.0-1 (oatkwed) MITIGATION MONITORING CHECKLIST Type Monitor Schedule Reporting Requirement* (3) An re-planting shall be accomplished during die winter months (4) Detennine and repair cause of f aflure prior to re-landscaping/re-hydroieeding 26. Provide tetnporuy service comncrions for aH PD public unlities/structurcs that may require re- location during project contraction 27. Implement the following SDG&E requirements PD for regional gas transmission line relocation: OM a. Maintain minimum 18-inch vertical separa- tion between any proposed underground utility and existing SDG&E facilities b. Maintain at least three feet of soil cover over the on-site gas mains at all times c. Notify SDG&B prior to commencement of construction activities near gas mains so that stand-by personnel may be dispatched to the construction site to monitor these activities d. Maintain vehicle access to on-site SDG&E easement at all time* e. No temporary or permanent structures shall be installed within SDG&E easement without prior written approval f. SDG&E's Gas Engineering Department shall review and approve all roadway improvement plans prior to final approval 28. Provide copies of the approved Traffic Control/ PD Detour Plan to County Sheriff's Dept (Encinitas Substation) and Bnchiitas/Carlshad Hie Depts. to advise mem of the variables potentially affecting response mode and time to the project area during the construction period Utility Companies' Engineers/ During road construction and permanent utility line No letter report required Qualified Agents relocations Constroction Supervisor Cities DPW Engineers SDG&E Representatives Construction Supervisor Cities DPW Engineers Commanding Lieutenant, Encinitas Sheriff's Station Hre Marshaus, Encinitas/ Carlsbad Fire Depts. Cities DP/DPW X-10 During road construction and permanent gas line relocation No letter report reqnried Prior to approval of final road improvement plans No letter report required 11.0 REFERENCES, PERSONS AND AGENCIES CONSULTED American Association of State Highway and Transportation Officials (AASHTO) 1990 A Policy on Geometric Design of Highways and Streets ASL Consulting Engineers 1988 Traffic Analysis for the Arroyo/La Costa (CT 88-3) Tentative Map Draft Environmental Impact Report Austin-Faust Associates, Inc. 1988 Traffic Analysis for the City of Encinitas General Plan Circulation Element Buchanan, Danny, Right-of-Way Liaison Officer, Pacific Bell Telephone Company 1991 Telecommunication with Michael J. Gonzales, BFMA (June). Chang, Howard, Ph.D. 1991 Drainage Study for Encinitas Creek. City of Carlsbad 1990 Arroyo/La Costa (CT 88-3) Tentative Map Final Environmental Impact Report (July 31). Diamond, Lynn, Research Analyst, City of Carlsbad Police Department 1991 Telecommunication with Michael J. Gonzales, BFMA (June). Everett, William T. 1979 Threatened, Declining, and Sensitive Bird Species in San Diego County. Fontanesi, Frank D., General Services Director, Olivenhain Municipal Water District 1991 Telecommunication with Michael J. Gonzales, BFMA (June). Gale, Jim, Traffic Engineering Technician, City of Carlsbad Public Works Department 1991 Telecommunication with Michael J. Gonzales, BFMA (June). Gallegos, Dennis and Andrew Pigniolo 1989 Cultural Resource Survey and Testing of a Portion of Site SDi-4872 (W-982) for the Olivenhain Road Alignment, Carlsbad, California. Guames, Ray, Traffic Engineering Technician, City of Encinitas Public Works Department 1991 Telecommunication with Michael J. Gonzales, BFMA (June). Hector, Susan, and Mac Davis 1989 A Cultural Resource Assessment of the Community Bank Project, La Costa, San Diego County. XI-1 Hendrickson, R., Sergeant, County of San Diego Sheriffs Department Encinitas Substation. 1991 Telecommunication with Michael J. Gonzales, BFMA (June). Jennings, Mark R. 1983 An Annotated Checklist of the Amphibians and Reptiles of California. JHK & Associates 1990 Traffic Analysis for the City of Carlsbad General Plan Circulation Element 1991 Intersection Analysis for Olivenhain Road/El Camino Real Intersection for the City of Carlsbad. Jones, J.K., et al. 1982 Revised Checklist of North American Mammals North of Mexico. Kurtz, James P., Senior Acoustician 1991 Personal Communication with Michael J. Gonzales, BFMA (June). LaMarsh, Robert J., Fire Chief, Encinitas Fire Protection District 1991 Telecommunication with Michael J. Gonzales, BFMA (June). Mock, Patrick, Senior Biologist, ERC Environmental and Energy Services Company 1989 Personal Communication with Michael J. Gonzales, BFMA (June). Roehl, Bill, Administrative Assistant, Leucadia County Water District 1991 Telecommunication with Michael J. Gonzales, BFMA (June). Rowson, Mark J., PJE., Project Design Consultants 1991 Contact Memorandum to Michael J. Gonzales, BFMA (February 4). Ruth, Michael, Project Hydrologist/Engineer, Nolte and Associates 1991 Telecommunication with Anne Marie Tipton-Golly, BFMA (May). Salvati, Steve, Management Intern, Encinitas Fire Protection District 1991 Telecommunication with Michael J. Gonzales, BFMA (June). San Diego Association of Governments (S ANDAG) 1988 Comprehensive Species Management Plan for the Least Bell's Vireo. Schultze, Lois, Secretary, County of San Diego Sheriffs Department, Encinitas Substation, Traffic Division 1991 Telecommunication with Michael J. Gonzales, BFMA (May). Smith, Brian F. 1990 An Evaluation of Cultural Resources within the Arroyo/La Costa Project, City of Carlsbad, California. XI-2 State of California, Department of Fish and Game (CDFG) 1990 Natural Diversity Data Base, Special Animals. State of California, Department of Transportation (Caltrans) 1987 Highway Design Manual Tate, James, Jr. 1986 The Blue List (National Audubon Society). Villegas, George, Senior Traffic Engineer, City of Encinitas, Public Works Department 1991 Telecommunication with James P. Kurtz, BFMA (April). Weston Pringle & Associates 1990 Traffic Analysis for the Arroyo/La Costa (CT 88-3) Tentative Map Final Environmental Impact Report Wheeler, Gary P. and Jack M. Fancher 1981 San Diego County Riparian Systems: Current Threats and Statuary Protection Efforts. Willdan and Associates 1991 .Intersection Analysis for Olivenhain Road/El Camino Real Intersection for the City of Encinitas. Wonseski, Tony, Project Engineer 1991 Telecommunication with Michael J. Gonzales, BFMA (June). M. IP XI-3 12.0 CERTIFICATION This Draft Environmental Impact Report presents a full analysis of all the identified resources and information concerning potentially significant environmental effects associated with the proposed Olivenhain Road Improvements Project, as required by the California Environmental Quality Act We hereby affirm that to the best of our knowledge and belief, the statements and information contained herein are in all respects true and correct Michael Gonz^les Project Manager This report was prepared by Brian F. Mooney Associates, of San Diego, California. Staff members contributing to this report are listed below. William R. Graham Michael Gpnzales Thomas M. Cherry Amy Fandel Donald E. Scoles John R. Cook W. Larry Sward James Kurtz Michael Baksh Anne Marie Tipton-Golly Debbie Surrcll Michael Scott Christy Rust Principal Associate Planner/Project Manager Senior Land Planner Assistant Environmental Planner Assistant Environmental Planner Senior Archaeologist Senior Biologist Senior Acoustician Assistant Archaeologist Assistant Biologist Production Specialist Graphic Artist Graphic Artist Consultants contributing to this report include: Project Design Consultants Dr. Howard Chang GEOCON, Inc. RMW Paleo Associates Nolle and Associates XH-1