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HomeMy WebLinkAboutCT 98-10; Carlsbad Raceway Business Park; Tentative Map (CT)CARLSBAD RACEWAY FINAL RIPARIAN MITIGATION PLAN September 10, 2004 Prepared for: H.G. FENTON COMPANY 7588 Metropolitan Drive San Diego, California 92108-4401 Prepared by : HELIX ENVIRONMENTAL PLANNING, INC. 8100 La Mesa Boulevard, Suite 150 La Mesa, California 91941-6476 Carlsbad Raceway Riparian Mitigation Plan TABLE OF CONTENTS Section Title SUMMARY 1 I. PROJECT DESCRIPTION 1 A. Project Location 1 B. Project Summary 1 C. Responsible Party 1 D. Jurisdictional Areas to be Filled by Habitat Type 1 E. Function and Value of Directly Impacted Jurisdictional Areas 3 1. Type of Jurisdictional Areas 3 2. Function and Value of Riparian and Wetland Habitats 3 II. GOAL OF MITIGATION 4 A. Type(s) of Created Habitat 4 B. Function and Value of Created Habitat.... 4 C. Time Lapse 5 D. Estimated Costs 5 III. FINAL SUCCESS CRITERIA 5 A. Target Function and Value 5 B. Target Hydrological Regime 5 C. Target Created Jurisdictional Acreage 6 IV. PROPOSED MITIGATION SITE 6 A. Location and Size of Mitigation Area 6 B. Ownership Status 6 C. Existing Function and Value of Mitigation Area 6 D. Present and Proposed Uses of Mitigation Area 6 E. Jurisdictional Delineation 6 F. Present and Proposed Uses of All Adjacent Areas 7 V. IMPLEMENTATION PLAN 7 A. Rationale for Expecting Implementation Success 7 B. Responsible Parties 7 1. Project Proponent 7 2. Landscape Architect 7 3. Restoration Specialist 7 4. Contractor(s) 8 C. Schedule 8 TABLE OF CONTENTS (cont.) Section Title Page V. IMPLEMENTATION PLAN (cont.) D. Site Preparation 8 1. Grading : 8 2. Fencing 9 E. Planting Plan 9 F. Irrigation Plan 11 G. As-built Conditions 12 1. As-built Submittal 12 2. Post-installation Report 12 VI. MAINTENANCE DURING MONITORING PERIOD 13 A. Maintenance Activities 13 1. General Maintenance 13 2. Fencing 13 3. Weed Control 13 4. Other Pests 14 5. Fertilization 14 6. Pruning 14 B. Responsible Parties 14 C. Schedule 14 VII. MONITORING PLAN 15 A. Success Criteria and Technical Monitoring Methods 16 1. Technical Monitoring 16 2. Annual Reports 17 B. Maintenance Monitoring 18 VIII. COMPLETION OF MITIGATION .1...18 A. Notification of Completion 18 B. ACOE and CDFG Confirmation 18 IX. CONTINGENCY MEASURES 18 A. Initiating Procedures 18 B. Alternative Locations for Contingency Mitigation 19 C. Funding Mechanism 19 D. Responsible Parties 19 X. REFERENCES CITED 20 TABLE OF CONTENTS (cont.) LIST OF FIGURES Follows Number Title 1 Regional Location Map 2 Project Vicinity 3 Final Wetland Restoration Plan. .2 .2 .6 LIST OF TABLES Number Title 1 Potential Impacts to ACOE Jurisdictional Areas 2 Potential Impacts to ACOE Jurisdictional Habitats. 3 Potential Impacts to CDFG Jurisdictional Areas 4 Potential Impacts to CDFG Jurisdictional Habitats. 5 Impacts/Mitigation 6 Southern Willow Scrub Plant Palette 7 Mule Fat Scrub Plant Palette 8 Freshwater Marsh Seed Mix 9 Maintenance Schedule 10 Success Criteria Milestones 11 Maintenance Monitoring Schedule Page .2 .2 .2 ...4 .10 .10 .11 .15 .15 .17 111 SUMMARY This plan presents a program for the mitigation of wetlands and non-wetland Waters of the U.S. for the Carlsbad Raceway site located in Carlsbad, San Diego County, California. The most recent wetland delineation was completed by HELIX Environmental Planning, Inc. in 2002 (HELIX 2002a). The purpose of this mitigation plan is to provide a framework for meeting mitigation obligations required in U.S. Army Corps of Engineers (ACOE) 404 Permit No. 982020500-RJL and California Department of Fish and Game (CDFG) Streambed Alteration Agreement No. R5-2002- 0088. Included in this document are a summary of project background information, an installation plan, and the monitoring program for the mitigation. I. PROJECT DESCRIPTION A. PROJECT LOCATION The Carlsbad Raceway property is located north of Palomar Airport Road and west of Business Park Drive in Carlsbad, San Diego County, California (Figures 1 and 2). On site, elevations range from approximately 310 feet to 495 feet. The site is currently a mix of developed and disturbed areas and natural habitats. Uses of the property include a drag strip, off-road motorcycle track, and associated parking areas. Surrounding land uses consist of industrial development and vacant or undeveloped land. The project site supports eight vegetation communities: Diegan coastal sage scrub, southern willow scrub, mule fat scrub, freshwater marsh, southern mixed chaparral, non-native grassland, agriculture, and disturbed/developed. B. PROJECT SUMMARY The proposed project includes the development of approximately 112 acres of the 145 acres on site as a business park consistent with existing zoning for the property. Currently, it is assumed that Melrose Drive will be constructed within the project boundaries as part of the Palomar Forum project, although impacts and mitigation from this road construction are considered in this report. C. RESPONSIBLE PARTY Mr. Allen Jones H.G. Fenton Company 7588 Metropolitan Dr. San Diego, CA 92108 Phone: (619)400-0120 Fax: (619)400-0111 D. JURISDICTIONAL AREAS TO BE FILLED BY HABITAT TYPE Two types of ACOE jurisdictional areas would be impacted on site, including wetlands (0.12 acre) and non-wetland Waters of the U.S. (0.17 acre; Tables 1 and 2; refer to the wetland delineation report for Carlsbad Raceway [HELIX 2002a] for more details). Jurisdictional wetland habitats to be impacted consist of 0.12 acre of freshwater marsh. No impacts to ACOE jurisdiction would occur from construction of Melrose Drive. HELIX Final Riparian Mitigation Plan for Carlsbad Raceway I FWP-06 / September 10, 2004 1 Table 1 POTENTIAL IMPACTS TO ACOE JURISDICTIONAL AREAS* Jurisdiction ACOE wetland ACOE Non-wetland Waters of the U.S. Existing 1.20 0.51 IMPACTS Melrose Drive . — Carlsbad Raceway Property Project 0.12 0.17 Total 0.12 0.17 Remaining 1.15 0.34 *A11 numbers are in acres. Table 2 POTENTIAL IMPACTS TO ACOE JURISDICTIONAL HABITATS JURISDICTIONAL HABITAT Freshwater marsh Streambed TOTAL ACRE 0.12 0.17 0.29 CDFG jurisdictional areas to be impacted (0.89 acre) include wetland habitats and streambed (Tables 3 and 4). The wetland habitat impacts include 0.14 acre of freshwater marsh, 0.14 acre of mule fat scrub, and 0.44 acre of southern willow scrub. Streambed impacts total 0.17 acre. Table 3 POTENTIAL IMPACTS TO CDFG JURISDICTIONAL AREAS* Jurisdiction CDFG jurisdictional areas Existing 4.82 IMPACTS Melrose Drive 0.15 Carlsbad Raceway Property Project 0.74 Total 0.89 Remaining 3.90 *A11 numbers are in acres. Table 4 POTENTIAL IMPACTS TO CDFG JURISDICTIONAL HABITATS JURISDICTIONAL HABITAT Freshwater marsh Southern willow scrub Mule fat scrub Streambed TOTAL ACRE 0.14 0.44 0.14 0.17 0.89 HELIX Final Riparian Mitigation Plan for Carlsbad Raceway I FWP-06 / September 10, 2004 ORANGE SAN DIEGO PROJECT LOCATION DIEGO * Sweetwater r:i»3 Reservoir ^ UNITEDBSJATES • "^^ MlxiCO y HELIX R^egionaS Location Map CARLSBAD RACEWAY Figure 1 >H CO O) i Q PQoo U I I I i i i i i i i i i E. FUNCTION AND VALUE OF DIRECTLY IMPACTED JURISDICTIONAL AREAS 1. Type of Turisdictional Areas Jurisdictional areas to be impacted by the proposed project include three riparian and wetland habitat types, in addition to streambed. Freshwater Marsh Approximately 0.12 acre out of 0.76 acre of ACOE Jurisdictional freshwater marsh would be directly impacted by the project. Approximately 0.14 acre out of 0.89 acre of CDFG Jurisdictional freshwater marsh would be directly impacted by the project. This community is comprised primarily of cattails (Typha sp.). Southern Willow Scrub No ACOE Jurisdictional southern willow scrub would be impacted by the project. Approximately 0.44 acre out of 3.34 acres of CDFG Jurisdictional southern willow scrub would be directly impacted by the project. Southern willow scrub consists of dense, broad-leaved, winter-deciduous stands of trees dominated by shrubby willows (Salix spp.) in association with mule fat (Baccharis salidfolia). This community occurs on loose, sandy, or fine gravelly alluvium deposited near stream channels during flood flows. Mule Fat Scrub Mule fat scrub does not fall under the jurisdiction of the ACOE on the Carlsbad Raceway site. Approximately 0.14 acre out of 0.18 acre of CDFG Jurisdictional mule fat scrub would be directly impacted by the project. On site, mule fat scrub is characterized by stands dominated by mule fat to the exclusion of almost all other plant species. Streambed Approximately 0.17 acre out of a total 0.51 acre (3,450 linear feet) of ACOE non-wetland Waters of the U.S. would be directly impacted by the project. In this case, CDFG Jurisdictional streambed is the same as ACOE non-wetland Waters of the U.S., and the impacts are also the same. These streambeds convey water but do not support riparian or wetland habitats. 2. Function and Value of Riparian and Wetland Habitats Riparian and wetland habitats serve a multitude of purposes. They have positive effects on water quality, wildlife, and the human population of an area. Important wetland functions include flood conveyance, flood storage, control of water quality, and sediment control. Wetlands also provide habitat for invertebrates, fish, amphibians, reptiles, birds, and mammals. Specifically, the riparian and wetland areas of the Carlsbad Raceway have a fairly well developed overstory but are narrow and, at the time of delineation, were largely void of herbaceous vegetation due to scouring from recent storm flows. Even so, they provide a moderate level of function and have moderate value. Finally, the non- wetland Waters of the U.S. (streambed) on site provide function and have value largely limited to flood conveyance. The existing function and value on the site would largely be retained with most riparian and wetland habitat being preserved and enhanced and facilities being installed to convey runoff, prevent sedimentation, and improve water quality. HELIX ___ Final Riparian Mitigation Plan for Carlsbad Raceway I FWP-06 / September 10, 2004 3 II. GOAL OF MITIGATION The goal of the mitigation plan is to compensate for the loss of ACOE and CDFG jurisdictional habitats and streambed and their associated function and value. The proposed mitigation would increase the amount of these habitats on site and provide improved flood conveyance, flood storage, control of water quality, and sediment control. Additionally, the mitigation would provide additional habitat for invertebrates, fish, amphibians, reptiles, birds, and mammals. A. TYPE(S) OF CREATED HABITAT The loss of southern willow scrub, freshwater marsh, and mule fat scrub would be mitigated by creating southern willow scrub, mule fat scrub, and freshwater marsh on site where disturbed habitat currently occurs. These, created habitats would connect existing wetland habitats in the main drainage on site. The acreage of southern willow scrub, freshwater marsh, and mule fat scrub impacted and the corresponding mitigation acreage is presented in Table 5. These habitats will be mitigated at a minimum 2:1 ratio to ensure no net loss of wetlands. Table 5 IMPACTS/MITIGATION Jurisdictional Resource Southern willow scrub Freshwater marsh Mule fat scrub Subtotal Streambed TOTAL ACREAGE Present On Site 3.34 0.76 0.21 4.31 0.51 4.82 Impacted* 0.44 0.14 0.14 0.72 0.17 0.89 Preserved On Site 2.90 0.62 0.07 3.59 0.34 3.93 Minimum to be Created On Site 1.32 0.28 0.28 1.88 0.17 2.05 Total Minimum On Site After Mitigation 4.22 0.90 0.35 5.47 0.51 5.98 Resulting Mitigation Ratio 3:1 2:1 2:1 2:1 l:lt — *Presents greatest amount impacted (i.e., CDFG jurisdiction). | Although only 0.17 acre is required, 1.1 acres will be created. Additionally, the loss of non-wetland Waters of the U.S. (streambed) would be mitigated by restoring a streambed connection with the main drainage where water is currently diverted in a previously upland area along the edge of the drag strip. The impacted acreage of non-wetland Waters of the U.S. (streambed) impacted and the corresponding mitigation acreage are presented in Table 5. B. FUNCTION AND VALUE OF CREATED HABITAT The created riparian and wetland habitats would increase the function and value of the existing habitats on site by expanding their area. Wildlife diversity and density in the drainage is anticipated to increase as a result of the mitigation plan. One of the goals of the mitigation plan is to increase the HELIX Final Riparian Mitigation Plan for Carlsbad Raceway / FWP-06 / September 10, 2004 value of the drainage for wildlife habitat. The increased riparian habitat will provide new nesting opportunities for riparian bird species. The increased cover will allow greater use of the drainage by larger mammals. Other wildlife species, notably amphibians, songbirds, and small- to medium-sized mammals should also increase in numbers and diversity. The increase in wildlife use will be primarily from the replacement of disturbed and/or weedy habitats with native riparian vegetation. C. TIME LAPSE The construction of the proposed mitigation site will occur concurrently with grading for the projects to be mitigated, or at the latest within one year from completion of the major site grading. If possible, installation of plant materials will occur at the start of the rainy season. The monitoring program will take place over a five-year period. The success criteria described below for this project will be met by the end of this period. These criteria represent an intermediate stage in the long-term development of the riparian habitat. It may take longer for the restored habitat to become equivalent to the natural riparian habitat. D. ESTIMATED COSTS Implementation of the mitigation, maintenance, and monitoring tasks described in this document are expected to cost approximately $240,000, excluding grading costs. This amount includes money for implementation and five years of biological monitoring and reports. III. FINAL SUCCESS CRITERIA The following sections provide standards to determine the successful implementation of the mitigation plan. Attainment of these standards indicates the mitigation area meets the habitat function and value described above. Methods to measure these success criteria are described in the following text. A. TARGET FUNCTION AND VALUE This mitigation plan would create approximately 1.88 acres of southern willow scrub, freshwater marsh, and mule fat scrub along the main stream in open space on site. The goal of this effort is to create riparian and wetland habitat similar to that found on other parts of site. Additionally, a minimum of 0.17 acre of streambed would be created on site to replace that lost by proposed development. B. TARGET HYDROLOGICAL REGIME The hydrological regime within the mitigation area would be altered from supporting disturbed upland habitats to supporting riparian and wetland habitats. The hydrological regime would vary with the habitat type. The target hydrological regime for the freshwater marsh would provide permanently saturated soils. The hydrological regime for the southern willow scrub and mule fat scrub would provide groundwater that is near the surface and subject to occasional flooding. The long-term source of water will be natural runoff, although temporary irrigation will be used as appropriate to add plant establishment and growth. HELIX Final Riparian Mitigation Plan for Carlsbad Raceway I FWP-06 / September 10, 2004 5 C. TARGET CREATED JURISDICTIONAL ACREAGE At the end of the monitoring period, a minimum of 1.88 acres of southern willow scrub, freshwater marsh, and mule fat scrub would be created as part of the project's proposed mitigation requirements. Additionally, 0.17 acre of streambed would be created on site. IV. PROPOSED MITIGATION SITE A. LOCATION AND SIZE OF MITIGATION AREA The riparian mitigation site is located on the Carlsbad Raceway site in 33 acres of open space (Figure 3). Upland areas adjacent to the riparian and wetland mitigation would be revegetated with coastal sage scrub as described in the Carlsbad Raceway Upland Mitigation Plan (HELIX 2002b). B. OWNERSHIP STATUS The mitigation area is owned by H.G. Fenton Company. A conservation easement is being placed on the property in perpetuity. The holder of this easement will be a land management organization or similar entity. C. EXISTING FUNCTION AND VALUE OF MITIGATION AREA Existing riparian and wetland habitats in the mitigation area include the main stream and three small tributaries. The existing riparian corridor varies (5 to 305 feet wide) with patchy riparian and wetland vegetation. Surrounding habitat is coastal sage scrub, southern mixed chaparral, and disturbed habitat. D. PRESENT AND PROPOSED USES OF MITIGATION AREA Presently many dirt roads and disturbed habitat areas used by motorcycles occur throughout the open space on site. All of the disturbed habitat in the open space is proposed to be restored, both with upland and riparian/wetland vegetation and managed as biological open space in perpetuity. E. JURISDICTIONAL DELINEATION Descriptions of the ACOE jurisdictional areas can be found in the jurisdictional delineation report (HELIX 2002a). Out of a total of 1.79 acres of ACOE jurisdictional areas on the project site, impacts would occur to 0.12 acre of freshwater marsh and 0.17 acre of non-wetland Waters of the U.S. Descriptions of the CDFG jurisdictional areas can be found in the jurisdictional delineation report (HELIX 2002a). Out of a total of 4.79 acres of CDFG jurisdictional areas on the project site, impacts would occur to 0.14 acre of freshwater marsh, 0.44 acre of southern willow scrub, 0.14 acre of mule fat scrub, and 0.17 acre of streambed. HELIX Final Riparian Mitigation Plan for Carlsbad Raceway I FWP-06 / September 10, 2004 Wetland areas exceed amount required. Final area will be determined during preparation of final construction documents for the restoration plan. Note: ' !This map is based on site conditions'as observed at the time of our field • investigations. The information presented herein was developed by visual inspection and/or aerial photograph interpretation. Note that both site conditions and applicable regulatory requirements may change. Job No: FWP-06 Date: 09/10/04 I:\GIS\F\FWP-06 CarlsbadRacewayjlalaVfwiMM.^mitigation - wetlands 9/27/02 Final Wetland Restoration Plan CARLSBAD RACEWAY F. PRESENT AND PROPOSED USES OF ALL ADJACENT AREAS Undeveloped land currently surrounds the proposed mitigation area. After development, the land immediately south and east of the mitigation would be a business park. Melrose Drive would occur to the west. V. IMPLEMENTATION PLAN A. RATIONALE FOR EXPECTING IMPLEMENTATION SUCCESS The areas selected for mitigation are directly adjacent to existing riparian and wetland vegetation. A soil study would be conducted to refine the exact placement of the mitigation and to confirm that appropriate hydrology exists for the mitigation effort. A vital part of this plan is to contour-grade the topography to create the associated hydrology necessary to increase the amount of riparian habitat in the mitigation areas. B. RESPONSIBLE PARTIES 1. Project Proponent H.G. Fenton Company will be responsible for financing the installation and monitoring of this mitigation plan. 2. Landscape Architect HELIX's licensed landscape architect Gary Ruyle will prepare the construction documents, including grading, irrigation, and planting plans. Mr. Ruyle will inspect the irrigation system and assist in other inspections (e.g., plant deliveries) as necessary. 3. Restoration Specialist Overall supervision of the site preparation, installation, maintenance, and monitoring of this mitigation project will be the responsibility of a restoration specialist. Day-to-day decisions regarding the implementation of this plan will be the responsibility of the restoration specialist. This person has the authority to substitute and change this plan as conditions of the site dictate, as long as the appropriate resource agencies are notified. The restoration specialist will educate all participants with regard to mitigation goals and requirements and directly oversee the grading operations and installation of plant materials. The restoration specialist will also provide guidance to the project proponent and contractor during the five-year maintenance phase. ACOE and CDFG shall be notified of who the restoration specialist is, along their address, telephone number, email address, and work schedule prior to initiating impacts to ACOE and CDFG jurisdictional areas. HELIX Final Riparian Mitigation Plan for Carlsbad Raceway / FWP-06 / September 10, 2004 4. Contractor(s) Under direction of the restoration specialist, the installation and maintenance contractor(s) will be responsible for completion of grading, pre-planting weed control, planting, and seeding. The restoration specialist will educate the contractor(s) on the installation and maintenance of riparian and wetland plant species. The contractor(s) will service the entire mitigation area at least once a month. Service will include but not be limited to weed control, dead plant replacement, and reseeding. The maintenance contractor will meet the restoration specialist at the site when requested and perform all checklist items in a timely manner as directed by the project proponent. The restoration specialist will educate the contractor on the maintenance of native plant habitat and the difference between native plants and non-native weeds. C. SCHEDULE Implementation of the mitigation is expected to begin in conjunction with site development and as soon as site conditions are appropriate. Initial activities will include marking of all mitigation areas and grading. Monitoring of the mitigation effort will begin with installation. The monitoring program will continue for five years. An annual report will be prepared and distributed to the ACOE and CDFG by January. At the conclusion of the monitoring period, a final report will be distributed to the ACOE and CDFG. D. SITE PREPARATION 1. Grading Grading is proposed to remove accumulated alluvium and bring the ground surface closer to the water table. This will allow for establishment and long-term survival of riparian and wetland plant species. The anticipated results of the grading effort are: (1) an increase in floodflow capacity; (2) enhancement of riparian and wetland vegetation components that will trap sediments and buffer the peak flows of the channel due to the increased hardscape in the watershed; and (3) removal of non-native vegetation. Site grading will eliminate some weed-infested soils. Care will be taken to reduce sedimentation of the existing riparian community and water through installation of silt fencing along the graded edge. All refuse will be removed and disposed of in a licensed landfill. Under the direct supervision of the restoration specialist, the grading contractor will conduct grading of the proposed mitigation areas. All areas to be graded will be marked with gypsum, or stakes and flagging. An on-site meeting will be held with the grading contractor and the restoration specialist to identify sensitive areas and devise a strategy for avoidance prior to initiation of mitigation activities. Sensitive areas to be avoided are the existing riparian and wetland habitats and non-wetland Waters of the U.S. (streambed). These areas will be clearly marked with stakes and flagging. Specific staging areas will be established in disturbed areas. All vehicles and construction equipment will be restricted to the staging area(s) when not required for mitigation activities. HELIX Final Riparian Mitigation Plan for Carlsbad Raceway I FWP-06 / September 10, 2004 Final grades must be at the same elevation as the adjacent existing wetlands and/or within 1 to 3 feet of groundwater. The ground surface following final grading should be left in a rough state with micro- and macro-topographic relief (including pits, ponds, hummocks, and secondary channels) that mimics wetland topography. The soil texture must be suitable for the intended plant community. To that end, areas planted with southern willow scrub, sycamore woodland, and mule fat scrub shall have at least a 2-foot depth (as measured from the surface) of silt loam, loam, sandy loam, or sand by (if necessary) over excavation and back filling the mitigation areas with suitable salvaged soils. Freshwater marsh areas may have finer soil textures and are not covered by the design criteria. Alluvial material and topsoil should be salvaged and reused to the extent practicable. 2. Fencing Existing riparian, wetland, and other native vegetation to be preserved will be protected during the mitigation area preparation process with construction fencing, which will limit access to open space and mitigation areas to workers and machines implementing the mitigation. Fencing will also be erected where necessary to assure that existing riparian vegetation is not damaged during installation of the mitigation plans. The restoration specialist will flag the limits of the mitigation work area prior to grading or clearing. A temporary fence will be erected around the created riparian mitigation areas. Such fencing will remain in place until the end of the grading process or until the restoration specialist considers it no longer necessary. Additional fencing may be required at any time if considered necessary by the restoration specialist to protect open space vegetation. Prior to any grading, the site will be inspected by the restoration specialist to ensure that all fencing has been installed correctly and in the proper locations. The restoration specialist will certify in writing to the ACOE and CDFG that the limits of the site open space areas have been properly fenced before the contractor may proceed with work. Silt fencing, or barriers, will be installed at the limits of construction to prevent additional impacts from the spread of silt from the construction zone into adjacent jurisdictional areas. If impacts do occur outside of the limits identified in this report, all work shall cease and the ACOE and CDFG will be notified immediately. Any impacts to jurisdictional areas outside of the previously approved area will result in a 5:1 mitigation ratio, which will be subject to ACOE and CDFG approval of design, installation, and establishment. E. PLANTING PLAN The plan creates 1.88 acres of southern willow scrub, freshwater marsh, and mule fat scrub, which serve as habitat for wildlife that depend on riparian plant species for food and cover. The applicant proposes to expand the existing riparian plant community based upon floristic composition described in the biological technical report for the Carlsbad Raceway. The plan for most of the area is to create a mosaic of southern willow scrub (Table 6) and mule fat scrub (Table 7) that would attain a mature overstory canopy coverage of 50 percent. This seed mix is expected to establish a diverse understory composed of low growing grass species and taller growing shrub species. The freshwater marsh habitat (Table 8) will be dominated by emergent, herbaceous perennials and will be established by seeding. HELIX Final Riparian Mitigation Plan for Carlsbad Raceway I FWP-06 / September 10, 2004 9 Table 6 SOUTHERN WILLOW SCRUB PLANT PALETTE Scientific Name Common Name Spacing on Center* (feet) Grouping Size Number or Lbs Per Acre OVERSTORY Salix gooddingii Salix exigua Salix lasiolepis Populus fremontii southwestern willow sandbar willow arroyo willow Fremont cottonwood 12 8 10 8 12-17 18-22 25-30 2-4 TOTAL 220 100 250 25 595 UNDERSTORY Baccharis salidfolia Sambucus mexicana Isocoma menziesii mule fat Mexican elderberry goldenbush 6 12 5 30-40 3-5 6-9 TOTAL 350 50 75 475 SEED MIXTURE Ambrosia psilostachya Artemisia douglasiana Juncus acutus ssp. leopoldii western ragweed Douglas sagewort southwestern spiny rush not applicable TOTAL 2 3 2 7 Table 7 MULE FAT SCRUB PLANT PALETTE Scientific Name Common Name Spacing on Center* (feet) Grouping Size Number or Lbs Per Acre CONTAINER STOCK Baccharis salidfolia Salix exigua Disticlis spicata Iva hayesiana Sambucus mexicana Leymus triticoides mule fat sandbar willow saltgrass San Diego marsh elder blue elderberry creeping wild rye 6 6 2 5 10 2 3-5 10-12 100 5-7 4-6 50 TOTAL 350 350 1,000 ' 225 55 500 2,480 SEED MIXTURE Ambrosia psilostachya Artemisia douglasiana Artemisia palmeri Oenothera hookeri Leymus condensatus western ragweed Douglas sagewort Palmer's sagewort California evening primrose giant wild rye not applicable TOTAL 1 3 2 1 2 9 *A11 container stock will be 1-gallon except for Disticlis spicata and Leymus triticoides, which will be installed as plugs. HELIX Final Riparian Mitigation Plan for Carlsbad Raceway / FWP-06 / September 10, 2004 10 Table 8 FRESHWATER MARSH SEED MIX Scientific Name Scirpus acutus Scirpus maritimus Eleocharis macrostachya Juncus acutus ssp. leopoldii Pluchea odorata Iva bayesiana Common Name viscid bulrush prairie bulrush spikerush southwestern spiny rush salt marsh fleabane San Diego marsh elder TOTAL Lbs/Acre 2 3 2 3 2 1 13 One-gallon nursery-grown container plants (grown from cuttings propagated from on-site or nearby sources) and native seed will be used in creating the riparian habitat. Seeding will include annual and perennial species. Fast-growing annual species that are quick to germinate will provide initial cover and protect freshly graded soils from erosion. During the course of plant succession, it is anticipated that perennial species will dominate over the long term. The species, size, density, and quantity for riparian mitigation areas are presented in Tables 6 and 7. The hydroseed lists include the plant name and pounds of seed per acre. This seed mix is expected to mature into a mosaic understory composed of low growing sub-shrub species and taller growing shrub species. F. IRRIGATION PLAN After the initial plant establishment period, water will be applied infrequently and only as needed to prevent the mortality of plants and seedlings. The irrigation schedule will attempt to develop a deep root growth by incorporating evenly spaced, infrequent, deep applications of water. To obtain deep penetration of water, the irrigation system may be activated several times in one 24-hour period. The irrigation system will incorporate the use of moisture sensors connected to an irrigation controller. This will allow for the application of water on an as-needed basis. Once the plant material is established and does not require supplemental irrigation, the above-ground portions of the system will be removed. The restoration specialist will determine how and when the system will be removed. The goal is to obtain germination and growth with the least amount of irrigation. Frequent irrigation encourages weed invasion and leaches nutrients from the soil. Native plantings that are infrequently irrigated may grow slower initially but will ultimately develop better as habitat. As a result, irrigation will be used for the first three years (or less) of the monitoring period. During the final two years, the monitoring would determine the success of the mitigation program without irrigation. HELIX Final Riparian Mitigation Plan for Carlsbad Raceway IFWP-06 I September 10, 2004 G. AS-BUILT CONDITIONS Two reports must be provided to the agencies following completion of the installation. An as-built submittal is due to the ACOE, CDFG, and City within 60 days, and a post-installation report is due to ACOE within 120 days. Any changes to the mitigation design during its implementation must also be made known to the ACOE immediately. 1. As-built Submittal An as-built report that includes the bulleted items below will be submitted to ACOE and CDFG within 60 days after completion of installation. • Cover sheet with a location map and sheet index; • Plan view map (11x17 or larger) of the natural and mitigation areas color-coded by vegetation type; • Overview map (l" = 200' scale) showing three pre- and post-construction cross section survey areas; • Set of sheets (H: 1" = 50' and V: 1"=10' showing the relative pre- and post-construction elevations of the 3 cross sections); • Topography-based plans showing the layout of planting, irrigation, and sampling (e.g., transect) locations; • A schedule of activities and events of the implementation; and • Representative photographs of the installation. 2. Post-installation Report A post-installation report that includes the following will be submitted to ACOE and CDFG within 120 days after completion of installation. • Rational and methods for selection of reference and sampling sites. ACOE has recommended stratified random placement of transects (stratified by community type with transects having an equivalent coverage of at least two 50-meter belt transects per acre) to ensure that all mitigation areas (i.e., effects of area, sample size, species composition, community type, heterogeneity, variability, etc.); • How reference area selection and sampling locations may affect the results (e.g., effects of area, sample size, species composition, community type, heterogeneity, variability, etc.); • How plants were sited in relation to soil conditions; • The habitat creation techniques used (e.g., soil amendments, etc.); • The acres of habitat created, restored, preserved and enhanced (total acreage and by vegetation type). HELIX Final Riparian Mitigation Plan for Carhbad Raceway / FWP-06 / September 10, 2004 12 VI. MAINTENANCE DURING MONITORING PERIOD A. MAINTENANCE ACTIVITIES The maintenance program is proposed to ensure the successful establishment and persistence of the riparian habitat. 1. General Maintenance Damage to plants, irrigation systems, and other facilities occurring as a result of unusual weather or vandalism will be repaired as directed by the restoration specialist. The cost of such repairs will be paid for as extra work. The contractor at his expense will repair any erosion damage caused by the contractor's inadequate maintenance or operation of irrigation facilities, as determined by the restoration specialist. Planted areas will .be kept free of debris and will be checked by the installation and monitoring contractor(s). During the first year of the contract, these events will be biweekly and monthly during the remainder of the contract. The areas also will be checked for any vandalism, irrigation modifications and scheduling, plant material condition and health, and weeding. These maintenance guidelines are specifically tailored for native plant establishment. Maintenance personnel will be fully informed of the habitat creation/enhancement program so that they understand the goals of the effort and the maintenance requirements. A professional with experience and knowledge in native habitat creation/enhancement maintenance will supervise all maintenance. 2. Fencing The contractor will be responsible for repairing all damage to protective fencing within two working days of such damage. If at any time workmen or machines damage vegetation outside the limits of work, the contractor will bear the full cost of having the landscape architect complete a restoration landscape plan for the area as well as the costs for monitoring the success of the restoration according to the same standards as the original mitigation. Only construction equipment necessary to accomplish the landscape installation will be allowed in the mitigation areas. Workers' vehicles will be parked outside the riparian open space and all equipment will be removed from the site as soon as its task is completed. No vehicular fluids will be added or changed on site. 3. Weed Control Weed eradication will be conducted as necessary to minimize competition that could prevent the establishment of native species. As weeds become evident, they should be removed by hand or controlled with the proper herbicides. The restoration specialist will determine the need for weeding and will contact the landscape contractor for any required work. Maintenance personnel will be trained to distinguish weed species from desirable native vegetation. HELIX | ^_ Final Riparian Mitigation Plan for Carlsbad Raceway / FWP-06 I September 10, 2004 13 A cleared space 18 inches from the base of the plant will be maintained around each container plant to minimize competition from other plants during the establishment period or until plants reach 3 feet in height. A mulch of chipped plant materials will be used to help maintain this weed-free area. Examples of weeds to be controlled include but are not limited to pampas grass (Cortaderia sp.), giant reed (Arundo donax), tamarisk (Tamarix spp.), cocklebur (Xanthium strumarium), bristly ox-tongue (Picris echioides), and rabbitsfoot grass (Polypogon monspe liens is). Plants will be replaced at the direction of the restoration specialist. The contractor will be responsible for replacing any dead or terminally diseased plants at least one month prior to the end of the initial establishment period. Plant replacement by the maintenance contractor will be completed within 90 days of written direction by the restoration specialist. 4. Other Pests Insects, vertebrate pests, and diseases will be monitored. Generally speaking, a high threshold of tolerance will be permitted before control measures are considered. Specific recommendations will be made only by a licensed pest control adviser as required by law. All applicable federal and state laws and regulations will be closely followed. The restoration specialist will be consulted on any pest control matters. 5. Fertilization Fertilizer will not be applied except in extraordinary circumstances and only at the written direction of the restoration specialist. 6. Pruning No post-installation pruning is necessary unless otherwise directed by the restoration specialist. B. RESPONSIBLE PARTIES H.G. Fenton Company will be the responsible party for ensuring implementation of the maintenance program. C. SCHEDULE Maintenance as described under Section VILA, will be contracted for a period of five years. VII. MONITORING PLAN Maintenance will occur according to the schedule outlined below in Table 9. This is a minimum requirement for maintenance, and additional visits may be necessary depending on site conditions. Additional maintenance visits will be conducted at the request of the restoration specialist. MELIX Final Riparian Mitigation Plan for Carlsbad Raceway IFWP-06 / September J 0, 2004 14 Table 9 MAINTENANCE SCHEDULE PHASE First 3 months following installation* Remainder of Year 1 Years 2 and 3 Years 4 and 5 SCHEDULE Twice per month Twice per month Monthly Every other month *Performed by the installation contractor (120-day installation period); remainder of five years performed by maintenance contractor. VII. MONITORING PLAN Monitoring will be carried out under the direction of the restoration specialist to direct maintenance activities (maintenance monitoring) and assess the progress (technical monitoring) of the restoration effort. Maintenance monitoring will rely on visual observations of plant establishment and growth and other site conditions (e.g., soil stability). Technical monitoring will rely on quantitative criteria to measure the success of the mitigation. Final and yearly success criteria are included to measure interim and ultimate habitat development (Table 10). Technical monitoring and reporting, including quantitative sampling, will be done for Years 3, 4, and 5. Annual reports will also be done for the first and second years. These reports will focus more on what has been done in the previous year for maintenance and what (if any) adjustments are necessary to ensure ultimate success of the restoration project. Table 10 SUCCESS CRITERIA MILESTONES1 CRITERIA Species diversity2 Similarity3'4 Native species cover (for trees, shrubs, and herbaceous species)4 YEAR 3 0.6 0.5 0.55 4 0.7 0.65 0.75 5 0.8 0.9 0.9 'Values are relative to reference site. 2Greater than or equal to amount shown. 'Percent total cover; weed cover for the area without maintenance would likely be much higher. The values given here for Years 3 and 4 are for habitat maintained by a landscape contractor. 4Less than or equal to amount shown. HELIX Final Riparian Mitigation Plan for Carlsbad Raceway I FWP-06 I September 10, 2004 15 A. SUCCESS CRITERIA AND TECHNICAL MONITORING METHODS 1. Technical Monitoring Technical monitoring shall be done to evaluate the success of the effort. Success is defined as the restoration of a functional ecosystem at this site. The means of determining success is a series of measurements for species diversity, recruitment, exotic species cover, and native species cover. All of these except weed cover should increase over time and eventually approach extant habitat in a reference site. Weed cover should be the opposite; it should decrease with time. The reference site will be extant habitat located in open space onsite. Technical monitoring will be done for the first time in September following the third growing season after installation; subsequent annual monitoring measurements will also be done in September. The reference sites shall be located within the preserved habitat covered by this plan. The reference site locations are subject to the approval of ACOE and CDFG. Reference sites must be approved by the ACOE and CDFG within 60 days of implementation of the plan. Data from the reference sites will only be conducted once, unless there is a major change in the canyon's preserved habitats, such that the original reference data is no longer relevant. Data from the reference sites will be collected during the first technical monitoring event (Year 3), which will allow for weed control to occur in the preserved habitat several years prior to data collection. Sampling Techniques One 5-meter by 50-meter belt transect per acre will be used to monitor the development of the revegetation. The transects will be randomly located for the first sampling event and permanently marked to facilitate their use in subsequent years. Herbaceous, shrub, and tree vegetation layers will be sampled by a line transect in the middle of the belt transect. At each 0.5-meter interval, the species that intercept that point will be noted according to strata. All species that occur within the belt transect will also be noted. Please refer to the California Native Plant Society vegetation sampling method for further details (Sawyer and Keller-Wolf 1995). The analysis must explicitly account for the effects of area and sampling size. Photo Documentation In addition to the technical measurements, several permanent stations for photo documentation will be established in each habitat type. Species Diversity and Recruitment Species diversity and recruitment are closely linked, and diversity increases with recruitment. Species diversity is the number of species in a given area: the higher the number of species, the higher the diversity. Recruitment is the successful, natural reproduction and/or establishment of plants in a given area. Recruitment should increase diversity to approach the number of species in the control site transects. At the end of the five-year monitoring period the species diversity of the treatment transects should be 0.8 of the species diversity of the reference area. Species diversity will be measured by inventory of all species within the belt transects. HELIX Final Riparian Mitigation Plan for Carlsbad Raceway I FWP-06 I September 10, 2004 14 Recruitment will also be noted during the technical monitoring events. Any seedlings within the belt transect will be counted by species and compared to the reference habitat. Exotic Species (Weeds) Cover Weeds are typically a problem with habitat restoration, particularly at the outset of the project. As the restoration takes hold, weed problems should decrease. Many weeds have become naturalized, and typically there is a tolerance for weeds that is reflected in what is present at the existing habitats on site. Weeds will be controlled as specified in the maintenance monitoring section, and at no time will weed cover in excess of 10 percent be allowed. Native Species Cover Native vegetation cover should increase over time and ultimately approach that of the existing adjacent habitat (Table 11). Cover within the restoration area is often slow at first as the plants become established, but with sufficient rainfall it should approach 100 percent of the existing adjacent habitat in five years. Cover will be measured and evaluated separately for tree, shrub and herbaceous life forms as compared to established control (as described above). Table 11 MAINTENANCE MONITORING SCHEDULE PHASE Grading/Site Preparation Installation SCHEDULE 2 times per week Daily Post Installation Year 1 Year 2 February to July August to January Years 3 to 5 Monthly Monthly Twice: September and December Quarterly: March, June, September, and December If the restoration area's criteria are measured to be 100 percent of the reference site, then the two sites are the same. For example, if the native species cover of the reference site is 60 percent and the native species cover of the restoration site is 42 percent, the restoration site has 0.7 of the reference site's native cover. Similarly, if weed cover at the reference site is 10 percent and weed cover at the restoration site is 12 percent, the restoration site has 1.2 of the reference site's weed cover. 2. Annual Reports As part of the monitoring program, the HELIX-prepared annual reports will be submitted to the ACOE and CDFG evaluating the success of the mitigation effort to date, along with any recommendations for future work that may be deemed necessary. Monitoring events that focus on HELIX Final Riparian Mitigation Plan for Carlsbad Raceway I FWP-06 / September 10, 2004 17 quantitative data collection (i.e., percent cover, species diversity, etc.) will occur annually for years three, four and five. Annual reports will include photo-documentation. All annual reports will be prepared and submitted by the following January. Analysis of data shall include variability estimates for the data when applicable. B. MAINTENANCE MONITORING The restoration specialist's monitoring program will begin with the construction process, and continue for five years following the completion of installation (Table 11). Items in need of attention will be provided to the project proponent and landscape contractor following each inspection. The monitor is also responsible for reporting any violations or non-authorized impacts to ACOE and CDFG jurisdictional areas within one day of their occurrence. VIII. COMPLETION OF MITIGATION A. NOTIFICATION OF COMPLETION H.G. Fenton Company shall notify the CDFG and ACOE of completion of the mitigation effort through the submittal of the five-year monitoring report. B. ACOE AND CDFG CONFIRMATION If the project meets all success standards at the end of the five-year monitoring period, then the mitigation will be considered a success. If not, the maintenance and monitoring program will be extended one full year at a time and a specific set of remedial measures (approved by the ACOE and CDFG) will be implemented until the standards are met. This process will continue until all Year 5 standards are met or until the ACOE and CDFG determine that other mitigation measures are appropriate. Should the mitigation effort meet all goals prior to the end of the five-year monitoring period, the ACOE and CDFG may at their discretion terminate the monitoring effort. Alternatively, a subsequent agreement may be negotiated with the ACOE and CDFG. Only areas that fail to meet the success standards will be subject to any subsequent agreement. IX. CONTINGENCY MEASURES A. INITIATING PROCEDURES If upon receipt of any of the annual monitoring reports the ACOE or CDFG determines that the mitigation effort is not meeting performance criteria for the project, the ACOE or CDFG shall notify H.G. Fenton Company in writing that the mitigation effort may require remedial measures for successful mitigation. H.G. Fenton Company shall have 30 days to respond, challenge, or confirm the determination that substantial work will be required. HELIX Final Riparian Mitigation Plan for Carlsbad Raceway / FWP-06 / September 10, 2004 18 B. ALTERNATIVE LOCATIONS FOR CONTINGENCY MITIGATION Since approximately 2.05 acres is being considered for mitigation on site and there is nearly 2.54 acres of potential wetland/streambed restoration shown on site (Figure 3), sufficient contingency mitigation area is present on site. If the success criteria are not being met on site, the ACOE and CDFG will work towards an alternative mutual solution on site. C. FUNDING MECHANISM H.G. Fenton Company shall be responsible for all costs associated with any remedial measures. D. RESPONSIBLE PARTIES H.G. Fenton Company shall be the responsible party for any remedial measures. HELIX final Riparian Mitigation Plan for Carlsbad Raceway / FWP-06 / September 10, 2004 1 ? X. REFERENCES CITED HELIX Environmental Planning, Inc. 2002a. Jurisdictional Delineation Report for Carlsbad Raceway. February 27. 2002b. Carlsbad Raceway Conceptual Coastal Sage Scrub Mitigation Plan. October 1. Sawyer, J.O. and T. Keeler-Wolf. 1995. A Manual of California Vegetation. California Native Plant Society. 472 pp. «*, HELIX Final Riparian Mitigation Plan for Carlsbad Raceway I FWP-06 / September 10, 2004 20 I I I I I I I I I I I I I I I I I I I Carlsbad! Mitigation Plan Prepared by: envupjpjjDtpl planning, inc. Carlsbad Raceway Project MITIGATION PLAN June 1,1998 Prepared for: Raceway Properties, LLC 12750 Carmel Country Road, Suite 204 San Diego, California 92130^2159 Prepared by: HELIX ENVIRONMENTAL PLANNING, INC. 8100 La Mesa Boulevard, Suite 150 La Mesa, California 91941-6452 I I I I I I I I I I I I I I I I I I I CARLSBAD RACEWAY PROJECT MITIGATION PLAN TABLE OF CONTENTS Section Page INTRODUCTION 1 EXISTING CONDITIONS 3 MITIGATION DESIGN 4 PLANT PALETTE 4 DESIGN MODIFICATIONS 5 ESSENTIAL PARTICIPANTS 5 Project Proponent 5 Landscape Architect 5 Restoration Specialist 6 Installation Contractor 6 Maintenance Contractor 6 Resource and Regulatory Agencies 6 GENERAL PLANTING GUIDELINES 6 Contact Growing and Sources 6 Substitutions 7 Inspection 7 Sources 7 Planting 7 Container Plant Guarantees .-. 7 Seed Guarantees 7 MAINTENANCE AND TECHNICAL MONITORING PROGRAMS 9 MAINTENANCE MONITORING 9 MAINTENANCE GUIDELINES 9 TECHNICAL MONITORING 11 SAMPLING TECHNIQUES 12 SUCCESS CRITERIA 13 Species Diversity and Recruitment 13 Cover by Weeds 13 Cover by Native Species 13 Monitoring Reports 14 FINAL RESOLUTION 14 LITERATURE CITED 15 I I I I I I I I I I I I I I I I LIST OF FIGURES After No. Title 1 Regional Location Map 1 2 Project Vicinity Map 1 3 Wetland and Upland Mitigation Areas 4 LIST OF TABLES On or After No. Title Page I I Potential Impacts to Jurisdictional Areas on the Carlsbad Raceway Property 1 2 Potential Impacts of the Carlsbad Raceway Project to Jurisdictional Habitats 2 3 Seed Mixes 4 1 4 Southern Willow Scrub Container Stock Plant List 5 5 Maintenance Schedule 8 6 Maintenance Monitoring Schedule 10 _ 7 Success Criteria Milestones for the Carlsbad Raceway 12 INTRODUCTION This report presents a conceptual mitigation plan for impacts to wetlands and riparian habitat (as defined by, and under the jurisdictions of, the U.S. Army Corps of Engineers and/or the California Department of Fish and Game) from the development of the Carlsbad Raceway project. The project site is in the City of Carlsbad, San Diego County, California, north of Palomar Airport Road and west of Business Park Road (Figures 1 and 2). The area to the immediate south is currently undeveloped. Existing development is located to the northeast and northwest. Graded pads occur to the west. Open space occurs to the north in the City of Vista. The proposed Project would develop approximately 112 of the 145 acres on site as a business park consistent with existing zoning for the property. Access through the site will be provided by a two lane roadway (Poinsettia Boulevard) running east-west. Access onto the property will be from Business Park at the eastern end and Melrose Drive at the western end. Currently, it is uncertain whether the Project will construct Melrose Drive within the Project boundaries, or whether some other funding source will be available. The Project also proposes to provide a key wildlife corridor running north-south that will help link existing open space on the Rancho Carrillo project to the south with additional open space provided along the northern portions of the site as well as off site to the north and northwest. Some of the jurisdictional areas on site are proposed to be impacted by several different projects. Impacts will come from a proposed extension of Melrose Drive and proposed development of industrial space on the Carlsbad Raceway property. A proposed extension of Poinsettia Avenue did not significantly impact any jurisdictional area. For a breakdown of impacts please see Tables 1 and 2 below. Table 1 POTENTIAL IMPACTS TO JURISDICTIONAL AREAS ON THE CARLSBAD RACEWAY PROPERTY1 Jurisdiction ACOE wetland ACOE non- vegetated Waters of the U.S. CDFG jurisdictional areas Existing2 1.28 0.51 4.79- Melrose Drive Impacts2 0.253 Carlsbad Raceway Property Project Impacts2 0.24 0.18 0.66 Total Impacts2 0.24 0.18 0.91 Remaining2 1.04 0.33 3.88 1 Impacts are based on the Preliminary Plan dated: April 1998 by O'Day Consultants 2 All figures are in acres 3 Impacted area consisted of State only jurisdictional southern willow scrub HELIX Mitigation Plan for the Carlsbad Raceway Project / KPM-01 /June 1,1998 RIVERSIDE COUNTY ORANGE SAN DIEGO COUNTY J COUNTY' L - SAN> ONOFREX FALLBROOK OCEANSIDE> CARLSBAD PROJECT LOCATION ENCINITAS) DEL MAR LAJOLLAr O o POINT \ LOMA' \ n 10 MILES WARNER LSPRINGS Lake Henshaw Lake a Wohlford V ESCONDIDO Sutherland CT3 » Reservoir /Lake\\Hodges\ JULIAN RAMONA San Vicente Reservoir -AMESA. EL \CAJON ALPINE Loveland Reservoir SAN iJAMUL ^{P Sweetwater f\S> Reservoir L Barrett Lake ^DULZURA \CHUL I VISTA IMPERIAL) BEACH Lakes YSIDRO;^^. '" MEXICO TIJUANAt ROSARITO^ HELIX Regional Location Map CARLSBAD RACEWAY I I I I I I I I I I I I I I I I I I I Table 2 POTENTIAL IMPACTS OF THE CARLSBAD RACEWAY PROJECT TO JURISDICTIONAL HABITATS1 Jurisdictional Habitat Freshwater Marsh Southern Willow Scrub Mule Fat Scrub Streambed TOTALS Federal (acres) 0.07 0.17 0 0.18 0.42 State (acres)2 0.07 0.28 0.13 0.18 0.66 Impacts are based on the Preliminary Plan dated: April 1998 by O'Day Consultants and do not include impacts from the extension of Melrose Drive2 State Jurisdictional Areas include Federal Jurisdictional Areas A total of approximately 0.96 acres is proposed for habitat creation/enhancement for impacts to U.S. Army Corps of Engineers and California Department of Fish and Game Jurisdictional areas, excluding the 0.18 of streambed. Streambed impacts will be mitigated through the relocation of the existing three-foot wide earthen channel that currently runs just north of the drag strip into a 15-foot wide channel running through the proposed wildlife corridor and adjacent to the northern boundary of the proposed project. Southern willow scrub will be planted over at least 0.82 acre and 0.14 acre of freshwater marsh will be planted along the margins of the restoration area. HELIX Mitigation Plan for the Carlsbad Raceway Project / KPM-01 /June 1,1998 Page 2 I I I I I I I I I I I I I I I I I I I EXISTING CONDITIONS The jurisdictional areas associated with the project consist of three tributaries and a main drainage that is an unnamed tributary to Agua Hedionda Creek which drains into the Agua Hedionda Lagoon. Elevations range from approximately 310 to 495 feet above mean sea level. Seven soil types are present on site. Altamont clays occur on approximately 65% of the site. Visalia sandy loams occur on approximately 20% of the site. Las Flores loamy fine sands and Cieneba very rocky coarse sandy loams both occur on about 5% of the site. Cieneba coarse sandy loams, Huerhuero loams, and Salinas clay loams occur collectively on approximately 5% of the site in the north. The Salinas clay loams occur on the west end of the main drainage on site (Bowman, 1973). Visalia sandy loams and Las Flores loamy fine sands have been described as being potentially hydric soils in flood plains and depression areas respectively (USDA 1992). Vegetation in the area of wetland impacts consists of freshwater marsh, southern willow scrub, mulefat scrub and disturbed areas. The Carlsbad Raceway property is currently a mix of developed and disturbed areas and undeveloped natural habitats. Uses of the property include a drag strip, off-road motorcycle track, and associated parking areas. A majority of the wetlands being impacted have had at least some past disturbance. No federally or state listed plant or animal species were observed in the wetland impact areas. HELIX Mitigation Plan for the Carlsbad Raceway Project / KPM-01 /June 1,1998 I I I I I I I I I I I I I I I I I I I MITIGATION DESIGN The mitigation concept is to create native wetland vegetation along the main east-west trending channel, and along the drainage entering from off site at the north-central portion of the site. Figure 3 depicts the approximate area (0.96 acres) needed for habitat creation in addition to additional areas that may be enhanced for future use as mitigation credits on other projects. Figure 3 also shows areas proposed for upland restoration and enhancement. These areas are not included in this mitigation plan. Grading and recontouring to create the appropriate hydrology will be done as necessary. Soil tests to determine the depth to the water table and soil conditions must be done prior to final approval of this plan. If necessary, the mitigation design will be modified to accommodate the soil conditions. Any modifications will be approved by the ACOE. PLANT PALETTE Two vegetation types will be installed: southern willow scrub and freshwater marsh. Southern Willow Scrub. The plan is intended to create habitat for indigenous wildlife that depend on riparian plant species for food and cover. This will be done by the application of seed. (Table 3) and planting of container stock (Table 4). Scientific Name Southern Willow Scrub Urtica dioica Artemisia douglasiana Ambrosia psilostachya Freshwater Marsh Typha latifolia Juncus acutus ssp. leopoldii Ambrosia psilostachya Carex spissa Scirpus robustus *Percent Purity/Germination Table 3 SEED MIXES Common Name hoary nettle Douglas mugwort western ragweed broad-leaved cattail southwestern spiny rush western ragweed San Diego sedge . prairie bulrush Lbs./Acre 2 3 6 3 10 2 1 6 %P/G* 50/60 10/50 5/30 80/20 90/70 2/30 90/40 98/65 HELIX Mitigation Plan for the Carlsbad Raceway Project /KPM-01 /June 1,1998 Page 4 LEGEND DCSS sws MFS FWM SMC NNG AC DIS -n Diegan coastal sage scrub Southern willow scrub Mule fat scrub Freshwater marsh Southern mixed chapparal Non-native grassland Agriculture Disturbed habitat/developed Inrliratp-q Hictnrherl hahifat Cd Ac Qa Sc Age Pe Ce Summer Holly (Comarostaphylos diversifolia) California adolphia (Adolphia California) Coast Live Oak (Qtterciis agrifolia) Ashy-spike moss (Selaginella cinerascens) Del Mar manzanita (Arclostaphyhs glandulosa ssp. crassifolia) Dot-seed Plantain (Plantago erecta) (potential quino checkerspot builertiy host plant) Owl's Clover (CastiUeja exserta) (potential quino checkerspot butterfly host plant) Permanent Impacts Temporary Impacts to be Revegetated Area to Have Soil Broken Up and Seeded Potential Wetland Restoration Areas 1 1 1 1 1•i 1 1 1 1 1 1 Table 4 SOUTHERN WILLOW SCRUB CONTAINER STOCK PLANT LIST Scientific Name /Common Name #Flants/Acre/ /Spacing Salix lasiolepis var. brace/mae/Bracelin's willow 460/8 Salix gooddingii/southwestem willow 70/8 Baccharis salicifolia/mule-fat 400/6 Rosa calif ornica/ California rose 153/6 Anemopsis calif ornica /yerba mansa 200/6 (feet) Freshwater Marsh. Freshwater emergent marsh will be created through the application of and planting of plugs taken of impacted freshwater marsh species if possible. Freshwater planted in areas with adequate groundwater. seed (Table 3) marsh will be Nursery grown container plants, propagated from cuttings collected in the project vicinity, and native hand-collected seed will be used in creating the riparian habitat. Container stock size (for example, one gallon, liners, etc.) will be determined at the time construction documents are prepared. DESIGN MODIFICATIONS Prior to the preparation of construction drawings, reference sites will be chosen for each types to be mitigated. These sites will be quantitatively sampled to ensure the vegetation matches the existing surrounding vegetation. The various plant palettes provided will necessary. ESSENTIAL PARTICIPANTS Successful implementation of this plan will require the expertise and input from several of the habitat to be installed be modified if people and /or entities. They are the project proponent, landscape architect, restoration specialist, and installation and maintenance contractors. Project Proponent The project proponent will be responsible for financing the installation and monitoring sites. In order to ensure the success of mitigation, the project proponent will enter into a the restoration five year bond agreement with the U.S. Army Corps of Engineers to cover the projected cost to install, report on the mitigation project. This agreement will be in the form of a 100 percent bond. monitor, and The bond will be structured so that portions of the bond may be released as interim milestones are met (subject to negotiation between the project proponent and the U.S. Army Corps of Engineers and Department of Fish and Game). Landscape Architect A landscape architect will prepare the construction documents for this restoration documents will be reviewed and approved by the restoration specialist. Restoration Specialist the California plan. These Overall supervision of the installation and maintenance contractors in the restoration areas will be the responsibility of the biologist, landscape architect, horticulturist, or other person knowledgeable in native HELIX Mitigation Plan for the Carlsbad Raceway Project /KPM-01 /June 1, 1998*Page5 I I I I I I I I I I I I I I I I I I I habitat restoration. This person is referred to as the restoration specialist in this report. After each visit, the restoration specialist will provide the project proponent and installation contractor with a written checklist of items in need of attention. All requests for work, in addition to the contractor's scope of work, will first be approved by the project proponent and then reported to the U.S. Army Corps of Engineers. The restoration specialist will educate all contractors with regard to mitigation goals and requirements. This education will be initiated at a pre-construction meeting. Installation Contractor The installation contractor is responsible for completion of any grading, soil preparation, pre-planting weed control, planting, and seeding. Once the restoration specialist has verified the completion of the installation, a 120-day installation maintenance period will begin. At the end of this period, the restoration specialist will certify completion of the installation contract, provided all installation and maintenance tasks have been finished. These items include, but are not limited to, weed control, dead plant replacement, and reseeding. Maintenance Contractor After the installation contract is completed, a maintenance contractor will be hired by the project proponent for the duration of the five-year monitoring period. The project proponent may change contractors at its discretion. The maintenance contractor will service the entire restoration area at least once a month. The maintenance contractor will meet the restoration specialist at the site, when requested, and will perform all checklist items in a timely manner. Resource and Regulatory Agencies The U.S. Army Corps of Engineers, under a 404 Permit, and the California Department of Fish and Game, under a 1603 Agreement, have direct regulatory responsibilities for the wetlands and riparian vegetation impacts from this project. These agencies will review and comment on the monitoring reports and success of this restoration. GENERAL PLANTING GUIDELINES Contract Growing and Sources Arrangements will be made, immediately upon finalization of the restoration plan, either by the project proponent or the installation contractor, to acquire container plant materials and seed required for restoration work. An additional 10 percent of the total number of container plants will be grown for replacements. A copy of this contract will be submitted to the restoration specialist by the owner or contractor as verification of this matter. Contract growing and seed collection will be conducted by an experienced native plant nursery or seed company such as, but not limited to: Tree of Life Nursery, San Juan Capistrano, California; Mockingbird Nursery, Riverside, California; or S&S Seeds, Carpinteria, California. Substitutions The installation contractor is expected to secure all plant materials well in advance of the expected planting date. No species should be substituted without approval of the restoration specialist. If the contractor is unable to obtain the proper species specified at the time of planting, commencement of the guarantee period will be delayed until all plants specified are planted. Substitution of plant material at the time of planting depends solely upon the discretion of the restoration specialist in consultation with HELIX Mitigation Plan for the Carlsbad Raceway Project / KPM-01 /June 1,1998 Pd()G 6 I I I I I I I I I I I I I I I I I I I the landscape architect. All approved substitutions will be documented by the installation contractor in the final set of "as-built" plans. Inspection All plant materials will be inspected by the restoration specialist and approved as healthy, disease free, and of proper size prior to planting. Overgrown, root-bound container stock will be rejected. In addition, the restoration specialist will approve the final layout of all plant materials in the field, prior to planting, to ensure their correct ecological positioning. It is preferred that the source of all propagules used at the site be from wild sources within San Diego County and as close to the restoration site as possible. The restoration specialist will work closely with the contractor and the suppliers to approve all sources of plant materials. The contractor will provide the restoration specialist with information on the sources of all plant and seed materials grown/collected for the project for final approval. If necessary, the restoration specialist will help the grower locate local sources for plant materials. Planting All container plants will be planted in a hole at least twice the diameter of the container and twice the depth. The top of the root ball will be set one inch above finish grade. Willow cuttings, if used, shall be properly inserted in wet or moist soil. The backfill will be amended in accordance with any recommendations made as a result of the soil tests. A mulched, weed-free zone will then be established around each container plant, extending for at least 24 inches from the base of the tree species and 12 inches from the base of the shrub species. The mulch will consist of weed free, chipped plant material (maximum chip length is 2 inches). The mulch will be two to four inches thick and must not come in contact with the collar of the plant. Container Plant Guarantees All plants determined to be dead or terminally diseased by the restoration specialist will be replaced 90 days after installation or as soon as they die (whichever comes first) and then as required by the maintenance program. Unless substitutions are approved by the restoration specialist, the replacement plants will be the same species and at least the same size as originally planted. Seed Guarantees Adequate quantities of seeds for desired species will be ensured by collecting one to two seasons prior to the planting date. Donor habitats will not be excessively degraded by the collection methods. Collection areas and approximate quantities obtained from each site will be noted and mapped by the seed collector. Each day's collections will be removed from the site and stored in a cool, dry place free of rodents. Seed will be cleaned to a grade normally acceptable in the seed trade, with all sticks and large plant parts removed. Storage costs and insurance will be included in the price per pound of seed. Seeds will be tested for percent purity, percent germination, and the number of live seeds per pound. Testing costs will be included in the seed costs per pound and will be the responsibility of the seed supplier. Results of the seed tests will be made available to the restoration specialist prior to seed delivery. Seed collections, handling, and storage techniques will be observed by the restoration specialist. HELIX Mitigation Plan for the Carlsbad Raceway Project / KPM-01 /June 1,1998 P QQ6 7 I I I I I I I I I I I I I I I I I I I MAINTENANCE AND TECHNICAL MONITORING PROGRAMS Two methods will be employed to monitor this habitat creation project: maintenance monitoring and technical monitoring. Maintenance monitoring is essential in order to rectify problems before they jeopardize the project's success. Technical monitoring is used to evaluate the success of the mitigation effort and to generate data for future mitigation programs. MAINTENANCE MONITORING The purpose of this subsection is to outline the maintenance monitoring procedures to be followed and to identify the responsible parties who will implement and conduct these procedures as part of the maintenance monitoring program. The primary goal of maintenance monitoring is to provide quality assurance to the maintenance of the newly created habitat. The restoration specialist will monitor the grading, site preparation, planting, subsequent establishment, and growth in an effort to detect any problems at an early stage. Potential problems could arise from competition from weeds, irrigation failure, erosion, vandalism, and unacceptable levels of disease and predation. The restoration specialist will file a written memo with the project proponent, landscape contractor, and U.S. Army Corps of Engineers after completing each inspection. Each of these reports will identify maintenance concerns including mortality, vandalism, and weed-related issues. These reports will facilitate communication and coordination with the installation contractor who is responsible for implementing the maintenance monitoring program. MAINTENANCE GUIDELINES Damage to plants, irrigation systems, and other facilities occurring as a result of unusual weather or vandalism will be repaired as directed by the restoration specialist. The cost of such repairs will be paid for as extra work, although the contractor should provide typical replacement costs as part of his contract. Any erosion damage caused by the contractor's inadequate maintenance or operation of irrigation facilities, as determined by the restoration specialist, will be repaired by the contractor at his expense. Planted areas will be checked by the installation and monitoring contractors according to the schedule in Table 5. The areas will also be checked for any trash, vandalism, irrigation function and scheduling, plant material condition and health, and weeds. Table 5 MAINTENANCE SCHEDULE Phase Installation Post Installation February-May June-January Schedule Daily Semi-Monthly Monthly These maintenance guidelines are specifically tailored for native plant establishment. Maintenance personnel will be fully informed of the habitat creation program so that they understand the goals of the effort and the maintenance requirements. HELIX Mitigation Plan for the Carlsbad Raceway Project / KPM-01 /June 1,1998 PageS I I I I I I I I I I I I I I I I I I I Irrigation. After the first growing season, water will be applied infrequently and only as needed to prevent the mortality of plants and seedlings. The irrigation schedule will attempt to develop deep-root systems, where appropriate, through infrequent, deep applications of water. To obtain deep penetration of water, it may need to be applied several times in one 24-hour period. Once the plant material is established and does not require supplemental irrigation, the "above ground" portions of the system will be removed. The restoration specialist will determine how and when the system will be removed. The goal is to obtain germination and growth with the least amount of irrigation. Frequent irrigation encourages weed invasion and leaches nutrients from the soil. Native plantings that are infrequently irrigated may grow slower initially but will ultimately develop better as habitat. Protection of Extant Habitat. Fencing or flagging will be placed where necessary to ensure that existing riparian vegetation is not damaged during construction or installation of the mitigation plans. The restoration specialist will flag the limits of the mitigation work area prior to grading or clearing. Protection will remain in place until the end of the grading process or until the restoration specialist considers it no longer necessary. Additional protection may be required at any time if it is considered necessary by the restoration specialist to protect open space vegetation. Prior to any grading, the site will be inspected by the restoration specialist to ensure that all fencing or flagging has been installed correctly and in the proper locations. The restoration specialist will certify in writing to the U.S. Army Corps of Engineers that the limits of the open space areas have been properly marked before the contractor may proceed with work. If at any time workers or machines damage vegetation outside the limits of work, the installation contractor will bear the full cost of having the landscape architect complete a restoration landscape plan for the area as well as the costs for monitoring the success of the restoration according to the same standards as the original restoration. Only construction equipment necessary to accomplish the landscape installation will be allowed in the restoration areas. Workers' vehicles will be parked outside the open space, and all equipment will be removed from the site as soon as the task is completed. No vehicular fluids will be added or changed on site. Weed Control. Weed control will be conducted as necessary to minimize competition that could prevent the establishment of native species. As weeds become evident, they should be removed by hand or controlled with the proper herbicides. The restoration specialist will determine the need for weeding and will contact the maintenance contractor for any required work. Maintenance personnel will be trained to distinguish weed species from desirable, native vegetation. A cleared space, 12 inches (shrubs) to 24 inches (trees) from the base of the container plants will be free of weeds to minimize competition during the establishment period. A mulch of chipped plant materials will be used to help maintain this weed-free area. Examples of weeds to be controlled include but are not limited to: eastern cocklebur (Xanthium strumarium), giant reed (Arundo donax), tamarisk, prickly lettuce (Lactuca serriola), fennel, curly dock (Rumex crispus), eucalyptus, and Canary Island date palm (Phoenix canariensis). Other Pests. Insects, vertebrate pests, and diseases will be monitored. Generally speaking, a high threshold of tolerance will be permitted before control measures are considered. All specific recommendations will only be made by a licensed pest control adviser as required by law. All applicable HELIX Mitigation Plan for the Carlsbad Raceway Project/KPM-01/June 1,1998 1 1 1 1 federal and state laws and regulations will be closely followed. The restoration specialist will be consulted on any pest control matters. Plant Replacement. Plants will be replaced at the direction of the restoration specialist. The installation contractor will be responsible for replacing any dead or terminally diseased plants at least one month prior to turning the project over to the maintenance contractpr.Plant replacement by the maintenance contractor will be completed within 90 days of written direction by the restoration specialist. Replacement of dead plants will also occur at the end of the first year. All dead container plants not replaced by natural recruitment will be replaced with plants of the same size. Fertilization. Fertilizer will not be applied, except in extraordinary circumstances, and only at the I written direction of the restoration specialist. Pruning. No post-installation pruning is necessary unless specialist. otherwise directed by the restoration Monitoring Schedule. The restoration specialist's maintenance monitoring will begin with the construction process, and maintenance monitoring will commence at the site preparation phase (Table 6). 1 I 1 • 1 • Table 6 MAINTENANCE MONITORING SCHEDULE Phase Grading/Site Preparation/Installation Post Installation Years 1-2 February-May June-January Years 3-5 March-June July-February Schedule 2 times per week Monthly Bi-Monthly Monthly Quarterly As Built Plans. The landscape architect will prepare a set of as built plans. The level of details for these plans will be directly related to the degree the installation differs from the construction plans. For example, if the installation exactly reflects the construction plans, then a simple letter stating that fact is 1 1 1 all that is required. Conversely, if there are differences in the irrigation system or planting layouts, then plans reflecting these differences must be prepared. TECHNICAL MONITORING Technical monitoring is the first step in evaluating the success of the restoration effort. Success is the restoration of a functional ecosystem that is at least the same quality of that already existing on site. The means of determining this is a series of measurements for species diversity, recruitment, exotic species cover, and cover by native species. All of these, except weed cover, should increase over time. Weed cover should be the opposite and should decrease with time.These measurements will be compared with reference sites of freshwater marsh and southern willow scrub in nearby open space areas of the site. HELIX Mitigation Plan for the Carlsbad Raceway Project / KPM-01 /June 1, 1998 > • Page 10 I I I I I I I I I I I I I I I I I I I SAMPLING TECHNIQUES Data collection will focus on the vegetation. Methods will follow those of the California Native Plant Society Field Sampling Protocol (California Native Plant Society 1993). Data will be collected and analyzed separately for each vegetation type but will employ the same methods. The sampling method is based on a 50-meter long point-transect centered in a 50-meter by 5-meter plot which is randomly located in a subjectively chosen homogeneous patch of vegetation. At each 0.5-meter interval along the transect, a point is projected vertically down into the vegetation and up into the canopy. Each species intercepted by a point is recorded within designated vegetation layers (bare ground, herb, shrub, and/or tree). Percent cover for each species according to vegetation layer is calculated from these data. Finally, a list of all species within the plot is created. SUCCESS CRITERIA The purpose of this subsection of the technical monitoring program is to define specific performance standards by which to evaluate project progress. Success criteria measurements will be taken in August and compared with predetermined reference sites. Species Diversity and Recruitment Species diversity and recruitment are closely linked, as diversity increases with recruitment. The effect of recruitment on diversity should be to approach the level of species diversity of the reference sites. After five years, the mitigation should reach 80 percent of the species diversity of the reference sites. Cover by Weeds Weeds are typically a problem with habitat restoration, particularly at the onset of the project. As the restoration takes hold, the problems with weeds should decrease. Many weeds have become naturalized in our area and, therefore, the tolerance for weeds should reflect what is present at the reference sites. The measure for tolerance should be total cover of weed species. Weeds should be controlled as specified in the maintenance monitoring section. Cover by Native Species Cover by native vegetation should increase over time and ultimately approach that of the reference sites. Cover should be measured and evaluated separately for each habitat. The annual milestones for these parameters are presented in Table 7. HELIX Mitigation Plan for the Carlsbad Raceway Project / KPM-01 /June 1,1998 I I I I I I I I I I I I I I I I I I I Table 7 SUCCESS CRITERIA MILESTONES FOR THE CARLSBAD RACEWAY Criteria1 Species Diversity Cover by Weeds2 Cover3 by Native Herbs Cover3 by Native Shrubs Cover3 by Native Trees 1 40 140 60 20 20 2 50 130 70 40 40 Years 3 60 120 80 60 60 4 70 110 90 80 80 5 80 100 100 100 100 'Values are relative to reference site 2 Percent total cover 3 Cover class is by size Monitoring Reports Upon completion of the installation, the restoration specialist will prepare a letter report indicating that the installation is finished and that the five-year monitoring period has begun. At one year and thereafter, reports will be submitted annually. The annual reports will include both botanical and horticultural observations, as well as any wildlife use of the restoration area. Any remedial recommendations will also be made in the annual reports. A summary of whether the project is meeting the success standards will be included. Copies of all monitoring reports will be sent to the U.S. Army Corps of Engineers and the California Department of Fish and Game. HELIX Mitigation Plan for the Carlsbad Raceway Project / KPM-01 /June 1,1998 Page 12 I I I I I I I I I I I I I I I I I I I FINAL RESOLUTION If the project meets all success standards at the end of the five-year monitoring period,' the mitigation will be considered a success. If not, the maintenance and monitoring program will be extended one full year at a time, and a specific set of remedial measures (approved by the U.S. Army Corps of Engineers and the California Department of Fish and Game) will be implemented until the standards are met. Alternatively, a subsequent agreement may be negotiated with those agencies, where only areas that fail to meet the success standards will require additional work. This process will continue until all year-five standards are met or until the agencies determine that other mitigation measures are appropriate. Should the mitigation effort meet all goals prior to the end of the five-year monitoring period, the U.S. Army Corps of Engineers and the California Department of Fish and Game, at their discretion, may terminate their involvement in the monitoring effort. HELIX Mitigation Plan for the Carlsbad Raceway Project IKPM-01 /June 1,1998 P Q § 6 13 I • LITERATURE CITED B Bowman, R.H. 1973. Soil Survey of the San Diego Area, California. California Native Plant Society. 1993. Field Sampling Protocol. Revised February 9. • Kormanik, P.P. and A.C. McGraw. 1982. Quantification of vescicular-arbuscular mycorrhizae in plant roots. Pp. 37-46 In: N. C. Schenck, ed. Methods and Principles of Mycorrhizal Research. St. Paul: _ American Phytopathological Society. ~ Phillips, J.M. and D.S. Hayman. 1970. Improved procedures for clearing roots and staining parasitic and vescicular-arbuscular mycorrhizal fungi for rapid assessment of infection. Transactions British H Mycological Society 55:158-161. I I I I I I I I I I I I HELIX • Mitigation Plan for the Carlsbad Raceway Project/KPM-01/June 1,1998 Pd(]6 14