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RP 04-23; Carlsbad Village Townhomes; Redevelopment Permits (RP) (5)
ENVIRONMENTAL IMPACT ASSESSMENT FORM - PART I (TO BE COMPLETED BY THE APPLICANT) CASE NO: DATE: OTf 5er. l^O^ BACKGROUND \. CASENAME: 2. LEAD AGENCY NAME AND ADDRESS: 3. CONTACT PERSON AND PHONE NUMBER: Dh»V\1p LS€ 5bAMBS . 4. PROJECT LOCATION: 5. 6. PROJECT SPONSOR'S NAME AND ADDRESS: Bj^g^i^tfT GENERAL PLAN DESIGNATION: 7. ZONING; 8. OTHER PUBLIC AGENCIES WHOSE APPROVAL IS REQUIRED(Le.^ermi^ finaicing approval or participation agreements): p^S^fi^iS^ j* ((LffX^^^Qi^P^tBft7\ oD>, 9. PROJECT DESCRIPTION/ ENVIRONMENTAL SETTING AND SURROUNDING LAND USES: Rev. 07/26/02 RECEIVED OCT 9 1 2004 HOUSING &RE0EViLOPMT INSTRUCTION SHEET FOR FILLING OUT ENVIRONMENTAL IMPACT ASSESSMENT FORM - PART I This Enviromnental Impact Assessment (EIA) Form - Part I will be used to determine what type of environmental documentation (i.e., Environmental Impact Report, Mitigated Negative Declaration, Negative Declaration or Exemption) will be required to be prepared for your application, per the Califomia Environmental Quality Act (CEQA) and Title 19 of Carlsbad's Mimicipal Code. The clarity and accuracy of the information you provide is critical for purposes of quickly determining the specific environmental effects of your project. Judicial decisions have held that a "naked checklist," that is a checklist that is merely checked "yes impact" or "no impact," is insufficient to comply with the requirements of the Califomia Environmental Quality Act. When preparing this form, each "yes impact" or "no impact" answer must be accompanied by a written explanation justifying the "yes impact" or "no impact" answer. Any environmental studies (i.e., biological, cultural resource, traffic, noise) that are necessary to substantiate a "no impact" or "yes impact" determination should be submitted as an attachment to this Environmental Impact Assessment. This is especially important when a Negative Declaration is being sought. The more information provided in this form, the easier and quicker it will be for staff to complete the Environmental Impact Assessment Form - Part II. ENVIRONMENTAL FACTORS POTENTIALLY AFFECTED: The summary of environmental factors checked below would be potentially affected by this project, involving at least one impact that is a "Potentially Significant Impact," or "Potentially Significant Impact Unless Mitigation Incorporated" as indicated by the checklist on the following pages. I I Aesthetics I I Agricultural Resources I I Air Quality I I Biological Resources I I Cultural Resources I I Geology/Soils I I Noise • Hazards/Hazardous Materials D Population and Housing I I Hydrology/Water Quality Q Public Services I I Land Use and Planning Q Recreation • Mineral Resources Q Transportation/Circulation • Mandatoiy Findings of Q ^^^.^.^^ ^ ^^^.^^ ^ Significance — Rev. 07/26/02 ENVIRONMENTAL IMPACTS STATE CEQA GUIDELINES, Chapter 3, Article 5, Section 15063 requires that the City conduct an Environmental Impact Assessment to determine if a project may have a significant effect on the environment. The Environmental Impact Assessment appears in the following pages in the form of a checklist. This checklist identifies any physical, biological and human factors that might be impacted by the proposed project and provides the City with information to use as the basis for deciding whether to prepare an Environmental Impact Report (EIR), Negative Declaration, or to rely on a previously approved EIR or Negative Declaration. • A brief explanation is required for all answers except "No Impact" answers that are adequately supported by an information source cited in the parentheses following each question. A "No Impact" answer is adequately supported if the referenced information sources show that the impact simply does not apply to projects like the one involved. A "No Impact" answer should be explained when there is no source document to refer to, or it is based on project-specific factors as well as general standards. • "Less Than Significant Impact" applies where there is supporting evidence that the potential impact is not significantly adverse, and the impact does not exceed adopted general standards and policies. • "Potentially Significant Unless Mitigation Incorporated" applies where the incorporation of mitigation measures has reduced an effect from "Potentially Significant Impact" to a "Less Than Significant Impact." The developer must agree to the mitigation, and the City must describe the mitigation measures, and briefly explain how they reduce the effect to a less than significant level. • "Potentially Significant Impact" is appropriate if there is substantial evidence that an effect is significantly adverse. • Based on an "EIA-Part I", if a proposed project could have a potentially significant adverse effect on the environment, but all potentially significant adverse effects (a) have been analyzed adequately in an earlier EIR or Mitigated Negative Declaration pursuant to applicable standards and (b) have been avoided or mitigated pursuant to that earlier EIR or Mitigated Negative Declaration, including revisions or mitigation measures that are imposed upon the proposed project, and none of the circumstances requiring a supplement to or supplemental EIR are present and all the mitigation measures required by the prior environmental document have been incorporated into this project, then no additional environmental document is required. • When "Potentially* Significant Impact" is checked the project is not necessarily required to prepare an EIR if the significant adverse effect has been analyzed adequately in an earlier EIR pursuant to applicable standards and the effect will be mitigated, or a "Statement of Overriding Considerations" has been made pursuant to that earlier EIR. • A Negative Declaration may be prepared if the City perceives no substantial evidence that the project or any of its aspects may cause a significant adverse effect on the environment. • If there are one or more potentially significant adverse effects, the City may avoid preparing an EIR if there are mitigation measures to clearly reduce adverse impacts to less than significant, and those mitigation measures are agreed to by the developer prior to public review. In this case, the appropriate "Potentially Significant Impact Unless Mitigation Incorporated" may be checked and a Mitigated Negative Declaration may be prepared. Rev. 07/26/02 • An EIR must be prepared if "Potentially Significant Impact" is checked, and including but not limited to the following circumstances: (1) the potentially significant adverse effect has not been discussed or mitigated in an earlier EIR pursuant to applicable standards, and the developer does not agree to mitigation measures that reduce the adverse impact to less than significant; (2) a "Statement of Overriding Considerations" for the significant adverse impact has not been made pursuant to an eariier EIR; (3) proposed mitigation measures do not reduce the adverse impact to less than significant; or (4) through the EIA-Part I analysis it is not possible to determine the level of significance for a potentially adverse effect, or determine the effectiveness of a mitigation measure in reducing a potentially significant effect to below a level of significance. A discussion of potential impacts and the proposed mitigation measures appears at the end of the form under DISCUSSION OF ENVIRONMENTAL EVALUATION. Particular attention should be given to discussing mitigation for impacts, which would otherwise be determined significant. Rev. 07/26/02 Issues (and Supporting Information Sources). (Supplemental documents may be referred to and attached.) AESTHETICS - Would the project: a) Have a substantial adverse effect on a scenic vista? b) Substantially damage scenic resources, including but not limited to, trees, rock outcroppings, and historic buildings within a State scenic highway? c) Substantially degrade the existing visual character or quality of the site and its surroundings? d) Create a new source of substantial light and glare, which would adversely affect day or nighttime views in the area? PotentiaHy Significant Impact Potentially Significant Unless Mitigation Incorporated Less Than Significant Impact No Impact • • • • • • • • • • • • II. AGRICULTRAL RESOURCES - (In determining whether impacts to agricultural resources are significant environmental effects, lead agencies may refer to the Califomia Agricultural Land Evaluation and Site Assessment Model-1997 prepared by the Califomia Department of Conservation as an optional model to use in assessing impacts on agriculture and farmland.) Would the project: a) Convert Prime Farmland, Unique Farmland, or Farmland of Statewide Importance (Farmland), as shown on the maps prepared pursuant to the Farmland Mapping and Monitoring Program of the Califomia Resources Agency, to non-agricultural use? b) Conflict with existing zoning for agricultural use, or a Williamson Act contract? c) Involve other changes in the existing environment, which, due to their location or nature, could result in conversion of Farmland to non-agricultural use? III. AIR QUALITY - (Where available, the significance criteria established by the applicable air quality management or air pollution control district may be relied upon to make the following determinations.) Would the project: a) Conflict with or obstmct implementation of the applicable air quality plan? b) Violate any air quality standard or contribute substantially to an existing or projected air quality violation? • • • n • • • • • • • n • n • n • H • n Rev. 07/26/02 Issues (and Supporting Information Sources). (Supplemental documents may be referred to and attached.) c) Result in a cumulatively considerable net increase of any criteria pollutant for which the project region is in non-attainment under an applicable federal or state ambient air quality standard (including releasing emissions which exceed quantitative thresholds for ozone precursors)? d) Expose sensitive receptors to substantial pollutant concentrations? e) Create objectionable odors affecting a substantial number of people? IV. BIOLOGICAL RESOURCES - Would the project: a) Have a substantial adverse effect, either directly or through habitat modifications, on any species identified as a candidate, sensitive, or special status species in local or regional plans, policies, or regulations, or by Califomia Department of Fish and Game or U.S. Fish and Wildlife Service? b) Have a substantial adverse effect on any riparian, aquatic or wetland habitat or other sensitive natural community identified in local or regional plans, policies, or regulations or by Califomia Department of Fish and Game or U.S. Fish and Wildlife Service? c) Have a substantial adverse effect on federally protected wetlands as defined by Section 404 of the Clean Water Act (including but not limited to marsh, vemal pool, coastal, etc.) through direct removal, filing, hydrological intermption, or other means? d) Interfere substantially with the movement of any native resident or migratory fish or wildlife species or with established native resident or migratory wildlife corridors, or impede the use of native wildlife nursery sites? e) Conflict with any local policies or ordinances protecting biological resources, such as a tree preservation policy or ordinance? f) Conflict with the provisions of an adopted Habitat Conservation Plan, Natural Community Conservation Plan, or other approved local, regional, or state habitat conservation plan? g) Impact tributary areas that are environmentally sensitive? Potentially Significant Potentially Unless Less Than Significant Mitigation Significant No Impact Incorporated Impact Impact • • • • • • • • • • • • • • • • • • • X • H • n • ^ • • • ;^ • X • H • X • K • X Rev. 07/26/02 Issues (and Supporting Information Sources). (Supplemental documents may be referred to and attached.) V. CULTURAL RESOURCES - Would the project: a) Cause a substantial adverse change in the significance of a historical resource as defined in §15064.5? b) Cause a substantial adverse change in the signifi- cance of an archeological resource pursuant to §15064.5? c) Directly or indirectly destroy a unique paieontologi- cal resource or site or unique geologic feature? d) Disturb any human remains, including those interred outside of formal cemeteries? VI. GEOLOGY AND SOILS - Would the project: a) Expose people or stmctures to potential substantial adverse effects, including the risk of loss, injury or death involving: i. Rupture of a known earthquake fault, as delineated on the most recent Alquist-Priolo Earthquake Fault Zoning Map issued by the State Geologist for the area or based on other substantial evidence of a known fault? Refer to Division of Mines and Geology Special Publication 42. ii. Strong seismic ground shaking? iii. Seismic-related ground failure, including liquefaction? iv. Landslides? b) Result in substantial soil erosion or the loss of topsoil? c) Be located on a geologic unit or soil that is unstable, or that would become unstable as a result of the project, and potentially result in on- or off-site landslide, lateral spreading, subsidence, liquefaction, or collapse? d) Be located on expansive soils, as defined in Table 18 - 1-B of the Unifomi Building Code (1997), creating substantial risks to life or property? Potentially Significant Potentially Unless Less Than Significant Mitigation Significant No Impact Incorporated Impact Impact • • • X • • • • • • X • • • X • • • K • • • X • • • H • • n • • • X • • • X • • • Rev. 07/26/02 Issues (and Supporting Information Sources). (Supplemental documents may be referred to and attached.) e) Have soils incapable of adequately supporting the use of septic tanks or altemative wastewater disposal systems where sewers are not available for the disposal of wastewater? VII. HAZARDS AND HAZARDOUS MATERIALS - Would the project: a) Create a significant hazard to the public or the environment through the routine transport, use, or disposal of hazardous materials? b) Create a significant hazard to the public or environment through reasonably foreseeable upset and accident conditions involving the release of hazardous materials into the environment? c) Emit hazardous emissions or handle hazardous or acutely hazardous materials, substances, or waste within one-quarter mile of an existing or proposed school? d) Be located on a site which is included on a list of hazardous materials sites compiled pursuant to Govemment Code Section 65962.5 and, as a result, would it create a significant hazard to the public or environment? e) For a project within an airport land use plan, or where such a plan has not been adopted, within two miles of a public airport or public use airport, would the project result in a safety hazard for people residing or working in the project area? f) For a project within the vicinity of a private airstrip, would the project result in a safety hazard for people residing or working in the project area? g) Impair implementation of or physically interfere with an adopted emergency response plan or emergency evacuation plan? h) Expose people or stmctures to a significant risk of loss, injury or death involving wildland fires, including where wildlands are adjacent to urbanized areas or where residences are intermixed with wildlands? VIII. HYDROLOGY AND WATER QUALITY - Would the project: a) Violate any water quality standards or waste discharge requirements? Potentially Significant Potentially Unless Less Than Significant Mitigation Significant No Impact Incorporated Impact Impact • • • • • • • • • • • • • n • • • • • K • K • X • ^ • X • X • X • X • • • X Rev. 07/26/02 Issues (and Supporting Information Sources). (Supplemental documents may be referred to and attached.) b) Substantially deplete groundwater supplies or interfere substantially with ground water recharge such that there would be a net deficit in aquifer volume or a lowering of the local ground water table level (i.e., the production rate of pre-existing nearby wells would drop to a level which would not support existing land uses or planned uses for which permits have been granted)? c) Impacts to groundwater quality? d) Substantially alter the existing drainage pattem of the site or area, including through the alteration of the course of a stream or river, in a manner, which would result in substantial erosion or siltation on- or off- site? e) Substantially alter the existing drainage pattem of the site or area, including through the alteration of the course of a stream or river, or substantially increase the flow rate or amount (volume) of surface runoff in a marmer, which would result in flooding on- or off- site? f) Create or contribute mnoff water, which would exceed the capacity of existing or planned stormwater drainage systems or provide substantial additional sources of polluted mnoff? g) Otherwise substantially degrade water quality? h) Place housing within a 100-year flood hazard area as mapped on a Federal Flood Hazard Boundary or Flood Insurance Rate Map or other flood delineation map? i) Place within 100-year flood hazard area stmctures, which would impede or redirect flood flows? j) Expose people or stmctures to a significant risk of loss injury or death involving flooding, including flooding as a result of the failure of a levee or dam? k) Inundation by seiche, tsunami, or mudflow? 1) Increased erosion (sediment) into receiving surface waters. m) Increased pollutant discharges (e.g., heavy metals, pathogens, petroleum derivatives, synthetic organics, nutrients, oxygen-demanding substances and trash) into receiving surface waters or other alteration of receiving surface water quality (e.g., temperature, dissolved oxygen or turbidity)? Potentially Significant Potentially Unless Less Than Significant Mitigation Significant No Impact Incorporated Impact Impact • • • K • • • 1^ • • • K • n • X • • • • • • X • • • • • • X • • • • • • • • • • • • Rev. 07/26/02 Issues (and Supporting Information Sources). (Supplemental documents may be referred to and attached.) n) Changes to receiving water quality (marine, fresh or wetland waters) during or following constmction? o) Increase in any pollutant to an already impaired water body as listed on the Clean Water Act Section 303(d) list? p) The exceedance of applicable surface or groundwater receiving water quality objectives or degradation of beneficial uses? IX. LANDUSE AND PLANNING - Would the project: a) Physically divide an established community? b) Conflict with any applicable land use plan, policy, or regulation of an agency with jurisdiction over the project (including but not limited to the general plan, specific plan, local coastal program, or zoning ordinance) adopted for the purpose of avoiding or mitigating an environmental effect? c) Conflict with any applicable habitat conservation plan or natural community conservation plan? X. MINERAL RESOURCES - Would the project: a) Result in the loss of availability of a known mineral resource that would be of future value to the region and the residents of the State? b) Result in the loss of availability of a locally important mineral resource recovery site delineated on a local general plan, specific plan, or other land use plan? XI. NOISE - Would the project result in: a) Exposure of persons to or generation of noise levels in excess of standards established in the local general plan or noise ordinance or applicable standards of other agencies? b) Exposure of persons to or generation of excessive groundboume vibration or groundboume noise levels? c) A substantial permanent increase in ambient noise levels in the project vicinity above levels existing without the project? d) A substantial temporary or periodic increase in ambient noise levels in the project vicinity above levels existing without the project? • Potentially Significant I ^cc T^liQn r Kji^iiiiaiiy Significant Mitigation j-rCoo i nsm Significant No Impact Incorporated Impact Impact • • • • • • • • • X • • • g • • • X • • • X • • • • • • • • • X • • • n • • • • • • X 10 Rev. 07/26/02 Issues (and Supporting Information Sources). (Supplemental documents may be referred to and attached.) e) For a project located within an airport land use plan or, where such a plan has not been adopted, within 2 miles of a public airport or public use airport, would the project expose people residing or working in the project area to excessive noise levels? f) For a project within the vicinity of a private airstrip, would the project expose people residing or working in the project area to excessive noise levels? XII. POPULATION AND HOUSING - Would the project: a) Induce substantial growth in an area either directly (for example, by proposing new homes and businesses) or indirectly (for example, through extension of roads or other infrastructure)? b) Displace substantial numbers of existing housing, necessitating the constmction of replacement housing elsewhere? c) Displace substantial numbers of people, necessitating the constmction of replacement housing elsewhere? XIII. PUBLIC SERVICES a) Would the project result in substantial adverse physical impacts associated with the provision of new or physically altered govemment facilities, a need for new or physically altered govemment facilities, the constmction of which could cause significant environmental impacts, in order to maintain acceptable service ratios, response times, or other performance objectives for any of the public services: i) Fire protection? ii) Police protection? iii) Schools? iv) Parks? v) Other public facilities? XIV. RECREATION a) Would the project increase the use of existing neighborhood and regional parks or other recreational facilities such that substantial physical deterioration of the facility would occur or be accelerated? Potentially Significant Potentially Unless Less Than Significant Mitigation Significant No Impact Incoiporated Impact Impact • • • • • • • • • • • • • • • • • • • • • • • M • X • • ^ n X • 11 Rev. 07/26/02 Issues (and Supporting Information Sources). (Supplemental documents may be referred to and attached.) b) Does the project include recreational facilities or require the constmction or expansion of recreational facilities, which might have an adverse physical effect on the environment? XV. TRANSPORTATION/TRAFFIC - Would the project: a) Cause an increase in traffic, which is substantial in relation to the existing traffic load and capacity of the street system (i.e., result in a substantial increase in either the number of vehicle trips, the volume to capacity ratio on roads, or congestion at intersections)? b) Exceed, either individually or cumulatively, a level of service standard established by the county congestion management agency for designated roads or highways? c) Result in a change in air traffic pattems, including either an increase in traffic levels or a change in location that results in substantial safety risks? d) Substantially increase hazards due to a design feature (e.g., sharp curves or dangerous intersections) or incompatible uses (e.g., farm equipment)? e) Result in inadequate emergency access? f) Result in insufficient parking capacity? g) Conflict with adopted policies, plans, or programs supporting altemative transportation (e.g., bus tum- outs, bicycle racks)? XVI. UTILITIES AND SERVICES SYSTEMS - Would the project: a) Exceed wastewater treatment requirements of the applicable Regional Water Quality Control Board? b) Require or result in the constmction of new water or wastewater treatment facilities or expansion of existing facilities, the constmction of which would cause significant environmental effects? c) Require or result in the constmction of new storm water drainage facilities or expansion of existing facilities, the constmction of which could cause significant environmental effects? d) Have sufficient water supplies available to serve the project from existing entitlements and resources, or are new or expanded entitlements needed? Potentially Significant Impact Potentially Significant Unless Mitigation Incoiporated • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • Less Than Significant No Impact Impact • X • ^ • X • 1^ • JK 12 Rev. 07/26/02 Issues (and Supporting Information Sources). (Supplemental documents may be referred to and attached.) e) Result in a determination by the wastewater treatment provider, which serves or may serve the project that it has adequate capacity to serve the project's projected demand in addition to the provider's existing commitments? f) Be served by a landfill with sufficient permitted capacity to accommodate the project's solid waste disposal needs? g) Comply with federal, state, and local statutes and regulations related to solid waste? XVII. MANDATORY FINDINGS OF SIGNIFICANCE a) Does the project have the potential to degrade the quality of the environment, substantially reduce the habitat of a fish or wildlife species, cause a fish or wildlife population to drop below self-sustaining levels, threaten to eliminate a plant or animal community, reduce the number or restrict the range of a rare or endangered plant or animal or eliminate important examples of the major periods of Califomia history or prehistory? b) Does the project have impacts that are individually limited, but cumulatively considerable? ("Cumula- tively considerable" means that the incremental effects of a project are considerable when viewed in connection with the effects of past projects, the effects of other current projects, and the effects of probable fiiture projects?) c) Does the project have environmental effects, which will cause the substantial adverse effects on human beings, either directly or indirectly? XVIII. EARLIER ANALYSES Potentially Significant Potentially Unless Less Than Significant Mitigation Significant No Impact Incorporated Inqjact Impact • • • • • • • • • • • K • U • X • ^ • ^ • ^ Earlier analyses may be used where, pursuant to the tiering, program EIR, or other CEQA process, one or more effects have been adequately analyzed in an earlier EIR or negative declaration. Section 15063(c)(3)(D). In this case a discussion should identify the following on attached sheets: a) Earlier analyses used. Identify earlier analyses and state where they are available for review. b) Impacts adequately addressed. Identify which effects from the above checklist were within the scope of and adequately analyzed in an earlier document pursuant to applicable legal standards, and state whether such effects were addressed by mitigation measures based on the earlier analysis. c) Mitigation measures. For effects that are "Less Than Significant with Mitigation Incorporated," describe the mitigation measures, which were incorporated or refined from the earlier document and the extent to which they address site-specific conditions for the project. 13 Rev. 07/26/02 DISCUSSION OF ENVIRONMENTAL EVALUATION AIR QUALITY—Would the project: a) Conflict with or obstruct implementation of the applicable air quality plan? No Impact. The project site is located in the San Diego Air Basin which is a federal and state non-attainment area for ozone (O3), and a state non-attainment area for particulate matter less than or equal to 10 microns in diameter (PMio). The periodic violations of national Ambient Air Quality Standards (AAQS) in the San Diego Air Basin (SDAB), particularly for ozone in inland foothill areas, requires that a plan be developed outlining the pollution controls that will be undertaken to improve air quality. In San Diego County, this attainment planning process is embodied in the Regional Air Quality Strategies (RAQS) developed jointly by the Air Pollution Control District (APCD) and the San Diego Association of Govemments (SANDAG). A plan to meet the federal standard for ozone was developed in 1994 during the process of updating the 1991 state- mandated plan. This local plan was combined with plans from all other Califomia non-attainment areas having serious ozone problems and used to create the Califomia State Implementation Plan (SIP). The SIP was adopted by the Air Resources Board (ARB) after public hearings on November 9th through 10th in 1994, and was forwarded to the Environmental Protection Agency (EPA) for approval. After considerable analysis and debate, particularly regarding airsheds with the worst smog problems, EPA approved the SIP in mid-1996. The proposed project relates to the SIP and/or RAQS through the land use and growth assumptions that are incorporated into the air quality planning document. These growth assumptions are based on each city's and the County's general plan. If a proposed project is consistent with its applicable General Plan, then the project presumably has been anticipated with the regional air quality planning process. Such consistency would ensure that the project would not have an adverse regional air quality impact. Section 15125(B) of the State of Califomia Environment Quality Act (CEQA) Guidelines contains specific reference to the need to evaluate any inconsistencies between the proposed project and the applicable air quality management plan. Transportation Control Measures (TCMs) are part of the RAQS. The RAQS and TCM plan set forth the steps needed to accomplish attainment of state and federal ambient air quality standards. The Califomia Air Resources Board provides criteria for determining whether a project conforms with the RAQS which include the following: Is a regional air quality plan being implemented in the project area? Is the project consistent with the growth assumptions in the regional in the regional air quality plan? The project area is located in the San Diego Air Basin, and as such, is located in an area where a RAQS is being implemented. The project is consistent with the growth assumptions of the City's General Plan and the RAQS. Therefore, the project is consistent with the regional air quality plan and will in no way conflict or obstmct implementation of the regional plan. b) Violate any air quality standard or contribute substantially to an existing or projected air quality vioiation? Less Than Significant Impact. The closest air quality monitoring station to the project site is in the City of Oceanside. Data available for this monitoring site through April, 2002 indicate that the most recent air quality violations recorded were for the state one hour standard for ozone (one day in both 2000 and 2001) and one day in 2001 for the federal 8-hour average for ozone and one day for the 24-hour state standard for suspended particulates in 1996. No violations of any other air quality standards have been recorded recently. If there is grading associated with the project, the project would involve minimal short-term emissions associated with grading and constmction. Such emissions would be minimized through standard constmction measures such as the use of properly tuned equipment and watering the site for dust control. Long-term emissions associated with travel to and from the project will be minimal. Although air pollutant emissions would be associated with the project, they would neither result in the violation of any air quality standard (comprising only an incremental contribution to overall air basin quality readings), nor contribute substantially to an existing or projected air quality violation. Any impact is assessed as less than significant. c) Result in a cumulatively considerable net increase of any criteria pollutant for which the project region is non-attainment under an applicable federal or state ambient air quality standard? 14 Rev. 07/26/02 Less Than Significant Impact. The Air Basin is currently in a non-attainment zone for ozone and suspended fine particulates. The proposed project would represent a contribution to a cumulatively considerable potential net increase in emissions throughout the air basin. As described above, however, emissions associated with the proposed project would be minimal. Given the limited emissions potentially associated with the proposed project, air quality would be essentially the same whether or not the proposed project is implemented. According to the CE(^A Guidelines Section 15130 (a)(4), the proposed project's contribution to the cumulative impact is considered de minimus. Any impact is assessed as less than significant. EARLIER ANALYSIS USED AND SUPPORTING INFORMATION SOURCES The following documents were used in the analysis of this project and are on file in the City of Carlsbad Plaiming Department located at 1635 Faraday Avenue, Carlsbad, California, 92008. 1. Final Master Environmental Impact Report for the City of Carlsbad General Plan Update (MEIR 93-01). City of Carlsbad Planning Department. March 1994. 15 Rev. 07/26/02 t LIST OF MITIGATING MEASURES (IF APPLICABLE) PA^fAeWT 6r sc^ccL pees n& •5CHOOL p»Tw^r ATTACH MITIGATION MONITORING PROGRAM (IF APPLICABLE) 16 Rev. 07/26/02 COAST GEOTECHNICAL CONSULTING ENGINEERS AND GEOLOGISTS September 20, 2004 RECEIVED OCT ?1 ZGB4 Bob Enright 31499 Lake Vista Circle Bonsall, CA 92003 HOUSING & REDEVELOPMENT DEPARTMENT RE: PRELIMINARY GEOTECHNICAL INVESTIGATION Proposed Nine (9) Townhomes 2685 and 2687 Roosevelt Carlsbad, Califomia Dear Mr. Enright: Inresponse to yourrequestandin accordance withour Proposal and AgreementdatedMayl7,2004, wehaveperfonnedapreliminarygeotechnical investigation onthesubjectsitefortheproposedm^^ townhomes' project. The fmdings ofthe investigation, laboratory test results and recommendations for foundation design are presented in this report. From a geologic and soils engineering point of view, it is our opinion that the site is suitable for the proposed development, provided the recommendations in this report are implemented dunng the design and construction phases. If you have any questions, please do not hesitate to contact us at (858) 755-8622. This opportunity to be of service is appreciated. Respectfully submitted,^^'^ COAST (3E0TECHN|t^^i Mark Burwell Engineering Geologi Vithaya Singhanet, Geotechnical Engiri 779 ACADEMY DRIVE • SOLANA BEACH, CALIFORNIA 92075 (858) 755-8622 • FAX (858) 755-9126 PRELIMINARY GEOTECHNICAL INVESTIGATION Proposed Nine (9) Townhomes 2685 and 2687 Roosevelt Carlsbad, California Prepared For: Bob Enright 31499 Lake Vista Circle Bonsall, CA 92003 September 20, 2004 W.O. P-426064 Prepared By: COAST GEOTECHNICAL 779 Academy Drive Solana Beach, California 92075 TABLE OF CONTENTS VICINITY MAP 4 INTRODUCTION 5 SITE CONDITIONS 5 PROPOSED DEVELOPMENT 5 SITE INVESTIGATION 6 LABORATORY TESTING 6 GEOLOGIC CONDITIONS 7 CONCLUSIONS 10 RECOMMENDATIONS 11 A. GRADING-REMOVALS/RECOMPACTION 11 B. TEMPORARY SLOPES/EXCAVATION CHARACTERISTICS 12 C. FOUNDATIONS 13 D. SLABS ON GRADE (INTERIOR AND EXTERIOR) 13 E. RETAINING WALLS 14 F. SETTLEMENT CHARACTERISTICS 15 G. SEISMIC CONSIDERATIONS 15 H. SEISMIC DESIGN PARAMETERS 15 I. PRELIMINARY PAVEMENT DESIGN 16 J. UTILITY TRENCH 16 K. DRAINAGE 17 L. GEOTECHNICAL OBSERVATIONS 17 M. PLAN REVIEW 18 LIMITATIONS 18 REFERENCES 20 APPENDICES APPENDIX A LABORATORY TEST RESULTS EXPLORATORY BORING LOGS CROSS SECTION A-A' TOPOGRAPHIC MAP APPENDIX B REGIONAL FAULT MAP SEISMIC DESIGN PARAMETERS DESIGN RESPONSE SPECTRUM APPENDIX C GRADING GUIDELINES Topo USA® 5.0 VICINITY MAP KREMEY-ER .KN.QWJLES.AyE.. :iR SUBJECT PROPERTY Scale 1 :5.600 Data use subject to license. © 2004 DeLomie. Topo USA® 5.0. www.delorme.com D IJO 330 4B0 640 BOO 0 40 eo 130 in 300 1" = 466.7 ft Data Zoom 15-0 Coast Geotechnical September 20, 2004 W.O. P-426064 Page 5 INTRODUCTION This report presents the results of our geotechnical investigation on the subject property. The purpose ofthis study is to evaluate the nature and characteristics ofthe earth materials imderlying the property, the engineering properties ofthe surficial deposits and their influence on the proposed residential project. SITE CONDITIONS The subject property is located north of Grand Avenue, along the west side of Roosevelt Street, in the city of Carlsbad. The subject property consists of approximately 0.46 acres of very gently west sloping terrain. The property is occupied by three (3) separate residential structures. Relief on the site is approximately 2.0 vertical feet. The subject property is bounded by developed residential and commercial lots on the north, south and west. Vegetation includes grass and several palm trees adjacent to the street. Most of the rest of the site, with the exception of planters, is generally void of significant vegetation. Drainage is generally by sheet flow to the southwest. PROPOSED DEVELOPMENT Preliminary plans for the development of the site were prepared by David Soanes, Architect. The Coast Geotechnical September 20, 2004 W.O. P-426064 Page 6 project includes demolition of existing structures and the construction of nine (9) townhomes. The attached two story imits will be constructed over a subterranean garage/basement located approximately 4.0 feet below the existing grade. SITE INVESTIGATION Site exploration included four (4) exploratory borings drilled to a maximum depth of 12 feet. Boring No. 4 was converted to a groimdwater monitoring well (piezometer). Earth materials encountered were visually classified and logged by our field engineering geologist. Undisturbed, representative samples of earth materials were obtained at selected intervals. Samples were obtained by driving a thin walled steel sampler into the desired strata. The samples are retained in brass rings of 2.5 inches outside diameter and 1.0 inches in height. The central portion of the sample is retained in close fitting, waterproof containers and transported to our laboratory for testing and analysis. Standard penetration tests were performed in Boring Nos. 3 and 4. LABORATORY TESTING Classification The field classification was verified through laboratory examination, in accordance with the Unified Soil Classification System. The final classification is shown on the enclosed Exploratory Logs. Coast Geotechnical September 20,2004 W.O. P-426064 Page 7 Moisture/Density The field moisture content and dry unit weight were determined for each of the undisturbed soil samples. This information is usefiil in providing a gross picture ofthe soil consistency or variation among exploratory excavations. The dry unit weight was determined in pounds per cubic foot. The field moisture content was determined as a percentage of the dry unit weight. Both are shown on the enclosed Laboratory Tests Results and Exploratory Logs. Maximum Drv Densitv and Optimum Moisture Content The maximum dry density and optimum moisture content were determined for selected samples of earth materials taken fi'om the site. The laboratory standard tests were in accordance with ASTM D-1557-91. The results of the tests are presented in the Laboratory Test Results. Expansion Index Tests Expansion Tests were performed on selected samples. Test procedures were conducted in accordance with the Uniform Building Code, Standard No. 29-2. The classification of expansive soil, based on the expansion index, are as indicated in Table 29-C ofthe Uniform Building Code. The test results are shown on the enclosed Laboratory Test Results. GEOLOGIC CONDITIONS The subject property is located in the Coastal Plains Physiographic Province of San Diego. The Coast Geotechnical September 20,2004 W.O. P-426064 Page 8 property is underlain at relatively shallow depths by Pleistocene terrace deposits. The terrace deposits are underlain at depth by Eocene-age sedimentary rocks which have commonly been designated as the Santiago Fonnation on published geologic maps. The tenace deposits are covered by soil deposits and, in part, by fill deposits. A brief description of the earth materials encountered on the site follows. Artificial Fill No evidence of significant fill deposits were observed on the site. Minor fill deposits, up to 2.5 feet, appear to be located along the northwestem portion of the property. Additional minor fill deposits are present in and aroimd the existing structures and driveway areas. The fill is composed of tan to reddish brown silty, fine and medium-grained sand in a dry and hard condition. Residual Soil Site exploration suggests the underlying tenace deposits are blanketed by approximately 6.0 to 12 inches of brown clayey sand to sandy clay. The soil is generally damp and stiff The contact with the underlying tenace deposits is gradational and may vary across the site. Tenace Deposits Underlying the surficial materials, poorly consolidated Pleistocene tenace deposits are present. The upper 4.5 to 6.0 feet ofthe tenace deposits are composed of tan to brown clayey, fine and medium- Coast Geotechnical September 20, 2004 W.O. P-426064 Page 9 grained sand in a soft and near saturated condition. The sediments grade to weakly cemented, tan, fine and medium-grained sand with pebbles and cobbles. Regionally, the Pleistocene sands are considered flat-lying and are underlain at depth by Eocene-age sedimentary rock units. Expansive Soil Based on our experience in the area and laboratory testing of selected samples, the residual soil and clayey Pleistocene tenace deposits reflect an expansion potential in the low range but approaching the medium range. Groundwater Groundwater was encountered in all four exploratory borings below the upper clayey deposits, in the sandy cobble zone, at an approximate depth of 8.0 feet below the existing grade. Tectonic Setting The site is located within the seismically active southem Califomia region which is generally characterized by northwest trending Quatemary-age fault zones. Several of these fault zones and fault segments are classified as active by the Califomia Division of Mines and Geology (Alquist- Priolo Earthquake Fault Zoning Act). Based on a review of published geologic maps, no known faults transverse the site. The nearest active fault is the offshore Newport-Inglewood Fault Zone located approximately 4.6 miles west of Coast Geotechnical September 20, 2004 W.O. P-426064 Page 10 the site. It should also be noted that the offshore Rose Canyon Fault is not a continuous well-defined feature, but rather a zone of right stepping en echelon faults. The complex series of faults has been refened to as the Offshore Zone of Deformation (Woodward-Clyde, 1979) and is not fiilly understood. Several studies suggest that the Newport-Inglewood and the Rose Canyon faults are a continuous zone of en echelon faults (Treiman, 1984). Further studies along the complex offshore zone of faulting may indicate a potentially greater seismic risk than cunent data suggests. Other faults which could affect the site include the Coronado Bank, Elsinore, San Jacinto and San Andreas Faults. The proximity of major faults to the site and site parameters are shown on the enclosed Seismic Design Parameters. Liquefaction Potential Liquefaction is a process by which a sand mass loses its shearing strength completely and flows. The temporary transformation of the material into a fluid mass is often associated with ground motion resulting firom an earthquake. Owing to the moderately dense nature of the Pleistocene tenace deposits and the age of the sediments, the potential for seismically induced liquefaction and soil instability is considered low. CONCLUSIONS 1) The proposed townhouses will be constructed over a subtenanean parking structure, located approximately 4.0 feet below the existing grade. Coast Geotechnical September 20, 2004 W.O. P-426064 Pageil 2) It is anticipated that relatively soft clayey tenace deposits will be exposed along the base of the parking excavation. A minimum of 3.0 feet ofthe tenace deposits should be removed and replaced as properly compacted fill, in order to support proposed footings and slabs on grade. 3) Groimdwater was encountered approximately 8.0 feet below the existing grade. It should be noted that fluctuations in the groundwater level can occur. 4) Some degree of difficulty should be anticipated in compaction ofthe clayey tenace deposits, due to the high groundwater conditions and soil characteristics. It is suggested that where sandy deposits are encountered in the garage excavation, that they be stockpiled and mixed with the underlying clayey tenace deposits. Such an approach will aid in compaction characteristics and reduce potential expansion. RECOMMENDATIONS Grading-Removals/Recompaction If structural footings or slabs on grade are planned outside the proposed subtenanean walls, the existing fill, soil and weathered tenace deposits should be removed and replaced as properly compacted fill. As previously indicated, granular deposits encoimtered during the subtenanean excavation should be stockpiled for latter mixing with clayey tenace deposits. Removals should Coast Geotechnical September 20, 2004 W.O. P-426064 Page 12 include the entire building pad, extending a minimum of 5.0 feet beyond the building footprint, where applicable. The depth of removals are anticipated to be on the order of 3.0 feet below the proposed garage grade. However, deeper removals may be necessary based on conditions revealed during grading. Most of the existing earth deposits are generally suitable for reuse, provided they are cleared of all vegetation, debris and thoroughly mixed. Prior to placement of fill, the base ofthe removal should be observed by a representative ofthis firm. Additional recommendations may be necessary, at that time. The exposed bottom should be scarified to a minimum depth of 6.0 inches, moistened as required and compacted to a minimum of 92 percent ofthe laboratory maximum dry density. Fill should be placed in 6.0 to 8.0 inch lifts, moistened or aerated to approximately 1.0-2.0 percent above optimum moisture content and compacted to a minimum of 90 percent of the laboratory maximum dry density. Fill, soil and weathered tenace deposits in areas of proposed concrete flatwork and driveways should be removed and replaced as properly compacted fill. Imported fill, if necessary, should consist of non-expansive granular deposits approved by the geotechnical engineer. Temporary Slopes/Excavation Characteristics Temporary excavations should be trimmed to a gradient of 3/4:1 (horizontal to vertical) or less depending upon conditions encountered during grading. The Pleistocene tenace deposits are generally weakly cemented but may contain hard concretion layers. Based on our experience in the area, the tenace deposits are easily rippable with conventional earth moving equipment in good working order. All excavations should be constructed in accordance with Cal-OSHA requirements. Coast Geotechnical September 20, 2004 W.O. P-426064 Page 13 Foundations The following design parameters are based on footings founded into approved compacted fill deposits with an expansion potential in the low range. Footings for the proposed residences should be founded a minimum of 18 inches below the lower most adjacent subgrade, at the time of foundation construction for single-story and two-story structures. A 12 inch by 12 inch grade beam should be placed across the garage opening. Footings should be reinforced in accordance with the project structural engineer's recommendations. For design purposes, an allowable bearing value of 2000 pounds per square foot may be used for foundations at the recommended footing depths. The bearing value indicated above is for the total dead and frequently applied live loads. This value may be increased by 33 percent for short durations of loading, including the effects of wind and seismic forces. Resistance to lateral load may be provided by fiiction acting at the base of foundations and by passive earth pressure. A coefficient of fiiction of 0.35 may be used with dead-load forces. A passive earth pressure of 300 pounds per square foot, per foot of depth of fill penetrated to a maximum of2000 pounds per square foot may be used. Slabs on Grade (Interior and Exterior) Slabs on grade should be a minimum of 5.0 inches thick and reinforced, as recommended by the Coast Geotechnical September 20, 2004 W.O. P-426064 Page 14 project structural engineer. Slabs should be designed in accordance with structural considerations, anticipated settlement and an expansion approaching the medium range. The slab should be underlain by a minimum 2.0-inch sand blanket. Where moisture sensitive floors are used, a minimum 6.0-mil Visqueen or equivalent moisture barrier should be placed over the sand blanket and covered by an additional two inches of sand. Utility trenches underlying the slab may be backfilled with on-site materials, compacted to a minimum of 90 percent of the laboratory maximum dry density. Slabs including exterior concrete flatwork should be reinforced and provided with saw cuts/expansion joints, as recommended by the project structural engineer. All slabs should be cast over dense compacted subgrades. Retaining Walls Cantilever walls (yielding) retaining nonexpansive granular soils may be designed for an active- equivalent fluid pressure of 35 pounds per cubic foot. Restrained walls (nonyielding) should be designed for an "at-rest" equivalent fluid pressure of 58 pounds per cubic foot. Wall footings should be designed in accordance with the foundation design recommendations. All retaining walls should be provided with an adequate backdrainage system (Miradrain 6000 or equivalent is suggested). The soil parameters assume a level granular backflll compacted to a minimum of 90 percent of the laboratory maximum dry density. Coast Geotechnical September 20,2004 W.O. P-426064 Page 15 Settlement Characteristics Estimated total and differential settlement over a horizontal distance of 30 feet is expected to be on the order of 1.0 inch and VA inch, respectively. It should also be noted that long term secondary settlement due to irrigation and loads imposed by stmctures is anticipated to be 1/4 inch. Seismic Considerations Although the likelihood of ground rupture on the site is remote, the property will be exposed to moderate to high levels of ground motion resulting fi"om the release of energy should an earthquake occur along the numerous known and unknown faults in the region. The Newport-Inglewood Fault Zone located approximately 4.6 miles west of the property is the nearest known active fault and is considered the design earthquake for the site. A maximum probable event along the offshore fault segment is expected to produce a peak bedrock horizontal acceleration of 0.38g and a repeatable ground acceleration of 0.25g. Seismic Design Parameters (1997 Uniform Building Code) Soil Profile Type - Sp Seismic Zone - 4 Seismic Source - Type B Near Source Factor (NJ -1.1 Near source Acceleration Factor (NJ - 1.0 Seismic Coefficients C, = 0.44 C =0.71 Coast Geotechnical September 20,2004 W.O. P-426064 Page 16 Design Response Spectrum = 0.645 T„ = 0.129 Nearest Type B Fault - 4.6 miles Preliminarv Pavement Design The following pavement section is recommended for proposed driveways: 4.0 inches of asphaltic paving or 5.0 inches of concrete on 6.0 inches of select base (Class 2) on 12 inches of compacted subgrade soils Subgrade soils should be compacted to the thickness indicated in the structural section and left in a condition to receive base materials. Class 2 base materials should have a minimum R-value of 78 and a minimum sand equivalent of 30. Subgrade soils and base materials should be compacted to a minimum of 95 percent of their laboratory maximum dry density. The pavement section should be protected fi'om water sources. Migration of water into subgrade deposits and base materials could result in pavement failure. Utility Trench We recommend that all utilities be bedded in clean sand to at least one foot above the top of the conduit. The bedding should be flooded in place to fill all the voids around the conduit. Imported Coast Geotechnical September 20,2004 W.O. P-426064 Page 17 or on-site granular material compacted to at least 90 percent relative compaction maybe utilized for backfill above the bedding. The invert of subsurface utility excavations paralleling footings should be located above the zone of influence of these adjacent footings. This zone of influence is defmed as the area below a 45 degree plane projected down fi'om the nearest bottom edge of an adjacent footing. This can be accomplished by either deepening the footing, raising the invert elevation of the utility, or moving the utility or the footing away fi'om one another. Drainage Specific drainage pattems should be designed by the project architect or engineer. However, in general, pad water should be directed away firom foundations and aroimd the structure to the street. Roof water should be collected and conducted to the street, via non-erodible devices. Pad water should not be allowed to pond. Vegetation adj acent to foimdations should be avoided. If vegetation in these areas is desired, sealed planter boxes or drought resistant plants should be considered. Other altematives may be available, however, the intent is to reduce moisture fi-om migrating into foundation subsoils. Irrigation should be limited to that amount necessary to sustain plant life. All drainage systems should be inspected and cleaned annually, prior to winter rains. Geotechnical Observations Stmctural footing excavations should be observed by a representative of this firm, prior to the Coast Geotechnical September 20,2004 W.O. P-426064 Page 18 placement of steel and forms. All fill should be placed while a representative ofthe geotechnical engineer is present to observe and test. Plan Review A copy ofthe fmal plans should be submitted to this office for review prior to the initiation of constmction. Additional recommendations may be necessary at that time. IIMITATIONS This report is presented with the provision that it is the responsibility of the owner or the owner's representative to bring the information and recommendations given herein to the attention ofthe project's architects and/or engineers so that they may be incorporated into plans. If conditions encountered during construction appear to differ firom those described in this report, our office should be notified so that we may consider whether modifications are needed. No responsibility for constmction compliance with design concepts, specifications or recommendations given in this report is assumed unless on-site review is performed during the course of constmction. The subsurface conditions, excavation characteristics and geologic stmcture described herein are based on individual exploratory excavations made on the subject property. The subsurface conditions, excavation characteristics and geologic stmcture discussed should in no way be constmed to reflect any variations which may occur among the exploratory excavations. Coast Geotechnical September 20,2004 W.O. P-426064 Page 19 Please note that fluctuations in the level of groundwater may occur due to variations in rainfall, temperature and other factors not evident at the time measurements were made and reported herein. Coast Geotechnical assumes no responsibility for variations which may occur across the site. The conclusions and recommendations of this report apply as ofthe cunent date. In time, however, changes can occur on a property whether caused by acts of man or nature on this or adjoining properties. Additionally, changes in professional standards may be brought about by legislation or the expansion of knowledge. Consequently, the conclusions and recommendations of this report may be rendered wholly or partially invalid by events beyond our control. This report is therefore subject to review and should not be relied upon after the passage of two years. The professional judgments presented herein are founded partly on our assessment of the technical data gathered, partly on our understanding of the proposed constmction and partly on our general experience in the geotechnical field. However, in no respect do we guarantee the outcome of the project. This study has been provided solely for the benefit of the client and is in no way intended to benefit or extend any right or interest to any third party. This study is not to be used on other projects or extensions to this project except by agreement in writing with Coast Geotechnical. Coast Geotechnical September 20, 2004 W.O. P-426064 Page 20 REFERENCES 1. Hays, Walter W., 1980, Procedures for Estimating Earthquake Ground Motions, Geological Survey Professional Paper 1114, 77 pages. 2. Seed, H.B., and Idriss, I.M., 1970, A Simplified Procedure for Evaluating Soil Liquefaction Potential: Earthquake Engineering Research Center. 3. Tan, S.S., and Giffen, D.G., 1995, Landslide Hazards in the Northem Part ofthe San Diego Metropolitan Area, San Diego County, Plate 35A, Open-File Report 95-04, Map Scale 1:24,000. 4. Treiman, J.A., 1984, The Rose Canyon Fault Zone, A Review and Analysis, Califomia Division of Mines and Geology. MAPS/AERIAL PHOTOGRAPHS 1. Aerial Photograph, 1982, Foto-Map D-7, Scale 1 "=2000'. 2. Califomia Division of Mines and Geology, 1994, Fault Activity Map of Califomia, Scale 1 "=750,000'. 3. Geologic Map of the Oceanside, San Luis Rey and San Marcos 7.5' Quadrangles, 1996, DMG Open File Report 96-02. 4. Pasco Engineering, 2004, Topographic Map 2685 and 2687 Roosevelt Street, Carlsbad, CA, Scale 1"=10'. 5. U.S.G.S., 7.5 Minute Quadrangle Topographic Map, Digitized, Scale Variable. APPENDED A LABORATORY TEST RESULTS TABLE I Maximum Dry Density and Optimum Moisture Content (Laboratory Standard ASTM D-1557-91) Sample Location B-1 @ 1.0'-4 . 0 Max. Dry Density (DCf) 120.5 Optimum Moisture Content 12.8 TABLE II Field Dry Density and Moisture Content Sample Location B-1 ® 2.0 B-1 @ 4.0 B-1 @ 6.0 B-1 @ 8.0 B-2 @ 2.0 B-2 @ 4.0 B-2 @ 6.0 B-2 @ 8.0 Field Dry Density (pcf) 98.8 104.2 85 .4 107.4 100.1 95 .2 96.4 Sample Disturbed Field Moisture Content % 23 .6 18.9 31.5 19.0 10.6 28.0 25.4 12 .1 TABLE III Expansion Index Test Results Sample Location B-1 @ 3.0'-4 . 0 Expansion Potential 48 (low) P-426064 LOG OF ExrtORATORY BOR#fG NO. 1 DRILL RIG: PORTABLE BUCKET AUGER BORING DIAMETER: 3.5" SURFACE ELEV.: 98' (Approximate) PROJECT NO. P-426064 DATE DRILLED: 07-08-04 LOGGED BY: MB H Q O U Pi w u < — 0.00 ;t«»t«t — .mhh § HH H $ w w w Q 98.00 HJ u o cn u ori < u c/i GEOLOGIC DESCRIPTION 98.8 104.2 85.4 107.4 SC 1.00 SOIL (Qs): Brown clayey sand, damp, stiff pi 9ioo|lMSS 23.6 I — 96.0 18.9 I 31.5 I 2.00 95.00 3.00 94.00 4.00 93.00 5.00 92.00 6.00 91.00 fir: SC TERRACE DEPOSITS (Qt): Tan to bm. clayey sand, v.moist. — 7.00 jij'uil.'S From 6', soft, saturated clayey sand aU..UI..-U.l.j-ll .Tnj'u.guj'jj GM 90.0ffl 19.0 I — 8.00 89.0W TERRACE DEPOSITS (Qt): Tan to Whitish tan, fme and med.-grained sand, pebbles/cobbles Groundwater @ 8' End of Boring @ 9' due to cobble 9.00 SHEET 1 OF 1 COAST GEOTECHNICAL LOG OF EXPfbRATORY BORir#; NO. 2 DRILL RIG: PORTABLE BUCKET AUGER BORING DIAMETER: 3.5" SURFACE ELEV.: 98' (Approximate) PROJECT NO. P-426064 DATE DRILLED: 07-08-04 LOGGED BY: MB u >^ H c/i P t u < § I—I H W w £ H g 98.00 O H CL, o L -•.:--.f<r.W r.U.Ur.W 1/1 u c/i 1/3 < H-I u t/2 GEOLOGIC DESCRIPTION 0.00 SM FILL (af):Tan to Reddish bra., silty fme and medium-grained sand, dense 97.00? — 1.00 100.1 10.6 I iffl 95.00 liElt^l SC SOIL (Qs): Brown clayey sand, damp, stiff — 3.00 SC 95.2 28.0 I — 94.00 96.4 25.4 I — 4.00 93.00 — 5.00 92.00 6.00 91.00 li.il ill TERRACE DEPOSITS (Qt): Tan to bm. clayey sand, v.moist. From 4', soft, saturated clayey sand Distrubei 12.1 1 — 7.00 — 90.00 *.i -j.J ''M GM — 8.00 TERRACE DEPOSITS (Qt): Grey to Whitish tan, fme and med.-grained sand, pebbles/cobbles Groundwater @ 8' End of Boring @ 8.5' due to cobble SHEET 1 OF 1 COAST GEOTECHNICAL LOG OF EXPibRATORY BORIl^ NO. 3 DRILL RIG: HOLLOW STEM AUGER BORING DIAMETER: 6.0" SURFACE ELEV.: 98' (Approximate) PROJECT NO. P-426064 DATE DRILLED: 09-13-04 LOGGED BY: MB o tx Q Q Pi Ui u < CJi CO 8 PH cn O HJ w w H W Q 98.00 8 O o IZ) U 00 1/2 3 5 CO 140 Poimd Hammer, 30 Inch Drop DESCRIPTION 0.00 FILL (af): Tan to bm. silty sand, with gravel Driveway SC 97.00 1.00 =: 96.00 SOIL (Qs): Brown clayey sand, damp, stiff Graditional Contact — 2.00 = 95.00 SC TERRACE DEPOSITS (Qt): Tan to bm. clayey sand, v.moist. 16 I 32 I 3.00 i 94.00 4.00 93.00 5.00 — 92.00' 6.00 ] 91.00 7.00 90.00' Medium dense 8.00 GM TERRACE DEPOSITS (Qt): Tan to Whitish tan, fme and med.-grained s pebbles/cobbles Groundwater @ 8' 89.00 — 9.00 — 88.00 10.00, 87.00 11.00! — 86.00g»{ End of Boring @ 12' 12.00 SHEET 1 OF 1 COAST GEOTECHNICAL LOG OF EXPEDRATORY BORI St NO.4 DRILL RIG: HOLLOW STEM AUGER BORING DIAMETER: 6.0" SURFACE ELEV.: 98' (Approximate) PROJECT NO. P-426064 DATE DRILLED: 09-15-04 LOGGED BY: MB o a. ^—^ H 5o Q CO W o CO g CO H o O Pi PH CO I HJ PQ 1-1 CO g p si PH pq Q 98.00 8 HJ u a PH o |..:t:Ci:l CO U CO CO CO s oo 140 Pound Hammer, 30 Inch Drop DESCRIPTION 0.00 FILL (af): Tan to bm. silty sand, with gravel Driveway SC = 97.00 !l 1.00 96.00 SOIL (Qs): Brown clayey sand, damp, stiff Graditional Contact — 2.00 SC TERRACE DEPOSITS (Qt): Tan to bm. clayey sand, v.moist. 12 I 34 I — 95.00 3.00 94.00 4.00 i 93.00 = 5.00 = 92.00 6.00 91.00 7.00 90.00 = 8.00 89.00 = 9.00 88.00 10.00 87.00 — 11.00 Medium dense GM TERRACE DEPOSITS (Qt): Tan to Whitish tan, fme and med.-grained s pebbles/cobbles Groimdwater @ 8' Note: Boring converted to monitoring well Bentonite seal fi-om 4 ft. to 7 ft. 86.00 End of Boring® 12' SHEET 1 OF 1 12.00 COAST GEOTECHNICAL CROSS SECTION A-A' (SHOWING GENERAL SUBSURFACE CONDITIONS) SCALE l"=10' It- n I—r r -V—r PROPOSED RESIDENCES PROPOSED RESIDENCES —h _L L PROPOSED GARAGE-EXISTING GRADE - .y^ - - --- ---- I 3 Qt (clayey) GW 1 Qt (sandy w/pebbles) GW (Groundwater) -110' -100' -90' GEOLOGIC UNITS af ARTIFICIAL FILL Qs RESIDUAL SOIL Qt TERRACE DEPOSITS COAST GEOTECHNICAL P-426()64 TOPOGRAPHIC SURVEY SEWER MANHOLE BENCHMARK ASSUMED ELEV'100.0- L Roo s eve It Str e e t SEW STHP —_ 7" DRIVE WAX' sew STHP EXISTING BUILOING 203-101-01,03 LEGEND SCALE: 1"=20' SYMBOLS BORING LOCATION (approx.) CONTACT (approx.) GEOLOGIC UNITS af ARTIFICIAL FILL Qs RESIDUAL SOIL Qt TERRACE DEPOSITS COAST GEOTECHNICAL P-426064 APPENDIK B *********************** * * * UBCSEIS * * * * Version 1.03 * * * *********************** COMPUTATION OF 1997 UNIFORM BUILDING CODE SEISMIC DESIGN PARAMETERS JOB NUMBER: P-426064 JOB NAME: ENRIGHT FAULT-DATA-FILE NAME: CDMGUBCR.DAT DATE: 03-20-2004 SITE COORDINATES: SITE LATITUDE: SITE LONGITUDE 33.1634 117.3507 UBC SEISMIC ZONE: 0.4 UBC SOIL PROFILE TYPE: SD NEAREST TYPE A FAULT: NAME: ELSINORE-JULIAN DISTANCE: 3 9.4 km NEAREST TYPE B FAULT: NAME: NEWPORT-INGLEWOOD (Offshore) DISTANCE: 7.3 km NEAREST TYPE C FAULT: NAME: DISTANCE: 99999.0 km SELECTED UBC SEISMIC COEFFICIENTS: Na 1 0 Nv 1 1 Ca 0 44 Cv 0 71 Ts 0 645 To 0 129 SUMMARY OF FAULT PARAMETERS Page 1 APPROX. SOURCE MAX. SLIP FAULT ABBREVIATED DISTANCE TYPE MAG. RATE TYPE FAULT NAME (km) (A,B,C) (Mw) (mm/yr) (SS,DS, ================================== ====== == ======= ==== = = ===== : = = = = ======= NEWPORT-INGLEWOOD (Offshore) 7. 3 B 6 . 9 1 50 SS ROSE CANYON 7 . 6 B 6 . 9 1 50 ss CORONADO BANK 33 . 7 B 7 . 4 3 . 00 ss ELSINORE-TEMECULA 38. 9 B 6. 8 5 00 ss ELSINORE-JULIAN 39. 4 A 7. 1 5 . 00 ss ELSINORE-GLEN IVY 53 . 3 B 6. 8 5 00 ss PALOS VERDES 56. 2 B 7. 1 3 . 00 ss EARTHQUAKE VALLEY 71. 6 B 6. 5 2 00 ss NEWPORT-INGLEWOOD (L.A.Basin) 72 . 5 B 6 . 9 1 00 ss CHINO-CENTRAL AVE. (Elsinore) 75. 1 B 6 . 7 1 00 DS SAN JACINTO-ANZA 75 . 1 A 7. 2 12 00 ss SAN JACINTO-SAN JACINTO VALLEY 75. 8 B 6. 9 12 00 SS ELSINORE-WHITTIER 81. 3 B 6 . 8 2 50 ss SAN JACINTO-COYOTE CREEK 85. 0 B 6. 8 4 00 SS ELSINORE-COYOTE MOUNTAIN 94 . 6 B 6. 8 4 00 ss SAN JACINTO-SAN BERNARDINO 95. 3 B 6. 7 12 00 ss SAN ANDREAS - Southern 104 . 1 A 7. 4 24 00 ss SAN JACINTO - BORREGO 107. 7 B 6 . 6 4 00 ss SAN JOSE 108. 4 B 6 . 5 0 50 DS CUCAMONGA 112 . 6 A 7 . 0 5 00 DS SIERRA MADRE (Central) 112 . 7 B 7. 0 3 00 DS PINTO MOUNTAIN 115 . 4 B 7. 0 2 50 SS NORTH FRONTAL FAULT ZONE (West) 121. 9 B 7. 0 1 00 DS CLEGHORN 123 . 8 B 6 . 5 3 00 SS BURNT MTN. 125 . 6 B 6. 5 0 60 SS RAYMOND 127. 1 B 6. 5 0 50 DS CLAMSHELL-SAWPIT 127. 7 B 6. 5 0 50 DS SAN ANDREAS - 1857 Rupture 128 . 6 A 7. 8 34 00 SS EUREKA PEAK 130. 1 B 6. 5 0 60 SS NORTH FRONTAL FAULT ZONE (East) 130. 7 B 6. 7 0 50 DS VERDUGO 131. 0 B 6 . 7 0 50 DS HOLLYWOOD 134. 2 B 6 . 5 1 00 DS SUPERSTITION MTN. (San Jacinto) 134 . 3 B 6. 6 5 00 SS ELMORE RANCH 140 . 1 B 6 . 6 1 00 SS LANDERS 141. 1 B 7 . 3 0 60 SS HELENDALE - S. LOCKHARDT 141. 5 B 7 . 1 0 60 SS SUPERSTITION HILLS (San Jacinto) 141. 8 B 6 6 4 00 SS SANTA MONICA 141. 8 B 6. 6 1 00 DS ELSINORE-LAGUNA SALADA 145. 1 B 7 0 3 50 SS MALIBU COAST 146 . 3 B 6 . 7 0 30 DS LENWOOD-LOCKHART-OLD WOMAN SPRGS 148 . 2 B 7 3 0 60 SS SIERRA MADRE (San Fernando) 151. 9 B 6. 7 2 00 DS JOHNSON VALLEY (Northern) 153 . 5 B 6 7 0 60 SS BRAWLEY SEISMIC ZONE 154. 4 B 6 5 25 00 SS EMERSON So. - COPPER MTN. 154 . 5 B 6. 9 0 60 SS SAN GABRIEL 154 . 8 B 7. 0 1 00 SS SUMMARY OF FAULT PARAMETERS Page 2 APPROX. SOURCE MAX. SLIP FAULT ABBREVIATED DISTANCE TYPE MAG. RATE TYPE FAULT NAME (km) (A,B,C) (Mw) (mm/yr) (SS,DS,BT) ANACAPA-DUME 154. 9 B 7 . 3 3 00 DS PISGAH-BULLION MTN.-MESQUITE LK 165. 1 B 7. 1 0 60 SS CALICO - HIDALGO 167. 0 B 7 1 0 60 SS SANTA SUSANA 167. 3 B 6. 6 5 00 DS IMPERIAL 168. 1 A 7. 0 20 00 SS HOLSER 176. 3 B 6. 5 0 40 DS SIMI-SANTA ROSA 184 . 0 B 6 7 1 00 DS OAK RIDGE (Onshore) 184. 7 B 6. 9 4 00 DS SAN CAYETANO 193 . 1 B 6 . 8 6 00 DS GRAVEL HILLS - HARPER LAKE 194. 2 B 6. 9 0 60 SS BLACKWATER 209. 2 B 6. 9 0 60 SS VENTURA - PITAS POINT 212. 2 B 6. 8 1 00 DS SANTA YNEZ (East) 212. 9 B 7. 0 2 00 SS SANTA CRUZ ISLAND 221. 5 B 6. 8 1 00 DS M.RIDGE-ARROYO PARIDA-SANTA ANA 222 . 8 B 6. 7 0 40 DS RED MOUNTAIN 226. 3 B 6 . 8 2 00 DS GARLOCK (West) 229. 1 A 7. 1 6 00 SS PLEITO THRUST 234 . 4 B 6 . 8 2 00 DS BIG PINE 240. 3 B 6. 7 0 80 SS GARLOCK (East) 244 . 1 A 7 . 3 7 00 SS WHITE WOLF 255. 0 B 7. 2 2 00 DS SANTA ROSA ISLAND 256. 4 B 6. 9 1 00 DS SANTA YNEZ (West) 258 . 3 B 6. 9 2 00 SS So. SIERRA NEVADA 268. 6 B 7. 1 0 10 DS LITTLE LAKE 273 . 5 B 6. 7 0 70 SS OWL LAKE 275 . 2 B 6. 5 2 00 SS PANAMINT VALLEY 275. 4 B 7 . 2 2 50 SS TANK CANYON 275. 7 B 6. 5 1 00 DS DEATH VALLEY (South) 285. 0 B 6. 9 4 00 SS LOS ALAMOS-W. BASELINE 300. 6 B 6. 8 0 70 DS LIONS HEAD 318. 1 B 6 . 6 0 02 DS DEATH VALLEY (Graben) 325 . 5 B 6 9 4 00 DS SAN LUIS RANGE (S. Margin) 327. 7 B 7 . 0 0 20 DS SAN JUAN 328 . 2 B 7 . 0 1 00 SS CASMALIA (Orcutt Frontal Fault) 336 . 1 B 6. 5 0 25 DS OWENS VALLEY 341. 7 B 7. 6 1 50 SS LOS OSOS 357. 7 B 6. 8 0 50 DS HOSGRI 363 . 9 B 7. 3 2 50 SS HUNTER MTN. - SALINE VALLEY 368. 5 B 7. 0 2 50 SS INDEPENDENCE 377. 5 B 6 . 9 0 20 DS RINCONADA 378 . 5 B 7. 3 1 00 SS DEATH VALLEY (Northern) 378 . 8 A 7. 2 5 00 SS BIRCH CREEK 433 . 8 B 6 . 5 0 70 DS SAN ANDREAS (Creeping) 434 . 6 B 5 . 0 34 00 SS WHITE MOUNTAINS 438 . 4 B 7. 1 1 00 SS DEEP SPRINGS 457. 0 B 6. 6 0 80 DS SUMMARY OF FAULT PARAMETERS Page 3 APPROX. SOURCE MAX. SLIP FAULT ABBREVIATED DISTANCE TYPE MAG. RATE TYPE FAULT NAME (km) (A,B,C) (Mw) (mm/yr) (SS,DS,BT) DEATH VALLEY (N. of Cucamongo) 462. 4 A 7 0 5 00 SS ROUND VALLEY (E. of S.N.Mtns.) 468 . 8 B 6 8 1 00 DS FISH SLOUGH 476 . 7 B 6 6 0 20 DS HILTON CREEK 494 . 9 B 6 7 2 50 DS ORTIGALITA 518 . 9 B 6 9 1 00 SS HARTLEY SPRINGS 519. 1 B 6 6 0 50 DS CALAVERAS (So.of Calaveras Res) 524 . 5 B 6 2 15 00 SS MONTEREY BAY - TULARCITOS 527. 2 B 7 1 0 50 DS PALO COLORADO - SUR 528 . 3 B 7 0 3 00 SS QUIEN SABE 537. 7 B 6 5 1 00 SS MONO LAKE 555. 1 B 6 6 2 50 DS ZAYANTE-VERGELES 556. 3 B 6 8 0 10 SS SAN ANDREAS (1906) 561. 5 A 7 9 24 00 SS SARGENT 561. 6 B 6 8 3 00 SS ROBINSON CREEK 586. 3 B 6 5 0 50 DS SAN GREGORIO 602 . 6 A 7 3 5 00 SS GREENVILLE 611. 3 B 6 9 2 00 SS MONTE VISTA - SHANNON 611. 7 B 6 5 0 40 DS HAYWARD (SE Extension) 611. 7 B 6 5 3 00 SS ANTELOPE VALLEY 626 . 6 B 6 7 0 80 DS HAYWARD (Total Length) 631. 5 A 7 1 9 00 SS CALAVERAS (No.of Calaveras Res) 631. 5 B 6 8 6 00 SS GENOA 651. 9 B 6 9 1 00 DS CONCORD - GREEN VALLEY 679. 2 B 6 9 6 00 SS RODGERS CREEK 718. 0 A 7 0 9 00 SS WEST NAPA 718. 8 B 6 5 1 00 SS POINT REYES 736. 9 B 6 8 0 30 DS HUNTING CREEK - BERRYESSA 741. 3 B 6 9 6 00 SS MAACAMA (South) 780. 7 B 6 9 9 00 SS COLLAYOMI 797 . 6 B 6 5 0 60 SS BARTLETT SPRINGS 801. 1 A 7 1 6 00 SS MAACAMA (Central) 822. 3 A 7 1 9 00 SS MAACAMA (North) 881. 8 A 7 1 9 00 SS ROUND VALLEY (N. S.F.Bay) 888. 0 B 6 8 6 00 ss BATTLE CREEK 911. 6 B 6 5 0 50 DS LAKE MOUNTAIN 946 . 4 B 6 7 6 00 SS GARBERVILLE-BRICELAND 963 . 5 B 6 9 9 00 SS MENDOCINO FAULT ZONE 1019. 8 A 7 4 35 00 DS LITTLE SALMON (Onshore) 1026 . 5 A 7 0 5 00 DS MAD RIVER 1029 . 3 B 7 1 0 70 DS CASCADIA SUBDUCTION ZONE 1033 . 5 A 8. 3 35 00 DS McKINLEYVILLE 1039. 7 B 7 0 0 60 DS TRINIDAD 1041. 2 B 7 3 2 50 DS FICKLE HILL 1041. 7 B 6 9 0 60 DS TABLE BLUFF 1047. 1 B 7 0 0 60 DS LITTLE SALMON (Offshore) 1060. 4 B 7 1 1 00 DS DESIGN RESPONSE SPECTRUM Seismic Zone: 0.4 Soil Profile: SD 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 Period Seconds APPENDIK C GRADING GUIDELINES Grading should be performed to at least the minimum requirements ofthe governing agencies, Chapter 33 ofthe Uniform Building Code, the geotechnical reportand the guidelines presented below. All ofthe guidelines may not apply to a specific site and additional recommendations may be necessary during the grading phase. Site Clearing Trees, dense vegetation, and other deleterious materials should be removed from the site. Non- organic debris or concrete may be placed in deeper fill areas under direction of the Soils engineer. Subdrainage 1. Duringgrading, the Geologist and Soils Engineer should evaluate the necessity of placing additional drains. 2. All subdrainage systems should be observed by the Geologist and Soils Engineer during construction and prior to covering with compacted fill. 3. Consideration should be given to having subdrains located by the project surveyors. Outlets should be located and protected. Treatment of Existing Ground 1. All heavy vegetation, rubbish and other deleterious materials should be disposed of off site. 2. All surficial deposits including alluvium and colluvium should be removed unless otherwise indicated in the text ofthis report. Groundwater existing in the alluvial areas may make excavation difficult. Deeper removals than indicated in the text ofthe report may be necessary due to saturation during winter months. 3. Subsequent to removals, the natural ground should be processed to a depth of six inches, moistened to near optimum moisture conditions and compacted to fill standards. Fill Placement 1. Most site soil and bedrock may be reused for compacted fill; however, some special processing or handling may be required (see report). Highly organic or contaminated soil should not be used for compacted fill. (1) 2. Material used in the compacting process should be evenly spread, moisture conditioned, processed, and compacted in thin lifts notto exceed six inches in thickness to obtain a uniformly dense layer. The fill should be placed and compacted on a horizontal plane, unless otherwise found acceptable by the Soils Engineer. 3. If the moisture content or relative density varies from that acceptable to the Soils engineer, the Contractor should rework the fill until it is in accordance with the following: a) Moisture content of the fill should be at or above optimum moisture. Moisture should be evenly distributed without wet and dry pockets. Pre-watering of cut or removal areas should be considered in addition to watering during fill placement, particularly in clay or dry surficial soils. b) Each six inch layer should be compacted to at least 90 percent of the maximum density in compliance with the testing method specified by the controlling governmental agency. In this case, the testing method is ASTM Test Designation D-1557-91. 4. Side-hill fills should have a minimum equipment-width key at their toe excavated through all surficial soil and into competent material (see report) and tilted back into the hill. As the fill is elevated, it should be benched through surficial deposits and into competent bedrock or other material deemed suitable by the Soils Engineer. 5. Rock fragments less than six inches in diameter may be utilized in the fill, provided: a) They are not placed in concentrated pockets; b) There is a sufficient percentage of fine-grained material to surround the rocks; c) The distribution of the rocks is supervised by the Soils Engineer. 6. Rocks greater than six inches in diameter should be taken off site, or placed in accordance with the recommendations of the Soils Engineer in areas designated as suitable for rock disposal. 7. In clay soil large chunks or blocks are common; if in excess of six (6) inches minimum dimension then they are considered as oversized. Sheepsfoot compactors or other suitable methods should be used to break the up blocks. 8. The Contractor should be required to obtain a minimum relative compaction of 90 percent out to the finished slope face of fill slopes. This may be achieved by either overbuilding the slope and cutting back to the compacted core, or by direct compaction ofthe slope face with suitable equipment. (2) If fill slopes are built "at grade" using direct compaction methods then the slope construction should be performed so that a constant gradient is maintained throughout construction. Soil should not be "spilled" over the slope face nor should slopes be "pushed out" to obtain grades. Compaction equipment should compact each lift along the immediate top of slope. Slopes should be back rolled approximately every 4 feet vertically as the slope is built. Density tests should be taken periodically during grading on the flat surface of the fill three to five feet horizontally from the face of the slope. In addition, if a method other than over building and cutting back to the compacted core is to be employed, slope compaction testing during construction should include testing the outer six inches to three feet in the slope face to determine if the required compaction is being achieved. Finish grade testing of the slope should be performed after construction is complete. Each day the Contractor should receive a copy of the Soils Engineer's "Daily Field Engineering Report" which would indicate the results of field density tests that day. 9. Fill over cut slopes should be constructed in the following manner: a) All surficial soils and weathered rock materials should be removed at the cut-fill interface. b) A key at least 1 equipment width wide (see report) and tipped at least 1 foot into slope should be excavated into competent materials and observed by the Soils Engineer or his representative. c) The cut portion of the slope should be constructed prior to fill placement to evaluate if stabilization is necessary, the contractor should be responsible for any additional earthwork created by placing fill prior to cut excavation. 10. Transition lots (cut and fill) and lots above stabilization fills should be capped with a four foot thick compacted fill blanket (or as indicated in the report). 11. Cut pads should be observed by the Geologist to evaluate the need for overexcavation and replacement with fill. This may be necessary to reduce water infiltration into highly fractured bedrock or other permeable zones,and/or due to differing expansive potential of materials beneath a structure. The overexcavation should be at least three feet. Deeper overexcavation may be recommended in some cases. 12. Exploratory backhoe or dozer trenches still remaining after site removal should be excavated and filled with compacted fill if they can be located. Grading Observation and Testing 1. Observation of the fill placement should be provided by the Soils Engineer during the progress of grading. (3) 2. In general, density tests would be made at intervals not exceeding two feet of fill height or every 1,000 cubic yards of fill placed. This criteria will vary depending on soil conditions and the size of the fill. In any event, an adequate number of field density tests should be made to evaluate ifthe required compaction and moisture content is generally being obtained. 3. Density tests may be made on the surface material to receive fill, as required by the Soils Engineer. 4. Cleanouts, processed ground to receive fill, key excavations,subdrains and rock disposal should be observed by the Soils Engineer prior to placing any fill. It will be the Contractor's responsibility to notify the Soils Engineer when such areas are ready for observation. 5. A Geologist should observe subdrain construction. 6. A Geologist should observe benching prior to and during placement of fill. Utility Trench Backfill Utility trench backfill should be placed to the following standards: 1. Ninety percent of the laboratory standard if native material is used as backfill. 2. As an alternative, clean sand may be utilized and flooded into place. No specific relative compaction would be required; however, observation, probing, and if deemed necessary, testing may be required. 3. Exterior trenches, paralleling a footing and extending below a 1:1 plane projected from the outside bottom edge of the footing, should be compacted to 90 percent of the laboratory standard. Sand backfill, unless it is similar to the inplace fill, should not be allowed in these trench backfill areas. Density testing along with probing should be accomplished to verify the desired results. (4)