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CC RES 1992-121 RESOLUTION NO. 92-121 A RESOLUTION OF THE CITY COUNCIL OF THE CITY OF RANCHO PALOS VERDES APPROVING GRADING APPLICATION NO, 1390 WHEREAS, on November 21, 1989 the City Council of the City of Rancho Palos Verdes adopted Resolution No. 89-109 approving Conditional Use Permit No, 79-2nd Revision and Tentative Tract Map No. 37885-2nd Revision for the creation of forty-two (42) residential lots and two (2) common open space lots on an approximately 163-acre site located north and west of the intersection of Forrestal and Pirate Drives, east of Klondike Canyon, and south of the City of Rolling Hills; and WHEREAS, the subject property is the site of a former quarry operation which created unique topographic features and geologic hazards on the site; a near vertical cut slope exists on the north side of Forrestal Drive and presents a safety hazard due to rock ravelling and sloughing; the deep quarry bowl located in the eastern portion of the site also presents a hazard due to the very steep slopes in the bowl; small landslides exist in the quarry bowl and apparently were formed by the loss of toe support resulting from the former quarry activities, scour, and erosion; and WHEREAS, the site is presently unsafe for development due to its extreme slopes, and risks of rockfall, mudflow, erosion, and debris flow, which risks are exacerbated by an apparently inactive fault on the project site and several active faults in the vicinity which can be expected to generate significant ground-shaking on the site; and WHEREAS, the conditions of approval of Conditional Use Permit No. 79 as approved on November 21, 1989 require the developer to devise a grading plan which will eliminate these hazards and make the site safe for the development proposed in the applications for Conditional Use Permit No. 79-2nd Revision and Tentative Tract Map No. 37885-2nd Revision and to obtain a grading permit for that grading plan prior to approval of the Final Tract Map; and WHEREAS, on December 1, 1989 the developer submitted Grading Application No. 1390 and Environmental Assessment No. 596 for the approval of approximately 810, 000 cubic yards of grading for development of the residential portion of the proposed development and approximately 1, 050, 000 cubic yards of remedial grading in the former quarry areas to correct identified geologic hazards on the property; and WHEREAS, a Draft Supplemental Environmental Impact Report (DSEIR) was prepared and circulated in accordance with the State of California Environmental Quality Act Guidelines, 2 Calif. Code of Regs. SS 15000 et seq. , which analyzed the environmental impacts of the proposed grading plan and potential revisions to said grading plan; and WHEREAS, after notice issued pursuant to the City's Development Code, the Planning Commission of the City of Rancho Palos Verdes held a public hearing on September 24, 1991 to consider Grading Application No. 1390 and the Final Supplemental Environmental Impact Report (FSEIR) at which time all interested parties were given an opportunity to be heard and to present evidence; and. WHEREAS, on October 8, 1991 the Planning commission adopted resolutions approving Grading Application No. 1390 and certifying the FSEIR; and WHEREAS, on October 21, 1992 the Seaview Homeowners Association filed a timely appeal of the Planning- Commission's approval of the grading permit and certification of the FSEIR; and WHEREAS, the City Council after holding duly noticed public hearings to consider the appeal of Grading Application No, 1390 and the FSEIR on December 3 , 1991, December 17, 1991, February 18, 1992 , June 16, 1992, and July 7, 1992, at which time all interested parties were given an opportunity to be heard and to present evidence, sustained the appeal of the Seaview Homeowners Association and denied Grading Application No. 1390; and WHEREAS, in September 1992, the developer submitted a modified grading plan substantially addressing the environmental concerns raised by the City Council with respect to previously denied Grading Application No. 1390. The modified plan involves moving Forrestal Drive slightly to the south and extending the quarry slope grading to the east by creating a fill slope adjacent to the quarry slope trimming. By so doing, the grading can be balanced on-site and the off-site export of material can be avoided. Additionally, a minimum amount of fill (10, 000 cubic yards) will be placed in the quarry bowl to eliminate identified drainage deficiencies in the bowl; and WHEREAS, an Addendum to the Supplemental Environmental Impact Report which analyzed the environmental impacts of modified Grading Application No. 1390 was prepared and circulated for thirty (30)- days; and Resolution No. 92-121 Page 2 WHEREAS, after notice issued pursuant to the City's Development Code, the Planning Commission of the City of Rancho Palos Verdes held public hearings on November 10, November 21, and November 24, 1992 , to consider the modifications to Grading Application No. 1390 and the Addendum to the Supplemental EIR at which time all interested parties were given an opportunity to be heard and to present evidence; and WHEREAS, the City Council held a duly noticed public hearing on December 7, 1992 , to consider the modifications to Grading Application No: 1390 and certification of the Supplemental EIR and Addendum at which time all interested parties were given an opportunity to be heard and to present evidence. NOW, THEREFORE, THE CITY COUNCIL OF THE CITY OF RANCHO PALOS VERDES DOES HEREBY FIND, DETERMINE, AND RESOLVE AS FOLLOWS: Section 1: That the foregoing recitals are true and correct. Section 2 : That the approximately 11972 , 000 cubic yards of grading proposed is not excessive beyond that necessary for the permitted primary use of the lot within the meaning of Section 17 .50. 070 (A) of the Development Code because the applicant, after fully exploring ex lorin alternative project designs, has modified the grading plan to dispose of excess cut materials on the site in a manner that does not cause unacceptable adverse environmental impacts, previously identified geologic hazards on the site will be eliminated, impacts to biological resources will be minimized, visual relationships of the unique topography of the site will be substantially preserved, drainage deficiencies identified on the site will be corrected and impacts related to the off-site export of excess cut material will be avoided. Section 3 : That the grading will not significantly or adversely affect visual relationships with neighboring sites within the meaning of Section 17. 50. 070 (8) of the Development Code as 1) the quarry slope remedial grading will be performed in a manner which minimizes grading quantities and achieves a more aesthetically pleasing cut slope by creating a jagged gradient, more akin to the existing slope while still eliminating the previously identified geologic hazards on the site, 2) the graded development site, and graded quarry slope will be re-vegetated to reduce the visual impact from neighboring sites, and 3) the minimal grading to eliminate drainage deficiencies at the bottom of the quarry bowl will preserve the unique topography of the bowl, as well as most of the valuable coastal sage scrub within the bowl area. Thus the modified grading plan, which includes a replacement/enhancement program to create 32 . 1 additional acres of quality coastal sage scrub, is consistent with the goals of ensuring the maximum preservation of the natural scenic character Resolution No, 92-121 Page 3 of the City, the maximum retention of groundcover, and the maintenance of *the visual continuity of hills and valleys, as required by Section 17. 50. 010 of the Development Code. - Section 4: That the nature of the proposed grading minimizes disturbance to the existing contours of the site within the meaning of Section 17 .50. 070 (C) of the Development Code because theproposed grading, as modified, involves th-e creation of a fill slope and the trimming of the quarry slope l*n . a manner T which reasonably matches the variable gradients which presently exist on the site and the minimal grading in the quarry bowl floor which, while eliminating the geologic hazards created by the former quarrying activities on the site and the drainage deficiencies of the bowl, will still preserve the existing contours of the quarry bowl. Section 5: That the application is consistent with the requirements of Section 17 ,50. 070 (D) (3) (a) because the proposed grading on slopes in excess of thirty-five percent will eliminate- _ the geotechnical safety hazards currently present on theproject site and by so doing will enhance the public health, safety, and welfare. Section 6:, That the application is consistent with the requirements of Section 17 .36. 040(C) because the grading will correct existing geotechnical hazards associated with the quarry face created by previous quarrying activity on the site. Section 7;- That the proposed grading is consistent with the goals and policies of the City's General Plan, although a majority of the grading would occur in areas included in "Resource Management Areas" designated in the City's General Plan Land Use Map, for the reasons detailed below: (a) Portions of the site are designated "RM 2 - Extreme Slope" , a district described by the General Plan as intended "to regulate use, development and alteration of land in extreme slope areas so that essential natural characteristics such as land form, vegetation and wildlife communities, scenic qualities and open space can be substantially maintained* The district further considers the risks,/ to public safety from, earth slides and slips, erosion and attendant siltation. " The proposed grading, as modified, is de$'igned to substantially maintain the landform of the site ' and minimize impacts on valuable vegetation and wildlife communities, including the California gnatcatcher, the cactus wren, the rufous crowned sparrow, Astragalus trichopodus, the host plant of the possibly extinct, endangered Palos Verdes Blue Butterfly, and the Crossosoma californicum, while removing or abating existing geotechnical risks to public safety created by former quarrying activities on the project site. Resolution No. 92-121 Page 4 The General Plan also states that, with respect to a site in the RM 2 district, " [d]etail[ed] engineering/geologic study must accompany any proposal for development or use and must demonstrate to the satisfaction of the City that the proposed development or use requires no alteration of topography, significant risk to human life or significant adverse environmental impact. " The modified grading plan has been analyzed through an Addendum to the Supplemental EIR which concluded that the geotechnical benefits provided by the project outweigh any unavoidable significant adverse environmental impacts to the site. (b) The General Plan's policies for the RM 9 - Natural Vegetation District include the following: "The wild flowers,, low coastal sage scrub, chaparral, and grasslands communities should be retained wherever possible. Any proposed development within this district should seek to revegetate with native material whenever clearing of vegetation is required. " The proposed grading includes mitigation to reduce impacts to coastal sage scrub habitat, designated as "significant natural plant community" in the General Plan and described by the Addendum to the DSEIR as "a critical resource because of its value as habitat for the California gnatcatcher and numerous other species. " The project mitigation includes a replacement/enhancement program to create 32 . 1 acres of additional quality habitat on the project site. Further, the project, as modified will avoid direct impacts on identified plants of the species Astragalus trichopodus and Crossosoma californicum. The portions of the site within the RM 9 district are also included by the General Plan Natural Environment Control District. Among the policies applicable to that district is the following: "Site activities shall regulate use, development, and alteration of land in slope areas, so that essential natural characteristics, such as land form, vegetation and wildlife communities, ground water recharge, scenic qualities, and open space can be substantially maintained. " The modified grading plan maintains the existing natural characteristics of the site, since it minimizes impacts to the existing landforms, preserves open space, and minimizes impacts on plant and animal life. Section 8: That, as detailed in the geotechnical and engineering reports prepared for this proposal, the grading necessary to eliminate geologic hazards associated with the quarry slope north of Forrestal Drive will generate some excess cut materials which the applicant, through the modified grading plan, proposes to use to create a fill slope adjacent to the quarry slope cut. The fill slope will result in less impacts to biological resources as compared to the same fill amount in the quarry bowl, will blend aesthetically with the adjacent gradient quarry slope cut, will be geotechnically feasible with the Resolution No. 92-12.1 Page 5 appropriate grading and engineering recommendations and will eliminate the adverse environmental impacts to air quality, traffic and noise associated with the off-site export of cut material. Section 9: The City Council declares the Final Supplemental Impact Report (FSEIR) and Addendum were prepared in accordance with the California Environmental Quality Act (CEQA) in compliance with City and State guidelines; and the City Council reviewed and considered the contents of the FSEIR and Addendum in reaching its decision on the project. The City Council further adopts and incorporates by reference the environmental findings and statement of overriding considerations set forth in City Council Resolution No. 92-121. -Section 10: For all the reasons stated above and based on information and findings included in the Supplemental Environmental Impact Report (SEIR) and Addendum, Staff Reports, minutes, records of proceeding, and evidence presented at the public hearings, the City Council hereby approves Grading Application No. 1390, subject to the attached conditions contained in Exhibit "A", which are necessary to protect the public health, safety, and general welfare in the area. PASSED, APPROVED, and ADOPTED this 7th day of December 1992 . y -0. 4 Wf ayor ATTEST: J Purcell ' My i Clerk STATE OF CALIFORNIA ) COUNTY OF LOS ANGELES ) ss CITY OF RANCHO PALOS VERDES ) I, JO PURCELL! City Clerk of the City of Rancho Palos Verdes, hereby certify that the above Resolution No. 92- 12r,was duly and regularly passed and adopted by the said City Council at a regular meeting held on December 7 1992 . (JHR2-A 819.MGC) X-1UJ_JEXAyC_LTX-`LTk' RANUMU = PAL RD E S Resolution No, 92-12:1 Page 6 EXHIBIT "A" CONDITIONS OF APPROVAL GRADING APPLICATION NO. 1390 A. GENERAL 1. Within thirty (30) days of adoption of the Resolution approving Grading Application No. 1390, the developer shall submit, in writing, a statement that he has read and understands all conditions of approval. 2 . The Developer shall adhere to all previously approved Conditions of Approval of Conditional Use Permit No, 79- Second Revision, as described in City Council Resolution 89-109, and Tentative Tract Map No. 37885-Second Revision, as described in City Council Resolution 89-110, except as modified herein. If for any reason the conditions of Grading Application No. 1390 are in conflict with the above referenced Conditional Use Permit and Tract Conditions, the stricter shall apply. 3 . Prior to recordation of the final map or prior to commencement of work, whichever occurs first, a bond, cash deposit, or other City approved security, shall be posted to cover the costs of grading in an amount to be determined by the City Engineer. 4. Development of the project will comply with all applicable Code and ordinance requirements for construction and grading. 5. No vegetation clearing of any kind, site preparation or grading shall occur on any portion of the property until issuance of a grading permit by the Department of Environmental Services. 6. Prior to grading permit issuance, a grading plan designed pursuant to all of the recommendations of the City's geotechnical consultant and geotechnical conditions of approval contained herein (Section E) , shall be submitted by the developer to the Director of Public Works for review and approval. Bo GRADING 11 The grading operation shall be limited to that necessary to develop the residential tract (creation of lots and streets) and to perform remedial grading, as designated on the submitted and approved grading plan. Grading quantities shall be in substantial compliance with the following cut and fill quantities: A) Development Grading Development Area Cut: 456, 000 cubic yards Development Area Fill: 271, 000 cubic yards B) Remedial Grading Development Area Cut: 350, 000 cubic yards Development Area Fill: 350,000 cubic yards Quarry Slope Cut: 180,000 cubic yards Quarry Slope Fill: 355, 000 cubic yards Quarry Bowl Fill: 10, 000 cubic yards The above quantities for the development area - remedial grading are approximate only and may vary with actual site conditions, as required by the City's geotechnical consultant or site geologist. The remaining quantities do not include grading for installation of the required low-permeable cap over the residential lots and, if necessary, removal of I'mudflow" deposits,, as specified in condition E,2,A, 1,a. 2 . The grading configuration for the quarry slope face shall 'involve trimming the slope at gradients of . 75: 1, 1: 1, and 1.5: 1. The adjacent fill slope shall be placed at a 1.5: 1 slope gradient. 3 . The minimum amount of fill necessary to create positive drainage and correct drainage deficiencies in the bowl, not to exceed 101, 000 cubic yards, shall be placed in the quarry bowl basin to the satisfaction of the Directors of Environmental Services and Public Works. 4 , There shall be no off-site exportation of fill material. All cut and fill quantities shall be balanced on site. 5. There shall be no blasting or use of specialized rock crushing equipment for carrying out the grading activity. 6. The south-facing buttress fill slope at the southeastern corner of the tract which is part of the proposed grading Exhibit "All Page 2 Resolution No, 92-121 for the residential development area shall not exceed a gradient of 1. 5: 1. 7. Any major revisions to the grading quantities or methods described above shall require approval of a Revision to Grading No. 1390 by the Planning Commission. CO GRADING/CONSTRUCTION PLAN 1. A grading/construction plan shall be submitted to the Director of Environmental Services prior to any grading permits being issued. Said plan shall include but not be limited to the following: A) A phasing plan B) Limits of grading C) Estimated length of time for rough grading and improvements D) Location of construction _trailer, construction signs, equipment storage area, and location and type of temporary utilities 2 . Prior to issuance of grading permits, a Circulation and Safety Plan and Program will be prepared and funded by the Developer which will include: A) Safety Training and Indoctrination B) Truck Inspection Program C) Route Designation D) Truck type E). Dust Control 3 . Prior to the issuance of grading permits or any work on- site, a traffic control plan designed by a registered traffic engineer shall be submitted to, and approved by, the Director of Public Works. The plan shall include provisions for flagmen, signage, lane closures, and any other measures necessary to assure safe and adequate ingress and egress at the site. 4. The grading activity on the site shall not disrupt the recreational activities at the Ladera Linda Community Center and on the adjacent Portuguese Bend playing fields. As such the grading operations involving the re-construction and alignment of Forrestal Drive and any other grading activity located on or within 100 feet of the Portuguese Bendp laying fields shall only be performed from January to Exhibit "A" Page 3 Resolution No. 92-121 May so as not to disrupt the recreational activities which are concentrated between June and December. This limitation may be modified by the Director of Environmental Services or Director of Recreation and Parks if recreational schedules on the fields change. 5. Prior to' issuance of the grading permits, the developer shall submit a plan to the Director of Environmental Services to construct a permanent, two-lane ramp projecting from Forrestal Drive (where a driveway apron currently exists) to permanently eliminate the need to access the soccer field parking lot off of Mainsail Drive. The construction of the ramp shall provide both temporary (during grading and development of the tract) and permanent access to the soccer field parking lot from Forrestal Drive. 6. To ensure the community's accessibility to Ladera Linda, flagmen shall monitor the ingress and egress of any trucks or heavy equipment which may traverse access points to the Ladera Linda Community Center and its related facilities. 7 . As required under the previously approved tract conditions of approval of Tentative Tract Map No. 37885 (STREETS, No. 6) , the developer shall be responsible for repairs to any neighboring streets which may be damaged during development of the tract, including but not limited to the designated access route(s) to the tract for any trucks or heavy equipment. Prior to issuance of grading permits, the developer shall post a bond, cash deposit, letter of credit or other City approved security in an amount sufficient to cover the costs to make permanent repairs of any damage to streets and appurtenant structures as a result of this development. In addition to providing such security, the developer shall pay for a pavement analysis of the streets to be used as designated access routes for any trucks or heavy equipment prior to the start of construction, and at completion of construction. The developer shall provide compensation for any loss of pavement life as determined by this study along the designated access routes for any trucks or heavy equipment that may occur as a result of this development. 8 . Prior to issuance of grading permits and/or building permits, a plan and program to control and prevent dust and windblown earth problems shall be submitted to the Director of Environmental Services for review and approval. Methods may include but shall not be limited to requiring truck covers, an on-site truck wash down station, street sweeping and on-site grade watering. Exhibit "All Page 4 Resolution No. 92-121 9. All construction and grading activities, including arrival of grading equipment and vehicles, and equipment warm up shall be limited to the hours of 7: 00 a.m. to 7: 00 p.m. , Monday through Saturday. 10. All grading and construction equipment will be stored on the project site. 11. Equipment maintenance (refueling, oil-changes, etc. ) areas will be restricted to areas designated in consultation with the City prior to construction and grading activities. 12 . All grading equipment, fixed or mobile, shall be equipped with properly operating and maintained mufflers. Any stationary on-site noise sources such as compressors, generators, or power saws shall be equipped with hospital grade mufflers for engine driven sources, or shall be surrounded by a temporary plywood enclosure as a noise baffle. 13 . Stockpiling and/or vehicle staging areas shall be designated on the project site and shall not be located on Forrestal Drive or any public street. These staging areas shall be located as far as practical from existing residential dwellings. 14 . Fugitive dust generation during cleaning, grading, earth moving, or excavation shall be controlled by regular watering, paving of construction roads, or other dust preventative measures in accordance with SCAQMD Rule 403 . 15. Construction activities will be temporarily halted on -high ozone days or during second stage smog alerts at the direction of the Director of Environmental Services. 16. To ensure public safety and to secure the site during construction, the Developer shall submit a fencing plan for approval to the Director of Environmental Services. Said plan shall replace and/or provide fencing at the top of the slope, adjacent to Forrestal Drive, in and around the Portuguese Bend fields, park, and adjoining slopes. Further, fencing shall be erected around the perimeter of the playing field at the Ladera Linda Community Center. 17 . Noncompliance with the above grading and construction restrictions shall be grounds to stop work immediately on the property. Exhibit "A" Page 5 Resolution No. 92-121 D. HYDROLOGY AND DRAINAGE I II AND ill�11l,lI 1 I f �!� 1. All proposed cut and fill slopes shall be landscaped and irrigated, wherever possible, to reduce potential erosion. To reduce the potential for nuisance water from over irrigation and to revegetate the unirrigated slopes, drought tolerant vegetation shall be used for landscaping purposes. Where feasible, drought tolerant plantings of the local origin coastal sage scrub community shall be used. All re- vegetation shall be subject to approval by the Director of Environmental Services. 2 . Impervious surface drains shall be installed to conduct surface waters across all proposed cut and fill slopes. These drains shall also reduce percolation to the groundwater of Klondike Canyon. In addition, quarry bowl surface drains shall be designed in a manner which allows water to pond in a small catchment basin for wildlife in the area. All surface drains shall be installed to the satisfaction and approval of the Directors of Public Works and Environmental Services. 3 . Measures will be taken to eliminate erosion downslope from the grading areas. Temporary measures could include sand bag, silt fences, and hay bales placed into drainage devices. An erosion control plan shall be approved by the city prior to issuance of Grading Permits. 4. The minimum width of the "rockfall catchment area" which traverses the slope beneath the relatively steep portions of the cut., shall be 23 feet with a minimum berm height of 4 feet. A 6-foot high rock protection fence shall be constructed along the top of the berm to increase the effective depth and width of the catchment area. 5. Vertical bench spacing of 54 feet on the slope above the 11rockfall catchment area" shall be constructed. 6. The 4-foot high berm structure and 6-foot high protection fence which are. proposed as part of the "rockfall catchment area" on the quarry slope shall be adequately screened from view by planting and maintaining drought tolerant vegetation along the downslope base of the berm structure. Exhibit "A" Page 6 Resolution No. 92-121 7. A "drainage/rockfall control bench" shall be constructed along the first 50 feet bench tier at the transition between the 3/4 : 1 and 1: 1 portions of the slope. A paved drainage bench with a minimum width of 12 feet shall be required with a 6-foot high rockfall control fence along the outboard edge of the bench. 8 . A paved "drainage/maintenance access bench" with a minimum width of 12 feet shall also be constructed along the second 50-foot bench tier, at the transition between 1: 1 and 1.5: 1 portions of the slope. 9. A paved drainage swale or small bench drain shall be included along the edge of the Forrestal Drive pavement, including the area behind the proposed retaining wall. A brow ditch along the crest of the proposed cut is also required with appropriate design measures where this drain intersects natural drainage courses. 10. Eventual undermining of the "drainage/maintenance access bench" at the top of the 1: 1 slope will likely require additional remediation and/or repair in the future. Four general options have been outlined below to mitigate and/or remediate areas of potential undermining. Based on further evaluation by the City Engineer (for measure effectiveness, maintenance impact, costs and aesthetic appeal) , at least one of the following measures shall be implemented by the developer or the Homeowners' Association, depending on who is responsible for maintenance at that time: A) Minimize erosion of the problematic intervals by reducing the potential for cyclic wetting and drying; a surface cover or membrane would be appropriate; landscape planting supported by an anchored geosynthetic grid is a possibility. B) Minimize erosion by locally reducing the slope gradient to an inclination at or below the "angle of repose. " C) Set back portions of the bench drain likely to be affected from the slope face and/or install a deepened foundation along the outboard edge of the drain. D) Provide remedial repairs to support the bench drain as it becomes necessary; this option would likely include provisions for local application of colored shotcrete supported on anchors drilled or driven into the bedrock. Exhibit "A" Page 7 Resolution No. 92-121 11, Accumulated soil and rock fragments shall be removed on a frequent basis to maintain the drainage and rockfall control ' capacity of the benches. Desalting basins and similar facilities which may be impacted by high sediment loads during periods of heavy rainfall shall be periodically checked and cleaned out. These maintenance requirements shall be the developer's responsibility until such time as the this responsibility is assumed by the Homeowners' Association. 12 . All new drainage structures and protective fencing proposed for the quarry slope shall be of an earth tone color and shall be reviewed and approved by the Director of Environmental Services* 13 , The ponding of water which occurs where a blocked canyon stream meets the northern edge of the quarry bowl, approximately 100 feet above the bowl floor, shall be eliminated by directing the water through some impermeable means to a controlled storm drain system. All drainage devices shall be designed in an - aesthetically pleasing and natural-looking manner and in a manner which provides captured water to the wildlife of the area. The developer shall submit a plan which eliminates this drainage deficiency to the Directors of Public Works and Environmental Services for review and approval. E. GEOLOGY 11 The three -multi-stage piezometers to monitor groundwater conditions at the site, as required by previously approved tract conditions of approval of Tentative Tract Map No. 37885 (GEOLOGY, No. 6) , shall be equipped so that they can be converted into dewatering wells if the Director of Public Works determines that the monitoring indicates a rise in the water table. 2 . Prior to grading permit issuance, a grading plan for the tract development, quarry slope cut, quarry slope fill and quarry bowl fill shall meet all of the geotechnical conditions of approval contained below and stipulated by the City's Consulting Geologist, Any variations to the approved geotechnical conditions contained below shall require approval from the City's geotechnical consultant. If any geotechnical conditions of approval cannot be satisfied by the developer and, as such, necessitate a major revision to Exhibit "All Page 8 Resolution No, 92-121 the approved grading quantities or methods, a revision to Grading Application No. 1390 shall be subject to approval by the Planning Commission. The specific geotechnical conditions for the grading project are as follows: Al Residential Development 1) All recommendations of the consultant, except as modified herein, shall be incorporated into the design and construction. Recommendations for Tensar Geogrids are excluded. a. All cuts into "mudf low" deposits shall be inspected by the consultant, the City geologists and geotechnical engineer to determine whether or not shear planes are present. If no shear planes are encountered, then work may proceed per the .consultant's recommendations. If shear planes are encountered, then all "mudflow" deposits shall be removed and replaced as an engineered fill. b. The recommended monitoring wells shall be incorporated into designs. C. Any geogrid reinforcement shall be designed to the satisfaction of the City's geotechnical consultant and City Engineer. 2) The. consultant shall review and approve the final plans and specifications by manual signature. 3) Before permits for grading may be issued, the consultant shall issue a statement, in accordance with Code Section 311 of the most current UBC adopted by the City, which requires that every report shall contain a finding regarding the safety of the site for the proposed structure or use against hazard from any variety of landsliding or settlement or slippage and a finding regarding the effect of the proposed building, grading, construction, and use of the site will have on the geological geolo ical stability of property outside the site. 4) The consultant shall continuously inspect and monitor all grading and test all fills placed. An as-graded soils and geologic report, complete with fill and compaction test locations, and geologic map, based upon continuous geologic mapping of key and fill bottoms, and cut exposes shall be submitted and reviewed by the City's Exhibit "A" Page 9 Resolution No. 92-121 geotechnical engineer, prior to issuance of a building permit for any structures founded in said fill or prior to issuance of the certificate of occupancy otherwise. The as- graded report shall contain specific recommendations: a. The consultant recommends that more specific evaluations of proposed building footprints, with regards to mitigation of large potential differential settlements, be performed prior to the start of grading. This shall be performed by the consultant and submitted to the City for approval. b. Provisions for monitoring settlement as recommended by the consultant shall be performed. 5) Foundations and floor slabs cast on expansive soils shall be designed in accordance with the consultant's - recommendations and conform to the minimum requirements of the Code and the City's guidelines. 6) Foundations shall be set back from descending slopes in accordance with the consultant requirements. Minimum foundation setbacks shall be determined in accordance with the expression H/3+5, where H is the height of the slope, measured in feet, The setback distance shall be measured horizontally from the top or face of the slope and need not exceed a distance of 25 feet. Foundations shall extend to such a depth as to be unaffected by any creep prone surf ficial soil and/or weathered bedrock. Field inspection and approval by the consultant(s) is required. 7) Construction of underground utilities shall be performed in accordance with accepted standards and subject to additional standards deemed necessary by the Director of Public Works and/or Building Official to avoid potential underground leakage. Additional standards shall include, but are not limited to, additional evaluations of settlement potential. Exhibit "A" Page 10 Resolution No. 92-121 8) Additional subdrainage facilities shall be installed at an intermediate level within the deeper fill as additional protection against potential deleterious effects of migrating groundwater. The type, number, and location of subdrainage facilities shall be approved by the City's geotechnical consultant. B� Quarry Bowl 1) All of the recommendations of the consultant, except as modified herein, shall be incorporated into the design and construction. 2) The consultant shall review and approve the final plans and specifications by manual signature. 3) Where fills are to be placed, including trench and retaining wall backfills, an as-graded soils and geologic report, complete with fill and compaction test locations, and geologic map, based upon continuous geologic mapping of key and fill bottoms shall be submitted and reviewed by the City's geotechnical engineer prior to issuance of a building permit for any structures founded in said fill or prior to issuance of the certificate of occupancy otherwise. 4) Where fill is placed at less than the Code required degree of compaction (90a) the consultant shall take sufficient tests to determine that the fill will have acceptable strength and settlement characteristics. No less than one direct shear test shall be performed and submitted for every eight feet of vertical lift. 5) Access to the quarry bowl area following completion of grading shall be restricted to authorized personnel maintaining planned drainage installations or any other City authorized personnel. 6) For the purpose of restricting non-authorized personnel from entering the quarry bowl, suitable fencing establishing a 50-foot wide buffer zone away from the top of the quarry bowl walls shall be installed. In addition, signage and a vehicular barricade shall be established at the entrance to the quarry bowl to restrict non-authorized personnel from entering the bowl. Signs shall restrict access to the bowl, warn of the rockfall hazard which exists and identify the area as a protected ecological area. The exact wording of the warning signs shall be approved by the Director of Exhibit "A" Page 11 Resolution No. 92-121 Environmental Services. All fencing and signage shall be installed immediately after all remedial grading activity has been completed in the bowl to the satisfaction of the Director of Environmental services. 7) Minor regrading of the landslide headscarp north of the quarry bowl shall be implemented as recommended in the previous Moore & Taber report for the quarry bowl area dated October 31, 1990 to the satisfaction of the City's geotechnical consultant. 8) The development of future surface drainage design plans shall be coordinated with the City's geotechnical consultant and Director of Public Works. The proposed drainage design shall be reviewed and approved by the City's geotechnical consultant and Director of Public Works prior to issuance of the grading permit. QuarX:y Slone 1) Before any approvals are granted for the development area, the consultant shall clarify that no potential failure surface with computed factors of safety less than 1. 50 pass behind the geologic setback line in the area of the proposed Forrestal Drive cul-de-sac. 2) Any geogrid reinforcement of the quarry slope shall be designed to the satisfaction of the City's geotechnical consultant and City Engineer. 3) All of the recommendations of the consultant, except as modified herein, shall be incorporated into the design and construction. An addendum clearly stating any proposed deviations from Chapter 70 and justifying same shall be submitted, 4) The consultant shall review and approve the final plans and specifications by manual signature. 5) Where fills are to be placed, including trench and retaining wall backfills, * an as-graded soils and geologic report, complete with fill and compaction test locations, and geologic map, based upon continuous geologic mapping of key and fill bottoms shall be submitted and reviewed prior to issuance of a building permit for any structures founded in said fill or prior to issuance of the certificate of occupancy otherwise, Exhibit "All Page 12 Resolution No. 92-121 6) Foundations and floor slabs cast on expansive soils shall be designed in accordance with the consultant's recommendations and conform to the minimum requirements of the Code and the City's guidelines. 7) Geologic reconnaissance, documentation of the slope performance and, as appropriate, development of specific maintenance and/or repair recommendations by a California Certified Engineering Geologist shall be performed on an annual basis by the developer or Homeowners' Association, whoever is responsible, for at least five years following completion of construction. The compiled information shall be summarized in a report to be submitted for review and approval by the City's geotechnical consultant. The necessity or frequency of future geologic evaluations beyond the fifth year shall be evaluated after submission of the fifth report. Fill Slope 1) Geogrid reinforcement of the slope face shall be installed to enhance surficial stability to the satisfaction of the City's geotechnical consultant and City Engineer. 2) Small interceptor or brow ditch-type drains shall be constructed along all fill/cut transitions which traverse the slope face. A specific detail for this portion of the slope design shall be developed prior to finalizing the grading plans. 3) A similar interceptor drain along the transition between the 1: 1 and 1. 5: 1 slope gradients near the eastern end of the slope shall be installed; or, alternatively, a more gradual transition shall be constructed. 4) A small area of 3/4 : 1 fill shown in the west- central portion of the slope. The proposed 1.5: 1 fill slope in this area shall be expanded as shown on Plate III of Moore & Taber's report dated March 27, 1992, and approved by the City's geotechnical consultant. Exhibit "A" Page 13 Resolution No. 92-121 5) The retaining wall proposed at the toe of the fill slope shall be designed to the satisfaction and approval of the City's geotechnical consultant and City Engineer. 6) A surface drain shall be constructed along the back of the proposed retaining wall at the toe of the planned fill slope (along the northern edge of Forrestal Drive) . 7) The existing storm drain and collection basin shall be extended through the area of the proposed fill 'slope, at the easterly end of the quarry slope. 8) Surface drainage conditions and requirements shall be evaluated and approved by the City's engineer prior to the issuance of a grading permit, 9) Prior to the issuance of a grading permit, a thorough geotechnical evaluation of the proposed fill slope shall be conducted, reviewed and approved by the City's geotechnical consultant. F. BIOLOGICAL RESOURCES 11 Prior to any project-related development activity, including any vegetation clearing, on the project site, the Crossosoma californicum shall be marked, fenced, and shall be carefully avoided during all grading activity. Although it is not on any rare or endangered species list, this plant is protected by the City as it is the only recorded mainland species. 2 . If, prior to or during grading, vegetation clearing, or other project-related activities, it is discovered that additional Crossosoma californicum plants exist on the site which have not been previously identified, all such activities will be halted, and the City notified, Any new Crossosoma californicum plants shall be marked and carefully avoided or transplanted to a safe location and preserved on the site, 3 . Prior to any project-related development activity, including vegetation clearing, on the project site, a qualified biologist will set up markers around the Astragalus plants, These markers will consist of visible stakes and ribbons completely surrounding the individual Astragalus plants, as described and mapped in the EIR Addendum* Exhibit "All Page 14 Resolution No, 92-121 4 . Prior to any grading or other project-related development activity on the project site, including vegetation clearing, a five-foot chain link fence will be constructed surrounding each of these Astragalus plants to establish conserved areas around each plant (the "Conserved Areas") . A qualified biologist will be present during the identification of fence locations so as to include individual plants that may be overlooked. 5. The Conserved Areas will be visibly marked both by markers and signs. The signs will indicate that they are strictly conserved areas, and are not to be disturbed. The grading, vegetation clearing, and other project-related development activities will be designed to avoid any contact with or disruption of these Conserved Areas. 6. All workers involved in project-related activities, including vegetation clearing, will be informed of the existence and location of the Conserved Areas and the conserved Astragalus plants. All workers not specifically involved in the setting up of the Conserved Areas or the examination of the Astragalus will be given specific instructions to avoid any contact with the Conserved Areas. 7 . If a Conserved Area is accidently disturbed by grading and/or other development activities, the area around each Astragalus will be "sifted" by a qualified Lepidopterist to determine whether any Palos Verdes Blue Butterfly (PVBB) pupae are present and to remove them from the substrate without damage. To mitigate the anticipated ated loss of the PVBB foodplant during the sifting process, 200 Astragalus seedlings will be established in appropriate coastal sage sites close by, but clearly beyond the range of any development activity. Seeds for the restock will be provided from on-site individuals. These seedlings will be irrigated for a period of one year to assure their persistence. If PVBB pupae are found, the U.S. Fish and Wildlife Service (USFWS) will be contacted and no further actions which affect the plant area will be taken without consultation with the USFWS. 8. If prior to or during grading, it is discovered that additional Astragalus plants exist on the site which have not previously been identified, a procedure will be established to notify a supervising project operator, and all grading and/or project-related activities will be brought to a halt until implementation of one of the following contingency measures: Exhibit "A" Page 15 Resolution No. 92-121 A) Establishment of an additional Conserved Area for the newly discovered Astragaluse B) Sifting of the Astragalus to determine if PVBB pupae are present* If it is determined that no pupae are present, an attempt will be made to transplant the analyzed plant to an appropriate site designated by the USFWSe 91 If a PVBB is sighted at any time, the USFWS will be contacted immediately and no further actions which affect the project site will be taken without direct consultation with the Service. 10, Should additional plants be located and subsequently lost, they will be replaced at the ratio of 50: 1. Monitoring will guarantee persistence of 50 percent of the plants set out after two years. 11. Fuel modification plans shall be implemented to avoid additional impacts to the coastal sage scrub habitat. A) The feasibility of incorporating fire sprinklers within individual homes will be investigated with the County Fire Marshall as an option to vegetation clearing* B) If necessary, periodic irrigation of existing and restored coastal sage scrub adjacent to development areas will be permitted to maintain vegetation moisture levels and to reduce fuel load. 12 . Prior to any grading or vegetation clearing of any portion of the site, a directed survey shall be conducted to locate on-site nests of California gnatcatchers. If eggs or young birds are found, the U.S. Fish and Wildlife Service shall be contacted prior to any grading or disturbance of habitat. If gnatcatcher nests are present, no grading, vegetation clearing, or removal of habitat will take place within 500 feet of known nesting sites during the nesting/breeding season (March I through June 30) , If nests, eggs or young birds are found and need to be removed, they shall be removed in compliance with the Federal Migratory Bird Treaty Act. 13 , During vegetation clearing or grading, all areas of coastal sage scrub to be avoided shall be protected through the construction of temporary fencing* No construction access, parking or storage will be permitted within the fenced areas. Vehicle transportation routes between cut-and-fill Exhibit "All Page 16 Resolution No. 92-121 locations will be restricted to a minimum number. Vehicle transportation routes shall be restored to create high- quality gnatcatcher habitat following construction. 14. Direct impacts to 11.3 acres of quality coastal sage scrub shall be mitigated by replacement of 23 .8 acres of coastal sage scrub habitat within graded cut-and-fill areas elsewhere on the project site (2: 1 areal replacement) . Habitat .replacement will be initiated concurrent with project impacts, subject to approval by the Director of Environmental Services. A) Replacement shall take place in three locations on the project site: 1) on the south-facing slopes directly adjacent to the development area (2 .5 acres) ; 2) on the south-facing cut-and-fill slope on the northern side of Forrestal Drive (12.8 acres) ; and 3) on the haul road and f ill area in the eastern quarry bowl (8. 5 acres) . 15. Direct impacts to 19.7 acres of disturbed coastal sage scrub/California gnatcatcher habitat shall be mitigated through the enhancement of the 20. 5 acres of degraded coastal sage scrub within the designated habitat preservation area (1: 1 areal enhancement) , subject to approval by the Director of Environmental Services. A) Coastal sage scrub/California gnatcatcher habitat enhancement shall take place in the 20. 5 acres of presently degraded coastal sage scrub habitat in the eastern portion of the project area. Enhancement will include: 1) the removal of existing non-native invasive species such as ice plant (Carpobrotus edulis) , pampas grass (Cortaderia atacamensis) and mustards (Brassica s.p.p. ) ; 2) the removal of human disturbances (off-road vehicle use) ; 3) the de-compaction of disturbed soils; 4) the re-introduction of appropriate coastal sage scrub species by seed and by container; and 5) the construction of protective fencing around the perimeter of the habitat preservation Exhibit "A" Page 17 Resolution No. 92-121 area. Habitat enhancement will be initiated prior to or concurrent with project impacts. 16. Revegetation of the remedial grading areas shall be performed by the Developer using seeds or nursery-grown plants, preferably with seeds, other propagules, or transplants from this property consisting of plants of the local origin coastal sage scrub community, subject to approval by the Director of Environmental Services* 17 . Irrigation systems will be installed and maintained by the project developer until the Director of Environmental Services is satisfied that the replacement vegetation required through these conditions is established. 18. A bond in an amount to be determined by the Director of Environmental Services will be posted by the developer to assure adequate establishment of the vegetation, 19. A qualified biologist shall be present on-site during all remedial grading activity, including vegetation clearing, in the quarry bowl to ensure that all identified plants are protected and conserved pursuant to the conditions outlined above, 20. All coastal sage scrub replacement/enhancement efforts will be monitored by a qualified biologist for a period of five years following implementation* At that time, a program for the longterm preservation of preserved and restored coastal sage scrub habitat shall be submitted to the California Department of Fish and Game, the U.S. Fish and Wildlife Service, and the Director of Environmental Services for review and approval. Go TRAILS 11 The Developer shall adhere to previously approved Conditions of Approval of Conditional Use Permit No, 79 - Second Revision as described in city council Resolution 89-109 , Particularly, Condition No. X states that construction of the public trails shall be the obligation of the developer. Construction shall coincide with the project grading activity. and shall be completed upon certification of rough grading. Dedication of the public trails shall occur at the time the final map is recorded, 20 ' All trails shall avoid restricted access areas. These areas shall be fenced off and identified through adequate signage Exhibit "All Page 18 Resolution No. 92-121 to be provided by the developer after review and approval of the Director of Environmental Services. H. ARCHAEOLOGYIPALEONTOLOGY 1. Grading and clearing operations and construction of infrastructure improvements shall be monitored on-site by a qualified archaeologist and paleontologist. 2 . Any significant specimens recovered will be donated to the City or other appropriate public repository for future use or display. I. MITIGATION MONITORING 1. The Mitigation Reporting and Monitoring Program described in attached Appendix "A" shall be implemented by the Developer in cooperation with and under the review of the Director of Environmental Services. 2 . All costs associated with implementation of the Mitigation Reporting and Monitoring Program shall be the responsibility of the Developer. 3 . No project-related activity, including vegetation clearing, shall occur on the site until an environmental monitor is hired as a consultant to the City for implementation of the approved mitigation monitoring program. jhr2:GR1390.con Exhibit "All Page 19 Resolution No. 92-121