Loading...
HomeMy WebLinkAboutTC Ord 1980-11-19 ORDINANCE NO. 233 N.S. AN ORDINANCE OF THE TOWN COUNCIL OF THE TOWN OF TIBURON APPROVING THE CHAN & TAI MASTER PLAN BE IT ORDAINED by the Town Council of the Town of Tiburon as follows: Section 1. Findings. A. A Master Plan has been submitted by Chan & Tai Architects for the development of ten lots on 5.5 acres of land off Gilmartin Drive. B. The Master Plan is described as follows: (1) Map entitled, "Master Plan Tiburon Property, Assessor's Parcel No. 55-261-01", by Chan & Tai Architects, dated May 31, 1979; (2) Environmental Information Form, Project Description and Statement of Concepts. C. A focused Environmental Impact Report was prepared by HKS Associates for this project, and it has been reviewed by the Planning Commission (Commission) and the Town Council (Council). D. The Master Plan application was complete on July 22, 1980, at which time the Town received a copy of the Preliminary Title Report (the final document necessary to complete the application). E. A soils report prepared by Donald Herzog & Associates, Inc., reveals that there are two landslide areas at the site: that some of the landslides are active; that even the dormant s11de areas are susceptible to future movement; that reactivation of the dormant slides could be caused by severe rainfall, irrigation, water from broken underground utliities, and/or ground shaking during earthquakes. The report further points out that landslides could distort structures built on slide areas, or could undermine improvements located above the slirle areas. F. The geotechnical investigation conducted as part of the preparation of the E.I.R. concluded that while implementation of the development as proposed would be geotechnically feasible, it would require that extensive corrective measures be taken. G. Development of the project site as proposed will require grading and earth moving of some 57,000 cubic yards of dirt, which the Town Council finds to be excessive and contrary to the Tiburon General Plan. The adverse environ- mental impact of this type of earth work in this area can only be mitigated by reducing the number of lots to a maximum of six. This will allow for the siting of the structures in areas less susceptible to on-site environmental constraints to development, thus offsetting significant adverse geologic and biotic impacts found to result from the proposed development as submitted. This reducation in density would also result in reducing hydrology, traffic, visual quality, and public finance impacts of the project. H. Geotechnical investigations conducted as part of the E.I,R. study concluded that implementation of the development as proposed would be feasible -2- only after the completion of extensive corrective measures to eliminate the existing geologic hazards from landsliding and expansive soils. A reduced density alternative would enable development of the property in such a way that land rehabilitation could be substantially minimized. I. The E.I.R. recommends that the proposal be approved, but that approval be condition-d upon the development of no more than seven residential units, thus restricting development from identified landslide areas, and that construction on the sites be limited to areas within specific building envelopes. J. The project is located in the RPD-2 zone which provides for a denisty of not less than 1.1 or more than 2.5 dwelling units per gross acre. The zoning regulations further provide that the meximum number of units that can be developed on this site is six, unless findings are made that maximum effort has :)been made to minimize grading and that there has been maximum retention and preservation of natural elevations, ridgelands, natural features, lands too steep for development and land that is geologically unstable. The Council cannot make the necessary findings. K. Section 21081 of the Public Resources Code provides that the Town may not approve a development project which has a significant adverse environmental effect unless measures to mitigate the adverse effect are infeasible, the conditions herein imposed are the minimum necessary to enable the Town to comply with Section 2l08l and the Town's General Plan. L. The Planning Commission has held a duly noticed Public Hearing on the application. M. The Planning Commission has recommended that the Council approve the Master Plan provided certain conditions are imposed. N. The Council has held a duly noticed Public Hearing for the purpose of reviewing the Master Plan and the recommendations of the Commission and to receive comments and recommendations from the public. ~ecti o_~ Approva 1 . The Master Plan described above is approved, subject to the conditions spt forth herein. Section 3. Conditions. A. Development be restricted to a maximum of 6 lots provided, however, that the maximum number of lots may be increased to seven as recommended by the Planning Commission, if, at the Precise Plan stage, applicant establishes that a seven lot development is feasible without requiring extensive corrective measures to eliminate the existing geologic hazards from landsliding and expansive soils and the the Town Council finds that the other conditions specified in paragraph J of Section 1 of this Ordinance have been met. B. Applicant shall submit a Precise Plan in compliance with applicable provisions of the Zoning Ordinance no later than February l7, 1981, (90 days from adoption of the Master Plan). In the event applicant fails to submit the required Precise Plan by said date, thus preventing the Town from processing this application within the time limits prescribed by law, the approval authorized hereby shall be automatically revoked and approval of the Master Plan shall become null and void and the application deemed denied. -3- C. Applicant comply with all applicable subdivision regulations. D. Applicant comply with mitigation measures as contained in the E.I.R. and modi fi ed in Exhi bi t 'IA II attached. E. All utilities be undergrounded and that service be guaranteed by the agency providing the utilities in writing prior to recordation of the Final Map. F. Applicant comply with all requirements of the Marin Municipal Water District necessary to ensure adequate water pressure including the requirements outlined in the letter from Mr. Stroeh dated February 4, 1980. G. Applicant satisfy requirements of the Tiburon Fire Protection District including those set forth in the letter from Mr. Barber dated January 30, 1980. H. All streets be offered for dedication. I. Applicant submit all proposed deed and title restrictions including future roadway easements and scenic easements to the Department of Community Development for review and approval by the Town Attorney prior to the filing of the Final Map. J. No building permits be issued for construction of any structures until they have received site plan and architectural approval. K. Applicant comply with the provisions of any Ordinance of the Town requiring contribution to a Tiburon Boulevard Traffic Improvement Fund. L. All requirements and standards including but not limited to drainage, grading~ soils and traffic, shall be subject to review and approval by the Town Engineer, M. All retaining walls be poured, textured, colored concrete Section 4. i~pa r a b ilitr . If any section, subsection, sentence, clause or phrase of this Ordinance is for any reason held to be invalid or unconstitutional by the decision of a court of competent jurisdiction, such decision shall not affect the validity of the remaining portions of the Ordinance. The Town Council of the Town of Tiburon hereby declares that it would have passed this Ordinance and each section, subsection, clause or phrase thereof, irrespective of the fact that anyone or more other sections, subsections, sentences, clauses or phrases may be declared invalid or unconstitutional, Section 5. Effective Date. This Ordinance shall take effect and be in force thirty days after the date of passage, and before the expiration of fifteen (15) days after its passage, the same shall be published, with names of the members voting for or against the same at least once in a newspaper of general circulation published in the Town of Ti buron, -4- PASSED AND ADOPTED at a regular meeting of the Town Council of the Town of Tiburon held on November 19 , 1980 by the following vote: AYES: NOES: ABSENT: COUNCILMEN: Edelstein, Bergsund, Hanson, Rockey, Bass COUNCILMEN: None COUNc ILMEN: None ATTEST: ~ OBERT L. KLEINERT, Town Manager/Clerk Town of Ti buron Date drafted 7/31/80 Dates revised 8/18/80, 9/26/80 and 11/14/80 EX H I BIT II A II Chan & Tai A. Geologic Considerations - Mitigation Measures 1. Stabilization of the landslide areas should include excavation and compaction of the landslides, installation of subdrainage systems, and buttressing. 2. To ensure stabilization of any cut made into the expansive clay soils, the bottom of any excavation should be benched into firm supporting materials and, in some locations subdrains may be required. Fill should be placed within lifts, moisture condensed as required for compaction, and compacted to at least 90 percent relative compaction. For preliminary planning, cut and fill slopes should not be inclined steeper than two hori- zontal to one vertical (2:1) or 50 percent slope. 3. Foundation design must take expansive soil effects and instabil- ity problems into account. Control methods could include: - Addition of lime to the soil. - Compaction to low densities, maintaining water contents on the wet side of optimum.1 - Replacement of the upper layer of expansive soils found throughout the study area with non-expansive imported materials. - Construction of special drilled pier and grade beam founda- tions with supported floors. Specific foundation design would depend on relative costs and specific lot conditions. On sloping areas, foundations for structures can include cast-in-place concrete piers with grade beams to provide lateral support. In leveled areas underlain by compacted fill or by shallow bedrock, satisfactory support could be obtained from conventional shallow spread footings. 4. Residential structures and other on-site facilities, such as utilities, should be designed to include proper earthquake resistent features. B. Hydrologic Considerations - Mitigation Measures 1. Impervious surfaces should be limited by minimizing street widths and driveway areas. 2. The drainage systems should be designed to reduce discharge of post project peak volume flows to pre-project volumes by incorporating runoff delay mechanisma, such as plunge pool sumps or detention ponds. 3. In addition to on-site drainage improvements, the project developer should be responsible for upgrading the project of lCompaction of expansive soil when it is wet reduces the swelling characteristics of the soil. Ex h i bit II A lip. 2 Chan & Tai the existing drainage system of Sub-watershed E which extends from the point where stormwater flow is discharged off site, to the outfall in Richardson Bay. Specific systems design should be completed by a qualified engineer in accordance with the Tiburon Drainage Master Plan of 1975, and closely coordinated with the Town Engineer. Costs can be borne solely by the project proponent or shared among those who would benefit from such improvements by formation of an assessment district. 4. Site preparation, grading, and other major construction activities should only be permitted during th'e dry season. (May-October). 5. Avoid grading on excessively steep slopes and limit clearing of vegetation to building pad, parking, and street areas only. Vegetative cover is difficult to reestablish on slopes greater than 25 percent. 6. Apply temporary groundcover on exposed oils during the construction phase and permanent groundcover when develop- ment is completed. Special attention should be given to slopes greater than 15 percent. 7. Frequent sweeping of paved areas will reduce buildup of urban pollutants and reduce the concentration of these compounds in storm water runoff. 8. Install and maintain regularly, sand and grease traps in inceptor chambers which collect storm water runoff from impervious areas. 9. Drainage facilities shall be designed so that runoff is not discharged directly into the drainage swale. This could include a 100 foot setback of the discharge pipe to allow for natural filtering through vegetative buffers in addition to use of sediment traps, sand bag sediment barriers or sediment basins at the point of discharge. C. Traffic Considerations - Mitigation Measures 1. The Tiburon Boulevard/Gilmartin Drive intersection should be improved as a stop-sign controlled intersection -- requiring vehicles approaching Tiburon Boulevard from Gilmartin Drive to stop before entering the through flow of traffic. A pedestrian crosswalk should be provided across Tiburon Boulevard. 2. The Tiburon Boulevard/Gilmartin Drive intersection should be improved to provide the following channelization of vehicles. ~,~ pro ~s_~__1.Q_~l!l!.~J:.~~<2.liQJl Tiburon Boulevard Northbound-One through lane and one right-turn channel. Gilmartin Drive Southbound-One through lane and one left-turn channel. Westbound -One left-turn lane and one right-turn lane. Ex h i bit II A" p. 3 Chan & Tai Leaving the Intersection Tiburon Boulevard Southbound-One lane Northbound-One through lane and a merge channel for turns from Gilmartin Drive Gilmartin Drive Eastbound -One Lane 3. If it is determined appropriate at a future date, the intersections of Tiburon Boulevard with San Rafael Avenue and Rock Hill Road, immediately north and south of Gilmartin Drive should be signalized to produce gaps in the vehicle flows and allow turning movements into and out of Gilmartin Drive to be made more freely. (These are higher volume intersections, thus signalization would be more effective for areawide circulation conditions than at Gimartin Drive.) The appropriate contribution to the Tiburon Boulevard traffic improvement fund should be made for future improvements. 4. The bus stop which presently exists just north of the Tiburon Boulevard/Gilmartin Drive intersection should be relocated slightly farther north, to provide room for the channelization widening of Tiburon Boulevard and to minimize interference between buses and turning vehicles. This bus stop could be improved with a bus shelter, bench and telephone, if appropriate. 5. Street lights, consistent with the Tiburon Boulevard Master Plan, could be installed at the bus stop, as well as at the Tiburon Boulevard/Gilmartin Drive intersection. 6. Gilmartin Drive should be improved to a 28-foot width (curb- to-curb) with a four foot wide sidewalk on one side only. This would provide two ten-foot lanes and a 9-foot parking lane on one side. 7. To reduce the temporary increases in traffic congestion near the Tiburon Boulevard/Gilmartin Drive intersection during construction of the proposed developments, vehicles involved with construction could proceed past Gilmartin Drive to the Lyford Drive intersection, make a U-turn and enter Gilmartin Drive with a single right-hand turn. No work requiring construction vehicles on the Boulevard permitted during the peak morning and afternoon commute hours or during the peak school traffic hours which would interferewit.h through traffic movements along Tiburon Boulevard or with the safety of children. D. Visual Considerations - Mitigation Measures 1. In order to minimize the visual impacts of the single family dwellings on the ridgeline area, building sites should be selected at the lowest possible elevations and structures should be designed with maximum building heights measuring no more than 25 feet high. Exhibit "A" p. 4 Chan & Tai D. Visual Considerations - Miti~ation Measures (cont'd) 2. Exterior building surfaces should be of natural earth tone colors, and natural roof materials should be used in order to blend structures into the natural surroundings, subject to approval by the Board of Adjustments and Review. 3. Generous landscaping, including vegetating with native species, should be provided to buffer the development from the adjacent open space.