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HomeMy WebLinkAbout3.1 S. TOWN OF LOS ALTOS HILLS November 10, 1998 Staff Report:.to the Planning Commission RE: SITE DEVELOPMENT PERMIT FOR A POND AND LANDSCAPE PLAN; LANDS OF SCOTT, 27860 BLACK MOUNTAIN ROAD;FILE#246-97-ZP-SD. FROM: Shaunn O'Connor, Assistant Planner APPROVED BY: Curtis S. Williams, Planning Direr _ RECOMMENDATION That the Planning Commission: Approve the requested Site Development Permit, subject to the attached conditions of approval. CODE REQUIREMENTS Section 10-2.301(c)(3)(iv) - of the Site Development Ordinance requires Planning Commission review of excavations exceeding an area of 10,000 square feet. This application for a new pond and landscaping has been forwarded to the Planning Commission for review and approval. Criteria for review from the Site Development Ordinance include grading, drainage, pathways and landscape screening. Zoning Code review encompasses compliance with development area requirements and setbacks. BACKGROUND The subject property for the proposed pond and landscaping is located near the terminus of Black Mountain Road on the southern side (Assessor's Parcel No. 182-12-078, Lot 3 of Tract 3908, established in 1965). There are no subdivision conditions of approval for this site.The property extends approximately 487 feet southeast of Black Mountain Road. A 28- foot wide driveway and public utilities easement exists along the frontage of Black Mountain Road. The site is currently vacant (a residence, pool, caretaker house, tool shed and barn existing on the site were demolished several years ago) and the adjacent lots are developed. The applicant's residence (Assessor's Parcel No. 182-12-64, Lot 5 of Tract 3908, established in 1965) abuts the back southeastern half of the site. • Planning Commission Lands of Scott November 10, 1998 Page 2 DISCUSSION Site Data: Gross Lot Area: 3.221 acres Net Lot Area: _ 3.011 acres Average Slope: 3.7 Lot Unit Factor: 3.011 Floor Area and Development Area: Area Maximum Proposed Existing Increase Left Development 45,165 10,451 0 10,451 +34,714 Floor 18,066 0. _ 0 0 18,066 - The adjoining lot with the Scott residence (lot 5).complies with all development standards - without the benefit of the subject property. - Site and Design The applicant is requesting approval of a site development permit for a new pond and landscaping. The proposed project will include 10,451 square feet of development area for the pond and bogs and additional landscaping on the property. A mulch driveway is proposed as access to the pond for maintenance. No lighting is proposed for this project. The proposed pond will have a maximum depth of 4 feet and will have a surface area of approximately 9,000 square feet. The additional 1,451 square feet will be used for bogs and patio area. A meandering pathway is proposed around the pond with a connection to the Scott's residence at 27860 Black Mountain Road. The proposed pond is designed to have a natural form and is located in a clearing between -the trees on the site. Some-of the excavated soil will be used as fill for existing depressions on the site and the remainder will be spread in open areas to a maximum depth of two feet. Maintenance & Vector Control The pond will be maintained on a weekly basis. This will include maintaining water quality and clarity, keeping the filtration system in working order, removal of debris, and the overall health of the fish and plants. A pond maintenance agreement (condition #3) is required to be recorded, stating that the property owners will be responsible for maintaining the pond water clarity, proper vector control and the integrity of the darn on the northeast side of the pond. Planning Commission Lands of Scott • November 10, 1998 Page 3 The size of the pond requires appropriate vector control and proper County approval. Staff has included condition #4 requiring an approval letter from Santa Clara County Vector Control, prior to acceptance of plans for building plan check. Visibility The project site is fairly level with an average slope of 3.7%. The mild topography lends itself to hiding the pond. The landscaping and dam, at the northeast end of pond, will be the most visible elements on the site. Trees &Landscaping The project site is fairly open and is studded with oaks, pines, eucalyptus and fir trees and a large cluster of trees in the southeast corner of the site. The arborist's report recommends that trees within the construction zone be fenced to protect roots and branches from construction injury (see condition#5). Screening is proposed to be planted along the Black Mountain Road frontage and along the driveway up to Mr. Scott's residence. Additional trees are shown on the site plan, but the types of trees have not been selected. The Environmental Design Committee _ -_ • recommends that plantings consist of native species. Condition #6 requires that planting emphasize native species and that a landscape plan be submitted for review by staff and the Environmental Design Committee prior to acceptance of plans for building plan check. Grading &Drainage The pond is shown as having a maximum depth of 4', requiring 945 cubic yards of soil to be excavated. All of the excavation will be used on site for fill (195 cubic yards for fill in depressions and 750 cubic yards to be spread on the site, 2 feet maximum) and a dam (35 cubic yards) on the northeastern side of the pond. Two neighbors that live on Foothill Lane have voiced concern about increased runoff _ from the proposed two feet of fill to be spread on the site. The residences on the east side of Foothill Lane had drainage problems due to last year's rains. The Commission may prefer to have the applicant export the 750 cubic yards of excavated soil that is proposed to be spread on site. If so, condition#1 should be modified accordingly. The Engineering Department has reviewed the plans and has recommended conditions of approval as specified in Attachment 1. The Engineering Department has suggested that the site drainage be designed as surface flow wherever possible to avoid a concentration of runoff. This has been included in condition #8. The applicant proposes an overflow mechanism near the dam that will route water forty feet away to a four inch by twenty foot long perforated tee set on a two foot wide base of cobble stones to dissipate the water flow. The Engineering Department will review and approve the final drainage plan prior to acceptance of plans for building plan check. Planning Commission - - Lands of Scott _ November 10,1998 Page 4 • Geotechnical Review The Town geotechnical consultant, Cotton, Shires & Associates, has reviewed the plans and has visited the site. Approval of the project is subject to the conditions as specified in the Town Geologist's report of December 17, 1997 (see Attachment 3). Condition #7 includes the recommendations of the Town Geologist. Committee Review The Environmental Design Committee recommends native plantings. Staff is available to answer any questions that the Commission or the public may have. ATTACHMENTS 1. Recommended conditions_of approval; 2. Worksheet#2; • 3. Letter from Cotton, Shires &Associates,Inc. dated December 15, 1997.(three pages); 4. Environmental Design & Protection Committee evaluations, received November 11, 1997; 5. Plans. cc: Daniel Lima Michael Scott Renaisance Landscaping 27856 Black Mountain Road 2120 Church Ave. Los Altos Hills, CA 94022 San Martin, CA 95046 Planning Commission Lands of Scott November 10, 1998 Page 5 ATTACHMENT 1 RECOMMENDED CONDITIONS FOR SITE DEVELOPMENT PERMIT FOR A POND AND LANDSCAPING PLAN LANDS OF SCOTT, 27860 BLACK MOUNTAIN ROAD File#246-97-ZP-SD A. PLANNING DEPARTMENT: 1. Any modifications to the approved plans shall be approved by the Planning Director or the Planning Commission, depending on the scope of the changes. 2. No outdoor lighting has been approved with this permit. Any changes to outdoor lighting shall be approved by the Planning Department. Lighting fixtures shall generally be shielded and directed downward. Lighting shall be low wattage, shall not encroach or reflect on adjacent properties, and the source of lighting should not be directly visible from off site. No lighting may be placed within the setbacks. 3. A pond maintenance agreement shall be recorded for the property, stating that the property owner will be responsible for maintaining the pond through proper vector control, water clarity and maintenance of the integrity of the dam on the northeast side of the pond. The City Attorney will prepare the pond maintenance agreement and the signed, notarized document shall be returned to the Town prior to acceptance of plans for building plan check. 4. The applicant shall submit a letter of approval from the Santa Clara County Vector Control prior to acceptance of plans for building plan check. 5. Prior to beginning any grading operation, all significant trees are to be fenced at the drip line. The fencing shall be of a material and•structure to clearly delineate the drip line. Town staff must inspect the fencing and the trees to be fenced prior-to commencement of grading. The property owner shall call for said inspection at least three days in advance of the inspection. The fence must remain throughout the course of construction. No storage of equipment, vehicles or debris shall be allowed within the drip lines of these trees. 6. Proposed landscaping shall emphasize native species. A landscape plan shall be submitted for review and approved by the Planning Department and the Environmental Design Committee prior to acceptance of plans for building plan check. Staff will visit the site prior to final inspection to determine if any additional plantings will be needed to screen the pond or to restore areas disturbed by grading or construction. Planning Commission Lands of Scott - November 10, 1998 Page 6 7. As recommended by Cotton, Shires & Associates in their report dated December 15, 1997, the applicant shall comply with the following: a. The applicant should retain a geotechnical consultant to address the items in the above mentioned report regarding fill placement specifications, pond liner and appropriate amoring for the overflow. The applicant's geotechnical consultant shall review and approve all geotechnical aspects of the development plans (i.e., site preparation and grading, site drainage improvements and design parameters for foundations and driveway) to ensure that his recommendations have been properly incorporated. The results of the plan review should be summarized by the geotechnical consultant in a. letter and submitted to the Town _ Geotechnical Consultant- for review and approval prior to the acceptance of plans for building plan check. b. The geotechnical consultant shall inspect, test (as needed), and approve all geotechnical aspects of the project construction. The inspections should include, but not necessarily be limited to: site preparation and grading, site surface and subsurface drainage improvements, and placement pond liner. The consultant shall verify that new fill materials are properly keyed and benched into competent earth materials. The results of these inspections and the as-built conditions of the project shall be described by the geotechnical consultant in a letter and submitted to the Town Engineer for review prior to final inspection. For further details on the above requirements, please refer to the letter from Cotton, • Shires & Associates dated December 15, 1997. B. ENGINEERING DEPARTMENT: 8. The site drainage associated with the proposed development must be designed_ as surface flow wherever possible to avoid concentration of the runoff. The proposed drainage shall be designed to maintain the existing flow patterns. A final grading and drainage plan shall be submitted for approval by the Engineering Department prior to acceptance of plans for building plan check. Final drainage and grading shall be inspected by the Engineering Department and any deficiencies corrected to the satisfaction of the Engineering Department prior to final inspection. A letter shall be submitted from the project engineer stating that the drainage improvements were installed as shown on the approved plans and in accordance with their recommendations prior to final inspection. 9. Any, and all, changes to the approved grading and drainage plan shall be submitted as revisions from the project engineer and shall first be approved by the Town Planning Commission Lands of Scott _ November 10, 1998 Page 7 Engineering Department. No grading shall take place during the grading moratorium between November 1 and April 1 except with prior approval from the City Engineer. No grading shall take place within ten feet of any property line except to allow for the construction of a driveway access. 10. All public utility services serving this property shall be placed underground. 11. An erosion andsediment control plan shall be submitted for review and approval by the Engineering Department prior to acceptance of plans for building plan check. The contractor and the property owner shall comply with all appropriate requirements of the Town's NPDES permit relative to grading and erosion/sediment control. The first 100 feet of the driveway shall be rocked during construction and all cut and fill slopes shall be protected from erosion. All areas on the site that have the native soil disturbed shall be protected for erosion control during the rainy season and shall be replanted prior to final inspection. 12.Two copies of a grading and construction operation plan shall be submitted by the property owner for review and approval by the City Engineer and Planning Director prior to acceptance of plans for building plan check. The grading/construction plan shall address truck traffic issues regarding dust, noise, and vehicular and pedestrian traffic safety on Black Mountain Road and surrounding roadways; storage of construction materials; placement of sanitary facilities; parking for construction vehicles; and parking for construction personnel. A debris box (trash dumpster) shall be placed on site for collection of construction debris, if required by the Engineering Department. Arrangements must be made with the Los Altos Garbage Company for the debris box, since they have a franchise with the Town and no other hauler is allowed within the Town limits. 13. The property owner shall inform the Town of any damage and shall repair any damage caused by the construction of the project to pathways, private driveways, and public and private roadways, prior to final inspection and shall provide the Town with photographs of the existing conditions of the roadways and pathways prior to acceptance of plans for building plan check. Upon completion of the construction, a final inspection shall be required to be set with the Planning and Engineering Departments two weeks prior to final building inspection approval. CONDITION NUMBERS 3, 4, 6, 7a, 8, 11, 12 and 13 SHALL BE COMPLETED AND SIGNED OFF BY THE PLANNING DIRECTOR AND THE CITY ENGINEER PRIOR TO ACCEPTANCE OF CONSTRUCTION PLANS FOR PLAN CHECK BY THE BUILDING DEPARTMENT. NOTE: The Site Development permit is valid for one year from the approval date (until November 10, 1999). All required building permits must be obtained within that year and work on items not requiring a building permit shall be commenced within one year and completed within two years. • `^WN OF LOS ALTOS MILLS j ATTACHMENT Z 26379 Fremont Road • Los Altos Hills,California 94022.• (415) 941-7222 • FAX (415) 941-3160 _ PLANNING DEP WORKSHEET #2 EXISTING AND PROPOSED DEVELOPMENT AREA AND FLOOR AREA • TURN IN WITH YOUR APPLICATION • PROPERTY OWNER'S NAME SC.O-r1'- _PROPERTY ADDRESS, 278(DO SLACK MOUNTAIN ZO,\1„' CALCULATED BY K. LEETS DATE 4 - 11- q 1 1. DEVELOPMENT AREA (SQUARE FOOTAGE) : . - Existing Proposed Total (Additions or Deletions) - A. House and Garage (from Part B) ----- B. B. Decking C. Driveway and Parking ___ (Measured 100' along centerline) - D. Patios and Walkways — E. Tennis Court - -- I F. Pool and Decking — G. Accessory Buildings (from Part B) — H. Any other coverage ?()-ID — l ) TOTALS 2 1C)-ye-9-f__ L6-1 t0/14S-1 Maximum Development Area Allowed - MDA (from Worksheet #1) I 4511 Los I 2. FLOOR AREA (SQUARE FOOTAGE) ExistingProposed Total (Additions or Deletions) A. House and Garage a. 1st Floor - __ b. 2nd Floor - `- c. Attic and Basement — - — —_ d. Garage — B. Accessory Buildings a. 1st Floor b. . 2nd Floor c. Attic and Basement --- TOTALS d . 0 -- Maximum Floor Area Allowed - MFA (from Worksheet #1) . I 16 ) 0(2. 62 I E TOWN USE ONLY CHECKED BY DATE - y — _ ._ . =1 La.: MAC FID/ORIGINALS/f LANNINC/w0rkshect 02 Revised 12/I19/93 COTTON, SHIRES & ASSOCIATES, INC. ATTACHMENT CONSULTING ENGINEERS AND GEOLOGISTS h'` DEC 17i , Decemlier•15,.1997 L3467 TO: Susan Manca • Planner TOWN OF LOS ALTOS HILLS 26379 Fremont Road Los Altos Hills,California 94022 SUBJECT: Geotechnical Review - RE: Scott Pond and Landscape Improvements - #246-97-ZP-SD 27860 Black Mountain Road At your request, we have completed a geotechnical review of proposed site improvements using: Site Development Plan (1 sheet, 20-scale) prepared by Clements and Associates, dated April 17, 1997. In addition, we have completed a recent inspection of site conditions and reviewed pertinent technical maps from our office files. DISCUSSION The applicant proposes to construct a pond and bog garden requiring approximately 1,20. 0 cubic yards of excavation and 400 cubic yards of fill. The proposed pond is located in the east-central portion of the property. No residential structures are currently located on the property. - SITE CONDITIONS The proposed pond site is generally characterized by relatively level to gently inclined,north-facing ridge crest topography. Minor grading has previously occurred in the vicinity of the pond, with existing excavations possibly trapping small amounts of surface water. An apparent prism of artificial fill is located near the northernmost portion of the pond and along the eastern edge of the pond. Existing fill may have a maximum depth on the order of 3 feet. Northern California Office Southern California Office 330 Village Lane 5245 Avenida Encinas • Suite A Los Gatos,CA 95030-7218 Carlsbad,CA 92008-4374 (408)354-5542 • Fax(408)354-1852 (760)931-2700 • Fax(760)931-1020 ATTACHMENT. Susan Manca December 15, 1997 Page 2 L3467. The site is underlain, at depth, by mapped bedrock materials of the Franciscan Complex (greenstone and sandstone). The bedrock is overlain by a mantle of potentially expansive silty clay. • CONCLUSIONS AND RECOMMENDED ACTION Based on our site inspection and review of the development plan, it appears that construction of the proposed pond is geotechnically feasible. However, to minimize any potential for failure of fill embankments that retain water, it is important that proposed fill be placed in a properly engineered manner (to specific compaction specifications) under the inspection of a geotechnical consultant. Some of the existing site fill may need to be reworked to provide a suitable base for placement of proposed engineered fill. To avoid generating any adverse subsurface seepage with potential offsite impacts, consideration should be given to incorporating a clay liner (or other relatively impermeable liner material) into the design of the pond. Consideration should also he given to utilization of appropriate surface armoring at the location of the proposed overflow to prevent scour/erosion. We recommend geotechnical approval of the general pond concept with the • following conditions: 1. Limited Geotechnical Evaluations and Plan Review - The applicant should retain a geotechnical consultant to address the above items regarding fill placement specifications,pond liner and appropriate armoring for the overflow. The consultant shall review and approve all geotechnical aspects of the development plans (i.e., site preparation and grading, and site drainage improvements) to ensure that his recommendations have been properly incorporated. The results of the plan review should be summarized by the geotechnical consultant in a letter and submitted to the Town Engineer for review and approval prior to issuance of construction permits. 2. Geotechnical Field Inspection-The geotechnical consultant shall- inspect, test (as needed), and approve all geotechnical aspects.of the project construction. The inspections should include,but riot necessarily be limited to: site preparation and grading, site surface and subsurface drainage improvements, and placement of the pond liner. The consultant shall verify that new fill materials are properly keyed and benched into competent earth materials. The results of these inspections and the as-built conditions of the project shall be described by the geotechnical consultant in a letter and submitted to the Town Engineer for review prior to final (as- built) project approval. A cent`TATre TAT!"' ATTACHMENT ?j Susap Manca December 15,1997 Page 3 L3467 Thisreview has been performed to provide technical advice to assist the Town in its discretionary permit decisions. Our services have been limited to review of the documents previously identified, and a visual review of the property. Our opinions and conclusions are made in accordance with generally accepted principles and practices of the geotechnical profession. This warranty is in lieu of all other warranties, either expressed or implied. Respectfully submitted, COTTON, SHIRES AND ASSOCIATES,INC. TOWN GEOTECHNICAL CONSULTANT Ted Sayre Supervising Engineering Geologist CEG 1795 - C� '"e Patrick O.Shires Principal Geotechnical Engineer • GE 770 POS:TS:rb Cn-r-rnm STTTRFS &- A SSOCTATES. INC' ATTACHMENT 9 ENVIRONMENTAL DESIGN COMMITTEE LANDSCAPE/HARDSCAPE EVALUATION �. Applicant's Name: Address: �7/1 a ��✓ �[�C _�%Ly ,/�Gt' �—�-!- Reviewed by: � Date: //. .1007 Mitigation needed: Visibility from off site: from distance Ad, (directions), from nearby neighbors (directions) (include need for screening for privacy). Noise: from pump/pool C, air conditioner , sport court . Light: from fixtures , automobile headliglits" - Fence materials: color , open/s lid . Erosion control • Other: .-----7?-00G04(714 } 6�?� Planting Plan Evaluation: (Circle required trees and shrubs on plan) • - - Are species appropriate: Deciduous? Future height (view, solar, drive/path blockage) Fire hazard Hardiness/frost Drought tolerance Meet mitigation needs Creeks and drainage: Is_there a conservation easement? Are there sufficient • protections in place. Will fences impact wildlife migration? Invasive species should not be planted near a waterway. • • Other: Are there obstructions to pathways, including future growth of plants? Are all noise mitigations in place? No construction in road right-of-way. cg//tizarfifi-ic 41,0 Kce P - P :.I►,'/ November 3, 1998 City of Los Altos Hills Attn: Shaunn O'Connor 26379 Fremont Road Los Altos Hills, CA 94022 Dear Mr. O'Connor, Thank you for reviewing with my wife and I the proposed plans for Mr. Scott's property. I have several reservations based on my review. First, I am surprised by the size of the proposed pond. The excavation of 945 cubic yards of soil would certainly indicate a major water containment area. This much water surface area coupled with the proposed adjacent marsh areas would seem to offer an excellent breeding ground for mosquitoes. I also might add that during the spring of the year, the din from the assembled frog population could be interesting. Additionally, it appears this much surface water would be an attractive refuge for wild birds. I can not judge what impact this would have on surrounding homes. Perhaps someone that has lived around a duck pond could offer some thoughts. I have noted the plans call for raising the grade level adjacent to my property from an existing topography elevation of 105 to 107. Your map indicates that the topography level of my driveway is 103 and since my driveway is only a short distance from the existing 105 elevation, I am very concerned that when an extra two feet is added to the existing grade level on Mr. Scott's property, we could encounter a serious drainage problem. It is my understanding that several of the existing homes on Foothill Lane have experienced drainage problems, and therefore, anything that alters the current elevation of this property should be looked at carefully. I for one would feel more comfortable if the proposed pond is reduced in size- and that the existing grade on Mr. Scott's property is not altered. Thank you for your consideration. Sincerely, 'IYK'an Michael M. Scott 27856 Black Mountain Road; Los Altos Hills, CA 94022 *Voice: 650-941-3092 *Fax: 650-941-8547 *E-mail: WurmFafner@aol.corn Thursday, October 29, 1998 To: LAH Planning Committee, LAH Staff and Neighbors From: Mike Scott4/K,S Subject: Pond and Landscaping for 27860 Black Mtn Road Summary: The best way to understand what is proposed is to visit 27856 Black Mtn Road and see my existing small pond. The plantings around and in it are very similiar to those planned for 27860. Please call me at the above phone number to arrange for a mutually agreeable time for your visit. Comments: The attached plans are to install a pond in the previous residence basement area. Existing natural drainage • routes will be maintained. The pond area will be excavated down 4 feet, a water proof membrane installed, and then will be partially refilled with dirt to grow water lilies and lotus flowers. Reeds will be planted in separate "bog" areas. Any left over dirt will be distributed around the site. No dirt will be removed from the site. No existing trees will be removed and over 18 new trees will be planted. The pond is planned as a "water garden" and not as a "fish . pond;" although small "Mosquito" fish, provided by Santa Clara County, will be used to provide pest control. An airation system is planned to maintain water quality and no chemicals will be used. I expect an increase in wildlife, particularly birds, that will visit the area. RECEIVED OCT 291998 TOWN OF LOo hLiU6 HILLS / �'