Loading...
HomeMy WebLinkAbout3.3ok TOWN OF LOS ALTOS MILLS January 7, 2010 Staff Report to the Planning Commission RE: SITE DEVELOPMENT PERMIT FOR A GROUND MOUNTED SOLAR PHOTOVOLTAIC SYSTEM (46' L X 13' W X 5'6" H) AND A VARIANCE FOR THE STRUCTURE TO ENCROACH UP TO 21 FEET WITHIN THE REAR PROPERTY LINE SETBACK; LANDS OF BILGER; 25901 VINEDO LANE; FILE #142 -09 -VAR FROM: Nicole Horvitz, Assistant Planner APPROVED BY: Debbie Pedro, AICP, Planning Director RECOMMENDATION: That the Planning Commission: Approve the requested variance, subject to the recommended Conditions of Approval and Findings of Approval in Attachments 1 & 2. BACKGROUND The subject property is located on the north side of Vinedo Lane. Surrounding uses include single-family homes on adjacent properties to the north, east, and south, and single-family homes across Vinedo Lane to the west. On February 22, 1995, the Planning Commission approved the construction of a new 4,689 square foot two story residence with a 3,171 square foot basement, swimming pool, and roof mounted solar pool heating system on this property (SDP # 2-94-ZP-SD-GD). On July 15, 2009, the applicant submitted a Site Development and variance application for a new 598 sq. ft. (46' L x 13" W x 5'6" H) ground mounted solar photovoltaic system to be constructed within the rear property line setback. CODE REQUIREMENTS The request requires Planning Commission review per Section 10-1.1003 (Variances) of the Zoning Ordinance. The Planning Commission must make affirmative findings in order to approve a variance per Section 10-1.1007 (b). Findings for the setback variance are included in this report for the Commission's review. (Attachment 2) DISCUSSION Site Data: Gross Lot Area: 1.29 acres Net Lot Area: 1.18 acres Average Slope: 22.2% Lot Unit Factor: .87 Item 3.3 Staff Report to the Planning Commission Lands of Bilger January 7, 2010 Page 2 Floor Area and Development Area: Area Maxitnum Proposed Existing Increase Left Development 9,070 9,047 8,949 98* 23 Floor 4,689 0 4,675 0 14 *500 square feet exempt from development area per Section 10-1.502(7) of the Los Altos Hills Municipal Code Variance The applicant is requesting approval of a variance for the 598 square foot ground mounted solar photovoltaic system encroaching up to 21 feet within the east (rear) properly line setback. The solar panels will have a maximum height of 5'6" sloping down to a height of 1'. The solar panels will be placed on a downhill slope facing the applicant's residence. x268gale Pflth tt It ii Ustina Graft According to the applicant, there is no suitable alternative location to place the new solar energy system on the property. When the new residence was constructed in 1997, a solar hot water system was installed on the roof of the house and there is inadequate area remaining on the south and west facing roof for additional solar panels. As for ground space, the majority of the rear yard area outside the required setbacks is the leach field for the property's septic system. The Santa Clara County Department of Environmental Health does not allow ground mounted solar systems to be located on top of leach fields. Solar panels are considered an accessory structure and must be located at least 10' away from the leach field. (Attachment 5) Due to these limitations, the applicant is proposing to place the solar energy system within the rear property line setback in an area that is least obtrusive to the neighbors. Staff s recommended Findings of Approval are included as attachment 2. Trees & Landscaping The property currently has a mix of landscape screening trees, primarily located near the residence which consists of oaks, maples, and pistache, along with a mixture of shrubs scattered around the property. The solar panels will not be visible to the nearest adjacent neighbor to the east as there are dense shrubs and trees along the rear property line. However, since there is sparse vegetation along south (side) property line, staff recommends that the applicant install a minimum of six (6) 15 gallon evergreen shrubs or R- Staff Report to the Planning Commission Lands of Bilger January 7, 2010 Page 3 trees between the new panels and the south property line to help mitigate the view of the solar panels from the neighbors at 25851 Vinedo Lane. (Condition #5) Neighbor Comments To date, staff has received one letter from the abutting neighbor to the north at 25961 Vinedo Lane (Lands of Bergh) supporting the variance request. (Attachment 3) Committee Comments The Environmental Design and Protection Committee commented that there is no other location available on the site to locate the solar panels. (Attachment 4) CEQA STATUS The project is categorically exempt from California Environmental Quality Act (CEQA) pursuant to Section 15303(e) of the CEQA Guidelines. ATTACHMENTS 1. _ Recommended Conditions of Approval 2. Recommended Findings of Approval for the Variance 3. Letter from Neighbor at 25961 Vinedo Lane dated November 18, 2009 4. Environmental Design & Protection Committee comments dated December 11, 2009 5. Santa Clara County Department of Environmental Health, Bulletin "A" 6. Worksheet #2 7. Development plans: Site Plan and Elevations Staff Report to the Planning Commission Lands of Bilger January 7, 2010 Page 4 MKT-41-0,1T_I_moors RECOMMENDED CONDITIONS OF APPROVAL FOR A GROUND MOUNTED SOLAR PANEL SYSTEM LANDS OF BILGER, 25901 VINEDO LANE A: PLANNING DEPARTMENT: 1. Any changes or modifications to the approved plans shall be approved by the Planning Director or the Planning Commission, depending upon the scope of the changes. 2. Prior to beginning any grading operation, all significant trees, particularly the heritage oak trees, are to be fenced at the drip line. The fencing shall be of a material and structure (chain-link) 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 fencing must remain throughout the course of construction. No storage of equipment, vehicles or debris shall be allowed within the drip lines of these trees. Existing perimeter plantings shall be fenced and retained throughout the entire construction period. 3. No new fencing is approved. Any new fencing or gates shall require review and approval by the Planning Department prior to installation. 4. No new lighting is approved. No lighting may be placed within setbacks except two entry or driveway lights. Any additional outdoor lighting shall be approved by the Planning Department prior to installation. 5. The applicant shall install a minimum of six (6) 15 gallon evergreen shrubs between the new ground mounted panels and the south property line prior to final inspection of the solar panels. 6. The height of the solar panel system shall not exceed 5'6" from the natural or finished grade, which ever is lower. B. ENGINEERING DEPARTMENT: 7. Any, and all, changes to the proposed Site Plan shall first be approved by the Town Engineering Department. No grading shall take place during the grading moratorium (October 15 to April 15) except with prior approval Staff Report to the Planning Commission Lands of Bilger January 7, 2010 Page 5 from. the City Engineer. No grading shall take place within ten feet of any property line. 8. Any, and all, areas on the project site that have the native material disturbed shall be protected for erosion control during the rainy season and shall be replanted prior to final inspection. 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. NOTE: The Site Development permit is valid for one year from the approval date (until January 7, 2011). 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. N Y Staff Report to the Planning. Commission Lands of Bilger January 7, 2010 Page 6 ATTACHMENT 2 RECOMMENDED FINDINGS FOR APPROVAL FOR A VARIANCE TO ALLOW ENCROACHMENT WITHIN THE SETBACK LANDS OF BILGER— 25901 VINEDO LANE 1. Because of exceptional and extraordinary circumstances applicable to the subject property, including size, shape, topography, location or surroundings, the strict application of the provisions of this Title is found to deprive such property of privileges enjoyed by other properties in the vicinity and under identical zoning classification. The site is developed with existing structures. Due to the location of the septic leach field on the property and lack of available roof area on the house, placement of the ground mounted solar photovoltaic system within the property line setback is the least obtrusive location that would also allow the optimal and efficient operation of the system. 2. Upon the granting of the variance, the intent and purpose of the applicable sections of the Zoning Ordinance will still be served and the recipient of the variance will not be granted special privileges not enjoyed by other surrounding property owners. The proposed development would not be out of character for the homes in the neighborhood or within the Town. There will be no specific, adverse impact on public health and safety with the approval of this variance. 3. The granting of such variance will not be materially detrimental to the public welfare or injurious to the property, improvements or uses within the immediate vicinity and within the same zoning district. The solar panels would have negligible visual impacts to the neighbors. There is existing landscape screening east of the structure that will limit off site views. Additional shrubs required to be planted between the solar panels and the south property line will help mitigate the structure from neighbor's views. 4. The variance will not authorize a use or activity which is not otherwise expressly authorized by the Zoning District regulations governing the parcel of property. A solar photovoltaic system is an authorized accessory use and structure in the R -A zoning district and would be compatible with existing land uses in the surrounding areas. November 18, 2009 Planning Commission Los Altos Mills 'Town Fall Dear Sir or Madame: Attaclunent 3 0 CO tea- M CD C M W We are the Bilger's next door neighbors on Vinedo Lane and wanted you to know that we support their solar project. Please do not hesitate to contact us if you have any questions. Thank you. ��ui • L Arndt and Daren Bergh 25961 Vinedo Lane 650-941-3135 Attachment 4 Environmental ]Design and Protection Committee J Reviewed by: Pal-, Date la Applicant ToEW" F LEIS j�LTOS HIUS, Name L Address o�. 5 4 0 l V i L4 - Site impact/lighting/noise: Creeks, drainage, easements: Existing Vegetation: Significant issues/comments: Im shyl 0 to] a lk 91-64,41M., -11 no, 1 -0 PURPOSE This bulletin is compendium of Santa Clara County ordinance and policy provisions related to the design, permitting and installation of individual on-site sewage disposal systems. It is intended to provide the technical guidance for homeowners, designers and installers of on-site sewage disposal systems. PERMIT REQUIREMENTS A permit must be obtained from the Department of Environmental Health (DEH) to construct, reconstruct or repair anon-site sewage disposal system. Permits will only be issued in the Town of Los Altos Hills where a sanitary sewer is not available within 200 feet of the building. On-site sewage disposal systems cannot be used if soil conditions, topography, high ground water or other factors indicate that this method of sewage disposal is unsuitable. To obtain a permit, four sets of the site plan showing the proposed sewage disposal system, and any required supporting documents, must be submitted to DEH for review and approval. FEES Fees, as prescribed by resolution of Santa Clara County Hoard of Supervisors, are payable separately to the Department of Environmental Health for services described throughout this bulletin. SITE PLANS Site plans must include the following information and details: 1. Show all proposed and any existing sewage disposal systems drawn accurately to a scale of at least 1 inch = 20 feet. Large parcels must also show the entire site in a larger scale. 2. If the slope of the lot is less than 10% indicate direction and percent of slope with an arrow. If the slope exceeds 10% show elevation contour lines at 2 foot intervals. 3. Note the assessor's parcel number (APN), site address, Town file number (if applicable), and any subdivision, tract or lot numbers. 4. Show the North arrow and scale. 5. Show the location of all wells, springs, creeks, drainage swales or water courses on the property or within 100 feet of property lines. 6. Show all existing and proposed structures, driveways, culverts, patios, decks, paved areas, swimming pools, large trees, water lines, etc. 7. Show all existing and proposed cuts, slopes or embankments over 67%, slides and flood plain boundaries. 8. Include the name, address and telephone number of the legal owner and/or applicant. 9. Show the name of adjoining property owners. 10. Show the property boundaries and their recorded lengths. 11. Show all recorded easements and right-of-ways and their purpose. 12. Indicate the name of the water company or otherwise indicate the domestic water source. 13. Show all existing or proposed sewage disposal systems within 100 feet of an existing or proposed well. 14. Show the location of all components of the sewage disposal system. 12-03 ENisting.. Pavement ADJACENT PROPERTY Drainfleld .l :J SAMPLE SITE PLAN STATE AVENUE 3 Proposed Right of Way Lu 0 PROPOSED DWELLING BARN 1500 GAL. 51 MIN. SEPTIC TANK E' NIIN. r Diversion Valvc L FIELD #1 �Inspci tion �lliscrs FIELD I#2 - EXPANSION FIELD # 11()O' Alin. ti, rlf �I EXPANSION FIELD /#2 CREEK Utility Easement SITE PLOT PLAN OF BUILDING' SITE FOR: " NAME STATE AVE. ADDRESS PHONE NO. 300' SITE ADDRESS LOCATION SKETCH Scale Date 3 12-03 Property Corner' Existing Well DEVELOPMENT REQUIREMENTS Land use and building permit applications are evaluated for adequate sewage disposal and water supply. Other conditions such as hazardous materials storage or use, illegal dumping or illegal uses may also be evaluated during field investigations. Evaluation/testing of any existing septic systems may also be required to determine condition and adequacy. Fees are collected separately y the Department of Environmental Health (DEH) for all services. Site Approval, A site assessment, soil profile and percolation test will be required for sites for which Subdivision and Use septic systems are proposed to determine feasibility and size of a system. Permits An approved water supply is required as a condition of approval for building sites, subdivisions and most use permits. Proof of adequate potable domestic water for subdivisions may be required prior to deeming the application complete if water availability is unknown or poor. Otherwise, proof of adequate domestic water supply is required prior to map recordation. Individual wells or water systems with up to 14 connections are regulated by DEH. The California Department of Health Services regulates all other water systems. Building Additions Minor building_ additions (up to 500 square feet) 3 and accessory structures (barns, and Accessory detached garages, swimming pools, cabanas, etc.) are evaluated on an individual Structures basis. The construction of an additional septic tank/drainfield may be required if the existing system is undersized, shows evidence of failure, consists of a cesspool, or if there is an intensification of use (usually an addition of bedrooms or family room). Major building additions (over 500 square fee) 3 require that the septic system meet current standards. Current standards required at least a 1,500 -gallon septic tank and a dual drainfield system and expansion area sized and sited to current code. Building additions/accessory structures will not be approved where it would result in a reduction in the size of the drainfield or any required drainfield reserve area. Secondary Dwellings Each detached secondary dwelling must be served by a separate septic system that conforms to current code. Septic System Sizing Primarily the number of bedrooms and the ability of the soil to absorb water Criteria determine septic system sizing. Soil may be unsuitable for a septic system if it absorbs water too fast, or too slowly. Rooms that are designated other than bedrooms (e.g., bonus rooms, libraries, offices, etc.) may be counted as bedrooms if they are configured as such and have convenient access to full bathroom facilities. Maximum Slope The maximum slope on which a drainfield may be installed is 50%. Pump Systems Septic systems that require pumping of the effluent from the septic tank to the drainfield are generally allowed only where it is not feasible to develop a site with a gravity flow system. Pump systems must be engineered per the DEH Effluent Pump System Guidelines. 3 Cumulative square footage since March 2, 1984. 4 12-03 SITE EVALUATION In order to determine if an on-site sewage disposal system can be utilized, the Department of Environmental Health (DEH) must evaluate each site. The site evaluation consists of a site assessment, a soil profile trench and a percolation test. Fees are collected separately by the Department of Environmental Health for all services. Site Assessment A preliminary review of the physical features of the site, including slope of the land, proximity to cuts, steep slopes, drainage ways, wells, and other features that may limit the available drainfield area. Prior to conducting the assessment, an application/authorization for access form must be signed and a site plan must be provided to DEH. Following the assessment, a written report will be provided by DEH. The report will briefly describe any limitations to development of the site using an on-site sewage disposal system. Soil Profile A soil profile typically consists of a backhoe excavation to at least 11 feet deep. DEH must be present during the excavation. The purpose of the profile is to 1), determine the suitability of the soils for on-site sewage disposal, 2) verify that there will be adequate separation between the bottom of the drainfield and bedrock, ground water or impermeable limiting soil strata. If there are site characteristics or historical documentation that a shallow ground water table is likely to occur during the rainy season a wet weather ground water investigation will be required. The investigation must be conducted during normal wet weather ground water conditions in accordance with DEH policy. Percolation Test A percolation test is conducted to determine the size of the drainfield that will be required. DEH must be advised of the day and time of the test so that a portion of the test may be monitored. Geotechnical If slopes in the drainfield area exceed 20%, a geotechnical report and complete engineered Report (Slope installation plan will be required. The report and plan must be prepared by a State >20%) Registered Civil Engineer, State Certified Engineering Geologist or a State Registered Environmental Health Specialist. MAINTENANCE AND OPERATIONAL SUGGESTIONS 1. The solids that accumulate in the septic tank should be removed by pumping every 3-5 years to prevent their entering and clogging the drainfield. Licensed septic tank pumpers may be located in the phone book yellow pages or a list maybe obtained from the Department of Environmental Health. 2. The diversion valve setting should be changed annually to extend the life of the septic system 3. Garbage disposals should be used sparingly or not at all. Their use contributes to solids accumulation in the septic tank and results in the need for more frequent pumping. 4. The use of water softeners is not recommended in clayey soils. Sodium from these units may alter the soil chemistry and result in reduced drainfield efficiency, and possible failure. A system utilizing off-site regeneration is recommended. Any on-site regeneration water should drain to a subsurface rock filled sump. 5. Swimming pools or spas must not be drained or backwashed into the septic system. After ensuring water is free of disinfectants such as chlorine, algaecides or filter aids, such as diatomaceous earth water may be used for on-site irrigation. Cartridge filters should be used to avoid the necessity for backwashing. Filters can be rinsed clean in a laundry or janitorial sink. 6. Avoid planting trees in the drainfield or close to the septic tank. Their roots may invade the drainfield or septic tank and cause blockage of the system. 12-03 SITING REQUIREMENTS Maximum Slope Drainfields will not be approved on slopes that exceed 50%. Drainfields will only be approved on slopes over 20% with additional investigation (see Site Eveluation section). Fill Drainfields must be placed in native soil and no more than 1 foot of fill may be placed over the native grade. Septic Tank & The tank and diversion valve must be located to be easily accessible for maintenance. Diversion Valve Depth of Soil There must be at least 3 feet of dry permeable soil (no ground water, open fractured rock or impermeable soils) beneath the drainfield on sites with moderate percolation rates. Very fast percolation rates may require greater depth of soil beneath the drainlines. Site Drainage On-site drainage must be designed to discharge storm water below the drainfield. Percolation Rate Measured From Foundation Soil percolation rates must be between 1 — 120 minutes per inch. Property Line 1, Swimming Pool, Domestic Water Line Septic Tank Diversion valve Top of Cut Bank, Steep Slope (over 67%), Drainage Swale, Watercourse Well Reservoir Easment or Right of Way Paved Surfaces MINIMUM SETBACKS (In Feet) - To Septic Tank 5 10 NA Max. 10 Ft. Reccomended 50 100 200 NA NA Trees Over 18 Inches Diameter NA 'No part of a septic system may cross a property line. To Leachfield 10 10 6 NA 50 100 200 5 5 Minimum 15 Feet Reccomended SEPTIC SYSTEM INSTALLATION REQUIREMENTS 1. The approved septic system/site plan, stamped by the Department of Environmental Health (DEH) must be available on the job site. 2. The contractor must hold a class A, C-42 or C-36 contractor's license from the Contractor's State License Board of the State of California, and be registerd with DEH. 3. DEH must be notified at least 24 hours prior to starting work. 4. Trenches must not be excavated when the soil is so wet that soil compaction or smearing of trench walls occurs. Compaction and smearing are problematic in clayey sois and can cause reduced drainfield efficiency. 5. Septic system installation or repair work is prohibited between November 1 and April 1. Emergency repairs may be allowed with approval of an erosion control plan by the Town of Los Altos Hills. 6. No part of the septic tank or drainfield may be covered without approval from DEH. 6 12-03 I TTPICAL SEPTIC TANK Gas tight risers or equivalent Ground Surface Service z ids Inlet 1114 Scum LayeOutlet r _ _ _ _ _ - - _ , - _ _ IWater Level n Slud a Effluent filter may be %� required at outlet 1 Concrete tanks must be used, where possible. Alternative materials are approved on a site specific basis. The Department of Environmental Health (DEH)maintains a list of approved septic tanks. DRAINLINE DETAIL .L outlet SEPTIC TANK DIVERSION VALVE overfill to allow 1 backfill (earth) for settlement filter fabric or untreated 12" min. building paper \ tight line •r.:.; •r•: •:.r•: •r : -:•1 4"perforated pipe t� max. slope 2" per 100 feet 6' Min. 4" 36"; `f mi INSPE Ir V, r,. .r•. •r•. •r,. t• ..r, t r• ••�• 1 3/4" to 2-1/2" Washed Rock ' 1 811 —il Two drainfields, each 50% of the total size required shall be installed and interconnected with an approved diversion valve. DEH maintains a list of approved diversion valves. An additional reserve area must be provided to allow for at least 100% future expansion of the disposal field. Drainline pipes must be of approved, perforated pipe at least 4 inches in diameter. The tightline from the septic tank to the diversion valve must be ABS or schedule 40 PVC joined with glue, cement or elastomeric seal to be water tight. The drainline trench bottom must be level, at least 18 inches wide, with 36 inches of rock beneath the drainpipe and must be no deeper than 8 feet. 7 12-03 DRAINFIELD SYSTEM ON LEVEL LAND DRAINFIELD SYSTEM ON HILLSIDE OR SLOPING LAND End View 12" Mitt. 4 Min. TEE' CD 36" Min. ' Differing ground slopes may require the use of various combinations of fittings. Distance between drainlimes increases as the elope increases. 0 Note: Popover must be at least 4" lower than septic tank outlet. Tight + L i ne Earth Filter �""— 1 8 •• Dam Fabric 10' ISin. 12-03 SEPTIC TANK r r ~ tr s • i 1i . Y•-- EARTH "'•�•. AM UNDISTURBED,'..• •...�.�_ 1 WHIN. Earth .� .. ,, ti �` +' '.iy. •'. i Dam _ ..,,' .�•'i •' IN 4 18" Trench Width - End View 12" Mitt. 4 Min. TEE' CD 36" Min. ' Differing ground slopes may require the use of various combinations of fittings. Distance between drainlimes increases as the elope increases. 0 Note: Popover must be at least 4" lower than septic tank outlet. Tight + L i ne Earth Filter �""— 1 8 •• Dam Fabric 10' ISin. 12-03 Attachment 6 TOTALS 4 (p %S - Maximum Floor Area Allowed - MFA (from Worksheet #1) TOWN USE ONLY I CHECKED BY I DATE 141 L000,� I TOWN Y N OF IROS ALTOS S PLANNING DEPARTMENT 26379 Fremont Road - Los Altos Hills, California 94022 - (650} ' 7 5 > 41-3160 WORKSHEET EXISTING AND PROPOSED #2 DEVELOPMENT AREA - AND FL MI TURN IN WITH YOUR APPLICATION PROPERTY OWNER'S NAME PROPERTY ADDRESS CALCULATED BY o i 21�,-1 d Ct DATE 7A 1. DEVELOPMENT AREA Existing Proposed Total (SQUARE FOOTAGE) (Additions/Deletions) A. House and Garage (from Part 3. A.) 14 (e -75- B Der-king 4 ZyS C. Driveway and Parking (Measured 100' along centerline) J 77 1 1 7-7 D. Patios and Walkways E. Tmaaia-C-omt jcictY �qr rd� j gg 15%eMp�� L7 F. Pool and Decking G. Accessory Buildings (from Part B) H. Any other coverage Z{ 7S TOTALS cj O Maximum Development Area Allowed - MDA (from Worksheet #1) 0-7 (�) 2. TOTAL EVRERVIOUS SURFACE Existing Proposed Total (SQUARE FOOTAGE) TOTALS 3. FLOOR AREA (SQUARE FOOTAGE) Existing Proposed Total (Additions/Deletions) A. House and Garage a. 1 st Floor 2 -71 LP 271 LP b. 2nd Floor ,moo 1-151 C. Attic and Basement 3 17 /vl Z 1 d. Garage B. Accessory Buildings a. 1st Floor b. 2nd Floor c. Attic and Basement TOTALS 4 (p %S - Maximum Floor Area Allowed - MFA (from Worksheet #1) TOWN USE ONLY I CHECKED BY I DATE 141 L000,� I