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HomeMy WebLinkAboutSP-24-19 - Supplemental - 1215 Dorset Street (7) Memorandum Date: April 26, 2024 To: Marty Gillies Development Review Planner City of South Burlington Planning & Zoning Department 180 Market Street, South Burlington VT, 05401 (802) 846-4106 From: JeƯrey Lewis, P.E., Aldrich + Elliott, PC RE: Dorset Street Water Storage Tank A+E Project 23022 Project Need The City of South Burlington is requesting approval to build a second water storage tank at 1225 Dorset Street. The existing tank, named ‘South Burlington East Tank’, or SBET, has a storage volume of 2.1 million gallons. The tank will be constructed by the City to support the City-owned water distribution system, specifically a portion of the system known as the ‘High Service Area’. The parcel at 1225 Dorset Street is owned by the Champlain Water District (CWD), which previously received DRB approval for construction of a communications tower and the existing tank. Increased storage capacity for the High Service area is recommended to ensure that the South Burlington Water System maintains compliance with Vermont Water Supply Rules, specifically, WSR Sections 2.1 and 7.0.1. The water system is currently utilizing/allocating 98% of the existing storage capacity available in the existing tank. A second water storage tank is required to bring this number below 80%. Description of Project A second water storage tank will be constructed on the existing site. The new tank will be a welded steel standpipe design to match the existing with a volume of 2.1 million gallons. The new tank will be painted to match the existing as required by Act-250’s “minimal landscape disturbance” provisions. The tank will be painted ‘Tank Light Gray’ (F073A4190A) with a ‘Tank Blue Gray’ (F073B3934A) Trim. The new tower will have a diameter of 53 feet and a height of 125 feet to match the existing tank and provide an additional 2.1 million gallons of storage for the South Burlington Water distribution system. In order to construct the water storage tank a 75 ft by 75 ft area of land will be cleared to bedrock, approximately 2 ft below the grade. A new foundation ring-wall will be poured directly on the bedrock and steel panels will be welded together on-site to form the 53 ft (diameter) by 125 ft (high) water storage tank. New tank fill and drain lines will be connected to the existing water distribution system by blasting a 4 ft wide by 5 ft deep trench through the ledge. Ledge is very high on site starting approximately 12”- 24” below grade. The new pipes will be 16” diameter to match existing and will be installed side-by- side to minimize the area of disturbance required. Zoning District: The project continues the existing land use and is in-line with the requirements of the Municipal Use District per LDR 7.03. 7.03.A: The project supports a critical component of the City’s water system, which is a listed municipal service in 7.03.A. 7.03.B: Municipal Facilities are listed as ‘Permitted’ in the MU district per Table C-1. 7.03.C: Dimensional Standards From Table C-2: Maximum Site Coverage: Buildings, Parking, and All other impervious surfaces: 70% Proposed following project: 9.2% Maximum Site Coverage: Buildings Only 30% Proposed following project: 0.05% Standard Setbacks (ft): Front: 40 220 ft to Tower Side: 15 25 ft to New Tank Rear: 30 25 ft to New Tank 13 Supplemental Regulations: 13.01 [Reserved for Transportation Demand Management] Not Applicable 13.02 OƯ Street Parking and Loading Public access to the lot is limited to protect the water system. Maintenance/access needs of the site are met with the gravel access road. 13.03 Bicycle Parking and Storage A small bike rack is provided at the entrance of the site, outside of the security fencing, which complies with the requirements of Table 13-3. 13.04 Landscaping, Screening, and Street Trees 13.04 B is not applicable as no parking lot is provided for security reasons. 13.04 C The applicant proposes to provide fencing along property boundaries to protect the water distribution system from intrusion. Further discussion with City DRB personnel is underway to understand what additional buƯering or landscaping requirements should apply to this project. 13.05 Stormwater Management The total area of impervious surface on the site is less than 5,000 sf therefore this application is exempt from requirements of Section 13.05. 13.06 Airport Approach Cones Development is outside of the Airport Approach Cones as shown on the Overlay Districts map. 13.07 Exterior Lighting Any exterior lighting proposed as part of this project (none is currently anticipated) will be downward facing and be in compliance with Act250 and LDR requirements. 13.08 Outdoor Storage and Display No outdoor storage of goods, materials, or vehicles is proposed as part of this project. 13.09 Solar Radiation The project adds a second tank to an existing site with identical dimensions to the first, in- line with current land use regulations. Abutting properties will not observe significant changes to available solar radiation from the existing condition. 13.10 Connections Across a Lot Construction is proposed to occur on a single lot, therefore this is not applicable. 13.11 Fences We are seeking approval to construct a fence with a barbed wire top and a height of 8 ft. This will match the existing fence installed on the site and provide the necessary protection to protect the drinking water system. This type of security fencing complies with VT water supply requirements and is standard construction for these types of projects. 13.12 Utility Cabinets and Similar Structures No new utility cabinets are proposed as part of this project. 13.13 Signs No Trespassing signs will be posted on the site fencing which are allowed by the City’s Sign Ordinance per Section 23, sub-section g. 13.14 Subsurface Sewage Disposal Systems No Sewage disposal system is required for this project. 13.15 Satellite Dishes No Satellite Dishes are proposed as part of this project. 13.16 Retaining Walls A retaining wall is proposed along the western portion (back line of the property border) of the property to avoid grading oƯ the owner’s lot. The retaining wall design shall be prepared by a Professional Engineer. 13.17 Residential Designs for New Homes No new homes are proposed as part of this project. Appendix A Performance Standards: A.1 Fire and Explosion Hazards The site will not involve storage of flammable or explosive materials and no burning of waste materials is proposed. A.2 Vibration The finished storage tank will not result in any vibrations. A.3 Noise Construction activities will be exempt from this standard under A.3.c.(iii) as construction of water lines are specifically exempt. The finished storage tank will not result in any measurable noise. A.4 Air Pollution No visible emissions will be produced due to this project. A.5 Odors No Odors are anticipated due to this project. A.6 Electromagnetic Radiation New water tower will not result in any additional electromagnetic radiation. A.7 Radioactive Radiation No element of the project is radioactive. A.8 Heat No heat will be produced as part of this project. A.9 Direct Glare No lighting is anticipated as part of this project, if any is added with will be Act250 compliant and will not result in glare oƯ property. A.10 Indirect Glare Project will continue existing site use and no new glare is anticipated. A.11 Liquid and Solid Wastes Site will be secured from the public to prevent any discharge or emission to the water supply system. A.12 Other Requirements Project is being reviewed through the VT Act 250 oƯice to ensure compliance with State Standards.