03-09-26 Planning Commission Meeting Packet

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Page: 5 9. The storm sewer system shall be designed to meet all City design standards including RCP pipe materials and maintaining the minimum pipe cover of 3 feet. Drain tile is required as part of the city standard street section at all localized low points in the street. 10. Per city requirements all storm sewer pipe easements must be a minimum 30-feet in width. Easements are needed for some storm sewer runs. MUNICIPAL WATER SUPPLY 1. Connection to the municipal water system is available near the proposed development in two locations. The applicant will be responsible for connecting to the existing 12-inch trunk watermain located along 50th Street. A minimum 8-inch ductile iron watermain will need to be extended along the new proposed streets into and throughout the development at developer’s sole cost. 2. A second connection point to the existing watermain system is required to create a looped watermain system, connecting to the existing 16-inch watermain located along Linden Avenue in the Sanctuary subdivision. 3. A watermain lateral stub will be required to the westerly plat limits. 4. The developer will also be responsible to place hydrants and water system valves internal to the site as determined by the Lake Elmo Public Works Director and Fire Department. 5. No watermain oversizing is anticipated for this development. However, further water main pipe sizing will be evaluated by the City prior to finalizing this design. All watermain to be installed would be required to meet the minimum 8-inch design standard. 6. When not located within the public right-of-way, minimum 30-foot easements centered over the pipe/hydrant are required without encroachments from retaining walls, trees, other small/dry utilities, or storm water management BMPs. Easements must be dedicated to the city as part of the plat. Dedicated watermain easements must be shown on all site, grading, utility, and landscape plans. WATEWATER MANAGEMENT / SANITARY SEWER 1. The proposed development is located outside of the City designated Municipal Urban Service Area (MUSA) for sanitary sewer service. The developer is therefore responsible to provide wastewater management infrastructure to support the proposed subdivision in perpetuity, including professional management of the system. All sewer infrastructure must be provided at the developer’s sole cost and will remain privately owned and maintained. 2. The Preliminary Plat/Plans propose a gravity sanitary sewer system to be privately owned and maintained but located within the public right-of-way and constructed to City design standards. 3. A privately owned and maintained duplex sanitary lift station is proposed at the gravity sewer end point to pump the wastewater to a community subsurface sewage treatment system located near the center of the subdivision in Outlot G (HOA owned). 4. The community wastewater treatment system will be designed to receive wastewater from all 58 lots requiring a treatment design capacity of 24,300 gallons per day (gpd). At this capacity (greater than 10,000 gpd) the system will be regulated and permitted as a large subsurface/sewage treatment system (LSTS) by the MPCA, requiring a State Disposal System (SDS) Permit. The proposed wastewater treatment system includes primary, secondary and tertiary treatment prior to the effluent being dispersed to a soil absorption area (drainfield). Wastewater treatment components include a series of septic tanks, flow equalization, aerobic treatment units, and a denitrification unit. The Plans show a minimum required soil absorption bed area of 36,450 sf with an additional 12,150 sf of reserve area. 5. Revisions to the Preliminary Plans are anticipated to relocate the proposed retaining wall outside of the public right-of-way and small/dry utility corridor. As construction plans are finalized, additional revisions may be necessary to ensure all required setbacks are maintained.