8.1. SR 08-03-2020 - Laserfiche WebLink

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Starting at the lift station, a 6-inch sanitary forcemain will run trenchless along County Road 33 (Ranch Road NW) to the Great Northern Trail. To stay within the utility easements and clear of the trail underpass, the 6-inch sanitary forcemain will be open cut and installed approximately 200 ft south to tie in to the existing 6-inch sanitary forcemain. A 6-inch check valve will be required on the upstream side of the connection point for each the Great Northern Trail forcemain and the Windsor Park forcemain to prevent backflow issues. B. LIFT STATION The proposed Windsor Park lift station would be located on the west side of the drainage ditch between Fresno Street NW & Concord Street NW and the top should be constructed 1 foot above the 100 year flood plain elevation at a minimum. The Windsor Park lift station will need to be sized similarly to the lift station on the Great Northern Trail forcemain in order to pump the 2.6 miles to the south discharge point. The pumps will need to be designed to pump 180 gallons per minute (gpm). The resulting maximum capacity of the new lift station will need to be 216,000 gallons per day (gpd), which will have an available capacity of 191,000 gpd for additional flow from the surrounding area. Due to the sizing required to pump 2.6 miles, the lift station may only have 2 hours of run time per day which could result in odor issues at the lift station or at the discharge point. The Windsor Park lift station can not be operated until construction is completed on the Great Northern Trail forcemain. The Windsor Park lift station cannot be operated simultaneously with the lift station on the Great Northern Trail forcemain so coordination is necessary. Currently both systems are designed to have minimal run times, so alternating pumping through the use of a SCADA system may not be problematic. As development occurs, and additional flow is added to the system, a master regional lift station is recommended to be constructed at the connection point of the two 6-inch forcemains. This will eliminate the scheduling/alternating flow issue, and allow for additional service to be provided in the region. It is not anticipated that this regional lift station will be required prior to 2040 given the current plans for develpement in the area. The costs for this future "Trunk" station will be paid for using Trunk Sewer Fees paid by all contributors to the area at the time of connection. See costs that have been included in Section VI. C. STORMWATER MANAGEMENT Best Management Practices (BMP's), as required by the Minnesota Pollution Control Agency (MPCA), will be utilized during construction to minimize erosion and sediment runoff from the construction site. These BMP's may include silt fence, construction sediment control entrances and storm water inlet protection. D. FUTURE SERVICE TO NEARBY NEIGHBORHOODS This project layout would allow for future gravity sanitary sewer service to extend to the nearby streets off of County Road 33 (Ranch Road NW). Because County Road 33 (Ranch Road NW) is at a higher elevation than many of the connecting streets, many of the homes can not feasibly be served without the use of additional lift stations or individual grinder pumps. Due to the existing road grades in the area, it is not recommended to construct the lift station at any additional depth or size than required for the Windsor Park 3,d Addition plan as the additional service area would be negligible and the trunk sanitary mains would need to be in excess of 30' deep. Prepared by: Bolton & Menk, Inc. Windsor Park 3rd Addition — Sewer Connection I R16.120038 Page 3