5.2. SR 08-08-2011 - Laserfiche WebLink

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wastewater from the major service areas of the City's current urban service area and direct it straight to the WWTF. These three lift stations include the TH 10 Lift Station, the Evans Avenue Lift Station, and the TH 169 Lift Station. Wastewater generated from the western portion of the Elk River urban service area, as well as a portion of the central area, is directed east and then southeast to the TH 10 Lift Station located along the west side of TH 10. The TH 10 Lift Station pumps wastewater directly to the WWTF through a 14-inch diameter forcemain that runs east across TH 10. Wastewater from the northern portion of the Elk River urban service area is directed south to the Evans Avenue Lift Station. The Evans Avenue Lift Station is located along Evans Avenue, just north of the intersection of Main Street and Evans Avenue. This lift station pumps wastewater south along Evans Avenue through a 14-inch forcemain that discharges directly to the WWTF. Wastewater from the eastern portion of the Elk River urban service area is directed west to the TH 169 Lift Station. The TH 169 Lift Station is located along the east side of TH 169, approximately 1500 feet south of Main Street (181St Avenue). Results and Conclusions The proposed development area (253 acres) is within the City's eastern urban service area that is served by the TH 169 Lift Station. The trunk sanitary sewer system from the study area north to the TH 169 Lift Station consists of 15-inch,l8- inch, and 24-inch gravity sewer pipe. The 15-inch gravity sewer pipe has a minimum full flow capacity of 1.6 MGD; the 18-inch gravity sewer pipe has a minimum full flow capacity of 2.4 MGD; and the 24-inch has a minimum full flow capacity of 4.1 MGD. The TH 169 Lift Station pumps wastewater west across TH 169 through a 14-inch forcemain that discharges directly to the WWTF. The total eastern urban service area encompasses an area approximately 2,935 acres in size. However, only about 50% of this area is currently served by sanitary sewer. The current estimate average daily wastewater flow to the TH 169 Lift Station is 0.388 MGD. This was based on a review of the City's GIS mapping and the number of parcels that have sanitary sewer service available. The estimate current peak hour wastewater flow to the TH 169 Lift Station is 1.40 MGD (970 gpm). The TH 169 Lift Station has two submersible solids handling pumps, each with a pumping capacity of 2.60 MGD (1800 gpm), based on design information. The TH 169 Lift Station is capable of being upgraded to provide a firm pumping capacity of 5.20 MGD (3600 gpm), with the installation of two additional pumps. Three development scenarios are being evaluated for the study area. The estimate average daily wastewater flows projected from the proposed development area range from 0.135 MGD for Scenario 1 to 0.375 MGD for Scenario 3. The estimated peak hour wastewater flows from the proposed development area range from 0.526 MGD for Scenario 1 to 1.351 MGD for Scenario 3. The existing eastern area City of Elk River Draft Alternative Urban Areawide Review July 2011 Page 44 of 84