CCP 03-28-1994 - Laserfiche WebLink

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. Based on review. of the topographic maps, it was concluded that, with the exception of the area to the northwest of Rice Creek and the TCAAP gravel pit area (see attached exhibit), the remainder of the TCAAP area could be served by a gravity interceptor system that conveys wastewater to the MWCC's L-35 lift station. As previously mentioned, the MWCC has always planned to serve TCAAP by an interceptor to lift Station L-35. Consequently, suchan interceptor system is in conformance with MWCC's plans. The northwestern area shown on the attached sketch appears to be too low to be served by a gravity interceptor to Lift Station L-35. Some of this area is flood plain of Rice Creek and cannot be developed. The State of Minnesota also owns part of this area. Consequently, the amount of land available in the northwestern area for redevelopment is limited. The most cost-effective way to provide sanitary sewer service to this area is probably a small lift station to pump wastewater up into the gravity interceptor system. The other area that cannot be served by the gravity interceptor system is the gravel pit area of TCAAP. Because of all the material that has been removed, ground elevations are too low to pick up this area by gravity. A small lift station would be required to provide sanitary sewer service to this area. , For preliminary planning purposes, it was ass!lmed that 1,800 acres would b~ redevel~. ~>_, Further, it was assumed that 1,000 gallons of wastewater per day would be generated per acre of--"':- . land that is redeveloped. This resulted in an average daily wastewater flow of 1,800,000 gallons - (1.8 MGD). The MWCC utilizes flow variation factors to determine peak flow rates when - planning interceptor sewers. For an average daily flow of 1.8 MG, the flow variation factor is 2.9. Therefore, the predicted peak flow rate is 1.8 MGD x 2.9 = 5.22 MGD or 3,625 gallons per minute (gpm). The U.S. Army will be constructing a 1,000 gpm interceptor sewer from TCAAP's main lift station to the City of Mounds View's 21-inch line at the intersection of U.S. Highway 10 and County Road H. As determined above, a 3,625 gpm interceptor would be required if all of ~ TCAAP redevelops and all of the wastewater flow is routed to Lift Station L-35. The U.S. Army has indicated that they would be willing to construct the interceptor sewer with the additional capacity that the City of Arden Hills will ultimately need, provided that the City of Arden Hills pays for the over-sizing. This would be a very economical solution for the City because much of the cost of the interceptor would be paid for by the U.S. Army. If the City elects to implement this option, the interceptor should be over-sized from the westerly border of TCAAP to the intersection of U.S. Highway 10 and County Road H. . lNTRRCRPTOR OWNFRSHTP By Metropolitan Council definition, an interceptor sewer must serve at least 1,000 acres and must convey wastewater flow from more than one community if it is to be classified a Metropolitan . facility that can be owned and operated by the MWCC. MSA contacted a Metropolitan Council staff member for a determination as to whether the TCAAP interceptor fit this definition. The staff member indicated that, on a preliminary basis, the TCAAP interceptor met the requirements of a Metropolitan facility and could be acquired by the MWCC. 049-2203.feb S2()..{)49.70