2018-01-24 CC Packet - Laserfiche WebLink

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Stantec CITY OF CENTERVILLE -2018 LOCAL WATER PLAN WATER RESOURCE MANAGEMENT PLAN 6.4 TOTAL MAXIMUM DAILY LOAD (TMDL) STUDIES TMDL studies have been completed and approved by the United States Environmental Protection Agency (U.S. EPA) for both Peltier and Centerville Lakes, and for the Lino Lakes Chain of Lakes. The Lino Lakes Chain of Lakes TMDL Report was approved on November 25, 2013, and the Lino Lakes Chain of Lakes TMDL Report was approved on September 27, 2013. Peltier Lake and Centerville Lake have been listed by the MPCA as impaired for nutrients, with phosphorus identified as the main pollutant causing the impairment. The TMDL report calls for a 46% reduction in total phosphorus loading for Peltier Lake and a zero percent reduction for Centerville. The assumption is that phosphorus reductions to Peltier Lake will benefit Centerville Lake as well. There is no specific reduction identified for the City; instead, the TMDL report calls for a "categorical reduction" of 46% that would need to be met by the contributing watershed. Specific implementation strategies affecting Centerville include implementing RCWD rules and meeting the requirements of the 2007 Environmental Assessment Worksheet prepared for the City's Downtown Development. The Lino Lakes Chain of Lakes are impaired for nutrients, again with phosphorus identified as the main pollutant. The TMDL report calls for no load reduction from MS4 communities within the watershed. Instead, internal loading and outflow from Peltier Lake are identified as the primary phosphorus sources. Meeting the load reduction requirement in the Peltier Lake TMDL is considered essential to meeting the Lino Lakes Chain of Lakes water quality goals. 6.5 STORMWATER RUNOFF RATE CONTROL To prevent flooding associated with increased runoff rates from new developments, rate control must be provided within each development that maintains existing runoff conditions (or less) for the 2-year, 10-year, and 100-year storm events. Rates must be determined using Atlas-14 precipitation frequency estimates. 6.6 MANAGEMENT OF CLEARWATER CREEK DITCH SYSTEM Most runoff in the City of Centerville is routed either directly or indirectly to Clearwater Creek. Clearwater Creek is a natural waterway connected to the Anoka-Washington Judicial Ditch 3 (AWJD 3) system. The Clearwater Creek Ditch System can be considered a "trunk storm sewer" for the entire City. RCWD, as the public drainage authority, is responsible for maintenance of the AWJD 3 system. The system will be managed in accordance with the rate control and water quality policies outlined in Sections 6.1 and 6.5. 6.7 INTERCOMMUNITY FLOWS The City is bounded on all sides by the City of Lino Lakes. Any flows leaving Centerville therefore enter Lino Lakes. Most the City drains to Peltier Lake, either directly or via Clearwater Creek. A portion of the City drains to Centerville Lake, which then drains to Peltier Lake. A 6.23 61