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a ntec CITY OF CENTERVILLE -2018 LOCAL WATER PLAN • Reducing transport from parks, residential and other areas by the use of buffers, and other disconnection of flow pathways. • Removing community vending machines for feeding geese and ducks. • Adding buffers in riparian areas near waterbodies to deter waterfowl congregation. Clearwater Creek is impaired for aquatic macroinvertebrate bioassessments and fishes bioassessments, although a TMDL has not yet been completed for the Creek. 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 AND JUDICIAL DITCH 3 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. Clearwater Creek and Judicial Ditch 3 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. Note that RCWD serves as the drainage authority for public ditches in the City of Centerville, such as Judicial Ditch 3, but not for Clearwater Creek, because it is a natural watercourse. 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 of 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 small area in the northwestern portion of the City drains directly to Lino Lakes. The Rice Creek Watershed District identifies the intercommunity flows from Centerville to Lino Lakes, via Anoka-Washington Judicial Ditch 3 as: • 2-year, 24-hour rainfall peak flow: 196 cfs • 10-year, 24-hour rainfall peak flow: 339 cfs • 100-year, 24-hour rainfall peak flow: 573 cfs • 100-year, 10-day snowmelt peak flow: 433 cfs Because of the large storage volume available in the two lakes, peak flows entering from the City will be greatly attenuated prior to discharge from Peltier Lake. As stated earlier in this chapter, the City requires that peak flow rates from the 2-, 10-, and 100-year storm events be 25 120