2018-09-12 CC Packet - Laserfiche WebLink

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a ntec CITY OF CENTERVILLE -2018 LOCAL WATER PLAN TABLE 6.1 —TP REMOVAL FACTORS FOR PROPERLY DESIGNED BMPs k & a;, m �� Infiltration Infiltration Feature 1.00 Water Reuse Irrigation 1.00 Biofiltration Underdrain 0.65 Filtration Sand or Rock Filter 0.50 Stormwater Wetlands Shallow Wetland 0.40 Pond/Wetland 0.55 Stormwater Ponds Wet Pond 0.50 Multiple Ponds 0.60 Infiltration may be infeasible, due to potential contamination (i.e. contaminated soils or potential stormwater hotspots), physical limitations (i.e. low permeability soils, bedrock close to the infiltration area, seasonal high water tables, or karst areas), or land use limitations (i.e. nearby wells or utility locations). In these cases, alternative BMPs are required, as listed in Table 6.1 These BMPs are stated in order of RCWD's preference, due to TP removal efficiencies. The City requires protective easements for all stormwater detention facilities and conveyance structures. These easements are intended to protect floodplain and stormwater storage areas from alterations that may interfere with storage and/or flow of surface water, particularly during flood conditions. They also serve as formal notice to the property owners and future property owners that the land within the easements may be inundated at any future date. Maintenance of stormwater facilities will be coordinated with the RCWD. Currently, inspections are performed in the spring and fall, with maintenance done as needed. Maintenance of the current system will continue to be a priority for the City. As new development occurs, developers will "turn over" these new stormwater facilities to the City Public Works Department, including trunk and lateral storm sewers, catch basins, stormwater BMPs, and ponds and outlet structures. With such a relatively new storm sewer system, there are currently few maintenance tasks other than street sweeping, which is done a minimum of twice per year. However, the City plans to formulate a Maintenance Plan Budget within five years. As an MS4 city, Centerville is ultimately responsible for the monitoring and maintenance of water bodies and other best management practices or structural stormwater conveyance systems as defined in its NPDES permit. It shall be city policy that the City is responsible for the monitoring and maintenance of elements of the City's MS4 system when those elements take drainage from public property or the public right-of-way. Where elements of the city's MS4 system are constructed on, and take drainage from, solely private property, city policy shall be that the private property owner is responsible for monitoring and maintenance of these items. If the property owner fails to complete such monitoring and maintenance, the City may complete this work and assess the associated costs to the property. 22 117