11-20-2006 Council Agenda - Laserfiche WebLink

Home Browse Search

Page 8: [1] Deleted -. Lee Elfering 10/15/2006 8:30:00 PM and grease control - For all stormwater plans for commercial or industrial developments and all other uses where the potential for pollution by oil or grease, or both, exists, the first 0.5 inches of runoff will be treated using the best oil and grease removal technology available. This requirement may be waived by the plan reviewer only when the applicant can demonstrate that installation of such practices is not necessary. Page 8: Deleted ,` Lee Elfering 1: 10/15/2006 8:31:00 PM calculations shall be according to the methodology described in the Natural Resources Conservation Service's Technical Release 55, "Urban Hydrology for Small Watersheds" (commonly known as TR -55), or other methodology approved by the community. For agricultural land subject to this section, the maximum runoff curve number (RCN) used in such calculations shall be 51 for Ilydrologic Soil Group (HSG) A, 68 for hydrologic soil group B, 79 for HSG C, and 84 for HSG D. The TR -55- specified curve numbers for other land uses shall be used. Heavily disturbed sites will be lowered one permeability class for hydrologic calculations. Lightly disturbed areas require no modification Page 8:; [3] Deleted !, i: Lee Elfering 10/15/2006:8:32:00 PM: Where practices have been implemented to restore soil structure to pre - developed conditions, no permeability class modification is required. Page 8: [4] Deleted Lee Elfering 10/15/2006 8:37:00 PM- stormwater facilities shall be designed, installed and maintained to effectively accomplish the following: Maintain predevelopment peak runoff rates for the 2 -year, 24 -hour storm event. Maintain predevelopment peak runoff rates for the 10 -year, 24 -hour storm event. At a minimum the storm sewer conveyance system shall be designed for this storm event. Low areas must have an acceptable overland drainage route with the proper transfer capacity when the storm event is exceeded. Safely pass the 100 -year, 24 -hour storm event. Page 8: [5] Deleted ;` Lee Elfering 10/16/2006, 7:41:00 AM Minimize impervious surface area and maximize infiltration - The project shall use existing natural drainage ways and vegetated soil surfaces to convey, store, filter, and retain stormwater runoff before discharge into public waters or a stormwater conveyance system (permanent pool areas of wet ponds tend to lose infiltration capacity and will not be accepted as an infiltration practice). The applicant shall limit the impervious surface of the developed site or subdivision by incorporating the following design considerations, consistent with zoning, subdivision, and PUD requirements: Narrowing street widths Reducing parking lot space Sidewalk locations -31-