Agenda - 06-01-1987 - Laserfiche WebLink

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C. Exceptions to the impervious surface limitations specified in a) and b ) above may be granted by City Council , upon recommendation from the Subdivision Review Board. Considera- tion of whether to orant such relief shall be based cn a demonstration, to the Council 's satisfaction, that the site plan reflects special features to safeguard against contamina- tion of stormwater leaving the property, including the infiltration, retention or detention of the first 1/2 inch of stormwater runoff from impervious surfaces. F. Snec i a l Runoff and Drainace Ccntrc I Recu i nemen I s- I t i s necessary To I ";sse several requirements on development in the Critical Watershed District in order to prevent damage to water quality that is not necessarily attributed to an individual property within a development. These requirements are specified below. 1 . Stormwater Runoff Retention. For development within the Water Quality Critical Area, measures shall be employed to infiltrate or retain the first 1/2 inch of stormwater runoff from impervious surfaces during a storm occurring within a 24-hour period. For development within the Limited Industrial Area, measures shall be employed to infiltrate; retain or detain (detention being least preferred) the fir 1/2 inch of stormwater runoff. Methods to accomplish that infiltration, retention or detention shall he shown on the site plan. The area to which this requirement shall apply may be for each individual lot within a single development, or, th e development as a whole. If the developer elects to satisfy �ev�. iOp, this requirement for the ceve i c ,,ent as a whole, the site plan shaII indicato how any devices or s es used to acaomp I i sh The retention cr infiltration sh,a i be maintained. 2. Stream Buffer. For all perennial streams indicated by a solid blue line on the USCS tocog raph i c =is for land within Critical Watershed District, a 50--foot vegetaTive buffer left in its natural state siloI I be maintained on both sides of The stream bark. For all areas desicreted as floodway or flcodway fringe on the official Zoning hiap and located within The Critical Watershed District, a iJ ft. vegetative buffer shall be maintained on both sides of the stream bar•' Street crossings, utility lines, recreational and greenway facilities and recreation related paved surfaces may be allowed as exceptions to the vegetative buffer requirement in perennial stream buffer areas, flcodways and floodway fringe areas. Such intrusion shall be minimized or mitigated, to the extent possible. D. Street Runoff and Drainace. New streets constructed within the Water Quality Critical Area shall not require curb and gutter. New streets which cross perennial streams within the Water Quality Critical Area shall be designed in such a way to avoid direct runoff from pavement surface into the stream it crosses. Such design features shall be indicated on the site plan. -5-