Res 1991-148 - Laserfiche WebLink

Home Browse Search

§ 36-5 SAN MARCOS RIVER CORRIDOR § 36-6 Sec. 36-5. Overland flow and natural drainage. (a) Natural drainage patterns shall be preserved whenever possible and the loss of the previous character of the soil should be limited in order to prevent erosion and attenuate the impact of contaminants collected and transported by storm water. Open surface drainage through grasslined swales shall be preferred. Drainage objectives can best be accomplished by leaving portions of a subdivision in an underdeveloped and natural state and located to receive runoff from the developed areas for purposes of unchannelized, overland flow. The use of streets as the central drainage network is prohibited. (b) Construction of enclosed storm sewers and impervious chan- nel linings shall be permitted only when the director, on the basis of competent engineering evidence, concludes that such storm sewers or impervious linings are the only justifiable option available. In the event that storm water drainage systems and/or culverts are necessary, such systems shall be designed to miti- gate their impact on water quality through the use of approved control strategies to control sediment, neutralize contaminants, and dissipate energy by the use of multiple smaller outlets when- ever practical, by locating discharges to maximize overland flow, and by any.other strategies which will accomplish the objectives defined and discussed herein. (Ord. No. 1985-79, § 1(5),8-1-85) Sec. 36-ß. Velocity attenuation and surface drainage channels. (A) All drainage channels that are to be constructed or that are to be altered for drainage purposes shall conform to the criteria of this section. (B) Surface drainage channels shall be designed to minimize potential erosion and to increase the bottom width to flow depth ratio: Supp. No. 22 1060.150.1