A. Natural hydrologic conditions may be altered unnecessarily by poorly planned development practices, such as introducing unneeded impervious surfaces, destroying existing drainage swales, constructing unnecessary storm sewers and changing local topography. A traditional approach has been to remove runoff from a site as quickly as possible and capture it in a detention basin. This leads ultimately to the degradation of water quality as well as expenditure of additional resources for detaining and managing concentrated runoff at some downstream location.
B. Developers shall use design practices that minimize postdevelopment runoff rates and volumes, which minimize artificial conveyance and storage facilities and which simulate predevelopment hydrologic conditions. Forced infiltration is often necessary to offset the loss of infiltration by creation of impervious surfaces.
C. Preserving natural hydrologic conditions requires careful alternative site design practices that include preserving natural drainage features, minimizing impervious surface area, reducing the hydraulic connectivity of impervious surfaces, and protecting natural depression storage.
D. A careful consideration of the existing topography and implementation of a combination of the above-mentioned techniques mentioned in this section may avoid construction of costly stormwater management facilities. Other benefits include reduced potential of downstream flooding, water quality degradation of receiving streams/water bodies and enhancement of aesthetics and reduction of development costs. Beneficial results include more stable baseflows in receiving streams, improved groundwater recharge, reduced flood flows, reduced pollutant loads and reduced costs for conveyance and storage.