Basins for this purpose shall be constructed to temporarily detain the stormwater runoff which exceeds the maximum peak flow rate authorized by this Title.
A. Storage Volumes: The volume of storage provided in these basins, together with such storage as may be authorized in other on-site facilities, will be sufficient to control the excess runoff from the 100-year storm of any duration.
B. Maximum Depth: The maximum planned depth of stormwaters stored shall not normally exceed five feet (5').
C. Side Slopes: The side slopes of the basin will conform as closely as possible to regraded or natural land contours, shall be under twenty percent (20%), and shall be planted with perennial varieties of grass approved by the Enforcement Officer. If the side slopes exceed twenty percent (20%), erosion control and safety measures shall be provided, as approved by the Enforcement Officer.
D. Outlet Control Structures: Outlet control structures shall be designed to operate simply and automatically. Such structures shall be designed to limit discharges into existing or planned downstream channels or conduits so as not to exceed predetermined maximum approved peak rates.
E. Emergency Spillway: Emergency overflow facilities must be provided in all instances so that stored waters will not exceed the safe capacity of the basin. (Ord. 93-498, 11-9-93)