Detention, retarding, and retention basins will be constructed as close to the Master Plan facilities as possible so that they can be eliminated in the future upon completion of the ultimate facilities.

Freeboard will not be required in detention, retention, or retarding basins. However, an emergency spillway which can convey 125% of peak postdevelopment 25-year flow in a safe manner and preclude upstream flooding will be required.

Basin side slopes shall be 2:1 or flatter, subject to slope stability analysis. Side slopes of 4:1 or flatter will be required if slope is planned to be mowed.

Retention, retarding, and detention basin designs will incorporate a 15 ft. wide all weather drive access road to the basin floor to facilitate maintenance. The maximum slope of the access road shall be limited to 15 percent. Proper turning radius or a hammerhead shall be provided. The paved section shall be 12 feet wide and shall have a structural section of 3" AC over 4" aggregate base compacted to 95% or 5" PCC over proper base prepared as recommended by the soils engineer.

For flow-by detention basins, a reinforced concrete low flow channel shall be provided from basin inlet(s) to basin outlet.

For retention basins and retarding basins, an approved energy dissipater shall be provided at the basin's inlet to preclude erosion. In addition, those basins which incorporate retention storage, shall have a bypass flow device to carry nuisance water around and out of the basins should upstream drywells fail.

All basins shall be fenced with a 6-foot high fence or wall approved by the City. Access to the basins shall be gated (15 ft. minimum) and locked.