Provisional No Detention Districts. These watershed areas may discharge postdevelopment peak runoff without detention facilities without adversely affecting the total watershed peak flow. In certain instances; however, the "local" runoff conveyance facilities, which transport runoff from the site to the main channel, may not have adequate capacity to safely transport increased peak flows associated with not providing detention for a proposed development. In those instances, the developer shall either use 100% release rate control or provide increased capacity of downstream drainage elements to convey increased peak flows consistent with §
218-38H. In determining if adequate capacity exists in the local watershed drainage network, the developer shall assume that the entire local watershed is developed per current zoning and that all new development would use the runoff controls specified in this Part
1. Similarly, any capacity improvement shall be designed to convey runoff from development of all areas tributary to the improvement consistent with the capacity criteria specified in §
218-38H.