A. The controlled release rate of stormwater runoff from the proposed development shall not exceed the existing safe storm drainage capacity of the natural downstream outlet channel or stormwater system.
B. Detention ponds shall conform to the following criteria:
the release rate shall be an average value computed as a direct ratio of the tributary watershed area. This value shall not exceed an average runoff rate of 0.15 inches per hour. The rate at which stormwater runoff is delivered to a designated stormwater storage area shall be unrestricted.
C. A channel system shall be designed with adequate capacity to convey through the development the stormwater run-off from all tributary upstream areas, assuming development of the upstream areas.
D. The required volume for stormwater detention shall be calculated on the basis of the runoff from a one-hundred-year frequency rainfall or a twenty-four-hour duration as published by a recognized agency. This volume of storage shall be provided for the fully developed watershed that is tributary to the area designed for detention purposes. The stormwater release rate shall be considered when calculating the stormwater storage capacity and the control structure designed to maintain a relatively uniform flow rate regardless of the depth of stormwater in the storage area.
E. Design calculations for stormwater detention shall be submitted to the city engineer for review and approval.
(Ord. 81-10 § 9.1 (B), 1980).