(A) The increased storm water runoff resulting from a proposed development should be detained on-site by the provisions of appropriate wet or dry bottom reservoirs, by storage on flat roofs, parking lots, streets, lawns or other acceptable techniques. Measures which retard the rate of overland flow and the velocity in runoff channels shall also be used to control the runoff rate partially. Detention basins shall be sized to store excess flows from storms with a 100-year return period. Control devices shall limit the discharge to a rate no greater than that prescribed by this chapter (see §§ 155.075 and 155.076). When detention is required, all parts of the developing site should drain through the detention/retention basin. Detention is not required for offsite drainage. If the detention/retention basin intercepts off-site drainage, the storage volume and the outlet size should be based on the entire contributing watershed area.
(B) As an alternative, the developer may construct, at his or her sole expense, improvements downstream which would make detention unnecessary. Detailed plans and specifications for these alternative improvements must be submitted along with all required engineering data prior to construction and must be accepted by the engineer and approved by the Board prior to construction. In addition, the developer must obtain and provide the town with written evidence that he or she has obtained the approval of all property owners on whose property any such downstream improvements are to be constructed.
(Ord. 1995-10 § XIV A, passed 10-13-1995)