(A) Detention policy. It is recognized that most streams and drainage channels serving the county do not have sufficient capacity to receive and convey stormwater runoff resulting from continued urbanization. Accordingly, the storage and controlled release of excess stormwater runoff, as well as compensation for loss of floodplain storage, shall be required for all developments and redevelopments (as defined in § 152.005) located within the county. Release rate requirements, downstream restriction considerations, acceptable outlet, adjoining property impact considerations, policy on dams and levees, and compensatory floodplain storage rates are detailed in the Hendricks County Stormwater Technical Standards Manual.
(B) Direct release provisions. Due to unknowns regarding the future development patterns and the associated proposed stormwater quantity and quality management systems within a watershed, it is the policy of the County Drainage Board to discourage direct release of runoff from a new development or redevelopment without providing detention. However, in rare circumstances where a comprehensive watershed-wide hydrologic study or watershed plan of a major stream adopted by the County Drainage Board and/or the County Surveyor (not a “beat the peak” analysis) substantiates the benefits of (or allows for) direct release for a proposed development located adjacent to a major stream, the detention requirements set in this subchapter may be waived. Other special circumstances when such a waiver may be considered by the county include situations where the design of a regional pond has already taken into account the provision of direct release in certain areas in the watershed.
(Ord. 2017-03, passed 1-24-2017)