The structural and nonstructural stormwater management measures established in this chapter shall be used, either alone or in a combination, in developing a stormwater management plan.
(A) Nonstructural stormwater management measures.
(1) The following nonstructural stormwater management practices shall be applied according to the Design Manual to minimize increases in new development runoff:
(a) Natural area conservation;
(b) Disconnection of rooftop runoff;
(c) Disconnection of non-rooftop runoff;
(d) Sheet flow to buffers;
(e) Grass channels; and
(f) Environmentally sensitive development.
(2) The use of nonstructural stormwater management practices shall be encouraged to minimize the reliance on structural BMPs.
(3) The minimum control requirements listed in § 53.030 of this chapter may be reduced when nonstructural stormwater management practices are incorporated into site designs according to the Design Manual.
(4) The use of nonstructural stormwater management practices may not conflict with existing state or local laws, ordinances or policies.
(5) Nonstructural stormwater management practices used to reduce the minimum control requirements must be recorded and remain unaltered by subsequent property owners. Prior approval from the Town Planning and Zoning Commission, its agent(s) or the Town Engineer shall be obtained before nonstructural stormwater practices are altered.
(B) Structural stormwater management measures.
(1) The following structural stormwater management practices shall be designed according to the Design Manual to satisfy the applicable minimum control requirements established in § 53.030 of this chapter:
(a) Stormwater ponds;
(b) Stormwater wetlands;
(c) Stormwater infiltration practices;
(d) Stormwater filtering practices; and
(e) Water quality swales and grass drainage channels.
(2) The performance criteria specified in the Design Manual with regard to general feasibility, conveyance, pretreatment, treatment and geometry, environment and landscaping and maintenance shall be considered when selecting structural stormwater management practices.
(3) Structural stormwater management practices shall be selected to accommodate the unique hydrologic or geologic regions of the state.
(C) Alternative structural and nonstructural stormwater management practices. Alternative structural and nonstructural stormwater management practices may be used for new development water quality control if they meet the performance criteria established in the Design Manual. Practices used for redevelopment projects shall be approved by the Town Planning and Zoning Commission, its agent(s) or the Town Engineer.
(D) Modifying minimum control requirements. For the purposes of modifying the minimum control requirements or design criteria, the owner/developer shall submit at the request of the Town Planning and Zoning Commission, its agent(s) or the Town Engineer an analysis of the impacts of stormwater flows downstream in the watershed. The analysis shall include hydrologic and hydraulic calculations necessary to determine the impact of hydrograph timing modifications of the proposed development upon a dam, highway, structure or natural point of restricted stream flow. The point of investigation is to be established with the concurrence of the Town Planning and Zoning Commission, its agent(s) or the Town Engineer.
(Ord. passed 7-14-2008)