(A) Minimum control requirements.
(1) All stormwater best management practices (BMPs) shall be designed in a manner to minimize the need for maintenance, and reduce the chances of failure. In addition, all stormwater management facilities shall be designed so that the specific storm frequency storage volumes (e.g., recharge, water quality, channel protection, 10 year, 100 year), as requested by the Village, are met. The only exception would be if the Village grants the applicant a waiver or the applicant is exempt from such requirements.
(2) If hydrologic or topographic conditions warrant greater control than that provided by the minimum control requirements, the Village reserves the right to impose any and all additional requirements deemed necessary to control the volume, timing, and rate of runoff.
(B) Site design feasibility.
(1) Stormwater management practices for a site shall be chosen based on the physical conditions of the site. Among the factors that should be considered:
(a) Topography;
(b) Maximum drainage area;
(c) Depth to water table;
(d) Soils;
(e) Slopes ;
(f) Terrain;
(g) Head; or
(h) Location in relation to environmentally sensitive features or ultra-urban areas.
(2) Applicants shall consult the most recent version of the Rainwater and Land Development Manual from the Ohio Department of Natural Resources for guidance on the factors that determine site design feasibility when selecting a stormwater management practice.
(C) Conveyance issues.
(1) All stormwater management practices shall be designed to convey stormwater to allow for the maximum removal of pollutants and reduction in flow velocities. This shall include, but not be limited to:
(a) Maximizing of flowpaths from inflow points to outflow points;
(b) Protection of inlet and outfall structures;
(c) Elimination of erosive flow velocities; or
(d) Providing of underdrain systems, where applicable.
(2) The Erosion and Sediment Control Plan, required by the Village’s Erosion and Sediment Control/Grading Ordinance, shall provide detailed information on the requirements for conveyance for each of the approved stormwater management practices.
(D) Pretreatment requirements. Every stormwater treatment facility shall have an acceptable form of water quality pretreatment, in accordance with the practices listed in the most recent version of the Rainwater and Land Development Manual from the Ohio Department of Natural Resources. Certain stormwater treatment practices are prohibited even with pretreatment in the following circumstances:
(1) Stormwater is generated from highly contaminated source areas known as "hotspots";
(2) Stormwater is carried in a conveyance system that also carries contaminated, non-stormwater discharges;
(3) Stormwater is being managed in a designated groundwater recharge area; and
(4) Certain geologic conditions exist (e.g., karst) that prohibit the proper pretreatment of stormwater.
(E) Non-structural stormwater practices. The use of non-structural stormwater treatment practices is encouraged in order to minimize the reliance on structural practices. Credit in the form of reductions in the amount of stormwater that must be managed can be earned through the use of non-structural practices that reduce the generation of stormwater from the site. Applicants wishing to obtain credit for use of non-structural practices must ensure that these practices are documented and remain unaltered by subsequent property owners.
(Ord. O-1974-04, passed 2-23-04)