Oregon, OH Environmental Rules: Stormwater Management (2026)

06, part of the subdivision improvement standards, sets the city's storm sewer design and stormwater management requirements. Storm sewers must flow just full at a five-year intensity-duration-frequency storm, with minimum pavement gutter elevations set to the ten-year hydraulic grade line, calculated using the Rational Method and, where a system outlets to a stream or ditch, referenced to the twenty-year high-water elevation in the city's Comprehensive Ditch Plan. Under subsection (c), any site development involving one acre or more of property must include on-site storm water detention or retention consistent with the city's current Storm Water Management Plan (SWMP): the minimum detention volume is the storage produced by a twenty-five-year post-developed storm inflow, with discharge limited to the five-year pre-developed storm outflow, and the detention calculations must be submitted with the site grading plans for approval by the Director of Public Service.

Subsection (d) requires every storm water collection system to include treatment for sediment removal using the best management practices listed in the current SWMP, with construction and maintenance conforming to Ohio EPA Permit No. OHC000002 (or its current renewal) and shown on the site's Erosion Control Plan. Developers and property owners must maintain any post-construction structural BMP, and the Department of Public Service inventories and inspects them.