Olentangy River Watershed - General Permits


Draining 543 miles of Central Ohio landscapes, the Olentangy River watershed provides drinking water, recreation, agricultural drainage and other public goods for over 250,000 watershed residents. Its waters and habitats are home to unique and diverse communities of fish, mussels and other aquatic life. Recent studies document declines in its water quality and stream habitat. Among the most visible and widely publicized threats to the Olentangy’s water quality and habitats is the conversion of farm and forest acreage to residential and commercial land uses at an exceptionally rapid pace. 

The river system drains Ohio’s first and sixth most rapidly populating counties - Delaware and Morrow, respectively. Delaware County’s most rapidly developing townships - Delaware, Liberty and Orange - overlap the river’s State Scenic River section. Areas of the Whetstone Creek subwatershed, located within Morrow County, are designated as Exceptional Warmwater Habitat (EWH) with two tributaries being designated as Coldwater Habitat (CWH). Approximately two miles of the Olentangy River is designated as EWH within Franklin County. This area is currently receiving the greatest pressure for development within Franklin County’s portion of the watershed.

As a result, Ohio EPA has developed an alternative general permit for storm water associated with construction activity specific for portions of the Olentangy River watershed. This alternative permit implements many of the basic recommendations regarding the programs, activities and Best Management Practices developed through the Total Maximum Daily Load process. Ohio EPA believes implementation of these recommendations is necessary to protect the unique water quality and biological integrity of the Olentangy River watershed.

Ohio EPA currently has three NPDES construction storm water general permits (CGPs):

  • Statewide CGP
  • Big Darby Creek Watershed CGP
  • Portions of Olentangy River Watershed CGP

Ohio EPA is proposing to combine all three general permits into one with the Statewide CGP renewal (OHC000005).  Draft OHC000005 incorporates the Big Darby Creek watershed CGP and Portions of the Olentangy River watershed CGP requirements as appendices.  These two watersheds’ current conditions, that exceed the statewide CGP, have been included as appendices.  Please go here for more information.