The Olentangy River Watershed TMDL

Background

The Olentangy River Total Maximum Daily Load (TMDL) report was approved by U.S. EPA on September 19, 2007. The report is the twenty-seventh Ohio TMDL project approved by U.S. EPA under Section 303(d) of the Clean Water Act. TMDL reports identify and evaluate water quality problems in impaired water bodies and propose solutions to bring those waters into attainment with water quality standards.

The Olentangy River is located in Central Ohio in Crawford, Richland, Delaware, Franklin, Marion and Morrow Counties. The Olentangy River is approximately 93 miles long and flows from the east side of Galion; west then south through agricultural land surrounding Caledonia; past the Villages of Claridon and Waldo before entering Delaware Lake. Downstream from Delaware Lake the mainstem flows through the City of Delaware and areas of suburban development before reaching the City of Columbus. The mainstem joins the Scioto River in downtown Columbus.

Ohio EPA conducted a comprehensive physical, chemical and biological survey of the Olentangy River watershed in 2003 and 2004, and several problems were identified. The survey results were published in December 2005 (see below). The primary causes of impairment are siltation, nutrient enrichment, habitat alteration, flow alteration, and contamination by pathogens. TMDLs were calculated for total suspended solids, total phosphorus, fecal coliform, and habitat via the Qualitative Habitat Evaluation Index. Recommendations include use of agricultural conservation practices for upland areas and progressive channel maintenance, addressing failing home sewerage treatment systems, better waste treatment for point sources, and a higher level of storm water management in urban and developing areas.

The TMDL Report

• TMDL Report [PDF 765K]
  • Appendix A: Supplemental Maps [PDF 2,961K]
  • Appendix B: Supplemental Tables and Figures [PDF 116K]
  • Appendix C: Use Attainment Status [PDF 38K]
  • Appendix D: Response to Public Comments [PDF 56K] 

Many of the documents referenced in the TMDL report can be found under Forms and Publications on the Ohio EPA Division of Surface Water Web page.

Supplemental information

The following documents provide background information on the Olentangy River watershed.

• Fact Sheet. Olentangy River Watershed TMDL Report [PDF 408K]
• Biological and Water Quality Study of the Olentangy River, Whetstone Creek and Select Tributaries, 2003-2004. Crawford, Delaware, Franklin, Marion and Morrow Counties, Ohio.
  • Report [PDF 8,780K]
  • Appendices [PDF 798K]
• Olentangy River Watershed: Total Maximum Daily Load Study. The Ohio State University. March 2006. [PDF 6,278K]

Groups Active in the Watershed

• Friends of the Lower Olentangy Watershed
• Olentangy Watershed Alliance

For more information contact:

Vince Mazeika
Ohio EPA
Central District Office
50 West Town Street, Suite 700
P.O. Box 1049
Columbus, Ohio 43216-1049
e-mail: vince.mazeika@epa.state.oh.us
telephone: (614) 728-3855

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