Ottawa River Watershed (Toledo area) and River Raisin Watershed

Ottawa River (Toledo area) and River Raisin watershedsThe Ottawa River watershed is located in northwestern Ohio along the Michigan-Ohio border. The River Raisin is a river in Michigan, a small portion of which drains in Ohio immediately west of the Ottawa River. Together the watersheds drain a total of 173 square miles in Ohio and flow through two counties. Major municipalities partially or fully in the watershed include Toledo, Sylvania, Berkey, Lyons and Metamora.

The western portion of the watershed is primarily cultivated crop land. The eastern portion of the watershed is almost entirely urban development. A portion of the unique Oak Openings region is located near the south-central edge of the watershed.





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Tenmile Creek is located in northwest Ohio.  Portions of the watershed were studied in 2011.  Tenmile Creek flows into the Ottawa River at Sylvania in Lucas County.  The Tenmile Creek watershed is divided into two subwatersheds, as follows:

  • 04100001 03        Ottawa River-Frontal Lake Erie
  • 04100002 03        Little River Raisin-River Raisin

TMDL Report

The TMDL report is in preparation.

Supplemental Information


The following implementation projects have been completed in the watershed.

  • In February 2012, a news release announced that a do not eat advisory in place since 1991 was changed to one meal per week advisories for all species of fish upstream of Secor Road at University of Toledo, and upstream of Auburn Avenue for all species other than common carp, which has a one meal per month advisory from Main Street in Sylvania to Secor Road at the University of Toledo.

    The do not eat advisory remains in place from Auburn Avenue to the mouth of the Ottawa at Lake Erie because of PCB contamination.  Ohio EPA and U.S. EPA conducted remedial dredging in 2010 to address remaining PCB contamination and plan to evaluate the effectiveness of the project in reducing PCB concentrations in fish tissue during the 2014 season.