Ohio EPA Conducting Water Quality Study of St. Joseph, Tiffin Rivers

This summer, Ohio EPA staff is conducting water quality sampling in northwest Ohio’s St. Joseph River and Tiffin River watersheds. Both river systems are part of the larger Maumee River watershed.

The St. Joseph River is located in far northwestern Ohio. Its source is in Hillsdale County, Mich., and it flows southwest through rural portions of Williams and Defiance counties in Ohio before entering Indiana where it joins the St. Marys River in Fort Wayne to form the Maumee River.

The St. Joseph is fed by Fish Creek, Bear Creek, Eagle Creek, Nettle Creek, East Branch and West Branch St. Joseph River. Fish Creek is one of the most ecologically important streams in Ohio due to the presence of federally and state endangered mollusks.

The Tiffin River watershed includes streams in parts of four counties: Defiance, Fulton, Henry and Williams. It is primarily rural but includes drainage from small developed communities including Archbold, Bryan, West Unity and part of Defiance.

The field work is the first step in a federally required study called a Total Maximum Daily Load (TMDL). A TMDL is the maximum amount of pollutants a water body can receive on a daily basis without violating water quality standards.

Ohio EPA staff will collect water samples and fish and macroinvertebrate species from June through mid-October. The physical, biological and chemical data will help determine water quality problems in the rivers and develop options for improving resource quality in degraded areas.

Ohio EPA will share results of the study with communities in the watershed. The Agency relies on community input to develop watershed improvement plans.

Ohio EPA employees carry a photo ID and will request permission from private landowners if access to their property is needed.

Ohio EPA staff began an in-depth study of the Maumee River and its watershed in 2012. The Maumee River system is one of the largest tributaries in the Great Lakes. For more information, contact Ohio EPA’s Public Interest Center at (614) 644-2160 or go to From the link, click on separate tabs for the St. Joseph and Tiffin rivers for details.


The Ohio Environmental Protection Agency was created in 1972 to consolidate efforts to protect and improve air quality, water quality and waste management in Ohio. In the past 40 years, air pollutants dropped by as much as 90 percent; large rivers meeting standards improved from 21 percent to 89 percent; and hundreds of polluting, open dumps were replaced with engineered landfills and an increased emphasis on waste reduction and recycling. Ohio EPA….40 years and moving forward.


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