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CITIZEN CONTACT: Kristopher Weiss

Study of Rocky River Tributaries Released

Public Comment Period Open through August 21, 2020  

Ohio EPA today released a study examining water and sediment chemistry, habitat, fish, and other aquatic life from 28 named and unnamed rivers and streams that flow into the Rocky River in northeast Ohio. These small streams drain approximately 294 square miles in portions of Cuyahoga, Lorain, Medina, and Summit counties. 

The study shows that most small Rocky River tributaries have healthy fish and macroinvertebrate populations. Overall, water quality in the smaller streams has improved significantly compared to results from previous studies.

Of the 119.6 stream miles assessed, 79 percent (94 of 119) of the stream locations sampled were found to fully support existing and recommended aquatic life uses. 

Lower concentrations of mercury in fish caught throughout the study area have led to a fish consumption advisory recommendation of eating no more than one meal per week for most species and most fishable waters within the Rocky River basin. The exceptions were limited to smallmouth bass taken from the West Branch Rocky River and rockbass taken from the East and West Branches. The smallmouth bass showed elevated mercury concentrations in the past, and the existing advisory of one meal per month is recommended. In contrast, the rockbass had falling levels of mercury and now receives a recommendation of one meal per week (the general statewide advisory), replacing the previous, more stringent advisory of one meal per month.

The study also found many streams not meeting the human recreation-based water quality standard for E. coli bacteria. Bacterial contamination was present during both wet and dry weather events, indicating active nonpoint sources and permitted point sources. These sources include combined sewer overflows, sanitary sewer overflows, urban storm water, treated wastewater discharges, and failing home sewage treatment systems.

The study also found 10 streams or segments of the 28 water bodies evaluated are not meeting attainment for aquatic life uses. The leading cause and source of this impairment were  modification to the waterway and storm water from urban and suburban landscapes. Habitat alterations were the next leading cause of impairment.

The biological and water quality study is designed to assess the effects of various land uses, evaluate the influences of agricultural, industrial and commercial discharges and spills, and assess the performance of permitted wastewater treatment plants. The study also evaluates the quality of fish and macroinvertebrate communities in the streams, compares results with historic conditions and determines if streams are meeting designated aquatic life and human recreation uses.

Further details about the study, data and maps are contained in the report. The study is the second step in Ohio EPA’s five-step Total Maximum Daily Load process. Subscribe here for updates on this and other Ohio EPA Total Maximum Daily Load projects. 

Findings in the report, along with public comments received, will be developed into a Total Maximum Daily Load report, which is a plan to improve water quality in the watershed through potential permit limits on regulated dischargers and/or nonpoint source runoff reduction projects, whichever may be necessary to address water quality impairment at any given location. Ohio EPA works with local communities and watershed groups to implement projects and strategies to achieve water quality goals. 

To comment on the study, email EPATMDL@epa.ohio.gov or write to: TMDL Program, Ohio EPA Division of Surface Water, P.O. Box 1049, Columbus, OH 43216-1049. Comments are due by 5 p.m. August 21, 2020.


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. Since then, 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.

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