This summer, Ohio Governor Mike DeWine and Ohio Environmental Protection Agency (Ohio EPA) Director Anne Vogel announced that a comprehensive study of Ohio’s largest rivers shows tremendous improvements in water quality over the past several decades.
During the 2020 and 2021 field seasons, Ohio EPA conducted a biological census of large rivers across the state. This census was accompanied by observations of water quality, sediment chemistry, and whole-body fish tissue for contaminant analysis. The census used 156 sites spaced at intervals of approximately 8.8 miles, according to the Ohio EPA. The goals of the census were twofold: 1) to obtain a complete picture of the status of Ohio’s large rivers to serve as baseline for future comparisons and to gauge progress in water quality improvements relative to prior surveys; and 2) to identify the major remaining stressors impacting water quality and biological condition.
According to the Ohio EPA, major findings from the census were:
- The biological condition of Ohio’s large rivers has improved dramatically since surveys were first conducted in the 1980s. In the survey, 86% of the miles surveyed met expectations, and were judged to be in good to excellent condition. For comparison, in the 1980s, only 18% of the surveyed miles met expectations. The dramatic reversal is the direct result of investments in improved wastewater infrastructure and treatment, and agricultural soil conservation measures.
- Over-enrichment was identified as the most pervasive stressor impacting water quality, and in some instances, biological condition. The over-enrichment of our large rivers is characterized by excessive levels of phosphorus and nitrogen, and high biological oxygen demand.
- Legacy pollution from coal mining and heavy industry remains detectable in water quality and sediment samples, but causes only modest impact to aquatic life.
- Our large rivers are getting warmer. Water temperatures observed in the Ohio EPA data have increased successively over each decade surveyed. In the 1980s, the average temperature was 20.50 C. The average temperature obtained from the 2020-2021 survey was 23.20 C.
- The Mohican River was the only river to show a significant decline in condition. This decline was due to over-enrichment and sediment. Over-enrichment and warming stream temperatures can both be partially mitigated by improving the physical habitat quality and the riparian buffers of headwaters feeding our large rivers.
“This report not only shows the results of what farmers are currently doing to keep their soils healthy and nutrients in place to protect Ohio’s waterways through H2Ohio, it also highlights the efforts that have been done long before the program was an option,” said Adam Sharp, executive vice president of Ohio Farm Bureau. “This data is proof that progress has been made on the water quality front and that Governor DeWine’s H2Ohio initiative and other conservation programs that give farmers opportunities to find new and better nutrient management practices are, and will continue to make a difference in providing clean water for all Ohioans.”