Correction: An earlier version of this story misspelled Mike Ekberg’s last name.

DAYTON, Ohio (WDTN) — The Ohio Environmental Protection Agency released a study from 2020 and 2021 detailing the improvement of water quality since the 1980s, including the Great Miami River.

Mike Ekberg, manager of water monitoring and data analysis at the Miami Conservancy District, said, “You know, we place a real premium on protecting the quality of water here. Working with communities to keep high quality drinking water sources.”

The report that came out studied large rivers in Ohio, looking at the health of fish and macroinvertebrates in rivers compared to the benchmark.

The major finding in the study was that 86% of the 1,372 miles of river meet acceptable standards by the Clean Water Act and the state. Compare that to the 1980s, where 14% of the same miles met those standards. The improvement can be tied to the increase of technology and science.

Anne Vogel, Ohio EPA Director, said, “Improvements to our wastewater infrastructure. Everything to do with not dumping raw sewage in rivers into our waterways. So, we’ve seen our communities come a long way in terms of how we are treating wastewater.”

In the Great Miami River, there are stretches that do not meet those standards.

Ekberg said, “Things like nitrogen and phosphorus in our waters that that study kind of showed that those levels are still too high. And so we’re trying to work with local organizations to get those levels down to where they need to be.”

But how does excess nitrogen and phosphorus get into the waterways?

Vogel said, “So there are too many nutrients in certain river miles and certain stretches of our rivers, and it’s coming directly off of the fields.”

She added, “We rely on our partners in the agricultural community to try to keep that nitrogen and phosphorus, particularly on their farm field. And so that’s what we’ve been doing with H2Ohio agricultural practices and with wetlands.”

Another finding is that the temperature of these rivers are around 4 degrees Fahrenheit warmer than in the 1980s, and according to the EPA, warmer temperatures accelerate natural chemical reactions and release excess nutrients.

Temperatures can partially be relieved by improving the physical habitat quality and the riparian buffers of headwaters feeding into large rivers.