Solutions Journalism Series
This story is Part I of a two-part Solutions Journalism series about the Mohican River’s water quality and how local agencies are addressing the issue. Part II will be published on April 3.
The Mohican River was designated an Ohio scenic river in 2006.
The Ohio Department of Natural Resources only awards the title to rivers and streams with “pristine water quality, undeveloped riparian habitat and historic or outdoor recreation values that should be preserved.”
The Mohican River is one small part of the roughly 1,000 square-mile Mohican River Watershed that covers Ashland, Crawford, Knox, Morrow, Richland and Wayne counties.
But an Ohio Environmental Protection Agency survey of Ohio’s 29 major rivers published in 2024 found the Mohican River was the only river to show a significant decline in condition.
The report noted the decline was a result of over-enrichment and sediment, which caused a decrease in the abundance and species of fish present in the river — making the Mohican the only river to score negatively for its biological health.
High sediment levels means dirt and sand particles are clouding the water, sometimes blocking sunlight and carrying in nutrients.
Over-enrichment means too many nutrients, such as nitrogen and phosphorous, are present in the water, which can deplete oxygen levels and at high amounts, cause harmful algal blooms.
Nutrients enter waterways through:
- Agricultural practices: chemical fertilizers contain high concentrations of nutrients and when it rains, the fertilizers can run off the farms into streams and storm water drains. Livestock manure is also nutrient-rich, and animals often freely roam through or near on-property streams.
- Stormwater runoff: When it rains, the water picks up dirt and other particles with it off the pavements, which can contain nutrients.
- Failing septic systems: Old or broken septic systems cannot operate properly, discharging sewage into groundwater or streams, bringing those nutrients with it.
Streams flowing into Mohican River bring poor water quality
The Mohican River’s water quality did not suddenly degrade overnight: the decline represents a culmination of sediments flowing into the river from upstream water sources.
The OEPA report only examined the main stem of the Mohican River. Other reports have monitored other watersheds and sub watersheds located within the Mohican River Watershed have reflected similar trends.
Jerome Fork
Earlier this fall, the Ashland Soil and Water Conservation District graded Jerome Fork —one of the eight sub water basins contained within the Mohican Watershed — and 11 of its subwatershed streams an “F” on the watershed report card due to high levels of coliform and surfactants.
Surfactants are a diverse group of chemicals widely used in detergents and cleaning products that can be present in gray water (any domestic wastewater that did not come from the toilet, like bathing or laundry water).
“In simple terms, [coliform is] any type of runoff from sewer systems or manure runoff from fields. If you have a failing septic system, there is always going to be coliform present in the streams,” ASWCD water quality specialist Zoey Dudte said.
Dudte said the sample reveals poor management of residential septic systems and improper fertilizer and manure distribution on farmlands.
Clear Fork and Black Fork
Civil & Environmental Consultants, Inc.’s of Toledo prepared plans to improve water quality at the headwaters of Clear Fork Mohican River and the village of Pavonia’s stretch of the Black Fork Mohican River last year.
Those plans, called Nine-Element Nonpoint Source-Implementation Strategies, help examine existing water quality studies from state agencies to outline critical areas and develop plans to address them.
Environmental restoration can be expensive. But approved NPS-IS plans are eligible for Ohio Environmental Protection Agency funding.
The Black Fork NPS-IS plan revealed the sub watershed also faced nutrient enrichment and habitat alteration, but the report was largely based on water samples from 2007.
“It is likely that nutrient loss from the watershed above the Clear Fork Reservoir is causing eutrophication in the lake, contributing to excessive algae growth and formation of harmful algal blooms,” the report noted.
Eutrophication means over-enrichment of nutrients.
Poor water quality’s impact seen downstream
The most notable and widely proven source of pollution in the entire watershed is excessive amounts of phosphorus and nitrogen.
Those excess nutrients will eventually travel from the Mohican River to the Muskingum River to the Ohio River to the Mississippi River, which discharges into the Gulf of Mexico.
The Gulf of Mexico faces an annual dead zone that suffocates marine life. That dead zone is partially fueled by nutrients that enter Ohio waterways and fuel the growth of a harmful algal bloom (HAB) in the gulf.
The algal bloom depletes the gulf of oxygen and causes animals, like fish and shrimp, to leave the area, disrupting the entire food chain and habitat use, according to NOAA.
But HABs don’t just happen 900 miles south. They also happen in Ohio water sources, including the Ohio River, where a 2015 bloom spanned over 700 miles of the 981-mile-long river.
The Environmental Protection Agency described that bloom as unprecedented because blooms have historically only occurred in slow or unmoving water, as seen in the Great Lakes, rather than fast-moving waterways.
In the aftermath, water treatment plants and local officials scrambled to ensure clean drinking water. Scientists assembled to clean the bloom up and understand how it happened.
The Ohio River saw HABs again in 2019 and 2024. With the right conditions, any river could face the same issue.
“Water quality rehabilitation has been a pretty high priority around the state for the last few years. We have a lot of water quality issues around Ohio,” Richland County Park District Executive Director Jordan Tackett said.
That’s why he, and other local agencies, are using H2Ohio funds to improve water quality in the Mohican River watershed, and every water source downstream of it.
