Clean Water

Ohio River

The Ohio River basin – the area of land that drains into the Ohio River at any point – spans 15 states and supports more than 27 million people, or 10% of the U.S. population, with drinking water, jobs, and recreational opportunities.

Across the 15 states that comprise the Ohio River basin – Alabama, Georgia, Kentucky, Illinois, Indiana, Maryland, Mississippi, New York, North Carolina, Ohio, Pennsylvania, South Carolina, Tennessee, Virginia and West Virginia – there are 69 major tributaries that flow into the Ohio River.

The entire basin consists of more than 47,582 streams, ranging from large rivers, covering 41,000 square miles, to small streams, around 100 square miles.

The Ohio River itself runs through a series of diverse landscapes including forests, agricultural lands, and urban landscapes. Its 204,430 square miles encompasses:

  • tulip poplar-oak, yellow buckeye, and oak-hickory forests
  • forested wetlands
  • a wide range of wildlife, including rare, endangered, and threatened species such as paddlefish and winged mapleleaf freshwater mussels

In fact, the Ohio River basin supports nearly half of the freshwater fishes and over one-third of the mussel species in the United States, including 46 mussel species that are classified as endangered or species of concern.

The basin is a unique ecosystem that provides drinking water and recreational opportunities, and is a place of commerce, supporting such activities as mining, agriculture, manufacturing, and more.


Like many large ecosystems, the Ohio River Basin also threatened by pollution from sedimentation, nutrients, and stormwater, habitat destruction, and invasive aquatic species.

Many acres of land cover have been converted for extraction of energy resources, tilled and fertilized for agriculture, and cleared for new residential and commercial development. Sewage overflows and failing septic tanks plague many cities and towns across the Ohio River basin.


Crops, livestock, poultry, dairy products, orchards, and other agricultural products encompass nearly 35% of the Ohio River basin. The Ohio River Valley Water Sanitation Commission (ORSANCO) has reported nutrient pollution is increasing in the Ohio River basin.

Rivers like the Olentangy River in Ohio and Kanawha River, which flows through North Carolina, West Virginia, and Virginia, contribute a large amount of nutrients flowing into the Ohio River basin. In addition to nutrient pollution from farm field runoff, polluted urban rainwater runoff and sewage overflows have contributed to increased reports of algal blooms across the basin.

In fact, the Ohio River basin consists of more than 10% of the sewage overflow outfalls (raw sewage that falls out of pipes directly into our waterways) within the nation and urban landscapes account for 3% of land use within the basin.

In addition there are a large number of miles of impervious surfaces (surfaces that water cannot penetrate and therefore the ground underneath is not able to clean the water).


Population growth and development, both commercial and residential, have increased over the years and have resulted in the destruction or fragmentation of thousands of acres of quality habitat to the extent that they no longer provide their original function to the basin.

Habitats along the rivers (also called riparian corridors) have been paved over and once-protected wetlands have been turned into storm drainage units or filled in for development. The basin lost approximately 500,000 acres of wetlands between 1992 and 2001, and it is highly likely that even more wetlands have been lost or impacted in the last 8 years.

These landscape changes allow for more polluted rainwater runoff, flooding, and sedimentation. As a result, many of the rivers and streams within the basin have been identified as impaired by the U.S. EPA.


Invasive species are a global, federal, regional, state, and local problem that costs the nation an estimated $137 billion every year in control and clean-up costs.

Currently invasive species present within the basin include zebra mussels, purple loosestrife, kudzu, and several other plant and wildlife species. Purple loosestrife, while having beautiful purple flowers, diminishes waterfowl habitats, alters wetland functions, and chokes out native plants.

Zebra mussels have been documented as exacerbating nutrient pollution and algal blooms, since they filter out the good algae and spit out the bad algae more concentrated.

Asian carp, bighead and silver, also exacerbate toxic algal blooms and currently are a major focus of concern in the Ohio River basin. Anticipated effects of regional climate change are expected to intensify this problem as warming temperatures attract invasive species from even more southern states.

There are solutions to these problems and the OEC is working with our partners to protect and restore this vital Ohio River.