River Habitat

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Rivers: Lifelines to the World

Roughly 3.5 million miles of rivers and tributaries in the United States connect us to the sea, even if we live far inland. Most Americans live within a mile of a river or a stream. Rivers provide our communities with economic, ecological, and cultural value.

River habitats vary from high, stony streams, to flowing channels for ships and boats, to shallow wetland deltas. Rivers have striking regional differences that create distinct habitats. Compare the rapid, rocky Colorado to South Carolina’s sleepy, green Santee, or the forested, winding Ohio. A river bed may be stony or soft, lush with underwater vegetation, murky or clear. Each type of river provides an ideal environment for different species and different life stages.

Rivers have three distinct habitat areas:

• River beds, or the water channel itself.
• River banks, called the “riparian zone.” These include the land, trees, and water-loving animals and plants along the channel.
• Floodplains, or the low, flat land spreading out from the channel. This area periodically floods during heavy rains and snow melt. Sometimes floodplains stay soggy for a long time, creating rich wetland habitat.

Benefits of Rivers

Rivers provide important benefits—called ecosystem services—that impact our day-to-day lives. They provide drinking water, irrigation, transportation, and more. They also provide habitat for important fish species.

Community Benefits

Communities depends on rivers and streams for:

• Food—irrigating crops.
• Clean water—60 percent of our drinking water comes from American rivers.
• Electricity—generating hydro-electric power.
• Transportation—bringing grain, coal, ore, and imports to market.
• Recreation and tourism—providing a significant economic boost to waterfront areas.
• Flood protection—when waters rise, floodplains can absorb large amounts of water. This provides natural flood control for coastal communities, preventing billions of dollars in damages.

Sustainable Fisheries

Rivers are home to abundant fish and wildlife, including:

• Freshwater fish like bass, perch, bluegill, and catfish
• Migratory fish such as alewife, salmon, trout, and striped bass
• Invertebrates that provide food for fish
• Protected, endangered, and threatened species

Different areas of rivers provide habitat for different types of species. Trout thrive in highland streams, while catfish lurk near the bottom of slow-moving water. Migrating fish, like salmon, swim up to cooler, stony beds to reproduce. Floodplains provide calm shallow waters, allowing fish to grow larger before swimming out to sea. 

Even the smallest fish play an important role in the ecosystem. “Forage fish” like river herring swim upstream to multiply. They then head out to sea, providing food for important recreational and commercial species, such as cod, haddock, and striped bass.

Challenges for Rivers

People have harnessed the power of rivers throughout history. We’ve built dams for power and levees for shipping, dredged channels for navigation and canals for irrigation. We’ve built towns and cities along banks and washed their wastes downstream. These uses can all take a toll on a river’s health.

Dams and Other Barriers

Dams, culverts, and other barriers block migratory fish from returning to their historic spawning grounds. When fish can’t reach their habitat, they can’t reproduce and maintain or grow their populations. Dams also alter the amount of water and sediment traveling downstream, changing living conditions above and below the dam.

Structures like levees can control flooding in one area, but may increase flood risk in another. Disconnecting rivers from their floodplains increases the risk of extreme flooding and landslides.

Habitat Loss

Human activities can degrade or destroy important river and floodplain habitat. For example:

• Hard shorelines increase water velocity, hastening erosion and negatively affecting fish populations.
• Digging channels or straightening rivers destroys nearby floodplains and wetlands, and can lead to flooding.
• Riverside development can reduce shade, which can lead to warmer waters that threaten many species. Paved surfaces also increase polluted runoff from roadways, parking lots, and roofs.
• Overused rivers can run dry long before they reach the sea, destroying important habitat.

Polluted Runoff

Outdated farming methods can cause fertilizers, herbicides, and pesticides to contaminate rivers and streams. Excess nutrients and toxic chemicals can then concentrate in waterways, causing algal blooms and “dead zones” where underwater life is unable to survive.

Combined stormwater and sewage systems can overflow and pour untreated human waste into rivers. These overflows create disease risk and add nutrient pollution. The resulting algae overgrowth can be toxic to fish and people.

What We Do

NOAA works to protect and restore river habitats through a wide variety of programs and partnerships. We provide scientific expertise to community, state, and partner organizations that monitor water and wildlife. We also provide technical assistance and fund projects that restore healthy habitat. Our process builds community support and attracts multiple sources of funding to ensure ongoing commitment to healthy habitats.

We Protect Habitat

NOAA monitors and studies rivers nationwide to protect vital habitat for a variety of species, including people. Our work includes:

• Monitoring thousands of river gauges nationwide to make the United States a weather-ready nation. These devices provide flood forecasts and warnings that protect life and property.
• Collecting pre- and post-restoration data on water quality, fish populations and migration, water levels, and more.
• Coordinating with volunteer stream monitors who record data and watch for significant changes.
• Providing data, including aerial surveys, temperature, nutrient levels, instream flow, and more.
• Developing publications and programs for communities to learn about habitat health.

We Restore Habitat

The Office of Habitat Conservation’s NOAA Restoration Center provides funding and technical assistance to habitat restoration projects across the country, including in and near rivers and streams. 

Where river habitat has been disrupted by human activity, we work to repair damage and prevent further harm by:

• Removing dams and other barriers to fish migration. This work restores natural conditions to help fish survive and reproduce.
• Restoring riverbanks and floodplains. This reduces erosion and buffers extreme flooding while creating seasonal habitat for wetland creatures.
• Reconnecting wetlands and estuaries. This restores water movement, improves filtration, and provides shelter and food for young fish.

We Partner to Support River Habitat

We build consensus, broaden our impact, and leverage our efforts by working with non-profit, academic, corporate, and government partners at every level. This work includes:

• Working with other federal agencies, industry, states, non-governmental organizations, and Tribes through the NOAA Hydropower Program to identify and implement solutions to reopen rivers to migratory fish while preserving hydropower generation. 
• Collaborating with the U.S. Environmental Protection Agency, U.S. Fish and Wildlife Service, and state and local organizations to remediate and restore rivers damaged by hazardous waste or oil contamination.
• Providing funding to launch restoration projects that engage multiple partners.
• Sharing knowledge, expertise, and advice for best practices.
• Conducting research that enhances scientific understanding and provides data to universities, NGOs, and the public.
• Offering job skills training and jobs for veterans through conservation corps.

What You Can Do

• Know where your water comes from. Learn about your watershed and how well your water is protected. Support your local watershed organization and join in river cleanup days.
• Reduce polluted runoff. Disconnect downspouts from sewer systems, install rain barrels, and plant rain gardens. Permeable pavers, gravel beds, and green roofs also reduce runoff.
• Practice smart lawn care. Only apply fertilizer if necessary, use a mulching mower, mow less often, and water more deeply. In dry climates, forget the lawn and create a desert garden with native plants, rocks, and stones.
• Dispose of non-biodegradable products properly. Don’t pour them down toilets or drains.
• Volunteer. Serve as a stream monitor for a local watershed organization to collect data and contribute to smart water management.
• Launch a restoration project in your community. Resources like the Coastal Restoration Toolkit can help you find tools and information for starting a habitat restoration project in your area.

Case Study: Eel River Restoration

Demolition begins on the Benbow Dam in California. Credit: NOAA Fisheries.

The Eel River watershed was once the third largest producer of salmon and steelhead in California. Salmon numbers have declined alarmingly since the 1950s. As the longest salmon run in the state, the Eel is a high priority for successfully rebuilding salmon stocks. Coho, Chinook salmon, and steelhead are all listed on the Endangered Species List.

The NOAA Restoration Center has taken a watershed approach to restoring the Eel River. To do so, we partnered with Humboldt County Resource Conservation District, Ducks Unlimited, California Department of Fish and Wildlife, the California Conservation Corps, the Eel River Watershed Improvement Group, Mendocino Redwood Company, Pacific Watershed Associates, and other regional and local groups.

Together, we have:

• Restored 400 acres of estuary habitat. The Salt River Ecosystem Restoration project restored 7 miles of river channel and more than 380 acres of salt marsh. Native vegetation was also planted along the stream. The project significantly reduced flooding in Ferndale, California, and provided essential rearing habitat for salmon and steelhead.
• Removed the Benbow Dam. In 2016, NOAA and California State Parks removed the Benbow Dam, improving access to over 98 miles of high-quality habitat. California’s second largest dam removal improved public safety and liability for the state.
• Improved spawning and rearing habitat. In several major tributaries of the Eel River headwaters, sediment sources have been addressed by decommissioning dirt roads that are no longer needed. In-stream habitat has been improved by strategically placing large wood in the channel to improve pool habitat, cover, and gravel sorting.

As a result of these efforts, NOAA has documented increased numbers of juvenile salmon and steelhead trout using the estuary. This improves their survival in the ocean, helping ensure that they grow up and return to their spawning habitat. We will continue to focus on additional high-priority actions that improve habitat in the Eel River and support a healthy population of wild fish.

Case Study: Santee River Basin Watershed Planning

Santee Dam on the Santee River in South Carolina. Credit: South Carolina Department of Natural Resources.

The Santee River Basin, in North and South Carolina, supports some of the largest populations of migratory fishes on the East Coast of the United States. However, population levels remain depleted compared to historical levels. Several fish species in the southeastern U.S.—including endangered sturgeon, eels, and river herring—face threats including barriers to migration, poor water quality, habitat loss, and competition from invasive species.

Through the NOAA Hydropower Program, NOAA helps make previously-blocked upstream habitat accessible to fish, allowing them to breed and complete their life cycles. These efforts aid in the recovery of threatened and endangered species and contribute to the sustainability of economically important commercial and recreational fisheries.

To address the threats facing fish species in the Santee River Basin, NOAA worked with the U.S. Fish and Wildlife Service and resource agencies in the states of North Carolina and South Carolina to develop the Santee Basin Restoration Plan.

This plan takes a unique approach toward restoring migratory fish by planning for the entire watershed rather than addressing one project at a time. A basin or watershed plan offers an opportunity for management agencies to coordinate restoration activities, balance competing needs in the watershed, and maximize funding for mutual restoration priorities. The Santee Basin Plan provides several objectives to improve fish habitats including: improving water quality, increasing river flows, providing fish passage, and enhancing monitoring.

More Information

• Reopening Rivers for Migratory Fish
• Barriers to Fish Migration
• Improving Fish Migration at Hydropower Dams