Rivers—Habitat of the Month

Most Americans live within a mile of a river or a stream. It seems reasonable, considering there are more than 250,000 rivers spanning 3.5 million miles in the United States. The “headwaters,” or beginning of a river, can be small—like from a spring or mountain top snow melt—or they can be quite large, as when numerous smaller streams come together. As it travels, river water carves out a channel and carries sediment. When the water finally meets an ocean, lake, or wetland, the water slows down, fans out, drops the sediment it picked up, and creates  a mouth or “delta.”

A river is not just the water channel. Another important component is the land of trees and vegetation next to the channel, known as the riverbank or “riparian zone.” Beyond the riverbank, the low, flat land is called the floodplain. These lands flood periodically during heavy rains and snow melt. Sometimes floodplains stay soggy for a very long time creating rich wetland habitat for a variety of fish and wildlife.

Rivers: Lifelines to the World

Rivers have long been of immense economic, ecological, and cultural value to the people of the United States. Like the blood flowing in our veins, the water flowing in our rivers is essential to our day-to-day lives.

Did you know?

• Sixty percent of Americans get their drinking water from a river.
• Our economy depends on rivers for agricultural irrigation, hydro-electric power, transportation, recreation, and tourism.
• Rivers are home to a wide variety of fish and wildlife that depend on the river, riverbanks and floodplain.
• Freshwater fish, like perch, bluegill, and catfish
• Migratory fish, such as salmon, trout, and striped bass
• Riverbanks contain trees and vegetation that prevent soil erosion and filter polluted run-off.
• Floodplains absorb mass quantities of water that overflow the riverbanks, preventing billions of dollars in damages from downstream flooding.

Threats to Our Rivers

Throughout history, man has set out to harness the power of rivers for our own purposes. We’ve built dams and levees, dredged channels for navigation, constructed cities along banks and used the abundant water supply for crops. These techniques, however, often take a heavy toll on the health of the river.

• Dams block migratory fish from returning to their historic spawning grounds, reduce the amount of water and sediment traveling downstream, and alter the habitat above and below the dam.
• Channelization results in the destruction of adjacent floodplains and wetlands, reducing the land’s ability to absorb flooding water, and excess nutrients and pollutants. Damage to in-water habitat decreases fish populations, and increased water flow makes the soil erode faster.
• Levees may control flooding in one area, but it’s always at the sacrifice of another area. They also disconnect the river from its adjacent floodplain and wetlands, causing extensive damage to habitat.
• Agricultural runoff containing fertilizers, herbicides, and pesticides has multiple negative impacts on water quality and habitat.
• Urban development often results in the destruction of habitat and an increase in impervious surfaces such as roadways, parking lots, and roofs which send polluted storm water runoff into rivers.

NOAA: Conserving Rivers and Protecting You and Your Property

NOAA Fisheries works to protect and restore river habitat through a wide variety of programs and partnerships. We remove barriers to fish passage and restore and protect habitat to ensure healthy and abundant fish populations.

Among the programs we have launched is a partnership that will focus on conserving North Carolina’s Cape Fear River. The Cape Fear River Partnership is a group of federal, state, local, and NGO partners who are currently developing a watershed action plan to improve the Cape Fear for migratory fish and you.

In an effort to make the US a weather ready nation, NOAA’s National Weather Service monitors thousands of river gauges nationwide, providing timely flood forecasts and warnings for the protection of life and property.

• The ecosystem services associated with the corals reefs of Guam are likely to be impacted as a result of the planned relocation of approximately 8,600 Marines, dependents, and support personnel from military bases in Okinawa to Guam. This move will also require the construction of support facilities and a new deep-draft wharf for ships. NOAA has been engaged in consultations with the Navy and other federal partners to identify ways to reduce the impacts to coral habitat due to dredging and wharf construction. Ecosystem services concepts, including the use of Habitat Equivalency Analysis, will be used to help guide this process.