World Wildlife Fund

The U.S. Southeast Rivers and Streams region is in one of the most highly populated areas in the United States. And as more people move to the area there is increased pressure on freshwater resources. Runoff, water supply issues, suburban sprawl, unchecked road construction, unsustainable agricultural and forestry practices, dams, mining, and pollution threaten this rich ecoregion and the aquatic life that lives beneath its waters.

H. Neely Henry Dam - Coosa River, Alabama
© photo: WWF-Canon / Kevin SCHAFER

Dams
There are over 4,000 major dams in the Tennessee/Cumberland and Mobile Basins managed for power production, flood control and transportation. Dams affect aquatic biodiversity by turning river habitats into reservoirs. This results in changes to water level, oxygen availability, and decreased numbers and kinds of aquatic species. This also decreases the genetic diversity of species by separating one breeding population from another.

Runoff
Water pollution from soil runoff - known as siltation - is perhaps the most significant threat to freshwater. Siltation clogs fish gills, smothers eggs, destroys aquatic habitat and generally makes a river or stream an unfriendly, unhealthy place to fish, swim or play. In addition, toxins such as pesticides and fertilizers attach themselves to soil particles that ultimately wash into rivers and streams, as does runoff from streets, roofs and parking lots.

Development
Construction and road building threaten aquatic life in a variety of ways including increased run-off, lack of watershed planning and a general increase in paved surfaces. When construction and road building sites fail to use best management practices - such as retention ponds, silt fences and hay bales - the runoff after a rainstorm can be devastating to nearby rivers and streams. As suburban development spreads to accommodate human population growth, boundaries become less clearly defined because water moves from one place to another. 

Paving for new buildings and parking lots disrupts the water balance. Rain, no longer absorbed into the ground and surrounding vegetation, runs off these surfaces and increases the frequency of flooding. These waters can also carry oil, gasoline and other chemicals that affect water quality and aquatic life.

Aquaculture
Aquaculture, the farming of marine and freshwater species, provides nearly 50 percent of the seafood produced each year. As the industry grows, so do its negative impacts, such as waste products, the conversion of mangroves to fish farms, and the use of wild-caught fish as food for farmed fish.

Agriculture
Whether it is cows in the creek, Confined Animal Feeding Operations (CAFOs) or the practice of plowing to the edge of rivers and streams, unsustainable agricultural practices can threaten aquatic life. Farming without proper buffer zones between farm fields and rivers and streams results in runoff often carrying fertilizer and pesticides. Allowing cattle access to streams increases sedimentation and e-coli counts from animal waste.

Forestry
For the past several years, the Tennessee/Cumberland and Mobile basins have seen an alarming increase in large clear-cutting operations and chip mills. The Southeast now has over 140 of these facilities. Removing trees and other vegetation from the banks of rivers and streams increases water temperatures and lowers dissolved oxygen levels, which makes breathing difficult for aquatic species. If buffer zones are not used, runoff can also pollute waterways with silt.

Mining
Both the Tennessee/Cumberland and Mobile Basin contain numerous mines, both active and abandoned. The mining resources found in the region include coal, limestone, phosphate and stream rocks used for landscaping. Poor mining practices impact the region’s aquatic resources by changing the water’s pH levels, making it too acidic for aquatic life. Removing rocks from streambeds also disrupts habitats for fish, crayfish and aquatic insects.

Point sources of pollution
Although sewage treatment plants, manufacturing sites and other point sources must have permits to discharge pollutants into our rivers and streams, these permits are often written with few restrictions and without factoring in the cumulative effects on the environment.

Climate change
Climate change has brought a general drying trend throughout the more typically wet southeast. One only need scan any paper in the south to read about how the recent drought has caused significant and costly damage to human communities and other species. What will the region's response be?: interbassin transfers and more dams or the more reasonable, more cost effective, and more strategic need for implementing massive water conservation efforts and replacing the century old water infrastructure that would otherwise continue to waste hundreds of millions of gallons of water."