U.S. Southeast Rivers and Streams

As focal points for World Wildlife Fund’s Southeastern Rivers and Streams Program, the Tennessee, Cumberland, and Mobile River Basins – centered in Tennessee and Alabama – are host to the highest levels of freshwater biodiversity in North America. Among this trio of globally outstanding riverine systems are the most biologically rich aquatic habitats in fish, mussel, and crayfish species and have the highest number of endemic species in all of North America. Furthermore, the waterways of the Mobile Basin are home to the most significant population and diversity of freshwater snail species on the continent. All told, the freshwater resources of the American Southeast are truly unparalleled in their richness of aquatic life.

A jewel in this crown lies in the Coosa River – winding over 275 miles from its headwaters in Georgia. What begins as a river formed by two others (the Etowah and Oostanaula Rivers) meanders across northern Georgia into Alabama where it joins the Tallapoosa River to form the Alabama River. Despite an exceptional diversity of species and inherent ecological value, the abundance of freshwater resources in the southeastern United States has often resulted in short-sighted management decisions. For generations, dams, impoundments, and other water diversions and withdrawals have degraded or destroyed freshwater habitat. The consequences of these development-driven pressures is undeniable; the freshwater systems of the Mobile Basin have been the site of more than 50 percent of all species extinctions in North America since European settlement. Moreover, dams on the Coosa River eliminated important habitat for aquatic snails with the resultant extinction of at least 40 species of mussels and snails.

Although dams can bring benefits of flood protection, recreational opportunities, power generation, and irrigation, they generate profound environmental impacts. When a dam changes a river into a reservoir, it alters water depths, flows, temperatures, and other factors vital to the survival of native species. More importantly, dams isolate populations of fish and other aquatic species, disrupting their migrations and reproductive abilities resulting in the elimination of many riverine species from portions of their natural habitats. These isolated populations are thus, made more vulnerable to changes in their environments. Without avenues of migration, a stable environment is the only hope populations of aquatic species have of long-term survival.

Protecting the remaining free-flowing sections as well as improving managements on the impounded sections are critical to protecting the biodiversity of the river.  Because dams and impoundments can have such significant impact on the sustainability of aquatic species, sound management of these structures can play an important role in the future survival of such fauna. With this in mind, WWF is creating an action plan for protecting and restoring remaining aquatic habitat in the southeastern United States by reforming management practices of dam and impoundment structures in Mobile River Basins.