Cahaba River Society

A great diversity of life depends on the Cahaba River, Alabama’s longest remaining free-flowing river and the primary drinking water source for the state’s largest water system. The Cahaba flows 191 miles through central Alabama, and its 1,870 square mile watershed drains urban, suburban, and rural areas, forests, farms, cypress swamps and wetlands on its course from the southern Appalachian Mountains through the coastal plain to the Alabama River near Selma, in the Black Belt.

The Cahaba is the main drinking water source for the Birmingham Water Board, which serves 1/5th of Alabama’s population, in the Birmingham metropolitan area.  The drinking water is drawn from the main channel of the river. All lands in the upper 200 square miles of the watershed are the region’s drinking water source.

The Cahaba and its largest tributaries are major recreational, tourism, and educational assets for their communities and Alabama. Most of the Cahaba’s main channel is wild, beautiful, and very popular for canoeing, fishing, swimming, and environmental education. 

Upper Cahaba canoe launches and trails are within a 20 minute drive of downtown Birmingham. The middle Cahaba is the focus of ecotourism planning in Bibb County, home of the Cahaba National Wildlife Refuge, as a top strategy to strengthen rural economies.

The Cahaba has more species of fish per mile than any other river in North America. Scientists and international preservation groups agree that the freshwater biodiversity of southeastern rivers is globally significant.  Yet half of all species extinctions in the U.S. since European settlement have occurred in the Mobile River basin, which is most of Alabama.  The majority of these lost species were freshwater life.

The middle Cahaba has the largest stands of the spectacular Cahaba Lily remaining in the world.  In the past few years, 8 wildflower species previously unknown to science have been discovered in glades near the Little Cahaba River in Bibb County. 

The diverse richness of freshwater life that the Cahaba supports has received national and global recognition. Alabama has been identified as having the most aquatic species diversity in the Continental United States and indeed is the most species rich State east of the Mississippi River, when including plant and animal species. The Cahaba River was highlighted in the 2007 edition of the National Geographic Society’s College Atlas of the World, as representative of southeastern rivers, which were named as one of six places on earth that are examples of biological diversity. After an exhaustive worldwide study, the World Wildlife Fund has identified the 19 most important natural places to preserve in the world over the next 10 years. Only 3 places in the United States are on this short list, including our rivers & streams in the Tennessee and Mobile Basins, which is most of the State of Alabama.  The Cahaba watershed is right in the middle of this vital area. Also, the Nature Conservancy’s nationwide study of freshwater life, “Rivers of Life,” identified the Cahaba as one of eight rivers in the lower 48 states that must be saved.

Most of the upper and middle Cahaba has been placed on Alabama’s list of streams that do not meet Clean Water Act standards, due to suburban impacts in the upper watershed. The river’s main challenges are sediment, nutrient overloads from storm water and treated sewage, toxins in storm water runoff, erosion and bank collapses, human disease pathogens, destruction of natural forests and tributary streams, reduction in water supply, and flooding.

A tremendous amount of growth is planned for lands that drain to the Cahaba drinking water intakes, in communities such as Clay, Trussville, Vestavia Hills, and Leeds. The same development impacts and pollutants that are damaging the river’s significant aquatic life are also threatening the supply, quality and cost of our region’s drinking water. The Cahaba has lost 40% of mussel species and up to 40% of fish species downstream from urban growth areas. The Birmingham Water Board estimates that replacing the Cahaba as a drinking water source would cost more than the system’s total assets.

A review of climate change models demonstrates that there is uncertainty about whether Alabama’s climate will become wetter – leading to more flooding -or drier – causing more droughts.

Either way, improved storm water management in development is essential to safeguard water supplies, protect properties, and restore the Cahaba’s biodiversity.

The Cahaba River Society recommends the “Responsible Agenda for River Restoration and Growth,” a four-point approach to plan and design growth wisely to restore and conserve the Cahaba and our region’s drinking water.

Innovative development projects in the Cahaba watershed and Birmingham metro area are demonstrating that Low Impact Development (LID) practices can both meet the developer’s economic goals and safeguard water quality and water supply.

As U.S. business and industry begins to move toward “green practices”, research has shown that in many instances “green” is no more expensive than alternatives that are more environmentally harmful. Green practices can save up front on storm water management costs and deliver greater long term savings in energy efficiency and costs for drinking water and landscape maintenance.