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Alabama-Coosa-Tallapoosa (ACT) and Apalachicola-Chattahoochee-Flint (ACF) River Basins

Published Nov 5, 2010


The primary purpose of the ACT/ACF Gap Analysis was to create databases and maps of aquatic species distributions in portions of the Alabama-Coosa-Tallapoosa (ACT) and Apalachicola-Chattahoochee-Flint (ACF) River Basins by developing predictive models relating species distribution to local and landscape-level features. The research was a collaborative effort among the U.S. Geological Survey (USGS) GAP Analysis Program and USGS Cooperative Fish and Wildlife Research Units (CFWRUs) of Alabama and Georgia, the Institute of Ecology and the University of Georgia.


At the time of the study, federally listed animals included 6 mussels and 1 fish native to the Chattahoochee and Flint systems, 14 species of mussel and snail native to the ACT, and 10 fishes native to the ACT. At least 114 aquatic species in the ACT, Chattahoochee and Flint rivers are considered imperiled as a result of habitat degradation and loss (Ziewitz et al. 1995). Levels of species imperilment likely underestimate the actual extent of loss for unique stream types with high water quality and faunal integrity.

Conversion of forest to agriculture, urban growth and river impoundment for hydropower and navigation have altered stream and river habitat throughout much of the basins. The types of impacts on stream and river habitat include:

  • dams and reservoirs impound approximately 44 % of the ACT and 64% of the Chattahoochee mainstem rivers
  • some of the highest population growth rates in the nation are in these regions, bringing urban sprawl, impervious surface proliferation, and increasing pressures on streams for water supply
  • approximately 16 water supply reservoirs are in planning phases for construction on streams in the Coosa, Tallapoosa, Chattahoochee and Flint systems in Georgia (R. Goodloe, USFWS, personal communication)
  • interstate controversy and changes in legislation are occurring over water use in these systems and water allocation to downstream states

The intense and growing competition for water in these systems – to support population growth, expanding agriculture, for industry and hydropower, and to provide for healthy stream communities – reflects the urgency with which scientifically sound tools are needed to facilitate landscape-level planning and biodiversity conservation.

(text adapted from December 2004 project report)

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