Water Availability for Ecological Needs in the Upper Flint River Basin, Georgia The Flint River Science Thrust project of the U.S. Geological Survey is part of a federally funded program to address key national science priorities including landslides/debris flows, fire science, integrated landscape monitoring, and water availability. The purpose of the project is to advance the science needed to specify the hydrologic conditions necessary to support flowing-water ecosystems. This information is critical for management of water resources. Specific project goals include: • Develop conceptual models that relate hydrology, geomorphol- ogy, and water quality to biological management objectives. • Evaluate and determine the major factors driving the conceptual models and determine additional data needs. • Use the upper Flint River Basin to demonstrate a spatially explicit predictive model for evaluating water-supply develop- ment options that links watershed conditions to biological management objectives. • Identify research and monitoring needed to address critical uncer- tainties and data gaps determined during model development. Sustaining the ecological integrity of The U.S. Geological Survey (USGS) has and biologically diverse communities that aquatic ecosystems while meeting human the extensive research background and have been lost from impounded reaches of needs for water resources is a major chal- interdisciplinary capabilities that posi- many other eastern rivers. The upper Flint lenge facing society. In many regions, tion the agency to take a lead role in River Basin also supplies water to a grow- including the Eastern United States, the developing the science needed to improve ing population in the Atlanta metropolitan growing demand for water supply and management of water supply and aquatic area and is a major recreational resource for changing land use, such as urbaniza- ecosystems, especially in urbanizing land- the region, providing canoeing, white-water tion, are altering hydrologic regimes in scapes. To accomplish this goal, the USGS rafting, and sportfishing opportunities. streams and rivers that society depends Director selected “Water availability for Long-term streamflow gaging stations on for ecological services. These services ecological needs” as a national priority have provided flow data for more than include drinking, irrigation, and industrial science thrust program for 2006 – 2008. 90 years in the upper Flint River Basin. water supplies; assimilation and removal of Recently completed investigations of fresh- waste; mitigation of droughts and floods; UPPER FLINT RIVER BASIN water mussel distributions and fish-habitat control of river channel erosion; recreation; relations in the upper mainstem, and an fisheries; and maintenance of biological A number of factors make the upper Flint aquatic Gap Analysis Program (GAP), diversity. Meeting the challenge of balanc- River Basin an appropriate setting for provide baseline data for the system. ing human needs for water resources with developing science to address water and Continued growth in the Atlanta area protecting aquatic ecosystems requires ecosystem management issues. The upper will increase pressure on the ecological science-based information on what aspects Flint River flows unimpeded by major systems of the Flint River Basin because of natural, or unaltered, hydrologic condi- impoundments for about 195 river miles of the potential for increased water tions are essential for the long-term main- from its Piedmont headwaters onto the withdrawals, reservoir construction for tenance of healthy aquatic ecosystems. Coastal Plain Province and harbors habitats water storage, urban runoff, and additional U.S. Department of the Interior Fact Sheet 2006 – 3114 U.S. Geological Survey September 2006 wastewater loadings. Thus, this setting the Apalachicola River. The upper Flint Water-Supply and incorporates problems common to many River Basin has a drainage area of about regions and rivers in the Eastern United 2,630 square miles. Land use in the basin, Instream-Flow Issues States — how to balance water-supply which includes parts of the upper Coastal Most of the water supply in the upper development with protection of diverse Plain, consists of about 57 percent forest, Flint River Basin comes primarily from aquatic ecosystem — and provides an 17 percent agriculture, and 12 percent the Flint River or its tributaries. With- opportunity for interdisciplinary innova- urban, with most of the urban land drawal from the 32 permitted municipal tion in providing science-based solutions. concentrated in the extreme northern and industrial water-supply intakes part of the basin (Georgia Land Use totals about 108 million gallons per Trends, 1998). day (Mgal/d) and agricultural interests CHARACTERISTICS OF THE are permitted to remove an additional UPPER FLINT RIVER BASIN Population growth in the six-county 90 Mgal/d from streams in the basin Upper Flint Water Supply Management (Victoria P. Trent, Georgia Environmental The Flint River begins beneath Harts- Area (UFWSMA, shown below) has Protection Division, written commun., field – Jackson International Airport increased more than 200 percent since 2005). Proposals have been submitted on the south side of Atlanta and flows 1970, from 133,470 to 302,714 during to increase surface-water supply capac- southward across the Georgia Piedmont 2000 (CH2MHill, 2003). Predictions are ity in the upper Flint River Basin by and Coastal Plain to its junction with that more than 550,000 persons will live 12.7 Mgal/d (about 7 percent) by building the Chattahoochee River, later forming in the six-county UFWSMA by 2030. two additional reservoirs and expanding 84°30 EXPLANATION CLAYTON 305b assessed streams Municipal (blue) or industrial (brown) withdrawal—In FULTON Not supporting (303d listed) million gallons per day Partially supporting (303d listed) 33°30 Less than 0.2 FAYETTE Supporting (not listed) 0.2 to 1 HENRY Not assessed 1 to 5 Wastewater discharge Municipal 5 to 10 COWETA Industrial 10 to 20 Shoal 20 to 50 SPALDING Upper Flint ALABAMA GEORGIA CHATTAHOOCHEE Water Supply RIVER BASIN Management Area PIKE Atlanta MERIWETHER Metropolitan area LAMAR 33°00' PIEDMONT UPSON F l in t R iv Fall Line er 84°00' Upper Flint River Basin FLINT CRAWFORD TALBOT RIVER BASIN COASTAL PLAIN n a e c O c i t MARION n a l TAYLOR t A 0 5 10 MILES APALACHICOLA 32°30 RIVER BASIN 0 5 10 KILOMETERS N FLORIDA Base modified from MACON Gu U.S. Geological Survey lf o o f Mexic 1:100,000-scale digital data Most of the upper Flint River Basin is located in the Piedmont physiographic region of Georgia. The majority of the basin is relatively undeveloped; however, development spreading south from Atlanta will increase pressure on the available water in the basin. an existing reservoir (Georgia Depart- ment of Natural Resources, 2003a). Advancing the science of linking hydrology and stream ecology Under an interim State policy, required More than 200 methods for deriving “environmental” flow requirements have been minimum flows below new reservoirs or developed to meet the needs of water managers (Tharme, 2003). Many of these stream withdrawals must adhere to one of methods focus on the minimum flows needed to support survival of aquatic organ- three guidelines. Provide a minimum of: isms. Because flow conditions that drive ecosystem functions are complex, current • the monthly 7Q10 (the 7-day, emphasis in flow management is to identify hydrologic regimes necessary to consecutive low flow with a protect and maintain differing levels of ecological integrity (Arthington and Pusey, 10-year return frequency); 2003; King and others, 2003; Postel and Richter, 2003; Annear and others, 2004). • 30 percent of the mean-annual Current limitations on quantifying the linkages between flow regimes and ecosys- flow for unregulated streams; or tem processes underlie much of the uncertainty in predicting ecological effects of flow-regime alteration (Castleberry and others, 1996; Irwin and Freeman, 2002; • seasonally adjusted percentage Tharme, 2003). The USGS and its partners can advance the science underlying of mean-annual flow for environmental flow specifications by applying multidisciplinary expertise and data regulated streams. from other studies of riverine processes to build and evaluate alternative hypoth- The guidelines also suggest that site- eses regarding flow-regime effects on geomorphic and ecological processes — in specific studies can be used to determine this case, for a Piedmont river system. Through this process, the USGS anticipates minimum flows. addressing questions such as: Stormwater Runoff • What are the appropriate spatial scales for identifying geomorphic variation in hydrologic-ecologic linkages? Stormwater runoff increases as imper- vious surface increases. This affects • What are the relative roles of changes in sediment transport, water quality, stream geomorphology, water quality, and habitat conditions in altering ecological communities? temperature, aquatic ecosystems, and • How does altering the flow regime (magnitude, duration, frequency of stream baseflows. No statewide policy occurrence, seasonality, rate of change) influence persistence of native aquatic currently exists to manage stormwater species and communities? runoff except related to construction. Some municipal and county governments • How are direct effects of flow regulation and water diversion on physical and have implemented, or are in the process biological processes altered by