Geology topics

Research about Apalachicola-Chattahoochee-Flint River Basin

Source-linked reports with geographic coverage including Apalachicola-Chattahoochee-Flint River Basin.

9 recordsLinked to original sources

USGS2018

Stream fish colonization but not persistence varies regionally across a large North American river basin

Many species have distributions that span distinctly different physiographic regions, and effective conservation of such taxa will require a full accounting of all factors that potentially influence populations. Ecologists recognize effects of physiographic differences in topography, geology and climate on local habitat configurations, and thus the relevance of landscape heterogeneity to species distributions and abundances. However, research is lacking that examines how physiography affects the processes underlying metapopulation dynamics. We used data describing occupancy dynamics of stream fishes to evaluate evidence that physiography influences rates at which individual taxa persist in or colonize stream reaches under different flow conditions. Using periodic survey data from a stream fish assemblage in a large river basin that encompasses multiple physiographic regions, we fit multi-species dynamic occupancy models. Our modeling results suggested that stream fish colonization but not persistence was strongly governed by physiography, with estimated colonization rates considerably higher in Coastal Plain streams than in Piedmont and Blue Ridge systems. Like colonization, persistence was positively related to an index of stream flow magnitude, but the relationship between flow and persistence did not depend on physiography. Understanding the relative importance of colonization and persistence, and how one or both processes may change across the landscape, is critical information for the conservation of broadly distributed taxa, and conservation strategies explicitly accounting for spatial variation in these processes are likely to be more successful for such taxa.

Alabama, Florida, Georgia↗

USGS2017

Simulations of hydrologic response in the Apalachicola-Chattahoochee-Flint River Basin, Southeastern United States

A suite of hydrologic models has been developed for the Apalachicola-Chattahoochee-Flint River Basin (ACFB) as part of the National Water Census, a U.S. Geological Survey research program that focuses on developing new water accounting tools and assessing water availability and use at the regional and national scales. Seven hydrologic models were developed using the Precipitation-Runoff Modeling System (PRMS), a deterministic, distributed-parameter, process-based system that simulates the effects of precipitation, temperature, land cover, and water use on basin hydrology. A coarse-resolution PRMS model was developed for the entire ACFB, and six fine-resolution PRMS models were developed for six subbasins of the ACFB. The coarse-resolution model was loosely coupled with a groundwater model to better assess the effects of water use on streamflow in the lower ACFB, a complex geologic setting with karst features. The PRMS coarse-resolution model was used to provide inputs of recharge to the groundwater model, which in turn provide simulations of groundwater flow that were aggregated with PRMS-based simulations of surface runoff and shallow-subsurface flow. Simulations without the effects of water use were developed for each model for at least the calendar years 1982–2012 with longer periods for the Potato Creek subbasin (1942–2012) and the Spring Creek subbasin (1952–2012). Water-use-affected flows were simulated for 2008–12. Water budget simulations showed heterogeneous distributions of precipitation, actual evapotranspiration, recharge, runoff, and storage change across the ACFB. Streamflow volume differences between no-water-use and water-use simulations were largest along the main stem of the Apalachicola and Chattahoochee River Basins, with streamflow percentage differences largest in the upper Chattahoochee and Flint River Basins and Spring Creek in the lower Flint River Basin. Water-use information at a shorter time step and a fully coupled simulation in the lower ACFB may further improve water availability estimates and hydrologic simulations in the basin.

Apalachicola-Chattahoochee-Flint River Basin↗

USGS2016

Water use in the Apalachicola-Chattahoochee-Flint River Basin, Alabama, Florida, and Georgia, 2010, and water-use trends, 1985-2010

The Apalachicola-Chattahoochee-Flint (ACF) River Basin encompasses about 20,230 square miles in parts of Alabama, Florida, and Georgia. Increasing population growth and agricultural production from the 1970s to 2010 has prompted increases in water-resources development and substantially increased water demand in the basin. Since the 1980s, Alabama, Florida, Georgia, and the U.S. Army Corps of Engineers are parties to litigation concerning water management in the ACF River Basin. Estimating the 2010 water use in the ACF River Basin is one aspect of a multipart water resources study on the ACF River Basin that began in 2011. This ACF River Basin study is one focus area of the U.S. Geological Survey’s National Water Census program. The 2010 water-use estimates for the ACF River Basin are presented in this report. These estimates include an inventory of the quantity and sources of water withdrawn by category of use and location (State and river basin), and the surface-water returns in the ACF River Basin during 2010. Water-use trends from 1985 to 2010 in the basin also are presented. Offstream water-withdrawal data in the ACF River Basin are presented for each of the following categories: public supply, self-supplied domestic, self-supplied commercial, industrial, mining, agricultural (including crop irrigation, livestock, and aquaculture uses), and thermoelectric-power generation. Water-use data are compiled for the 14 subbasins in the ACF River Basin. For the counties in Alabama, Florida, and Georgia that are partially within the ACF River Basin, data are presented for only that part of the county that lies within the basin. A variety of Federal, State, local, private, and online sources in Alabama, Florida, and Georgia were used to gather surface-water and groundwater withdrawal, surface-water discharges (return flows), and water-use data for the ACF River Basin in 2010. The population in the ACF River Basin was 3.835 million in 2010, a 45-percent increase from the 1990 population of nearly 2.636 million. About 92 percent of the 2010 ACF population resided in Georgia with nearly 75 percent living in the Atlanta metropolitan area. In 2010, 1,645 million gallons per day (Mgal/d) of water were withdrawn from groundwater (576 Mgal/d) and surface-water (1,069 Mgal/d) sources in the ACF River Basin. About 89 percent of the groundwater and 83 percent of the surface-water withdrawals were from Georgia. About 5.6 percent of the total groundwater and nearly 4 percent of the total surface-water withdrawals in the ACF River Basin were from Florida, whereas about 5.3 percent of groundwater and nearly 16 percent of surface water were withdrawn in Alabama. Total water use (withdrawals plus public-supplied deliveries) in the ACF River Basin was 1,593 Mgal/d in 2010. About 56 Mgal/d of water withdrawn in the ACF River Basin was delivered (interbasin transfer) to basins beyond the ACF River Basin. About 564 Mgal/d of water was returned to surface-water bodies in the ACF River Basin. Most of that amount, 63 percent, was treated wastewater discharged by public wastewater-treatment facilities. Water used for once-through cooling by thermoelectric-power facilities accounted for nearly 24 percent of the surface-water returns in the basin. About 70 percent of all water withdrawals in the ACF River Basin were by self-supplied agricultural water users and public water suppliers. Agricultural withdrawals were greatest in the Flint River Basin (501 Mgal/d) with ground-water representing 84 percent of the withdrawals from that basin. Within the Flint River Basin, agricultural withdrawals were greatest in the Lower Flint River and Spring Creek subbasins. About 3.52 million people were served by public water suppliers in the ACF River Basin during 2010, and 88 percent of that population used surface water. Georgia had the largest public-supplied population, representing nearly 93 percent (3.17 million) of the public-supplied population in the ACF River Basin. Public water suppliers served 193,700 people (5.7 percent) in Alabama and 31,880 people in Florida (1.3 percent). Public-supply losses were estimated at 101 Mgal/d. Withdrawals for public supply (483 Mgal/d) and self-supplied industry (141 Mgal/d) were greatest in the Chattahoochee River Basin. Surface water accounted for 96 percent of all withdrawals in the Chattahoochee River Basin. Withdrawals for public supply were greatest in the Upper Chattahoochee River subbasin (366 Mgal/d), whereas self-supplied industrial withdrawals were greatest in the Lower Chattahoochee River subbasin (110 Mgal/d). Water-use trends in the ACF River Basin have varied during the 25 years between 1985 and 2010. Surface-water withdrawals declined between 1985 and 2000, sharply increased in 2000, and declined again between 2000 and 2010. In contrast, groundwater withdrawals increased between 1985 and 2000, declined in 2005, and increased between 2005 and 2010.

Alabama, Florida, Georgia↗

USGS2015

Evaluation and comparison of methods to estimate irrigation withdrawal for the National Water Census Focus Area Study of the Apalachicola-Chattahoochee-Flint River Basin in southwestern Georgia

Methods to estimate irrigation withdrawal using nationally available datasets and techniques that are transferable to other agricultural regions were evaluated by the U.S. Geological Survey as part of the Apalachicola-Chattahoochee-Flint (ACF) River Basin focus area study of the National Water Census (ACF–FAS). These methods investigated the spatial, temporal, and quantitative distributions of water withdrawal for irrigation in the southwestern Georgia region of the ACF–FAS, filling a vital need to inform science-based decisions regarding resource management and conservation. The crop– demand method assumed that only enough water is pumped onto a crop to satisfy the deficit between evapotranspiration and precipitation. A second method applied a geostatistical regimen of variography and conditional simulation to monthly metered irrigation withdrawal to estimate irrigation withdrawal where data do not exist. A third method analyzed Landsat satellite imagery using an automated approach to generate monthly estimates of irrigated lands. These methods were evaluated independently and compared collectively with measured water withdrawal information available in the Georgia part of the ACF–FAS, principally in the Chattahoochee-Flint River Basin. An assessment of each method’s contribution to the National Water Census program was also made to identify transfer value of the methods to the national program and other water census studies. None of the three methods evaluated represent a turnkey process to estimate irrigation withdrawal on any spatial (local or regional) or temporal (monthly or annual) extent. Each method requires additional information on agricultural practices during the growing season to complete the withdrawal estimation process. Spatial and temporal limitations inherent in identifying irrigated acres during the growing season, and in designing spatially and temporally representative monitor (meter) networks, can belie the ability of the methods to produce accurate irrigation-withdrawal estimates that can be used to produce dependable and consistent assessments of water availability and use for the National Water Census. Emerging satellite-data products and techniques for data analysis can generate high spatial-resolution estimates of irrigated-acres distributions with near-term temporal frequencies compatible with the needs of the ACF–FAS and the National Water Census.

Georgia↗

USGS2015

Effects of climate and land cover on hydrology in the southeastern U.S.: Potential impacts on watershed planning

The hydrologic response to statistically downscaled general circulation model simulations of daily surface climate and land cover through 2099 was assessed for the Apalachicola-Chattahoochee-Flint River Basin located in the southeastern United States. Projections of climate, urbanization, vegetation, and surface-depression storage capacity were used as inputs to the Precipitation-Runoff Modeling System to simulate projected impacts on hydrologic response. Surface runoff substantially increased when land cover change was applied. However, once the surface depression storage was added to mitigate the land cover change and increases of surface runoff (due to urbanization), the groundwater flow component then increased. For hydrologic studies that include projections of land cover change (urbanization in particular), any analysis of runoff beyond the change in total runoff should include effects of stormwater management practices as these features affect flow timing and magnitude and may be useful in mitigating land cover change impacts on streamflow. Potential changes in water availability and how biota may respond to changes in flow regime in response to climate and land cover change may prove challenging for managers attempting to balance the needs of future development and the environment. However, these models are still useful for assessing the relative impacts of climate and land cover change and for evaluating tradeoffs when managing to mitigate different stressors.

Alabama, Florida, Georgia↗

USGS2014

Influence of septic systems on stream base flow in the Apalachicola-Chattahoochee-Flint River Basin near Metropolitan Atlanta, Georgia, 2012

Septic systems were identified at 241,733 locations in a 2,539-square-mile (mi 2 ) study area that includes all or parts of 12 counties in the Metropolitan Atlanta, Georgia, area. Septic system percolation may locally be an important component of streamflow in small drainage basins where it augments natural groundwater recharge, especially during extreme low-flow conditions. The amount of groundwater reaching streams depends on how much is intercepted by plants or infiltrates to deeper parts of the groundwater system that flows beyond a basin divide and does not discharge into streams within a basin. The potential maximum percolation from septic systems in the study area is 62 cubic feet per second (ft 3 /s), of which 52 ft 3 /s is in the Chattahoochee River Basin and 10 ft 3 /s is in the Flint River Basin. These maximum percolation rates represent 0.4 to 5.7 percent of daily mean streamflow during the 2011–12 period at the farthest downstream gaging site (station 02338000) on the Chattahoochee River, and 0.5 to 179 percent of daily mean streamflow at the farthest downstream gaging site on the Flint River (02344350). To determine the difference in base flow between basins having different septic system densities, hydrograph separation analysis was completed using daily mean streamflow data at streamgaging stations at Level Creek (site 02334578), with a drainage basin having relatively high septic system density of 101 systems per square mile, and Woodall Creek (site 02336313), with a drainage basin having relatively low septic system density of 18 systems per square mile. Results indicated that base-flow yield during 2011–12 was higher at the Level Creek site, with a median of 0.47 cubic feet per second per square mile ([ft 3 /s]/mi 2 ), compared to a median of 0.16 (ft 3 /s)/mi 2 , at the Woodall Creek site. At the less urbanized Level Creek site, there are 515 septic systems with a daily maximum percolation rate of 0.14 ft 3 /s, accounting for 11 percent of the base flow in September 2012. At the more urban Woodall Creek site, there are 50 septic systems with an average daily maximum percolation rate of 0.0097 ft 3 /s, accounting for 5 percent of base flow in September 2012. Streamflow measurements at 133 small drainage basins (less than 5 mi2 in area) during September 2012 indicated no statistically significant difference in streamflow or specific conductance between basins having high and low density of septic systems (HDS and LDS, respectively). The median base-flow yield was 0.04 (f 3 /s)/mi 2 for HDS sites, ranging from 0 to 0.52 (ft 3 /s)/mi 2 , and 0.10 (ft 3 /s)/mi 2 for LDS sites, ranging from 0 to 0.49 (ft 3 /s)/mi 2 . A Wilcoxon rank-sum test indicated the median base-flow yields for HDS and LDS sites were not statistically different, with a p-value of 0.345. Because of the large size of the study area and associated variations in basin characteristics, data collected in September 2012 were also evaluated on the basis of the basins physical characteristics in an attempt to reduce or eliminate other basin characteristics that might affect base flow. Basins were evaluated based on geologic area, four geographic subareas, and 45-meter (147.6 ft) buffer zone; there were no statistically significant differences between median base-flow yield for HDS and LDS basins. It is probable that detection of the contribution from septic system percolation in base flow at many of the sites visited in September 2012 was obscured by a combination of the limitations of measurement accuracy and evapotranspiration. Detection of septic system percolation may also have been complicated by leaky water and sewer mains, which may have resulted in higher streamflows in LDS basins relative to HDS basins.

Georgia↗

USGS2013

Application of the Precipitation-Runoff Modeling System (PRMS) in the Apalachicola-Chattahoochee-Flint River Basin in the southeastern United States

A hydrologic model of the Apalachicola–Chattahoochee–Flint River Basin (ACFB) has been developed as part of a U.S. Geological Survey (USGS) National Climate Change and Wildlife Science Center effort to provide integrated science that helps resource managers understand the effect of climate change on a range of ecosystem responses. The hydrologic model was developed as part of the Southeast Regional Assessment Project using the Precipitation Runoff Modeling System (PRMS), a deterministic, distributed-parameter, process-based system that simulates the effects of precipitation, temperature, and land use on basin hydrology. The ACFB PRMS model simulates streamflow throughout the approximately 50,700 square-kilometer basin on a daily time step for the period 1950–99 using gridded climate forcings of air temperature and precipitation, and parameters derived from spatial data layers of altitude, land cover, soils, surficial geology, depression storage (small water bodies), and data from 56 USGS streamgages. Measured streamflow data from 35 of the 56 USGS streamgages were used to calibrate and evaluate simulated basin streamflow; the remaining gage locations were used for model delineation only. The model matched measured daily streamflow at 31 of the 35 calibration gages with Nash-Sutcliffe Model Efficiency Index (NS) greater than 0.6. Streamflow data for some calibration gages were augmented for regulation and water use effects to represent more natural flow volumes. Time-static parameters describing land cover limited the ability of the simulation to match historical runoff in the more developed subbasins. Overall, the PRMS simulation of the ACFB provides a good representation of basin hydrology on annual and monthly time steps. Calibration subbasins were analyzed by separating the 35 subbasins into five classes based on physiography, land use, and stream type (tributary or mainstem). The lowest NS values were rarely below 0.6, whereas the median NS for all five classes was within 0.74 to 0.96 for annual mean streamflow, 0.89 to 0.98 for mean monthly streamflow, and 0.82 to 0.98 for monthly mean streamflow. The median bias for all five classes was within –4.3 to 0.8 percent for annual mean streamflow, –6.3 to 0.5 percent for mean monthly streamflow, and –9.3 to 1.3 percent for monthly mean streamflow. The NS results combined with the percent bias results indicated a good to very good streamflow volume simulation for all subbasins. This simulation of the ACFB provides a foundation for future modeling and interpretive studies. Streamflow and other components of the hydrologic cycle simulated by PRMS can be used to inform other types of simulations; water-temperature, hydrodynamic, and ecosystem-dynamics simulations are three examples. In addition, possible future hydrologic conditions could be studied using this model in combination with land cover projections and downscaled general circulation model results.

Alabama, Florida, Georgia↗

USGS2006

Geohydrology of the lower Apalachicola-Chattahoochee-Flint River basin, southwestern Georgia, northwestern Florida, and southeastern Alabama

The lower Apalachicola-Chattahoochee-Flint (ACF) River Basin contains about 4,600 square miles of karstic and fluvial plains and nearly 100,000 cubic miles of predominantly karst limestone connected hydraulically to the principal rivers and lakes in the Coastal Plain of southwestern Georgia, northwestern Florida, and southwestern Alabama. Sediments of late-middle Eocene to Holocene in hydraulic connection with lakes, streams, and land surface comprise the surficial aquifer system, upper semiconfining unit, Upper Floridan aquifer, and lower semiconfining unit and contribute to the exchange of ground water and surface water in the stream-lake-aquifer flow system. Karst processes, hydraulic properties, and stratigraphic relations limit ground-water and surface-water interaction to the following hydrologic units of the stream-lake-aquifer flow system: the surficial aquifer system, upper semiconfining unit, Upper Floridan aquifer, and lower confining unit. Geologic units corresponding to these hydrologic units are, in ascending order: Lisbon Formation; Clinchfield Sand; Ocala, Marianna, Suwannee, and Tampa Limestones; Hawthorn Group; undifferentiated overburden (residuum); and terrace and undifferentiated (surficial) deposits. Similarities in hydraulic properties and direct or indirect interaction with surface water allow grouping sediments within these geologic units into the aforementioned hydrologic units, which transcend time-stratigraphic classifications and define the geohydrologic framework for the lower ACF River Basin. The low water-transmitting properties of the lower confining unit, principally the Lisbon Formation, allow it to act as a nearly impermeable base to the stream-lake-aquifer flow system. Hydraulic connection of the surficial aquifer system with surface water and the Upper Floridan aquifer is direct where sandy deposits overlie the limestone, or indirect where fluvial deposits overlie clayey limestone residuum. The water level in perched zones within the surficial aquifer system fluctuates independently of water-level changes in the underlying aquifer, adjacent streams, or lakes. Where the surficial aquifer system is connected with surface water and the Upper Floridan aquifer, water-table fluctuations parallel those in adjacent streams or the underlying aquifer. More...

Alabama, Florida, Georgia↗

USGS1996

Geohydrology and evaluation of stream-aquifer relations in the Apalachicola-Chattahoochee-Flint River basin, southeastern Alabama, northwestern Florida, and southwestern Georgia

The lower Apalachicola-Chattahoochee-Flint River Basin is underlain by Coastal Plain sediments of pre-Cretaceous to Quaternary age consisting of alternating units of sand, clay, sandstone, dolomite, and limestone that gradually thicken and dip gently to the southeast. The stream-aquifer system consists of carbonate (limestone and dolomite) and elastic sediments, which define the Upper Floridan aquifer and Intermediate system, in hydraulic connection with the principal rivers of the basin and other surface-water features, natural and man made. Separate digital models of the Upper Floridan aquifer and Intermediate system were con structed by using the U.S. Geological Survey's MODular Finite-Element model of two dimensional ground-water flow, based on conceptualizations of the stream-aquifer system, and calibrated to drought conditions of October 1986. Sensitivity analyses performed on the models indicated that aquifer hydraulic conductivity, lateral and vertical boundary flows, and pumpage have a strong influence on ground-water levels. Simulated pumpage increases in the Upper Floridan aquifer, primarily in the Dougherty Plain physiographic district of Georgia, caused significant reductions in aquifer discharge to streams that eventually flow to Lake Seminole and the Apalachicola River and Bay. Simulated pumpage increases greater than 3 times the October 1986 rates caused drying of some stream reaches and parts of the Upper Floridan aquifer in Georgia. Water budgets prepared from simulation results indicate that ground-water discharge to streams and recharge by horizontal and vertical flow are the principal mechanisms for moving water through the flow system. The potential for changes in ground-water quality is high in areas where chemical constituents can be mobilized by these mechanisms. Less than 2 percent of ground-water discharge to streams comes from the Intermediate system; thus, it plays a minor role in the hydrodynamics of the stream aquifer system.

Alabama, Florida, Georgia↗