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Organic compounds assessed in Chattahoochee River water used for public supply near Atlanta, Georgia, 2004-05
An investigation by the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program characterized the occurrence of 266 organic compounds in source water and finished water from the Chattahoochee River, which is the main water-supply source for the Atlanta metropolitan area. Source water is stream water collected at a surface-water intake prior to water treatment, and finished water is water that has passed through treatment processes prior to distribution. Samples were collected approximately monthly during 2004-05 and included 15 paired source-water and finished-water samples. Samples were collected during winter-spring high flow and summer-fall low flow, but storm events were not targeted during this Source Water-Quality Assessment (SWQA) study. Samples were analyzed for pesticides and degradates, gasoline hydrocarbons, solvents, disinfection by-products, personal care and domestic-use products, and other organic compounds. Community water systems are required to monitor regulated organic compounds under the Safe Drinking Water Act of 1996 (U.S. Environmental Protection Agency, 1998); however, most compounds included in this study are not regulated by Federal drinking-water standards (U.S. Environmental Protection Agency, 2007a). The Chattahoochee River study is part of an ongoing NAWQA investigation of community water systems across the United States. Additional details about the national study are given in Carter and others (2007).
Surface-water quality-assurance plan for the USGS Georgia Water Science Center, 2010
The U.S. Geological Survey requires that each Water Science Center prepare a surface-water quality-assurance plan to describe policies and procedures that ensure high quality surface-water data collection, processing, analysis, computer storage, and publication. The Georgia Water Science Center's standards, policies, and procedures for activities related to the collection, processing, analysis, computer storage, and publication of surface-water data are documented in this Surface-Water Quality-Assurance Plan for 2010.
Methods for estimating selected low-flow frequency and mean annual flow statistics at gaged and ungaged locations on streams in Georgia, North Carolina, and South Carolina
The U.S. Geological Survey, in cooperation with the Georgia Department of Natural Resources (Environmental Protection Division), North Carolina Department of Environmental Quality (Division of Water Resources), North Carolina Department of Public Safety (Office of Recovery and Resiliency), and South Carolina Department of Environmental Services, updated low-flow frequency, mean annual flow, and flow-duration statistics at 843 streamgages in and near Georgia, North Carolina, and South Carolina. The low-flow frequency statistics are annual minimum 1-day average flow with a 10-year recurrence interval (1Q10), annual minimum 7-day average flow for 2- and 10-year recurrence intervals (7Q2 and 7Q10, respectively), and annual minimum 30-day average flow with 2- and 3-year recurrence intervals (30Q2 and 30Q3, respectively). Monthly 1Q10 and 7Q10, and W7Q10 flow statistics for the winter period (November–March) also are presented. By using data from 604 of the streamgages on streams with streamflows that are not substantially affected by regulation or diversion and are not tidally influenced, regional regression equations were developed to predict flow statistics with prediction intervals at ungaged locations on streams with those same criteria. The regional regression analysis included data from 132 streamgages from adjacent States Alabama, Florida, Tennessee, and Virginia. The final regional regression equations include variables such as drainage area, streamflow variability, precipitation, percentage of impervious area, and percentage of the basin in various ecoregions. The low-flow statistics for the streamgages analyzed and the regional regression equations will be integrated into the U.S. Geological Survey StreamStats application ( https://www.usgs.gov/streamstats ) for Georgia, North Carolina, and South Carolina. StreamStats generates basin characteristics needed to compute low-flow frequency statistics for ungaged locations. A trend analysis of annual minimum 7-day average flows was done for 78 streamgages with at least 30 years of continuous record. Trends were evaluated for 30-, 50‑, 70-, and 90-year periods, ending in climate year 2021, and independence and short- and long-term persistence assumptions were considered. For all trend analysis assumptions, most streamgages did not exhibit significant trends in annual minimum 7-day average flows. Trends in annual precipitation and air temperature were similarly evaluated for the period 1895–2021 to assess the variability of climate for Georgia, North Carolina, and South Carolina.
Flood-tracking chart for the Withlacoochee and Little River Basins in south-central Georgia and northern Florida
The U.S. Geological Survey (USGS), in cooperation with other Federal, State, and local agencies, operates a flood-monitoring system in the Withlacoochee and Little River Basins. This system is a network of automated river stage stations (ten are shown on page 2 of this publication) that transmit stage data through satellite telemetry to the USGS in Atlanta, Georgia and the National Weather Service (NWS) in Peachtree City, Georgia. During floods, the public and emergency response agencies use this information to make decisions about road closures, evacuations, and other public safety issues. This Withlacoochee and Little River Basins flood-tracking chart can be used by local citizens and emergency response personnel to record the latest river stage and predicted flood-crest information along the Withlacoochee River, Little River, and Okapilco Creek in south-central Georgia and northern Florida. By comparing the current stage (water-surface level above a datum) and predicted flood crest to the recorded peak stages of previous floods, emergency response personnel and residents can make informed decisions concerning the threat to life and property.
Historic Flooding in Georgia, 2009
Heavy rains in southern Georgia during March 27-April 3, 2009, and in northern Georgia during September 16-22, 2009, caused severe flooding and widespread damages to residential, public, and commercial structures. Of the 159 counties in Georgia, 69 were declared disaster areas because of flooding. The heavy rainfall in southern Georgia resulted in severe flooding in the Satilla-St. Marys and upper Ochlockonee Basins and caused approximately $60 million in damages to the public infrastructure. The heavy rainfall in northern Georgia resulted in severe flooding on many streams within the upper Chattahoochee, Altamaha, and Coosa-Tallapoosa Basins and caused 10 deaths, evacuation of thousands of residents, and approximately $500 million in damages. The U.S. Geological Survey computed annual exceedance probabilities of the peak flows in 2009 at 238 streamgages throughout the State. Record peak flows were recorded at 40 streamgages for the respective periods of record as a result of the heavy rainfall during the two multiday events. The peak flows at 33 streamgages exceeded the 1-percent annual exceedance probability (100-year recurrence interval), and 19 of these exceeded the 0.2-percent annual exceedance probability (500-year recurrence interval).
Hydrogeology and Potentiometric Surface of the Dublin and Midville Aquifer Systems in Richmond County, Georgia, January 2007
INTRODUCTION The Dublin and Midville aquifer systems are part of the Cretaceous aquifer system that underlies most of Richmond County, Georgia (Gorday, 1985; Falls and others, 1997). The Cretaceous aquifer system is the second most productive aquifer in Georgia and is a major source of water in the region. About 220 million gallons per day (Mgal/d) of water was withdrawn from the Cretaceous aquifer system during 2000 in Georgia (Fanning, 2003). The Augusta-Richmond County Water System is the largest public water supplier in the county and withdrew 13 Mgal/d of ground water during 2000; withdrawals decreased from 2001 to 2005. The towns of Hephzibah and Blythe withdrew 0.4 and 0.03 Mgal/d, respectively. Industrial ground-water withdrawals are concentrated along the Savannah River and totaled 2.89 Mgal/d. To monitor seasonal and long-term water-level fluctuations and trends in the aquifers, the U.S. Geological Survey (USGS) - in cooperation with Augusta Utilities - maintains a countywide network of about 100 water-level monitoring wells in various aquifers, including a new continuous monitoring site (well 30AA33) and two existing USGS-Georgia Environmental Protection Division network sites (wells 29AA09 and 30AA04). Data compiled during this study were used to better define the hydrogeologic units and to construct an updated potentiometric-surface map for the area, which is used to better understand ground-water movement in the Cretaceous aquifer system. In addition, the potentiometric surface and related water-level data can be used for water-resource planning and to update ground-water flow models for the region (Clarke and West, 1997; Cherry, 2006).
Flood-tracking chart for the Chattahoochee River Basin in Metropolitan Atlanta, Georgia
The U.S. Geological Survey (USGS)—in cooperation with other Federal, State, and local agencies—operates a flood monitoring system in the Chattahoochee River Basin. This system is a network of 35 automated river stage stations that transmit stage data through satellite telemetry to the USGS Georgia Water Science Center in Atlanta. During floods, the public and emergency response agencies use this information to make decisions about road closures, evacuations, and other public safety issues. The emergency phone number for your area is listed under “Local flood emergency phone numbers.”
Watershed Effects on Streamflow Quantity and Quality in Six Watersheds of Gwinnett County, Georgia
Watershed management is critical for the protection and enhancement of streams that provide multiple benefits for Gwinnett County, Georgia, and downstream communities. Successful watershed management requires an understanding of how stream quality is affected by watershed characteristics. The influence of watershed characteristics on stream quality is complex, particularly for the nonpoint sources of pollutants that affect urban watersheds. The U.S. Geological Survey (USGS), in cooperation with Gwinnett County Department of Water Resources (formerly known as Public Utilities), established a water-quality monitoring program during late 1996 to collect comprehensive, consistent, high-quality data for use by watershed managers. Between 1996 and 2003, more than 10,000 analyses were made for more than 430 water-quality samples. Continuous-flow and water-quality data have been collected since 1998. Loads have been computed for selected constituents from 1998 to 2003. Changing stream hydrology is a primary driver for many other water-quality and aquatic habitat effects. Primary factors affecting stream hydrology (after watershed size and climate) within Gwinnett County are watershed slope and land uses. For the six study watersheds in Gwinnett County, watershedwide imperviousness up to 12 percent does not have a well-defined influence on stream hydrology, whereas two watersheds with 21- and 35-percent impervious area are clearly impacted. In the stream corridor, however, imperviousness from 1.6 to 4.4 percent appears to affect baseflow and stormflow for all six watersheds. Relations of concentrations to discharge are used to develop regression models to compute constituent loads using the USGS LOAD ESTimator model. A unique method developed in this study is used to calibrate the model using separate baseflow and stormflow sample datasets. The method reduced model error and provided estimates of the load associated with the baseflow and stormflow parts of the hydrograph. Annual load of total suspended sediment is a performance criterion in Gwinnett County's Watershed Protection Plan. Median concentrations of total suspended solids in stormflow range from 30 to 180 times greater than in baseflow. This increase in total suspended solids concentration with increasing discharge has a multiplied effect on total suspended solids load, 97 to 99 percent of which is transported during stormflow. Annual total suspended solids load is highly dependent on annual precipitation; between 1998 and 2003 load for the wettest year was up to 28 times greater than for the driest year. Average annual total suspended solids yield from 1998-2003 in the six watersheds increased with high-density and transportation/utility land uses, and generally decreased with low-density residential, estate/park, and undeveloped land uses. Watershed characteristics also were related to annual loads of total phosphorus, dissolved phosphorus, total nitrogen, total dissolved solids, biochemical oxygen demand, and total zinc, as well as stream alkalinity. Flow-adjusted total suspended solids, total phosphorus, and total zinc stormflow concentrations between 1996 and 2003 have a seasonal pattern in five of the six watersheds. Flow-adjusted concentrations typically peak during late summer, between July and August. The seasonal pattern is stronger for more developed watersheds and may be related to seasonal land-disturbance activities and/or to seasonal rainfall intensity, both of which increase in summer. Adjusting for seasonality in the computation of constituent load caused the standard error of annual total suspended solids load to improve by an average of 11 percent, and increased computed summer total suspended solids loads by an average of 45 percent and decreased winter total suspended solids loads by an average of 40 percent. Total annual loads changed by less than 5 percent on the average. Graphical and statistical analyses do not indicate a time tre
Flooding in southeastern United States from tropical storm Alberto, July 1994
In July 1994, parts of Georgia, Alabama and Florida were devastated by floods resulting from rainfall produced by Tropical Storm Alberto. The flooding resulted in 33 human deaths in towns and small communities or near swollen streams. Total damages to public and private property were estimated at nearly $1 billion dollars. This article highlights severe stream flooding resulting from Alberto and describes U.S. Geological Survey (USGS) efforts to document this event and provide information to those who need it.
Epic Flooding in Georgia, 2009
Metropolitan Atlanta-September 2009 Floods The epic floods experienced in the Atlanta area in September 2009 were extremely rare. Eighteen streamgages in the Metropolitan Atlanta area had flood magnitudes much greater than the estimated 0.2-percent (500-year) annual exceedance probability. The Federal Emergency Management Agency (FEMA) reported that 23 counties in Georgia were declared disaster areas due to this flood and that 16,981 homes and 3,482 businesses were affected by floodwaters. Ten lives were lost in the flood. The total estimated damages exceed $193 million (H.E. Longenecker, Federal Emergency Management Agency, written commun., November 2009). On Sweetwater Creek near Austell, Ga., just north of Interstate 20, the peak stage was more than 6 feet higher than the estimated peak stage of the 0.2-percent (500-year) flood. Flood magnitudes in Cobb County on Sweetwater, Butler, and Powder Springs Creeks greatly exceeded the estimated 0.2-percent (500-year) floods for these streams. In Douglas County, the Dog River at Ga. Highway 5 near Fairplay had a peak stage nearly 20 feet higher than the estimated peak stage of the 0.2-percent (500-year) flood. On the Chattahoochee River, the U.S. Geological Survey (USGS) gage at Vinings reached the highest level recorded in the past 81 years. Gwinnett, De Kalb, Fulton, and Rockdale Counties also had record flooding. South Georgia March and April 2009 Floods The March and April 2009 floods in South Georgia were smaller in magnitude than the September floods but still caused significant damage. No lives were lost in this flood. Approximately $60 million in public infrastructure damage occurred to roads, culverts, bridges and a water treatment facility (Joseph T. McKinney, Federal Emergency Management Agency, written commun., July 2009). Flow at the Satilla River near Waycross, exceeded the 0.5-percent (200-year) flood. Flows at seven other stations in South Georgia exceeded the 1-percent (100-year) flood.
Hydrogeologic setting, conceptual groundwater flow system, and hydrologic conditions 1995–2010 in Florida and parts of Georgia, Alabama, and South Carolina
The hydrogeologic setting and groundwater flow system in Florida and parts of Georgia, Alabama, and South Carolina is dominated by the highly transmissive Floridan aquifer system. This principal aquifer is a vital source of freshwater for public and domestic supply, as well as for industrial and agricultural uses throughout the southeastern United States. Population growth, increased tourism, and increased agricultural production have led to increased demand on groundwater from the Floridan aquifer system, particularly since 1950. The response of the Floridan aquifer system to these stresses often poses regional challenges for water-resource management that commonly transcend political or jurisdictional boundaries. To help water-resource managers address these regional challenges, the U.S. Geological Survey (USGS) Water Availability and Use Science Program began assessing groundwater availability of the Floridan aquifer system in 2009. The current conceptual groundwater flow system was developed for the Floridan aquifer system and adjacent systems partly on the basis of previously published USGS Regional Aquifer-System Analysis (RASA) studies, specifically many of the potentiometric maps and the modeling efforts in these studies. The Floridan aquifer system extent was divided into eight hydrogeologically distinct subregional groundwater basins delineated on the basis of the estimated predevelopment (circa 1880s) potentiometric surface: (1) Panhandle, (2) Dougherty Plain-Apalachicola, (3) Thomasville-Tallahassee, (4) Southeast Georgia-Northeast Florida-South South Carolina, (5) Suwannee, (6) West-central Florida, (7) East-central Florida, and (8) South Florida. The use of these subregions allows for a more detailed analysis of the individual basins and the groundwater flow system as a whole. The hydrologic conditions and associated groundwater budget were updated relative to previous RASA studies to include additional data collected since the 1980s and to reflect the entire groundwater flow system, including the surficial, intermediate, and Floridan aquifer systems for a contemporary period (1995–2010). Inflow to the groundwater flow system of 33,700 million gallons per day (Mgal/d) was assumed to be exclusively from net recharge (precipitation minus evapotranspiration and surface runoff). Outflow from the groundwater flow system included spring discharge (7,700 Mgal/d) and groundwater withdrawals (5,200 Mgal/d). Estimates for all components of the groundwater system were not possible because of large uncertainties associated with internal leakage, coastal discharge, and discharge to streams and lakes. A numerical modeling analysis is required to improve this hydrologic budget calculation and to forecast future changes in groundwater levels and aquifer storage caused by groundwater withdrawals, land-use change, and the effects of climate variability and change.
Simulation of groundwater flow in the Brunswick Area, Georgia, for 2004 and 2015, and selected groundwater-management scenarios
The Upper Floridan aquifer (UFA) is the principal water source for industrial and public supply in Glynn County, Georgia. Wells in active pumping centers that tap the UFA for industries near the city of Brunswick have created an upward hydraulic-head gradient in the Floridan aquifer system, which has allowed high chloride (saline) groundwater from the Fernandina permeable zone of the Lower Floridan aquifer (LFA) to migrate upward into freshwater zones. Chloride concentrations of more than 250 milligrams per liter—the State and Federal secondary drinking-water standard—have been measured in a 2-square-mile area near downtown Brunswick. An existing regional U.S. Geological Survey modular finite-difference groundwater-flow model (MODFLOW-2000) was modified using greater horizontal and vertical resolution to enable more detailed simulation of the effects of pumping in the vicinity of chloride contamination. Modifications to the regional model consisted of (1) limiting grid size to a maximum of 500 feet (ft) per side in the vicinity of the chloride plume; (2) representing the upper and lower Brunswick aquifers with distinct model layers; (3) similarly, representing upper and lower water-bearing zones of the UFA with distinct model layers in Glynn and Camden Counties, Ga.; and (4) establishing new hydraulic-property geographic zones in the UFA within Glynn County. The revised groundwater-flow model was calibrated to steady-state conditions that were assumed to exist during 2000 and 2004. The calibration and framework of the revised groundwater-flow model were documented in a separate report. For the current study, steady-state conditions were calibrated using October 2015 pumping rates in the Brunswick/Glynn County area as a 2015 Base Case. The 2015 Base Case simulation was used as the basis to evaluate seven groundwater-management scenarios in the Brunswick/Glynn County area. Seven groundwater management-scenarios were developed on the basis of short- and long-term groundwater-use projections for the UFA in the Brunswick/Glynn County area. Scenarios A and B simulated additional pumping in the upper water-bearing zone (UWBZ) of the UFA at existing public-supply wells located near a chloride plume and planned public-supply wells to be constructed north of downtown Brunswick. Scenario C simulated a shutdown at Brunswick Cellulose Inc. and Pinova Inc. and the resulting deactivation of nine production wells, with a combined total pumping of 31.3 million gallons per day (Mgal/d) for the 2015 Base Case simulation. Scenario D (three scenarios) simulated 12.5, 25, and 50 percent (designated Scenarios D1, D2, and D3) of the total pumping of 31.3 Mgal/d at Brunswick Cellulose and Pinova. The objective of Scenario D was to determine pumping rates that may reverse groundwater-flow directions toward the Brunswick Cellulose well field and potentially allow groundwater with higher chloride concentration to migrate toward nearby public-supply wells. Scenario E simulated an additional pumping of 5 Mgal/d from the UWBZ of the UFA at a recently constructed production well within the Brunswick Cellulose well field. Backward particle-tracking (MODPATH) analysis in public-supply wells located just outside the chloride plume to the north shows that predominant groundwater-flow directions are from the northeast toward the Brunswick Cellulose well field. The analysis covered 20- and 50-year periods for the 2015 Base Case and Scenario C simulations with 100 percent of backtracked particles remaining in the UWBZ and lower water-bearing zone of the UFA. Groundwater-flow directions are characterized by some vertical movement and dominant horizontal movement away from the chloride plume in the northern Brunswick area. For the 2015 Base Case simulation, the mean rate of particle movement ranged from 268 to 413 feet per year. For the Scenario C simulation, the mean rate of particle movement ranged from 89 to 182 feet per year with 50 percent of particles migrating from the chloride plume area. The rate of particle movement is influenced most by the horizontal hydraulic-head gradient in the UWBZ of the UFA. The revised groundwater-flow model is subject to the limitations documented in the original model. In addition, the values used for the specified-head boundaries in the Floridan aquifer system for the 2004 calibrated model were based on the sparse data available and were not changed for the 2015 update to the model. These model boundaries control 80 percent of the inflows and about 60 percent of the outflows. Composite-scaled sensitivities of the model parameters indicate the revised model is most sensitive to pumping rates, followed by the horizontal hydraulic conductivity in the UFA for zones along coastal Georgia.
U.S. Geological Survey Karst Interest Group Proceedings, San Antonio, Texas, May 16–18, 2017
Introduction and Acknowledgments Karst aquifer systems are present throughout parts of the United States and some of its territories, and have developed in carbonate rocks (primarily limestone and dolomite) and evaporites (gypsum, anhydrite, and halite) that span an interval of time encompassing more than 550 million years. The depositional environments, diagenetic processes, post-depositional tectonic events, and geochemical weathering processes that form karst aquifers are varied and complex. These factors involve biological, chemical, and physical changes that when combined with the diverse climatic regimes in which karst development has taken place, result in the unique dual- or triple-porosity nature of karst aquifers. These complex hydrogeologic systems typically represent challenging and unique conditions to scientists attempting to study groundwater flow and contaminant transport in these terrains. The dissolution of carbonate rocks and the subsequent development of distinct and beautiful landscapes, caverns, and springs have resulted in the most exceptional karst areas being designated as national or state parks. Tens of thousands of similar areas in the United States have been developed into commercial caverns and known privately owned caves. Both public and private properties provide access for scientists to study the flow of groundwater in situ . Likewise, the range and complexity of landforms and groundwater flow systems associated with karst terrains are enormous, perhaps more than for any other aquifer type. Karst aquifers and landscapes that form in tropical areas, such as the cockpit karst along the north coast of Puerto Rico, differ greatly from karst landforms in more arid climates, such as the Edwards Plateau in west-central Texas or the Guadalupe Mountains near Carlsbad, New Mexico, where hypogenic processes have played a major role in speleogenesis. Many of these public and private lands also contain unique flora and fauna associated with these karst hydrogeologic systems. As a result, numerous federal, state, and local agencies have a strong interest in the study of karst terrains. Many of the major springs and aquifers in the United States have developed in carbonate rocks, such as the Floridan aquifer system in Florida and parts of Alabama, Georgia, and South Carolina; the Ozark Plateaus aquifer system in parts of Arkansas, Kansas, Missouri, and Oklahoma; and the Edwards-Trinity aquifer system in west-central Texas. These aquifers, and the springs that discharge from them, serve as major water-supply sources and form unique ecological habitats. Competition for the water resources of karst aquifers is common, and urban development and the lack of attenuation of contaminants in karst areas due to dissolution features that form direct pathways into karst aquifers can impact the ecosystem and water quality associated with these aquifers. The concept for developing a platform for interaction among scientists within the U.S. Geological Survey (USGS) working on karst-related studies evolved from the November 1999 National Groundwater Meeting of the USGS. As a result, the Karst Interest Group (KIG) was formed in 2000. The KIG is a loose-knit, grass-roots organization of USGS and non-USGS scientists and researchers devoted to fostering better communication among scientists working on, or interested in, karst science. The primary mission of the KIG is to encourage and support interdisciplinary collaboration and technology transfer among scientists working in karst areas. Additionally, the KIG encourages collaborative studies between the different mission areas of the USGS as well as with other federal and state agencies, and with researchers from academia and institutes. To accomplish its mission, the KIG has organized a series of workshops that have been held near nationally important karst areas. To date (2017) seven KIG workshops, including the workshop documented in this report, have been held. The workshops typically include oral and poster sessions on selected karst-related topics and research, as well as field trips to local karst areas. To increase non-USGS participation an effort was made for the workshops to be held at a university or institute beginning with the fourth workshop. Proceedings of the workshops are published by the USGS and are available online at the USGS publications warehouse https://pubs.er.usgs.gov/ by using the search term “karst interest group.” The first KIG workshop was held in St. Petersburg, Florida, in 2001, in the vicinity of the large springs and other karst features of the Floridan aquifer system. The second KIG workshop was held in 2002, in Shepherdstown, West Virginia, in proximity to the carbonate aquifers of the northern Shenandoah Valley, and highlighted an invited presentation on karst literature by the late Barry F. Beck of P.E. LaMoreaux and Associates. The third KIG workshop was held in 2005, in Rapid City, South Dakota, near evaporite karst features in limestones of the Madison Group in the Black Hills of South Dakota. The Rapid City KIG workshop included field trips to Wind Cave National Park and Jewel Cave National Monument, and featured a presentation by Thomas Casadevall, then USGS Central Region Director, on the status of Earth science at the USGS. The fourth KIG workshop in 2008 was hosted by the Hoffman Environmental Research Institute and Center for Cave and Karst Studies at Western Kentucky University in Bowling Green, Kentucky, near Mammoth Cave National Park and karst features of the Chester Upland and Pennyroyal Plateau. The workshop featured a late-night field trip into Mammoth Cave led by Rickard Toomey and Rick Olsen, National Park Service. The fifth KIG workshop in 2011 was a joint meeting of the USGS KIG and University of Arkansas HydroDays, hosted by the Department of Geosciences at the University of Arkansas in Fayetteville. The workshop featured an outstanding field trip to the unique karst terrain along the Buffalo National River in the southern Ozarks, and a keynote presentation on paleokarst in the United States was delivered by Art and Peggy Palmer. The sixth KIG workshop was hosted by the National Cave and Karst Research Institute (NCKRI) in 2014, in Carlsbad, New Mexico. George Veni, Director of the NCKRI, served as a co-chair of the workshop with Eve Kuniansky of the USGS. The workshop featured speaker Dr. Penelope Boston, Director of Cave and Karst Studies at New Mexico Tech, Socorro, and Academic Director at the NCKRI, who addressed the future of karst research. The field trip on evaporite karst of the lower Pecos Valley was led by Lewis Land (NCKRI karst hydrologist), and the field trip on the geology of Carlsbad Caverns National Park was led by George Veni. This current seventh KIG workshop is being held in San Antonio at the University of Texas at San Antonio (UTSA). This 2017 workshop is being hosted by the Department of Geological Sciences’ Student Geological Society (SGS), and student chapters of the American Association of Petroleum Geologists (AAPG) and Association of Engineering Geologists (AEG), with support by the UTSA Department of Geological Sciences and Center for Water Research. The UTSA student chapter presidents, Jose Silvestre (SGS), John Cooper (AAPG), and Tyler Mead (AEG) serve as co-chairs of the 2017 workshop with Eve Kuniansky of the USGS. The technical session committee is chaired by Eve Kuniansky, USGS, and includes Michael Bradley, Tom Byl, Rebecca Lambert, John Lane, and James Kaufmann, all USGS, and Patrick Tucci, retired USGS. The logistics committee includes Amy Clark, Yongli Gao, and Lance Lambert (Department Chair), UTSA Department of Geological Sciences; and Ryan Banta and Allan Clark, USGS, San Antonio, Texas. The field trip committee is chaired by Allan Clark and includes Amy Clark, Yongli Gao, and Keith Muehlestein, UTSA; Marcus Gary, Edwards Aquifer Authority and University of Texas at Austin; Ron Green, Southwest Research Institute; Geary Schindel, Edwards Aquifer Authority; and George Veni, NCKRI. Additionally, two organizations have assisted the UTSA student chapters in hosting the meeting by donating funds to the chapters: the Edwards Aquifer Authority, San Antonio, Texas, and the Barton Springs Edwards Aquifer Authority, Austin, Texas. Additionally, Yongli Gao, Center for Water Research and Department of Geological Sciences, UTSA, helped develop sessions on cave and karst research in China for this workshop. These proceedings could not have been accomplished without the assistance of Lawrence E. Spangler as co-editor who not only has subject matter expertise, but also serves as an editor with the USGS Science Publishing Network. We sincerely hope that this workshop continues to promote future collaboration among scientists of varied and diverse backgrounds, and improves our understanding of karst aquifer systems in the United States and its territories. The extended abstracts of USGS authors were peer reviewed and approved for publication by the USGS. Articles submitted by university researchers and other federal and state agencies did not go through the formal USGS peer review and approval process, and therefore may not adhere to USGS editorial standards or stratigraphic nomenclature. However, all articles had a minimum of two peer reviews and were edited for consistency of appearance in the proceedings. The use of trade, firm or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. The USGS Water Availability and Use Science Program funded the publication costs of the proceedings.
Georgia's Surface-Water Resources and Streamflow Monitoring Network, 2006
The U.S. Geological Survey (USGS) network of 223 real-time monitoring stations, the 'Georgia HydroWatch,' provides real-time water-stage data, with streamflow computed at 198 locations, and rainfall recorded at 187 stations. These sites continuously record data on 15-minute intervals and transmit the data via satellite to be incorporated into the USGS National Water Information System database. These data are automatically posted to the USGS Web site for public dissemination (http://waterdata.usgs.gov/ga/nwis/nwis). The real-time capability of this network provides information to help emergency-management officials protect human life and property during floods, and mitigate the effects of prolonged drought. The map at right shows the USGS streamflow monitoring network for Georgia and major watersheds. Streamflow is monitored at 198 sites statewide, more than 80 percent of which include precipitation gages. Various Federal, State, and local agencies fund these streamflow monitoring stations.
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.
U.S. Geological Survey Karst Interest Group Proceedings, Carlsbad, New Mexico, April 29-May 2, 2014
Karst aquifer systems are present throughout parts of the United States and some of its territories, and have developed in carbonate rocks (primarily limestone and dolomite) that span an interval of time encompassing more than 550 million years. The depositional environments, diagenetic processes, post-depositional tectonic events, and geochemical weathering processes that form karst aquifers are varied and complex, and involve biological, chemical, and physical changes. These factors, combined with the diverse climatic regimes under which karst development in these rocks has taken place, result in the unique dual- or triple-porosity nature of karst aquifers. These complex hydrogeologic systems typically represent challenging and unique conditions to scientists attempting to study groundwater flow and contaminant transport in these terrains. The dissolution of carbonate rocks and the subsequent development of distinct and beautiful landscapes, caverns, and springs has resulted in the most exceptional karst areas of the United States being designated as national or state parks; commercial caverns and known privately owned caves number in the tens of thousands. Both public and private properties provide access for scientists to study the flow of groundwater in situ. Likewise, the range and complexity of landforms and groundwater flow systems associated with karst terrains are enormous, perhaps more than for any other aquifer type. Karst aquifers and landscapes that form in tropical areas, such as the cockpit karst along the north coast of Puerto Rico, differ greatly from karst landforms in more arid climates, such as the Edwards Plateau in west-central Texas or the Guadalupe Mountains near Carlsbad, New Mexico, where hypogenic processes have played a major role in speleogenesis. Many of these public and private lands also contain unique flora and fauna associated with these karst hydrogeologic systems. As a result, numerous federal, state, and local agencies have a strong interest in the study of karst terrains. Many of the major springs and aquifers in the United States have developed in carbonate rocks, such as the Floridan aquifer system in Florida and parts of Alabama, Georgia, and South Carolina; the Ozark Plateaus aquifer system in parts of Arkansas, Kansas, Missouri, and Oklahoma; and the Edwards-Trinity aquifer system in west-central Texas. These aquifers, and the springs that discharge from them, serve as major water-supply sources and as unique ecological habitats. Competition for the water resources of karst aquifers is common, and urban development and the lack of attenuation of contaminants in karst areas can impact the ecosystem and water quality of these aquifers. The concept for developing a platform for interaction among scientists within the U.S. Geological Survey (USGS) working on karst-related studies evolved from the November 1999 National Ground-Water Meeting of the USGS. As a result, the Karst Interest Group (KIG) was formed in 2000. The KIG is a loose-knit, grass-roots organization of USGS and non-USGS scientists and researchers devoted to fostering better communication among scientists working on, or interested in, karst science. The primary mission of the KIG is to encourage and support interdisciplinary collaboration and technology transfer among scientists working in karst areas. Additionally, the KIG encourages collaborative studies between the different mission areas of the USGS as well as other federal and state agencies, and with researchers from academia and institutes. The KIG also encourages younger scientists by participation of students in the poster and oral sessions. To accomplish its mission, the KIG has organized a series of workshops that are held near nationally important karst areas. To date (2014) six KIG workshops, including the workshop documented in this report, have been held. The workshops typically include oral and poster sessions on selected karst-related topics and research, as well as field trips to local karst features. Proceedings of the workshops are published by the USGS and are available online at http://water.usgs.gov/ogw/karst/kig . The first KIG workshop was held in St. Petersburg, Florida, February 13–16, 2001, in the vicinity of the large springs and other karst features of the Floridan aquifer system. The second KIG workshop was held August 20–22, 2002, in Shepherdstown, West Virginia, in proximity to the carbonate aquifers of the northern Shenandoah Valley and highlighted an invited presentation on karst literature by the late Barry F. Beck of P.E. LaMoreaux and Associates. The third KIG workshop was held September 12–15, 2005, in Rapid City, South Dakota, nearby to karst features in evaporites and limestones of the Madison Group in the Black Hills of South Dakota, including Wind Cave National Park and Jewel Cave National Monument. The workshop also included a featured presentation by Thomas Casadevall, Central Region Director, USGS, on the status of earth science at the USGS and evening trips to Jewel Cave led by Mike Wiles, National Park Service (NPS) and Wind Cave led by Rod Horrocks, NPS. The fourth KIG workshop was held May 27–29, 2008, and hosted by the Hoffman Environmental Research Institute and Center for Cave and Karst Studies at Western Kentucky University in Bowling Green, Kentucky, near Mammoth Cave National Park and karst features of the Chester Upland and Pennyroyal Plateau. The workshop featured a late-night field trip into Mammoth Cave with Rickard Toomey and Rick Olsen, NPS. The fifth workshop was held April 26–29, 2011, and was a joint meeting of the USGS KIG and University of Arkansas HydroDays, hosted by the Department of Geosciences at the University of Arkansas in Fayetteville. The workshop featured an outstanding field trip to the unique karst terrain along the Buffalo National River of the southern Ozarks and a keynote presentation on paleokarst in the United States by Art and Peggy Palmer. This sixth and current 2014 KIG workshop is hosted by the National Cave and Karst Research Institute (NCKRI) in Carlsbad, New Mexico, with Director of NCKRI, George Veni, serving as co-chair of the workshop with Eve Kuniansky, USGS. The session planning committee for this sixth workshop includes Van Brahana, USGS retired and University of Arkansas Professor Emeritus; Tom Byl, USGS and Tennessee State University; Zelda Bailey, former Director of NCKRI and retired Director, National Institute of Standards and Technology, Boulder Laboratory, Colorado; Patrick Tucci, USGS retired; and Mike Bradley, Allan Clark, Geoff Delin, Daniel Doctor, James Kaufmann, Eve Kuniansky, Randy Orndorff, Larry Spangler, and Dave Weary of the USGS. The karst hydrology field trip on Thursday will be led by Lewis Land (NCKRI karst hydrologist) and the optional Friday field trip on the geology of Carlsbad Caverns National Park will be led by George Veni. The keynote speaker is Dr. Penelope Boston, Director of Cave and Karst Studies at New Mexico Tech, Socorro, and Academic Director at NCKRI, who will address the future of karst research. Additionally, there is a featured presentation “Irish karst and its management,” by Caoimhe Hickey, The Geological Survey of Ireland, preceding a panel discussion on “Collaboration During Times of Limited Resources.” The extended abstracts of USGS authors were peer reviewed and approved for publication by the U.S. Geological Survey. Articles submitted by university researchers and other federal and state agencies did not go through the formal USGS peer review and approval process, and therefore may not adhere to our editorial standards or stratigraphic nomenclature and is not research conducted or data collected by the USGS. However, all articles had at a minimum of two peer reviews, and all articles were edited for consistency of appearance in the published Proceedings. The use of trade, firm or product names in any article is for descriptive purposes only and does not imply endorsement by the U.S. Government. The USGS, Office of Groundwater, provides technical support for the Karst Interest Group website and public availability of the Proceedings from these workshops, and the USGS Groundwater Resources Program funds the publication costs. Finally, the cover illustration is the work of Ann Tihansky, USGS, used since the first KIG workshop in 2000.
Monitoring and real-time modeling of Escherichia coli bacteria for the Chattahoochee River, Chattahoochee River National Recreation Area, Georgia, 2000–2019
The Chattahoochee River National Recreation Area (CRNRA) is a National Park Service unit/park with 48 miles of urban waterway in the Atlanta metropolitan area. The Chattahoochee River within the CRNRA is a popular place for water-based recreation but is known to periodically experience elevated levels of fecal-coliform bacteria associated with warm-blooded animals that can result in a variety of pathogen-related human illnesses. In 2000, the National Park Service entered into a public-private partnership with the U.S. Geological Survey (USGS) and the Chattahoochee Riverkeeper, called the Chattahoochee River BacteriALERT program, to monitor Escherichia coli ( E. coli ), which is a fecal indicator bacteria and a proxy for human health risk from waterborne pathogens. The BacteriALERT network monitors E. coli densities at three stations on the Chattahoochee River within the CRNRA, at Norcross (USGS station 02335000), Powers Ferry (USGS station 02335880), and Atlanta (USGS station 02336000). E. coli densities determined from water samples were compared to the U.S. Environmental Protection Agency’s Beach Action Value (BAV) of 235 colony forming units per 100 milliliters to assess whether conditions were considered safe for freshwater, primary contact recreational use. Sample E. coli densities exceeded the BAV for 15.5 percent of the samples collected at Norcross (n = 1,969) and 30.3 percent of the samples at Atlanta (n = 1,938) for the study period October 23, 2000, to May 23, 2019, and 33.6 percent of the samples from Powers Ferry (n = 134) for the study period May 5, 2016, to May 23, 2019. Models to predict E. coli densities in near real-time were developed for the three BacteriALERT stations. Models were developed using forward-stepwise multiple linear regression with the Bayesian Information Criteria and were calibrated with samples collected between October 4, 2007, and May 23, 2019. Explanatory variables included season, turbidity, water temperature, streamflow, upstream tributary streamflows, and temporal trend. The most statistically significant explanatory variables in the models were turbidity, upstream tributary streamflows, and season. The Norcross model had an increasing trend in E. coli densities of 2.3 percent per year. A significant trend was not detected for the Atlanta station, while trends were not assessed for Powers Ferry models due to the short (3-year) calibration period. Model adjusted R 2 s ranged from 0.686 (Atlanta) to 0.795 (Norcross with time trend) indicating that the models explained a substantial portion of the variations in E. coli densities. Evaluation of model predictions and residuals indicated that models were well posed and exhibited little bias. The models performed well in accurately determining compliance and exceedance of the BAV with low misidentification rates ranging from 3.5 percent (Norcross) to 11.3 percent (Powers Ferry). Misidentification was most common for densities near the BAV, and misidentification rates in the study were low despite fairly low model precisions because E. coli densities were infrequently near the BAV. The precisions of the models developed herein were comparable to the more complex models developed by Lawrence (2012) that were never implemented in the BacteriALERT program due to their computational complexity. The predictive E. coli models developed herein will improve the ability to assess the health risks of water-based recreational activities in the CRNRA in near real-time.