Geology topics

Julia L. Fanning

Publications and source records attributed to Julia L. Fanning.

4 recordsLinked to original sources

USGS2011

Water withdrawals, wastewater discharge, and water consumption in the Apalachicola-Chattahoochee-Flint River Basin, 2005, and water-use trends, 1970-2005

The Apalachicola-Chattahoochee-Flint (ACF) River Basin covers about 20,500 square miles that drains parts of Alabama, Florida, and Georgia. The basin extends from its headwaters northern Georgia to the Gulf of Mexico. Population in the basin was estimated to be 3.7 million in 2005, an increase of about 41 percent from the 1990 population of 2.6 million. In 2005, slightly more than 721,000 acres of crops were irrigated within the basin. In 2005, the total amount of water withdrawn in the ACF River Basin was about 1,990 million gallons per day (Mgal/d). Of this, surface water accounted for 1,591 Mgal/d (80 percent) and groundwater accounted for 399 Mgal/d (20 percent). Surface water was the primary water source of withdrawals in the northern and central parts of the basin, and groundwater was the primary source in the southern part. The largest surface-water withdrawals was from Cobb County, Georgia (410 Mgal/d, mostly from the Chattahoochee River and Lake Alatoona), and the largest groundwater withdrawals was from Dougherty County, Georgia (38 Mgal/d, mostly from the Upper Floridan aquifer system). Thermoelectric power generation accounted for the largest water withdrawals in 2005 at 788 Mgal/d (40 percent). Most of these withdrawals were used for once-through cooling, and nearly all water used for this purpose was returned to its source. Public supply accounted for 609 Mgal/d (30 percent) of total withdrawals in 2005, followed by agricultural self-supplied (including crop, golf course irrigation, and livestock) at 365 Mgal/d (18 percent), commercial-industrial self-supplied (including mining) at 191 Mgal/d (10 percent), and domestic self-supplied at 37 Mgal/d (2 percent). Public-supply withdrawals were lowest during January, February, and March (about 500 Mgal/d), and highest during September (about 700 Mgal/d). As the population of the ACF River Basin increased by 1.7 million (83 percent) in the 35 years between 1970 and 2005, total withdrawals in the basin increased by more than 515 Mgal/d (35 percent). Of this increase, surface-water accounted for 206 Mgal/d (15 percent) and groundwater accounted for 309 Mgal/d (350 percent). Since 1980, total water withdrawals have generally declined, except in 2000 when they peaked because of below-average rainfall. In 2000, an estimated 49 percent of the water withdrawn for public supply in the basin was consumed, and the remaining 51 percent was returned to the hydrologic system through wastewater treatment systems. In 2005, an estimated 38 percent was consumed and 62 percent was returned to the hydrologic system. This contrast between water withdrawals and wastewater discharges for these years was caused primarily by below-average rainfall during 2000 (a dry year) and above-average rainfall during 2005 (a wet year).

Scientific Investigations Report↗

USGS2009

Water Use in Georgia by County for 2005; and Water-Use Trends, 1980-2005

Water use for 2005 for each county in Georgia was estimated using data obtained from various Federal and State agencies and local sources. Total consumptive water use also was estimated for each county in Georgia for 2005. Water use is subdivided according to offstream and instream use. Offstream use is defined as water withdrawn or diverted from a ground- or surface-water source and transported to the place of use. Estimates for offstream water use include the categories of public supply, domestic, commercial, industrial, mining, irrigation, livestock, aquaculture, and thermoelectric power. Instream use is that which occurs within a stream channel for such purposes as hydroelectric-power generation, navigation, water-quality improvement, fish propagation, and recreation. The only category of instream use estimated was hydroelectric-power generation. Georgia law (the Georgia Ground-Water Use Act of 1972 and the Georgia Water Supply Act of 1978 [Georgia Department of Natural Resources, 2008a,b]) requires any water user who withdraws more than 100,000 gallons per day on a monthly average to obtain a withdrawal permit from the Georgia Environmental Protection Division. Permit holders generally must report their withdrawals by month. The Georgia Water-Use Program collects the reported information under the withdrawal permit system and the drinking-water permit system and stores the data in the Georgia Water-Use Data System.

Fact Sheet↗

USGS2009

Water use in Georgia by county for 2005; and water-use trends, 1980-2005

Water use for 2005 for each county in Georgia was estimated using data obtained from various Federal and State agencies and local sources. Total consumptive water use also was estimated for each county in Georgia for 2005. Estimates of offstream water use include the categories of public supply, domestic, commercial, industrial, mining, irrigation, livestock, and thermoelectric power. The only category of instream use estimated was hydroelectric-power generation. Total offstream water use from ground- and surface-water sources was about 5,471 million gallons per day (Mgal/d) in 2005. Surface water used in the process of thermoelectric-power generation was the largest volume of water withdrawn with withdrawals of 2,717 Mgal/d in 2005. Estimated instream water use for hydroelectric-power generation was 54,096 Mgal/d. Withdrawals for irrigation totaled 752 Mgal/d with 65 percent supplied by ground-water sources. Surface water provided 78 percent of the 1,180 Mgal/d withdrawn for public supply. Many counties in the northern Piedmont physiographic province of Georgia, an area of dense population, had a large percentage of withdrawals from surface-water sources. In contrast, in the southern Coastal Plain physiographic province part of the State, many counties had more withdrawals from ground-water sources. As part of the Georgia Water-Use Program, statewide water-use estimates have been compiled every 5 years since 1980. During this period, water use was greatest in 1980 at 6,725 Mgal/d. Water use decreased by 31 percent to 5,353 Mgal/d in 1990 then increased to 6,487 Mgal/d in 2000. By 2005, water withdrawals had decreased to an estimated 5,471 Mgal/d primarily because of a decline in withdrawals for thermoelectric-power generation and a decline in demands as 2005 was a normal year for precipitation compared to 2000, which was in drought. Throughout the period 1980–2005, water withdrawn for thermoelectric-power generation made up the largest volume of offstream water use in Georgia. Total withdrawals for thermoelectric-power generation decreased about 24 percent in 2005 compared to 2000, due to the decommissioning of three power plants in the State. In addition, several plants operated by Georgia Power Company were retooled during this period to increase water conservation. Public-supply use steadily increased from 1980 to 2000, concurrent with increasing population in the State; however, in 2005, there was a slight decrease in public-supply use. Conversely, industrial water use decreased during the period 1980–2005. Water withdrawals for irrigation during 1980–2005 followed changing hydrologic conditions, increasing during drier years (1980 and 2000) and decreasing during normal or wetter years. Withdrawals for the categories of domestic and commercial use remained about the same during 1980–2005. Livestock and mining use increased in 2005 compared to the 2000 estimates because of changes in estimation techniques. Consumptive water use was determined for each category of use and compiled for each county. Estimation techniques vary for each water-use category. While consumptive use varied for each county in 2005, from about 1 percent to nearly 100 percent of total withdrawals, consumptive-use estimates for the entire State totaled 1,310 Mgal/d, about 24 percent of total withdrawals.

Georgia↗

USGS2001

A field and statistical modeling study to estimate irrigation water use at Benchmark Farms study sites in southwestern Georgia, 1995-96

A benchmark irrigation monitoring network of farms located in a 32-county area in southwestern Georgia was established in 1995 to improve estimates of irrigation water use. A stratified random sample of 500 permitted irrigators was selected from a data base--maintained by the Georgia Department of Natural Resources, Georgia Environmental Protection Division, Water Resources Management Branch--to obtain 180 voluntary participants in the study area. Site-specific irrigation data were collected at each farm using running-time totalizers and noninvasive flowmeters. Data were collected and compiled for 50 farms for 1995 and 130 additional farms for the 1996 growing season--a total of 180 farms. Irrigation data collected during the 1996 growing season were compiled for 180 benchmark farms and used to develop a statistical model to estimate irrigation water use in 32 counties in southwestern Georgia. The estimates derived were developed from using a statistical approach know as "bootstrap analysis" that allows for the estimation of precision. Five model components--whether-to-irrigate, acres irrigated, crop selected, seasonal-irrigation scheduling, and the amount of irrigation applied--compose the irrigation model and were developed to reflect patterns in the data collected at Benchmark Farms Study area sites. The model estimated that peak irrigation for all counties in the study area occurred during July with significant irrigation also occurring during May, June, and August. Irwin and Tift were the most irrigated and Schley and Houston were the least irrigated counties in the study area. High irrigation intensity primarily was located along the eastern border of the study area; whereas, low irrigation intensity was located in the southwestern quadrant where ground water was the dominant irrigation source. Crop-level estimates showed sizable variations across crops and considerable uncertainty for all crops other than peanuts and pecans. Counties having the most irrigated acres showed higher variations in annual irrigation than counties having the least irrigated acres. The Benchmark Farms Study model estimates were higher than previous irrigation estimates, with 20 percent of the bias a result of underestimating irrigation acreage in earlier studies. Model estimates showed evidence of an upward bias of about 15 percent with the likely cause being a misrepresented inches-applied model. A better understanding of the causes of bias in the model could be determined with a larger irrigation sample size and increased substantially by automating the reporting of monthly totalizer amounts.

Georgia↗