«Chattahoochee River Basin Plan Section 3 Water Quantity This section addresses water quantity issues (availability and use), while water quality in ...»
Chattahoochee River Basin Plan
This section addresses water quantity issues (availability and use), while water quality in the
Chattahoochee basin is the subject of Section 4. Water use in the Chattahoochee River Basin is
measured by estimates of freshwater withdrawn from ground and surface water sources, while
water availability is assessed based on annual surface water flows and ground water storage.
Saline water is not used in the basin. Uses of water include both consumptive uses (in which the water is no longer available to the basin) and non-consumptive uses (in which the water is returned to the basin after use). About 20 percent of total Municipal and Industrial (M&I) water withdrawals in 1990 was not returned to surface or ground water sources, primarily due to evaporative losses.
Surface water is the primary water source in the Piedmont Province of the Chattahoochee River Basin because ground water yields from crystalline rock aquifers tend to be low. Within the Coastal Plain province, aquifer yields are higher and ground water withdrawals are an important part of the total water budget. Although most public-supply withdrawals in the Piedmont Province are from surface-water sources, with the exception of counties near or immediately below the Fall Line, most public-supply water in the Coastal Plain comes from ground water sources. The Floridan aquifer system supplied most of the ground water used in the basin in 1990, followed by the Claiborne, Clayton, Piedmont crystalline rock, and the Providence aquifer systems. As previously mentioned, the two sources of supply are not independent, because ground water discharge to streams is important in maintaining dryweather flow. Thus, withdrawal of ground water can, under certain conditions, also result in reduction in surface water flow.
Water use in the Chattahoochee basin is increasing, resulting in greater demands on what are essentially finite supplies. Total water withdrawals in the Apalachicola-Chattahoochee-Flint basin increased by 42 percent between 1970 and 1990 (Couch et al., 1996). During this period, total surface-water withdrawals increased by 29 percent; however, ground water withdrawals increased by 240 percent.
In the following sections, water availability is discussed from a number of viewpoints. First, the important topic of drinking water is presented, which includes both surface and ground water supplies. Then, general surface water availability is presented, followed by ground water availability.
3.1 Drinking Water Supply 3.1.1 Drinking Water Sources Chattahoochee River Basin water is the most utilized surface water source for drinking water in Georgia. The Chattahoochee River, and tributaries, serve a majority of the Atlanta metropolitan population including Fulton, DeKalb, Gwinnett, Forsyth, Douglas and Cobb counties, as well as the city of Columbus. Most surface water intakes are located on the Chattahoochee River, smaller tributaries and Lake Lanier. Communities located in the headwater area of the basin and below Columbus utilize ground water pumped from wells as a source of drinking water. The
locations of surface water intakes within each of the four Hydrologic Units of the Chattahoochee River Basin are shown in Figures 3-1 through 3-4.
The Chattahoochee River Basin provides drinking water for nearly 3 million people in the state of Georgia by municipal or privately owned public water systems. A public water system pipes water for human consumption and has at least 15 service connections or regularly serves at least 25 individuals 60 or more days out of the year. Public water system sources include surface water pumped from rivers and creeks or ground water pumped to the surface from wells or
naturally flowing from springs. There are three different types of public water systems:
community, non-community non-transient, and non-community transient.
A community public water system serves at least 15 service connections used by year round residents or regularly serves at least 25 year-round residents. Examples of community water systems are municipalities, such as cities, counties, and authorities which serve residential homes and businesses located in the areas. Other types of community public water systems include rural subdivisions or mobile home parks which have a large number of homes connected to a private public water system, usually a small number of wells.
A non-community non-transient public water system serves at least 25 of the same persons over six months per year. Examples of non-community non-transient systems are schools, office buildings, and factories which are served by a well.
A non-community transient public water system does not meet the definition of a noncommunity non-transient system. A non-community transient public water system provides piped water for human consumption to at least 15 service connections or which regularly serves at least 25 persons at least 60 days a year. Examples of a non-community transient are highway rest stops, restaurants, motels, and golf courses.
Private domestic wells serving individual houses are not covered by the state’s public water system regulations. However, the regulations for drilling domestic wells are set by the Water Well Standards Act and the local health department is responsible for insuring water quality.
In the Chattahoochee River Basin there are approximately 56 community public water systems utilizing surface water and serving 2,872,087 people and 113 community public water systems utilizing ground water and serving approximately 45,889 people.
3.1.2 Drinking Water Demands Drinking water demands are expected to increase due to the population growth in the Atlanta Metro area, especially in the subdivision communities in Gwinnett, Forsyth, Hall, Cobb and Douglas counties. Due to current and forecasted growth, many of the Atlanta metropolitan counties have adopted water conservation techniques, including ordinances for low flow household plumbing in new construction, limits on outside watering during the summer months, increased water rates to curb excess use, and public education. Projections of drinking water demand volumes are provided in Section 3.2 (surface water) and 3.3 (ground water).
3.1.3 Drinking Water Permitting The Georgia Safe Drinking Water Act of 1977 and the Rules for Safe Drinking Water (391-3-5) adopted under the act require any person who owns and/or operates a public water system to obtain a permit to operate a public water system from the Environmental Protection Division.
The permitting process is set in three phases: Inquiry & Discovery, Technical Review and Permitting. During these phases the owner must provide detailed description of the project;
demonstrate the reliability of water source site; render plans and specifications of demonstrating construction integrity of wells, plants and distribution system; conduct preliminary water sample testing; and submit legal documentation including application to operate a public water system. Permits contain specific conditions the owner must meet for different types of water sources, plants, and distribution systems, including list of approved water sources, filter rates, disinfection and treatment requirements, operator certification, documentation and reporting requirements, compliance with water sample testing schedule, and number of allowed service connections. Permits are issued for ten (10) years and are renewable. There are 332 active and permitted systems in the Chattahoochee River Basin.
Summary of EPD Drinking Water Program The Federal Environmental Protection Agency (EPA) promulgates the rules and regulations for drinking water and passes the responsibility of enforcing the rules to the states with primacy, such as the state of Georgia. In Georgia, public water systems are regulated by the Drinking Water Program (DWP) of the Environmental Protection Division (EPD). The Drinking Water Program in the state of Georgia is divided into Drinking Water Compliance Program (DWCP) and Drinking Water Permitting Program (DWPP). Both programs oversee the 2618 public water systems in the state of Georgia, including the 332 public water systems in the Chattahoochee River Basin.
3.2 Surface Water Quantity 3.2.1 Surface Water Supply Sources Surface water supplies in the Chattahoochee basin include water in rivers, ponds, and reservoirs, including a series of major impoundments on the Chattahoochee mainstem (see Section 2.1.4). Total median annual flow in the Chattahoochee past Andrews Lock and Dam is approximately 2.1 x 10 6 million gallons per year. Reservoirs provide a storage capacity within the basin of approximately 1.2 x 10 6 million gallons.
3.2.2 Surface Water Supply Demands and Uses Municipal and Industrial Demand Municipal and industrial (M&I) water demands include public supplied and private supplied residential, commercial, governmental, institutional, industrial, manufacturing, and other demands such as distribution system water losses. Total M&I water demand in the Georgia part of the Chattahoochee basin (exclusive of power generation cooling water) is expected to increase from 435 million gallons per day (MGD) in 1995 to 446 MGD in 2000 and to 462 MGD in 2005 (Davis et al., 1996) with passive conservation programs in place (see Table 3-1). These passive conservation measures include increases in water use efficiency resulting from recently implemented plumbing codes, the natural replacement of water fixtures, and known increases in water and wastewater prices since 1990. Additionally, in 1995 approximately 70 MGD was supplied from the Chattahoochee basin to regions outside the basin boundary. This demand is projected to increase to 75 MGD in 2000 and to 80 MGD in 2005.
Existing permits for municipal and industrial (non-agricultural) surface water withdrawals in the Chattahoochee River Basin are shown in Table 3-2 (including permits for power generation
cooling water). One-quarter of the non-power generation 1990 demand in the Chattahoochee basin is used in Fulton County. By 2050, this county demand is projected to increase to 31 percent of the total basin demand. In 1990, the residential sectors of the Chattahoochee basin used about the same amount of water as the manufacturing sector (36 percent and 38 percent, respectively). However, by 2050 the residential demand for water is projected to increase to 44 percent of demand in the Chattahoochee basin, while the demand for water by the manufacturing sector is projected to decline to 21 percent of the 2050 basin total demand.
Ninety-nine percent of the Chattahoochee basin M&I water demand in 2005 is projected to be supplied by surface water withdrawals (458 MGD). The ground water M&I withdrawals are projected to be only 4 MGD in the Chattahoochee basin.
Most of the M&I demand is not consumed, but is instead returned back to the Chattahoochee River Basin as treated waste water. In 2005 approximately 82 percent of the in-basin demand is projected to be returned to the river (see Table 3-1).
Agricultural Water Demand In 1992 approximately 117,000 acres in the Georgia portion of the Chattahoochee River Basin were devoted to the production of crops, orchards, turf, nursery, and aquaculture, and 7,600 acres were irrigated. The number of irrigated acres in the Chattahoochee basin is expected to increase to 8,800 by year 2000.
The 1992 agricultural water demand for counties in the Piedmont part of the Chattahoochee River Basin (Georgia and Alabama) was 10,401 MG (50%) and for the Coastal Plain part of the Chattahoochee River Basin 10,394 MG (50% of the total; see Table 3-3). Within Georgia, about 70% of the demand is in the Piedmont section, due to the comparatively small land area of the basin contained within the Coastal Plain. More than half the Coastal Plain demand in the basin is from Alabama. The total agricultural water demand in the entire Chattahoochee River Basin is expected to increase from 21,000 MG (57 MGD) in 1992 to 27,000 MG (75 MGD) in 2000 and to 33,000 MG (92 MGD) in 2010 (NRCS, 1996).
In the Piedmont part of the Chattahoochee River Basin most agricultural water is for livestock and aquaculture, and is supplied from surface water. In the Coastal Plain part of the Chattahoochee River Basin most agricultural water is for crops and orchards, and ground water supplies 44 percent of this water demand. Unlike municipal, industrial, and cooling water withdrawals, practically none of the water withdrawn for agricultural use is returned to streams.
Sixteen power-generating plants located along the mainstem Chattahoochee River use the water resources of the basin (Figure 2-9), including eleven hydropower facilities, four fossil fuel generating facilities, and one nuclear plant (Couch et al., 1996). Two additional powergenerating plants shown on Figure 2-9 are located at the outflow of Lake Seminole. Instream water use by the eleven hydroelectric plants constitutes nearly the entire flow within the river, except during flood conditions, but is nonconsumptive.
Of the 14 mainstem dams in the basin, only George W. Andrews Lock and Dam and City Mills are not operated for hydroelectric power production. The first power-generating dam was the Eagle-Phenix Dam, which was originally constructed in 1834 and reconstructed in 1865 to Table 3-3. Agricultural Water Demand for the Chattahoochee River Basin Year Piedmont Chattahoochee Coastal Chattahoochee Total (Georgia and Alabama) (MG per year, including crops/orchards, turf, nursery, livestock/poultry, and aquaculture demand, from NRCS, 1996, Based on Medium Demand Projections without Water Conservation)
provide hydropower to the Eagle and Phenix Mill. Eight dams are located on the Chattahoochee River just north of Columbus to take advantage of the natural gradient at the Fall Line (Figure 2-9). The total hydroelectric generation capacity is 699,720 kilowatts in the ACF River basin (Fanning et al., 1991).
Power Generation Water Demand Water for thermoelectric-power generation is considered an off stream use of water, and generally is moderately consumptive to non-consumptive. Thermoelectric power is generated at four fossil-fuel plants and one nuclear power plant located in the Chattahoochee River Basin.