«Chattahoochee River Basin Plan Section 5 $VVHVVPHQWV This section provides an evaluation of current conditions in the Chattahoochee River Basin, and ...»
Chattahoochee River Basin Plan
This section provides an evaluation of current conditions in the Chattahoochee River Basin, and
includes assessment of both water quantity (Section 5.1) and water quality (Section 5.2) issues.
The assessment results are combined with the evaluation of environmental stressors (Section 4)
to produce a listing of Concerns and Priority Issues in Section 6.
5.1 Assessment of Water Quantity
Water quantity issues in the Chattahoochee River Basin are being addressed comprehensively as part of the ACT/ACF study. In that process an Interstate Compact is to be established for the purpose of administering a water allocation formula which will partition the flow of the Chattahoochee and Flint Rivers among Alabama, Florida, and Georgia. The following sections provide a summary of preliminary findings from this study.
5.1.1 Municipal and Industrial Water Uses As noted in Section 3.2, Municipal and Industrial (M&I) demands in the Chattahoochee River Basin are expected to increase by about 6% between 1995 and 2005, virtually all from surface water sources. By the year 2050, M&I water use is expected to increase only another 16%, largely because industrial use will decrease substantially. Although there will undoubtedly be some problems in meeting these increased demands, given the high priority placed on meeting drinking water needs, meeting these demands should not exceed the availability of raw water sources, especially since approximately 80% of the M&I withdrawals are returned to the river.
Overall the surface water quality in the Chattahoochee River Basin is good for use as drinking water. However, surface water quality problems due to non-point source pollution such as agricultural and storm water runoff are concerns to municipalities which withdraw surface water from the Chattahoochee River and tributaries. The contaminant of most concern is high turbidity due to erosion and sediment runoff. Water high in turbidity can clog filters, interrupt the proper treatment of raw water, and increase the cost of the water to the consumers because more chemicals are needed to settle out the sediment. All public water systems in the state of Georgia that use surface water meet the federal Surface Water Treatment Rules for filtration and treatment.
Overall ground water quality is very good for use as drinking water from wells. Since most wells used in public water systems are constructed by licensed well drillers and draw from deeper aquifers, the number of contaminated wells is small. However, in the Chattahoochee Basin some public water system wells have been contaminated by local pollution sources such as leaky underground storage tanks, malfunctioning septic tank systems, and spills. Those wells that exceed the Maximum Contaminant Level (MCL) for a contaminant are either removed from service or addedtreatment to the system. Also, a few wells in the basin have been found to be under the direct influence of surface water due to the geology of the area in which the well is located. These wells are monitored and have additional treatment requirements.
5.1.2 Agriculture The water demand for agricultural use in the Chattahoochee Basin is, and will remain for the foreseeable future, a small portion of the total demand. Whether taken from surface or ground water sources, there is no reason to believe that the supply will not be adequate, even during a drought year.
5.1.3 Recreation In the Chattahoochee Basin the availability of water is most likely to have a significant effect on recreation through the way in which water levels are managed at Lake Lanier. Because of the significant recreational use of Lake Lanier, and the tremendous investment in homes and recreation activities around the lake, it is very important that water levels be kept as high as possible, especially in the spring, summer, and early fall. Water level management is as much a function of the way in which the reservoirs are operated as of water availability, however.
Should the Corps of Engineers operate the dam in a manner which emphasizes power production and a conservative flood control philosophy, water levels will not be kept as high as would be the case if storage were to be maximized as a precaution against a drought. Under the Corps’ conservative operational philosophy, when a drought occurs there will likely be a greater chance that water levels will drop below that which supports optimum recreation potential.
However, there are significant issues related to flood protection which must be considered carefully before normal pool levels are raised. The ACT/ACF Study should address this issue as well as that of water flow allocation in the basins.
5.1.4 Hydropower Hydropower production to meet peaking needs is dependent on timely release of water through the turbines in the major reservoirs. The continued release of sufficient quantities of water to meet the peaking demand during droughts will be dependent on the water allocation decisions made by the ACF Interstate Compact Commission, and also by decisions made within Georgia about in-state allocation of the available water supply. Given the priority for meeting drinking and agricultural water needs within Georgia, it is certainly possible that hydropower production could be curtailed at times when water availability is low.
5.1.5 Navigation The Chattahoochee River is navigable upstream to Columbus. Limitations to navigation have historically been associated with the requirement for extensive channel maintenance in the Apalachicola River in Florida. The amount of channel maintenance in the Apalachicola and the amount (and timing) of water to be made available for navigation support will be a subject of the ACF Study and will be part of the considerations involved in establishing a water allocation formula. Late summer and fall are typically the seasons in which water availability is most limited. At these times the Corps is usually only able to provide sufficient water to support navigation during limited time periods (navigation windows). It is unlikely that navigable channel depths will be provided on a full time basis in the future; however, it is hoped that satisfactory navigation channel conditions can be provided in a predictable manner to support Georgia’s shipping needs.
5.1.6 Waste Assimilation Capacity Sufficient flow for assimilation of treated wastewater in the Chattahoochee River is most critical in the reach between Atlanta, and West Point Lake. Criteria have been established for minimum stream flow for this purpose at Peachtree Creek. Georgia has obligations under the Clean Water Act to meet instream water quality standards, and the State places a high priority on this obligation (See Section 6.0). Only under extreme drought conditions, when sufficient water flow is not available after domestic water supply needs are met, would there be insufficient water to meet instream water quality standards.
5.2 Assessment of Water Quality This assessment of water quality is generally consistent with Georgia’s water quality assessments for CWA Section 305(b) reporting to EPA. It begins with a discussion of (1) water quality standards, (2) monitoring programs, and (3) data analyses to assess compliance with water quality standards and determine use support. Following this introductory material, detailed assessment results by sub-basin are presented in Section 5.2.4.
5.2.1 Water Quality Standards Assessment of water quality requires a baseline for comparison. A statewide baseline is provided by Georgia’s water quality standards, which contain water use classifications, numeric standards for chemical concentrations, and narrative requirements for water quality.
Georgia's water use classifications and standards were first established by the Georgia Water Quality Control Board in 1966. The water use classification system was applied to interstate waters in 1972 by EPD. Table 5-1 provides a summary of water use classifications and basic water quality criteria for each water use. Georgia also has general narrative water quality standards, which apply to all waters. These narrative standards are summarized in Table 5-2.
5-3 Section 5: Assessments Table 5-2. Georgia Narrative Water Quality Standards for All Waters (Excerpt from Georgia Rules and Regulations for Water Quality Control Chapter 391-3-6-.03 Water Use Classifications and Water Quality Standards) (5) General Criteria for All Waters. The following criteria are deemed to be necessary and
applicable to all waters of the State:
(a) All waters shall be free from materials associated with municipal or domestic sewage, industrial waste or any other waste which will settle to form sludge deposits that become putrescent, unsightly or otherwise objectionable.
(b) All waters shall be free from oil, scum and floating debris associated with municipal or domestic sewage, industrial waste or other discharges in amounts sufficient to be unsightly or to interfere with legitimate water uses.
(c) All waters shall be free from material related to municipal, industrial or other discharges which produce turbidity, color, odor or other objectionable conditions which interfere with legitimate water uses.
(d) All waters shall be free from toxic, corrosive, acidic and caustic substances discharged from municipalities, industries or other sources, such as nonpoint sources, in amounts, concentrations or combinations which are harmful to humans, animals or aquatic life.
(e) All waters shall be free from turbidity which results in a substantial visual contrast in a water body due to man-made activity. The upstream appearance of a body of water shall be observed at a point immediately upstream of a turbidity-causing man-made activity. The upstream appearance shall be compared to a point which is located sufficiently downstream from the activity so as to provide an appropriate mixing zone.
For land disturbing activities, proper design, installation and maintenance of best management practices and compliance with issued permits shall constitute compliance with [this] Paragraph...
In addition to the basic water quality standards shown above, Congress made changes in the Clean Water Act in 1987 which required each State to adopt numeric limits for toxic substances for the protection of aquatic life and human health. In order to comply with these requirements, in 1989 the Board of Natural Resources adopted 31 numeric standards for protection of aquatic life and 90 numeric standards for the protection of human health. Appendix B provides a complete list of the toxic substance standards that apply to all waters in Georgia. Georgia has adopted all numeric standards for toxic substances promulgated by the USEPA.Georgia is also developing site-specific standards for major lakes where control of nutrient loading is required to prevent problems associated with eutrophication. In September 1995, the Board of Natural Resources adopted lake standards for West Point Lake. Standards were adopted for chlorophyll a, pH, total nitrogen, phosphorus, fecal coliform bacteria, dissolved oxygen, and temperature.
Site-specific standards have also been adopted for Lake Walter F. George. The adopted standards for West Point Lake and Lake Walter F. George are presented in Table 5-3.
5.2.2 Surface Water Quality Monitoring EPD monitoring program integrates physical, chemical, and biological monitoring to provide information for water quality and use attainment assessments and for basin planning. EPD monitors the surface waters of the state to collect baseline and trend data, to document existing conditions, study impacts of specific discharges, determine improvements resulting from upgraded water pollution control plants, support enforcement actions, establish wasteload allocations for new and existing facilities, verify water pollution control plant compliance, document water use impairment and reasons for problems causing less than full support of designated water uses, and develop TMDLs. Trend monitoring, intensive surveys, lake, coastal,
biological, fish tissue, and toxic substance monitoring, and facility compliance sampling are the major monitoring tools used by EPD. Each of these is briefly described in the following sections.
Trend Monitoring. Long term monitoring of streams at strategic locations throughout Georgia, trend or ambient monitoring, was initiated by EPD during the late 1960s. This work was and continues to be accomplished to a large extent through cooperative agreements with federal, state, and local agencies who collect samples from groups of stations at specific, fixed locations throughout the year. The cooperating agencies conduct certain tests in the field and send stream samples to EPD for additional laboratory analyses. Although there have been a number of changes over the years, routine chemical trend monitoring is still accomplished through similar cooperative agreements.
Today EPD contracts with the United States Geological Survey (USGS) for the majority of the trend sampling work, and with the Columbus Water Works for samples on the Chattahoochee below Columbus. In addition to monthly stream sampling, a portion of the work with the USGS involves continuous monitoring at several locations across the State. An automatic monitor which continuously records dissolved oxygen, temperature, pH and conductivity data is located on the Chattahoochee River downstream of Atlanta.
In addition to work done by cooperative agreements, EPD associates collect samples monthly from locations on the Chattahoochee River between Buford Dam to downstream of Atlanta at Georgia Highway 92. EPD associates also collect water and sediment samples for toxic substance analyses, and macroinvertebrate samples to characterize the biological community at selected locations as a part of the trend monitoring effort. The trend monitoring network in place in the Chattahoochee in 1994 is shown in Figure 5-1.
In 1995, EPD adopted and implemented significant changes to the strategy for trend monitoring in Georgia. The changes were implemented to support the River Basin Management Planning program. The number of fixed stations statewide was reduced in order to focus resources for sampling and analysis in a particular group of basins in any one year in accordance with the basin planning schedule.