Environmental Protection and Stewardship
Results of new reservoir operations policy
|Click chart for data. View 2006 revisions of target figures.
The 2004 figure reflects outages at Blue Ridge and Chatuge dams that impacted minimum flows for that year.
In May 2004, TVA completed a comprehensive study of how it operates the Tennessee River system of dams and reservoirs. The purpose of the study was to determine whether changes in the operating policy would produce greater overall public value. As a result, TVA modified its reservoir operations to include new restrictions on the drawdown (lowering) of reservoir levels, higher winter water levels, and additional recreation releases from TVA dams.
The new operating policy was tested in 2004 and 2005, in both extremely dry and wet weather. In both cases it performed as it was meant to, minimizing flood damage during periods of heavy rain, but also providing enough water for hydropower and other downstream uses during dry weather. TVA was able to meet the objectives associated with the new policy: Water levels were higher through Labor Day on most tributary reservoirs, and targeted recreational releases were met with very few exceptions.
At the same time, TVA continued to meet its responsibilities for flood damage reduction, navigation and power production while also supporting water supply, improved water quality and recreation. The new reservoir operations policy is estimated to cost TVA about $14 million more in annual power production costs.
Dissolved oxygen target attainment
|Click chart for data. View 2006 revisions of target figures.
Previously reported in milligrams/liter day.
TVA’s new policy of maintaining higher reservoir levels through Labor Day may reduce oxygen concentrations in the water released through a dam because the water has stayed in the reservoir longer before it’s released. In 2005, TVA installed new oxygenation systems at eight hydro projects and upgraded equipment at an additional project to maintain oxygen levels in the tailwaters of several dams.
The need for improvements at three more sites is currently under evaluation in 2006. These systems, which benefit fish and other aquatic life that depend on an adequate supply of oxygen in the river, will require a total capital investment of around $17 million and add about $800,000 to TVA’s annual operating costs. For more information, view the video clip at right on water quality and dissolved oxygen.
TVA will continue to fine-tune its operation of the reservoir system as it monitors the effects on aquatic life, wetland plant communities, threatened and endangered species, waterfowl and shorebirds, and sensitive archaeological sites. To measure these effects, TVA is working with the U.S. Fish and Wildlife Service, the Tennessee Wildlife Resources Agency and other federal and state agencies to improve monitoring of these natural and cultural resources. Although more information is being obtained, the preliminary results are encouraging. Read a report on these studies in TVA River Neighbors.
Reducing flood damage is an important function of the reservoir system, and in 2004 TVA averted an estimated $12 million in damages in the TVA region and an additional $6 million along the lower Ohio and Mississippi rivers. No significant flood events occurred in the Tennessee Valley region in 2005, but the operation of TVA-managed reservoirs helped to avert about $14 million in damages along the lower Ohio and Mississippi rivers. Read more at Flood Damage Reduction.
Public input is an important part of TVA’s decision-making processes. One avenue for public feedback is the Regional Resource Stewardship Council, a group of 20 citizens from the TVA region who provide advice to TVA on its stewardship activities, including natural resource management, public land planning and management, water supply and recreation. The council also provides input on key environmental issues. For an example of an issue that the council brought to TVA’s attention, see the next story on water supply. To learn more about its meetings and recommendations, see Regional Resource Stewardship Council.
Water shortages have long been an issue in the dry western states, but with extensive urban growth in the Southeast the question is now hitting closer to home. Recent water wars between Alabama, Georgia and Florida have heightened public awareness of this issue.
Water shortages in some areas have led to increased requests for withdrawals of water from the Tennessee River system into neighboring regions, called interbasin transfers. If these transfers are large enough, they can upset the balance of water uses upstream and downstream, affecting reservoir levels, water quality, river system benefits and overall ecological health, especially in drought years. Such transfers may have a dampening effect on regional growth.
Based on a recommendation from the Regional Resource Stewardship Council, TVA joined with the seven states in the region to address these issues through an initiative called the Tennessee Valley Water Supply Partnership. Because it was not well understood how much water was used daily and returned to the TVA system, nor how many interbasin transfers were occurring from the system, TVA completed a water supply study in 2004. Using data from the study, TVA, in cooperation with the U.S. Geological Survey and the seven states, was able to project water usage to the year 2030 and identify areas that are experiencing water supply problems or might do so in the future. Subsequently, TVA revised its policy for permitting interbasin transfers to include the involvement of all seven states and additional restrictions on water withdrawals and transfers.
The study data were also incorporated into TVA’s Reservoir Operations Study to ensure that future water supply needs would not be affected by revisions to TVA’s reservoir operations policy.
Read more about Water Supply issues.
Ecological health monitoring
Activities that protect the health of the river system must be based on an accurate assessment of actual conditions, and for that reason TVA conducts extensive monitoring of the TVA region’s streams, rivers and reservoirs. It also surveys the availability and health of the most popular types of sport fish and monitors mosquito populations and aquatic plant growth.
Through its ecological health surveys, TVA assesses the presence of oxygen, chlorophyll, contaminants and other important indicators. It shares the relevant data with state agencies to help the states provide public-health advisories on eating fish caught in areas where contaminants may be present and on swimming at sites where bacteria levels might be a consideration.
There are usually only one or two state-issued bacteriological swimming advisories on TVA reservoirs in any given year. Twelve TVA reservoirs have state-issued fish consumption advisories; a reservoir may be listed in its entirety, or only a portion of it may be cited. View reservoir-specific information at Reservoir Ratings.
Protecting archaeological sites
TVA manages about 10,000 archaeological sites on the public lands under its care. The objects found at these sites, such as arrowheads, pottery and metal artifacts, give us important clues about the people who lived in the TVA region hundreds or thousands of years ago. Preventing and treating riverbank erosion helps preserve archaeological sites and prevents the destruction of places with religious and cultural significance to Native Americans.
In 2004-05, TVA’s watershed teams and Cultural Resources staff members protected the eroding riverbanks of 33 archaeological sites by installing riprap. These measures stabilized approximately 21.47 kilometers (13.34 miles) of critically eroding shoreline on TVA reservoirs throughout the region. Work carried out at the two archaeological sites described below provides a good example of the measures TVA takes to protect and preserve such significant cultural resources.
critically impaired shoreline improved
Click chart for data.
• In 2004, TVA stabilized a site on Watts Bar Reservoir by placing 137 meters (450 feet) of riprap. The site was occupied during the Archaic, Woodland and Mississippian prehistoric cultural periods (10,000 years to 500 years ago). The visible cultural features include a multiple mound complex and associated village. The site is considered eligible for listing on the National Register of Historic Places as a significant resource for understanding the prehistory of the southeastern United States.
• In 2005, TVA partnered with the U.S. Fish and Wildlife Service on a project in the Tennessee National Wildlife Refuge to protect 610 meters (2,000 feet) of shoreline. The site’s prehistoric occupations span the time period from 12,000 to 3,000 years ago. This site is also considered eligible for listing on the National Register. Read more about archaeology on TVA lands at Cultural Resources. Also see a special section for young people on the TVA Kids site.
A Thousand Eyes
Because the archaeological sites under TVA’s care are widely scattered, it’s difficult to protect them from looting and desecration. To help combat this problem, TVA has developed a program called A Thousand Eyes that enlists the assistance of the public in reporting illegal activity at cultural sites.
• TVA is cooperating with the National Park Service, the United States Forest Service, and other state and local agencies to jointly develop archaeological-site stewardship initiatives. TVA’s work to increase awareness of the criminal activity associated with illegal archaeological excavation has resulted in a number of calls from concerned citizens regarding looting at cultural sites in the TVA region.
• TVA staff members conduct presentations and field trips to help local groups and communities understand the significance of these sites as they relate to the region’s rich cultural heritage and the reasons why removing articles is forbidden.
• Several presentations were made in 2004 to groups on Guntersville and Cedar Creek reservoirs and to groups in the Bear Creek watershed.
• TVA staff members also sponsored an all-day symposium on TVA archaeology at the Southeastern Archaeological Conference. Read more about the Thousand Eyes project.