Newsletter April 2022

There are many hardy souls who enjoy Leesville Lake year-round for fishing and boating. In my youth, I was that sort of individual and enjoyed sailing and racing one-design sailboats on Long Island Sound. But like most, I now look forward to the milder weather that draws us to Leesville Lake, and those days are imminent.

As we begin the 2022 season of increased activity on Leesville Lake, it is appropriate to review what water monitoring activities in past seasons have revealed about our lake. As you are keenly aware, our lake has unique characteristics and faces several challenges. Leesville Lake is actually a pump storage reservoir for the Smith Mountain Hydroelectric Project. As such, the water level is dictated by dam operations, which in turn reflect current and anticipated power needs and management of water flow to control flooding, etc. The net result is that the water level on our lake varies considerably. The water level can increase dramatically and quickly as water enters from Smith Mountain Lake during power generation and then decrease dramatically as water is pumped back to Smith Mountain Lake to meet anticipated power demands – primarily due to changing temperatures locally and throughout the power grid that the project serves¹. Unfortunately, these fluctuations in water level can be difficult to predict. Power generation also occurs at Leesville Lake Dam, but here water must be released more consistently to support the Staunton (Roanoke) River. In addition to tail water release from Smith Mountain Lake, Old Woman’s Creek and the Pigg River serve as sources of water for Leesville Lake. The Pigg River is an impaired body of water that provides poor quality water to our lake. The dynamic between the Pigg River and Smith Mountain Lake dam operations is an important determinant of water quality in Leesville Lake.

Overall, Leesville Lake is a healthy, maturing lake. Although the Pigg River supplies poor quality water (bacteria, nutrients, sediment) to the lake, dilution effects and dam operations typically have prevented the Pigg River from decreasing overall lake water quality. Largely, the movement of water from Smith Mountain Lake through Leesville Lake and into the Staunton River serves to dilute and replace the Pigg River water that enters the lake with high quality water from Smith Mountain Lake. However, dam operations can also have deleterious effects on the lake. During pump-back operations, Pigg River water may be entrained in the upper portion of the Lake rather than being flushed out. Further, although the quality of water released from Smith Mountain Lake is very good for most parameters, turbines in the dam are at a position in the water column where the dissolved oxygen content declines throughout the summer. During late summer and fall, the oxygen content of water released from the dam is frequently unacceptable and does not meet the licensing requirements for dam operations. Low dissolved oxygen content stresses the lake’s ecosystem and fish populations.

The annual report on water quality in Leesville Lake, prepared by Dr. Shahady, has been submitted to Appalachian Power. It will be included in their yearly report to the Federal Energy Regulatory Commission (FERC), which oversees the hydroelectric project. In that report to FERC and in the upcoming meeting of the Water Quality Technical Review Committee for the Smith Mountain Lake Hydroelectric Project, we will stress the need for AEP to abide by the requirements of their license and rectify the decline in oxygen content that we have observed in recent years.

Because of the threat the Pigg River poses to the health of our lake, in 2018 we expanded our ongoing efforts to monitor water quality on the lake to include investigations on the Pigg River. Our studies identified a health risk at Rocky Mount due to contamination with human waste, which has been rectified. We have also identified areas in the river where bacterial contamination from cattle activity is evident and other regions where deer are primarily responsible for bacterial contamination in the watershed. Bacterial and nutrient contamination has been most evident following heavy rainfalls and we concluded that this was due to runoff from the surrounding hillsides of forested and agricultural lands. While we believe that this conclusion is valid, in the past two years we have found a degree of discordance between the bacterial content (E. coli content measured is used to indicate overall bacterial contamination) of water in regions of the river. This lack of correlation was evident in the regions of river shortly below the former power dam. In Dr. Shahady’s current report on the Pigg River, he presents the hypothesis that increased bacterial content and nutrients in the Pigg River water are largely due to river sediment, and those sediments are agitated by increased water flow during rain events. Furthermore, it is suggested that decreased water quality of the Pigg River during recent years is the continuing legacy of demolition of the former power dam, i.e., decreased water quality is evident shortly downstream from where this legacy sediment formerly was contained by, and accumulated behind, the power dam. Lack of foresight in demolition of that dam along with lack of communication with the Leesville Lake Community means that most likely we will continue to reap the “benefits” of dam demolition for years to come.

Of obvious concern to our community is the influx of bacteria entering our lake from the Pigg River. As stated above, water flow and dilution effects greatly temper the risk of this influx. Except for the initial months after demolition of the Pigg River Power Dam, E. coli concentrations in the lake consistently have been well below state guidelines for recreational use of waterways. Concentrations of E. coli in surface waters are readily assayed and have been used as an indicator of health risk. Because E. coli are ubiquitous gut bacteria, they serve as an indicator of fecal contamination and pathogen risk although they are typically nonpathogenic (some strains are pathogenic). Pathogens of concern are not only bacteria, but viruses, parasites, etc. But risk from them is related to the amount of fecal matter and that is assessed by E. coli concentrations. Our use of bacterial source tracking was important to gain further insight into health risk and sources of contamination. Our identification of human contamination of the waters in Rocky Mount was concerning and has been rectified. However, even during the period of contamination, concentrations of bacteria derived from human waste contamination were very low in waters entering Leesville Lake. Still our experience emphasize the need for continued monitoring.

The 2021 reports on Leesville Lake and Pigg River monitoring, prepared by Dr. Shahady, can be found on the Leesville Lake Association’s website https://leesvillelake.org/. In the Pigg River report you can find further discussion of the hypothesis of legacy sediments and a bit of history about the Pigg River.

I will conclude this report by thanking the excellent members of our Leesville Lake Association’s Water Quality Committee (Dave Waterman, Kathleen Giangi, Debbie Oliver, Charlie Hamilton) and Dr. Thomas Shahady, our collaborator at University of Lynchburg, for their efforts protect the health of Leesville Lake. Although I will continue to serve on this committee, I will be stepping down as chair.  Charlie Hamilton has volunteered to accept that duty. Charlie is a retired navy admiral with extensive management experience; our committee will be in very capable hands.

Respectfully,

Tony Capuco

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¹Of course, the dam is not a perpetual motion machine. It costs energy to pump water back to Smith Mountain Lake, but the unique value of the dam is that it can very rapidly (minutes) increase power output to meet spikes in energy demand across the power grid. Pumping water back to Smith Mountain Lake maintains the ability of the dam to provide this important function.