Why the Lake Levels Change
Appalachian Power, a subsidiary of American Electric Power (AEP), is licensed to operate the Smith Mountain Project by the Federal Energy Regulatory Commission (FERC). The Smith Mountain Project is made up of two lakes – Smith Mountain Lake (upper reservoir) and Leesville Lake (lower reservoir), and two Dams – Smith Mountain Dam and Leesville Dam. The two dams work together to create what is known as a pumped storage project. While the public may often view the lakes as separate locations, it’s important to know that they are operated in conjunction with each other for their primary purpose – to provide renewable, cost-effective, and reliable energy to Appalachian Power customers.
It is helpful to think of the project as a large battery – powered by water. During periods of high energy demand, water stored in Smith Mountain Lake passes through turbine-generators at Smith Mountain Dam to produce electricity. The water is then discharged into Leesville Lake. The water in Leesville Lake can then be retained until it is either pumped back into Smith Mountain Lake for re-use or discharged downstream through turbine-generators at Leesville Dam, which also produces electricity. Discharges from Leeville Dam are managed in accordance with the FERC license requirements to ensure sufficient downstream flow is maintained, supporting a healthy and sustainable aquatic ecosystem.
The normal full pond elevation at Smith Mountain Lake is 795 feet, and the typical operation range is between 793 and 795 feet. The operating range for Leesville is between 600 and 613 feet in elevation. These levels reflect the connection between the two lakes, where a 1-foot change in elevation at Smith Mountain Lake corresponds to approximately 6.5 feet of change in elevation at Leesville Lake. Refer to the graphic below or read lake level FAQs to learn more about the reservoirs.
Smith Mountain Lake
Leesville Lake
Throughout the day, water is released from Smith Mountain Lake into Leesville Lake to generate power. This exchange causes Smith Mountain water levels to lower as Leesville lake increases. The return cycle usually occurs at night.
Fast Facts about Smith Mountain Lake
The lake is bounded on the north shores by Bedford County and Smith Mountain Lake State Park, where campsites and cabins are available as well as boat rentals. The more than 1,500 acre park offers hiking trails, picnic areas and ranger programs, such as guided night hikes and canoe trips.
- Smith Mountain Lake is the second largest body of fresh water in Virginia.
- Combined, Smith Mountain and Leesville Lakes are almost 60 miles in length and include 600 miles of shoreline.
- Smith Mountain Lake has several public marinas, including Bridgewater, Parkway, Parkway 2, Mitchell's Point, and Smith Mountain Dock & Lodge.
- The community of Smith Mountain Lake has grown to over 22,000 in large part to vacationers who've decided to relocate permanently.
Common questions about lake levels
“Normal” lake levels refer to the target operating elevations for Smith Mountain Lake (SML) and Leesville Lake under typical conditions. These levels are maintained as closely as possible for hydroelectric generation and daily system operations. The base elevations for Smith Mountain Lake and Leesville Lake are as follows:
- Smith Mountain Lake: 795-foot elevation contour National Geodetic Vertical Datum of 1929 (NGVD 29).
- “Normal” operating range is between 795’ and 793’ elevation contours NGVD 29
- Leesville Lake: 600-foot elevation contour NGVD 29.
- “Normal” operating range is between 613’ and 600’ elevation contour NGVD 29
Minor fluctuations around these elevations are normal and expected. During high power demand water may be released from Smith Mountain Lake to Leesville Lake to generate electricity causing water levels at Smith Mountain Lake to decrease and water levels at Leesville levels to increase During low power demand, water may be pumped back from Leesville Lake to Smith Mountain Lake causing water levels at Smith Mountain Lake to increase and water levels at Leesville Lake to decrease.
Because Leesville Lake is much smaller than Smith Mountain Lake, its water level changes more quickly. For example:
- A 2-foot decrease in SML (795 → 793 feet)
- Can result in a 13-foot increase in Leesville (600 → 613 feet).
Yes. Annual minimum and maximum reservoir elevations, as well as the dates they occurred, are available going back to 1966.
In addition to power generation, natural inflows—including rainfall, runoff, and river flow—play an important role in lake levels.
High Inflow Conditions (Wet Weather)
- Heavy rainfall and increased streamflow can cause lake levels to rise above normal
- Both lakes may temporarily operate above normal levels
- Elevated levels help manage incoming water but may impact shoreline conditions
Low Inflow Conditions (Dry Weather)
- Reduced rainfall and inflow can lead to lower lake levels
- Water availability becomes more limited
- Operators may adjust generation and pumping to conserve water but must maintain the required releases from Leesville Lake in accordance with the Water Management Plan for the Smith Mountain Project.
- Extended dry periods can result in below-normal lake levels, affecting recreation and lake access
Water levels at Smith Mountain Lake may rise to—and occasionally exceed—the 800-foot elevation contour NGVD 29 during periods of high inflow. Conversely, lake levels may fall as low as the 787-foot elevation contour NGVD 29, and occasionally lower, during periods of low inflow or drought conditions. Historically, water levels measured at the Smith Mountain Dam reached approximately 799.79-foot elevation contour NGVD 29 in 1978 and dropped to 787.6-foot elevation contour NGVD 29 in 1970.
Leesville Lake operates under similar constraints. During normal operations, water levels at Leesville Lake typically fluctuate between the 613 foot and 600 foot elevation contours NGVD 29 as measured at the Leesville Dam. The Project boundary at Leesville Lake is located at the 620 foot elevation contour NGVD 29, as water levels have the potential to increase upstream depending upon flows released from Smith Mountain Dam. As with Smith Mountain Lake, water levels at Leesville can occasionally exceed or fall above or below these elevations due to flooding, drought, or maintenance requirements.
Appalachian Power cannot guarantee that water depths will be adequate for accessing the lakes during periods of low inflow (drought) or high inflow (flood). Such conditions may temporarily affect shoreline access, dock usability, and navigation, and lake users are encouraged to exercise caution during these periods.
Please see the following links for publicly available resources that may be helpful to address questions regarding droughts or floods:
- “Normal” lake levels are between 795-793-foot elevation contours NGVD 29 for Smith Mountain Lake and between 613-600-foot elevation contours NGVD 29 for Leesville Lake
- Daily fluctuations are normal due to hydropower operations
- Leesville Lake fluctuates more rapidly because it is smaller
- Weather and inflows significantly influence lake levels
- Wet conditions may raise levels above normal
- Dry conditions may lower levels below normal
- Appalachian Power cannot guarantee lake levels will be adequate for recreational access
- The system is actively managed to balance:
- Hydropower generation
- Flood control
- Water conservation
- Recreational use