SOUTH-DAKOTA RESERVOIR REPORT

Last Updated: March 16, 2026

In a sweeping review of the nation's dams and reservoirs based on the latest observations, a diverse picture of water storage levels emerges, showing a mix of surpluses and shortages that reflect the complex interplay of weather patterns, climate change, and water management practices. While some regions are experiencing higher-than-average reservoir levels, others are facing significant deficits, underscoring the importance of adaptive water resource management.

For instance, Lake Winnipesaukee in New Hampshire shows a lower current gage height compared to its average, hinting at potential concerns for local water supply if the trend persists. On a more positive note, New York's Indian Lake is holding steady, matching its average water surface elevation—a sign of stability in that watershed. In contrast, the Maurice R at Union Lake Dam in New Jersey reveals a stark drop in streamflow, a worrying sign that could point to drought conditions affecting both water availability and ecosystem health.

Pennsylvania's Prompton Reservoir and General Edgar Jadwin Reservoir, along with Beltzville Lake near Parryville, are all slightly above their average elevations, suggesting a healthy water balance. However, some reservoirs in the state, like Blue Marsh Lake and Indian Rock Dam, report lower-than-average water surface elevations, which could indicate emerging water stress.

Heading South, the situation becomes more concerning. North Carolina's Afterbay Reservoir at Dam NR McGehees Mill, Falls Lake, and B. Everett Jordan Lake all report lower water levels than average. Meanwhile, South Carolina's Lake Moultrie and Georgia's Lake Lanier exhibit decreasing water levels, aligning with broader concerns about water scarcity in the Southeast.

The West presents a mixed bag, with Colorado's John Martin Reservoir, Vega Reservoir, and Pueblo Reservoir displaying varying levels of storage relative to their averages. The stark decrease in storage at Arizona's Lake Powell reflects the ongoing water challenges in the Colorado River Basin, affected by prolonged drought and overallocation.

These snapshots offer a glimpse into the intricate and fluctuating state of our water resources. For water management researchers and hydrologists, these conditions not only guide immediate action but also inform long-term strategies for sustainability and resilience in the face of an uncertain climate future. The data serves as a reminder of the essential role of continuous monitoring and adaptive management in safeguarding our precious water supplies.

South Dakota has over 150 reservoirs and dams, with major reservoirs including Oahe, Sharpe, Francis Case, and Lewis and Clark. These reservoirs are fed by tributaries of the Missouri River, such as the James, White, and Cheyenne rivers. Snowpack in the Rocky Mountains, especially in Colorado and Wyoming, is a major source of water for these tributaries. Hydrology in the area is heavily influenced by seasonal trends, with high flows in the spring due to snowmelt and lower flows in the summer and fall. There have been several record high flows in recent years, including the historic flooding of the Missouri River in 2011. Drought conditions have also been an issue in some areas, leading to decreased water levels and increased concern for water use.

South Dakota has over 150 reservoirs and dams, with major reservoirs including Oahe, Sharpe, Francis Case, and Lewis and Clark. These reservoirs are fed by tributaries of the Missouri River, such as the James, White, and Cheyenne rivers. Snowpack in the Rocky Mountains, especially in Colorado and Wyoming, is a major source of water for these tributaries. Hydrology in the area is heavily influenced by seasonal trends, with high flows in the spring due to snowmelt and lower flows in the summer and fall. There have been several record high flows in recent years, including the historic flooding of the Missouri River in 2011. Drought conditions have also been an issue in some areas, leading to decreased water levels and increased concern for water use.