SOUTH-DAKOTA RESERVOIR REPORT

Last Updated: February 1, 2026

The latest observations of the nation's dams and reservoirs indicate varied water storage levels, reflecting a complex interplay of natural and managed water systems. Some reservoirs are experiencing surpluses, while others grapple with the effects of prolonged drought conditions. For instance, Lake Winnipesaukee at Weirs Beach, New Hampshire, is currently below its average gauge height, which could point to decreased inflows or increased water usage. Notably, major water bodies such as Lake Powell in Arizona report storage levels significantly under historical averages, hinting at the broader impacts of long-term drought exacerbated by climate change.

A contrasting scenario is observed at reservoirs like Pueblo Reservoir in Colorado, where storage levels surpass the average, potentially due to recent precipitation events or strategic water management. The variation in reservoir conditions underscores the importance of dynamic water management strategies to adapt to the environmental challenges and ensure sustainable water supplies. Hydrologists and water managers are thus continually monitoring these critical water sources to manage resources effectively, balancing ecological needs with human consumption and maintaining the overall health of watersheds.

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.