NRCS releases outlook on May water supply

On May 1, the U.S. Department of Agriculture’s Natural Resources Conservation Service (NRCS) published the May 2025 Wyoming Basin and Water Supply Outlook Report, which analyzes snowpack, precipitation, streamflow and reservoir storage across the state of Wyoming. 

As growers start to rely on water supply for the 2025 growing season, the report assesses the water supply outlook for the entire state of Wyoming, as well as individual basins including the Snake River, Madison Headwaters, Yellowstone River, Wind River, Big Horn River, Shoshone River, Powder River, Tongue River, Belle Fourche River, Cheyenne River, Upper North Platte River, Lower North Platte River, Laramie River, Sweetwater River, South Platte River, Little Snake River, Upper Green River, Lower Green River and Upper Bear River basins.

Snowpack and precipitation

According to NRCS, snow water equivalent (SWE) across the state of Wyoming was 72 percent of median as of May 1.

The highest SWE was reported in the Tongue River Basin at 112 percent of median, and the lowest SWE was reported in the Belle Fourche River Basin at zero percent of median.

The report also shows the Belle Fourche River, Cheyenne River, Laramie River, Little Snake River, Lower Green River, Lower North Platte River, Madison Headwaters, Powder River, South Platte River, Upper Bear River, Upper Green River and Yellowstone River basins were below 90 percent of the median SWE recorded from 1991 to 2020.

Additionally, the report notes the Tongue River Basin saw the highest precipitation over the past month at 126 percent of median, while the Laramie River Basin saw the lowest amount at 45 percent of median.

Streamflow yields

NRCS expects median streamflow yields in all Wyoming basins – except the Cheyenne, Little Snake, Lower Green and Upper Green – to average 89 percent from May through September. 

Streamflow yields for these four exceptions are expected to average 42 percent, 63 percent, 84 percent and 97 percent, respectively, from April through July. 

Expected streamflow yields for individual basins across the state include the Lower North Platte River Basin at 56 percent of median, the Powder River Basin at 78 percent of median, the Upper North Platte River Basin at 78 percent of median and both the Tongue and Laramie river basins at 88 percent of median.

NRCS predicts streamflow yields for the Snake River Basin, Shoshone River Basin, Yellowstone River Basin, Big Horn River Basin, Wind River Basin and Sweetwater River Basin will respectively report 97, 98, 100, 101, 102 and 112 percent of median. 

Reservoir storage

For the entire state of Wyoming, NRCS reports average reservoir storage at 94 percent of median, down from 98 percent the month prior. 

Reservoirs reporting numbers below median included those in the Cheyenne River Basin at 83 percent, the Belle Fourche River Basin at 85 percent, the Wind River Basin at 87 percent, the Lower North Platte River Basin at 90 percent and the Upper North Platte River Basin at 92 percent.

The Buffalo Bill Reservoir on the Shoshone, as well as the Lower Green River and the Big Horn River basin reservoirs reported numbers near median – 97 percent, 101 percent and 103 percent, respectively.

Reservoirs on the Snake River and Upper Green River were above median, posting numbers at 112 percent and 113 percent, respectively.

Hannah Bugas is the managing editor of the Wyoming Livestock Roundup. Send comments on this article to roundup@wylr.net.