YAKIMA, Wash. – The Bureau of Reclamation’s September 2026 total water supply available forecast for the Yakima basin indicates that irrigation demands will not be fully met this season because of winter snowpack less than half of normal, contributing to a fourth consecutive year of drought.
Storage in the Yakima basin reservoirs on Sept. 1 was 33% full with 348,970 acre-feet, which is 71.2% of average. Precipitation for August was 76% of average and for October–August was 112% of average.
The Yakima Basin Project began prorationing—allocating limited water supplies among users based on priority and entitlement—and storage control on May 21, 2026. Current projections for the September period show:
- senior water rights holders will receive 100% of their entitlements
- junior water rights holders will receive 60%, an increase of 2% from the early August forecast.
With prolonged dry conditions limiting reservoir inflows, available water will likely fall short of meeting all demands from the basin’s $4.5 billion agricultural sector while also maintaining the cool, flowing river conditions needed to support native fish populations.
Reclamation will continue to transparently communicate basin conditions via monthly water supply forecast using the latest data each month to reflect changing conditions as they develop.
“As we wind down operations for the season, we recognize that this water year has been challenging for communities, irrigators, and partners across the basin. Despite these difficulties, we remain steadfast in our commitment to reliable delivery of reliable water throughout the Yakima basin,” said Candace Carmack, Reclamation acting Columbia Cascade Area Office manager.
Reclamation manages the water in the five Yakima Project storage reservoirs, along with the basin’s unregulated inflows, to fulfill water rights, water contracts and instream flow obligations. Water shortages in the basin are shared equally by the junior water rights, which represent over half of the water rights in the basin.
The September forecast is based on flows, precipitation, snowpack, and reservoir storage as of Sept. 1, along with estimates of future precipitation and river flows. Other future weather conditions that determine the timing of the runoff and the demand for water also are critical in determining stream flows, the extent to which the reservoirs fill, and the water supply for irrigation.
For more information, visit Reclamation’s website at https://www.usbr.gov/pn/hydromet/yakima/.