09/10/2026
As the 2026 irrigation season winds down, let’s look at where the Yakima Basin’s five storage reservoirs stand heading into the off-season.
The Bureau of Reclamation began its annual “flip-flop” operation around August 27. During this process, releases from the upper reservoirs are reduced while releases from lower reservoirs increase, helping provide river conditions for Chinook salmon spawning while balancing irrigation and storage needs across the basin.
The effects of that shift can be seen in the reservoir graphic. Cle Elum and Keechelus have been drawn down, while water is also being released from Kachess, Bumping and Rimrock. Rimrock currently holds the greatest amount of remaining water.
The blue line on the water-year graph represents this year’s combined reservoir storage. Although storage is higher than it was at this time last year, shown in green, it remains below the historical average shown in red.
Looking ahead, El Niño adds another layer of concern. El Niño occurs when ocean temperatures in the central and eastern tropical Pacific become warmer than average, shifting weather patterns across North America. In Washington and much of the Northwest, El Niño winters often bring warmer and drier conditions.
Warmer winters can also mean that more precipitation falls as rain instead of snow. That distinction is important because the Yakima Basin relies heavily on mountain snowpack or what we call our “sixth reservoir," to store water through the winter and release it gradually during the spring and summer.
El Niño does not guarantee a dry winter, and many factors will influence our water supply over the coming months. However, if warmer and drier conditions develop and the basin does not receive enough mountain snow, we could unfortunately enter a fifth consecutive year of drought in 2027.
We’ll continue monitoring reservoir storage, precipitation and snowpack throughout the off-season and provide updates as conditions develop.
Sources:
https://www.usbr.gov/newsroom/news-release/5397
https://www.climatehubs.usda.gov/hubs/northwest/topic/el-nino-northwest-what-can-we-expect
https://www.usbr.gov/pn/hydromet/yakima/yaktea.html