Roza Water Users-

• Shut Down-Flows were ramped down slowly yesterday over several hours in steps to avoid having the canal walls collapse inward as the water receded, which can occur with rapid dewatering.

• System Maintenance-Roza crews will be taking advantage of the shutdown to work on a list of repairs that would otherwise have to wait until the offseason.

• Fish Flushing Pulses-There have been three flushing pulses so far in 2026 to push out-migrating salmon and steelhead smolt out to the Columbia River. These pulses have used roughly 25,000 acre feet of water either under the Endangered Species Act or through use of the reservoirs to release water in a pulse that later refills in the reservoirs.

Water that is used for flushing pulses or to aid up migrating adult salmon during low flow periodsafter prorationing began on May 21^st is roughly 17,000 acre feet. This water has been made available through federal and state funded water conservation projects. 67% of the saved water stays in the river in exchange for the federal and state governments funding 87.5% of the conservation project’s cost.  This program has been in place since 1994.

The state has also leased or otherwise acquired just over 10,500 acre feet which are available for in-stream flows to benefit fish.

• 2026 Smolt Outmigration-Coho and sub-yearling chinook are moving out now. River temperatures have remained favorable for now.

• Smolt Predation-Bird (pelicans, herons, mergansers, etc.) and fish (bass, pikeminnow, walleye, catfish, etc.)  predators consume over 90% of the outmigrating smolt in many years. These effects are the worst in the lower Yakima River from about Mabton to the confluence with the Columbia River. Recent studies have shown that non-native Channel catfish consume far more smolt than previously thought. One 24 inch catfish can have more than 20 smolt in its stomach! Higher flows and cloudy/murky water are very good for smolt survival.

• Power Generation Water-When you see water in the Roza Main Canal in the Pomona area, near the Army’s Yakima Training Center, during a shutdown or during the off season, that water is being used to generate power at Roza Power Plant in Terrace Heights. Power generation is a non-consumptive use of water and all of the water returns to the Yakima River near the Terrace Heights Drive bridge crossing of the Yakima River.   

• 2026 Grant Funding-Roza received a $5M grant from the state Legislature in 2026 to repair a portion of the 10.1 miles of concrete canal in the Moxee area which leak and need to be replaced. Those funds cannot be used for other expenses. The total project is estimated at over $20M and will occur in phases of several years. This work will occur next winter.

Roza also received $600K from the state in 2026 to seal cracks on the concrete lined Main Canal sections. These segments are mostly in the Pomona & Moxee areas, with a few other smaller sections downstream in the mid-valley. This grant will bring the total state funding of concrete sealing over the past 12 years to over $2.5M. These funds cannot be used for other projects or expenses.

• Flood Debris-You may have seen a large excavator in the river immediately upstream of Sunnyside Dam this week removing debris that was deposited during the December flood. The flood debris was interfering with the ability to operate the diversion structure properly and hold the pool.

• Why don’t I receive a refund or a credit on my assessment when Roza’s water supply is reduced? Irrigation assessments in Washinton are based on the acres assessed on each parcel. This is different than a municipal system where the monthly water bill is based on how much water is used rather than a flat annual rate per assessed acre. The annual assessment pays for the operation and maintenance of the water distribution system. The assessment does not pay for the water used.

Roza’s overall operational costs go up during drought years due to leasing water, additional overtime, pump back recovery of leakage, canal damage during shutdowns etc. Power costs are somewhat reduced in drought years because less water is pumped into the pump lateral canals.

Washington irrigation law does not provide for the assessment to be adjusted when less than a full supply is available or the landowner does not use the water that is available. Some examples include fallowed lands in which no crop is grown. For example, fallowed land is assessed. When the irrigation season ends early or there are service interruptions due to drought shutdowns, canal or pump failures the assessment remains the same. The assessment also remains the same when there are drought delivery restrictions imposed in order to lengthen Roza’s already shorted irrigation season.

• Data Centers-We are often asked about data centers and their use of water. There are no data centers using Yakima River surface water. There are data centers which use Columbia River water. Data centers have zero effect on Roza’s water supply.

Please feel free to call or text me if you have a question about Roza operations or basin wide water issues. Roza staff and I are available to meet with groups large or small to answer questions.

Scott Revell, District Manager- Roza Irrigation District,

(509) 840-2721 cell