Water spills from Roza Irrigation District's new re-regulation reservoir north of Sunnyside, Wash., into the main Roza Canal for the first time on March 15. Many miles upriver, the canal was also being charged at Roza Dam.

SUNNYSIDE, Wash. — The Roza Irrigation District, serving 72,000 acres — mostly farmland — from Selah to Benton City, began filling its 95-mile-long main canal on March 15.

It normally takes more than four days for water to flow from one end of the canal to the other and five to seven days for it to be fully charged, said Scott Revell, RID manager in Sunnyside. Water deliveries will begin about March 21, he said. Other irrigation systems throughout Central Washington also are starting their seasons.

But this year water to the lower 40 miles of the Roza Canal is arriving a couple days sooner. For the first time, water was spilled into the canal from the district’s new $31 million, 1,600-acre-foot re-regulation reservoir in Washout Canyon, five miles north of Sunnyside. It’s 55 miles downstream from the canal start and diversion from the Yakima River at Roza Dam. Water also flowed into the canal from a smaller re-regulation reservoir 30 miles down canal from Washout Canyon.

The season outlook is good with the U.S. Bureau of Reclamation forecasting 100 percent water supply for junior and senior water right holders in the Yakima Basin, Revell said.

A cool and wet spring is likely, but if warm, dry weather takes over it could change the outlook, he said.

Orchardists want water now for frost protection. Wine grapes and hops won’t need it for awhile, he said.

More than nine miles of lateral canals were piped this past winter.

The district used grants from the state and federal government to seal cracks in more than a 1.5 miles of concrete lined sections of the main canal. Over a half-mile of geotech liner was installed in the canal at Terrace Heights. All the work reduces leakage and allows for more efficient water use, Revell said.

Beside 95 miles of main canal, the district system has more than 350 miles of laterals serving 1,700 growers.

The U.S. Bureau of Reclamation is paying 65 percent of the Washout Canyon project and the state Department of Ecology and Roza district are each paying 17.5 percent.

The district uses about 300,000 acre-feet of water annually.

When a grower in the lower part of the district orders water it takes two days for it to arrive from the dam. By then the weather may have changed and the grower may not need as much. Water that isn’t used goes into one of several wasteways that takes it back to the Yakima River, Revell said.

The new reservoir allows the district to pump such excess water from the canal into the reservoir and hold it for later use in the lower half of the district instead of dumping it into the wasteways. It enables the water master at the dam to fine tune diversions, saving water and providing more equal shares to everyone in the district, Revell said.

The Washout Canyon reservoir is about half full with water from last season and will be brought up to a near-full operating level within a few days of the start of this season, he said.

Chain-link fencing is being installed around the reservoir now to keep people and animals out and is about three-fourths done, he said.

The district is the largest one most severely impacted in drought years, as it was in 2015, because it operates solely on junior water rights which are first restricted in droughts.