Cooler July brightens outlook for irrigators

July 30, 2015
Cooler July brightens outlook for irrigators

Reservoirs are low, but greatest demand has likely passed

By Scott Hammers

A cool-down in the second half of July has helped stretch supplies of water available to local farmers and ranchers, but area reservoirs are running low as the region enters what’s normally the driest month of the year.

And temperatures well into the 90s are predicted in Central Oregon for the next several days.

The two primary reservoirs that store most of Central Oregon’s irrigation water, Wickiup and Crane Prairie, were at 37 and 52 percent capacity as of Wednesday, respectively. Kyle Gorman, regional water master with the Oregon Department of Water Resources, said those levels are low but not unprecedented — water levels have been similar at the end of July at Wickiup once over the last 11 years and three times at Crane Prairie.

Both reservoirs are at a level that in an average year would not be seen until early to mid-September.

Gorman and others involved in managing irrigation in the area have raised concerns about supplies since the end of winter, when it became clear the snowfall that replenishes reservoirs as it melts was not going to materialize this year.

The atypically snowless winter was followed by a warmer than usual spring, and a record-hot June in most parts of Central Oregon.

Gorman said the rain and cooler weather that arrived earlier this month allowed his office to cut back the number of cubic feet per second of water it releases into the Deschutes River at Wickiup Reservoir. Irrigation districts draw their water from the Deschutes, primarily in the Bend area.

“That dip in July is very significant. We went from 1,900 cfs to about 1,300 cfs, and that’s due to the rain and conserving water the best we can to maintain supplies throughout the summer.”

Gorman singled out the North Unit Irrigation District, which provides water to nearly 59,000 acres in Jefferson County, for its efforts to limit water usage. As a junior water rights holder, the North Unit district would be among the first water users to be cut off if the watermaster’s office were to implement strict conservation measures.

Gorman said irrigators typically use more water in July than any other month. Although August is normally as hot as July and slightly drier, he said many of the crops grown locally are either harvested in August or purposely starved of water to dry out in preparation for harvest.

In mid-October, the watermaster’s office shuts down the canal system and restricts water flowing out of the reservoirs to replenish the supply of water for the following year. Gorman said it’s a little early to be making predictions about next year’s supplies, but a snowy winter would be a big help.

Gorman said the lack of spring and summer snowmelt has left lakes relatively low and reduced the flow of natural springs. Both help to recharge the reservoirs and, just as importantly, boost summer flows in the Deschutes and reduce the need for reservoir-stored irrigation water.

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