science environment

Less Water In Northwest Rivers Will Mean Less Hydropower

By Cassandra Profita (OPB)
May 6, 2015 1:30 a.m.
An aerial view of the Columbia River.

An aerial view of the Columbia River.

Amelia Templeton / OPB

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Water supply forecasts are looking bleak for many Northwest rivers this year. Managers say that means the region will generate less hydropower.

At a meeting in Portland this week, power managers with the Northwest Power and Conservation Council will hear an update on the region's snow pack and stream flow forecasts.

Jim Ruff, manager of main stem passage and river operations for the Council, submitted a memo to the council saying dismally low snow pack in many areas of the Columbia River Basin will mean less water in rivers, and that will negatively affect fish and wildlife, agriculture and hydropower generation.

John Fazio, the council's senior power systems analyst, said less water in Northwest rivers will mean less hydropower – but not so much less that the region won't generate what it needs.

"We're not anticipating a likelihood of a shortage or any problems for power supply this year," he said. "The lights will stay on, but the revenue will be less for utilities that have hydropower."

Ruff, who will present his report on water supply forecasts to the council on Wednesday, said snow levels in British Columbia and at higher elevations in the Rocky Mountains are OK, but they're low in many watersheds within the U.S. portion of the Columbia River Basin.

Oregon's Owyhee, Deschutes, Willamette, John Day, Umatilla and Walla Walla river basins are among the lowest with less than 12 percent of the median snow levels.

"Snowpack levels across the basin have been steadily declining because of continuing warm and drier than normal conditions," he said. "And many sites within these watersheds have no snow at all, so they're showing bare ground, which is unprecedented."

Ruff said peak snow pack accumulation is usually measured in the beginning of April, and many snow monitoring sites were bare at that point this year. In Oregon, 76 snow monitoring sites were at their lowest snow pack levels on record as of April 1. In Washington, statewide snow pack is 19 percent of average, and 70 snow monitoring sites are at record lows.

"That translates into below normal water supply forecasts for the Columbia River Basin," Ruff said. "It looks like it's going to be a fairly water-short year for the southern part of the basin."

Fazio said managers plan for hydropower generation based on the lowest water year on record. And this year doesn't look like it will be nearly that bad.

In good water years, he said, utilities including Bonneville Power Administration would use extra hydropower to replace more expensive electrical generation sources like natural gas or coal-fired power plants. And they would sell extra power to other areas such as California. This year, there won't be as much extra hydropower to sell because there will be less water in Northwest rivers, Fazio said.

"Because we have less than average, the region will be making less revenue from sales," he said. "Bonneville Power (Administration), in particular, probably won't be making as much money because there isn't as much power as in a normal year, but we're still going to meet all of our demands."

Fazio expects Northwest dams will only produce about a quarter of the extra hydropower utilities would normally sell on the power markets.

A key measurement for gauging water supplies for hydropower generation is the water runoff at The Dalles Dam on the Columbia River. Fazio said the lowest volume recorded there was 47.3 million acre feet in 1977. This year, the forecast is for 67 million acre feet. That's well below the average of 89 million acre feet, but safely above the danger zone where power managers would have to consider paying industries to use less electricity to reduce the power demand in the region.

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