Dam Management Plan Makes the Most of Columbia River’s Water

Like a waiter carrying a tray of water glasses in a crowded restaurant, chief power dispatcher Greg Lange has the same goal: Get the water where it needs to go and don’t spill any.

“In a low-water year, it’s a pretty precious commodity,” he says.

Lange, of course, doesn’t shimmy around chairs and tables, but utilities are not unlike customers, and the seven dams on the mid-Columbia River might be compared with the cook’s kitchen.

Lange’s balancing act occurs in the dispatch center for the Grant County Public Utility District, where demand for electricity and the supply of power available from Grand Coulee, Chief Joseph, Wells, Rocky Reach, Rock Island, Wanapum and Priest Rapids hydroelectric projects are computer coordinated with fresh data every four seconds.

The winter of 2000-2001 is turning out to be among the driest on record. Already there is talk of a statewide drought declaration and anticipation of problems with shortages by summer.

“We’re going to have to discuss how to share that shortage,” Lange says.

Since 1973 the seven dams have operated largely as a group, rather than as maverick projects each with its own generation plans for the day.

“The No. 1 principle is to prevent spilling on the seven projects,” Lange says. “The program manages the water as best as possible.”

The management program for the seven dams is formally known as the Mid-Columbia Hourly Coordination Agreement, part of a larger power system coordination plan for the Columbia River system.

In the hydropower business, water is money, and spilled water--that fierce, frothy rush down the face of a dam--is wasted water, unless you’re a fish.

The dams do routinely release water during the year to enhance salmon and steelhead survival, and while hourly coordination was once exclusively about matching load and generation, it now manages for fish migration needs as well.

“When releases are made to assist migration from the upstream reservoir at Grand Coulee, it has to get through the mid-Columbia projects,” says Ed Mosey, a spokesman for the Bonneville Power Administration, a federal power marketing agency in Portland, Ore.

Hourly coordination makes the most of the water available on the river.

“It kind of does save water,” says Tom Caine, a technical advisor and liaison on hourly coordination for BPA. “You get more megawatts produced per bucketful of water.”

The seven dams on the midsection of the Columbia River have a combined peak generating capacity of 13,500 megawatts, enough to light about 13 cities the size of Seattle.

The massive Grand Coulee, the largest concrete structure in North America, and Chief Joseph are both federal projects. Wells belongs to Douglas County PUD, Rocky Reach and Rock Island to Chelan County PUD, and Wanapum and Priest Rapids to Grant County PUD.

“We share the generation back and forth,” Lange says.

Seventeen utilities get electricity from the mid-Columbia projects.

The naturally erratic flows of the Columbia River at times make it a hydropower management challenge, with ranges from an 1894 record during a flood at The Dalles, Ore., of 1.24 million cubic feet per second to a December 1937 low of 36,000 cubic feet, or a ratio of 34 to 1. The Northeast’s famous St. Lawrence River has a natural ratio of 2 to 1.

Most of the 1,200-mile-long Columbia’s natural flow--the fuel for hydroelectricity--occurs during the six warmest months of the year, when demand for electricity in the Northwest’s temperate climate is typically low.

That makes water storage critical, and much of it is done by treaty with three dams in Canada and Libby Dam in western Montana.

The five nonfederal projects on the mid-Columbia each day send their generation requests to the dispatch center. The computer program assigns generation amounts to each of the five and sometimes all seven projects--based on the inflow of water--while trying to maintain a specified reservoir level at each project.

Except for Grand Coulee, there is paltry water storage behind the dams. Keeping the small reservoirs as full as possible as the water moves downriver from dam to dam allows for maximum generation of power.

Generation is then sent over contracted transmission paths back to the PUDs’ control areas so they can use it locally or sell it to somebody else.

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The River’s 7 Dams

The Grant County Public Utility District coordinates the flow of water for seven hydroelectric projects on the mid-Columbia River. They are:

* Grand Coulee Dam (U.S. Bureau of Reclamation): 6,800 megawatts

* Chief Joseph Dam (U.S. Army Corps of Engineers): 2,600 megawatts

* Wells Dam (Douglas County PUD): 840 megawatts

* Rocky Reach Dam (Chelan County PUD): 1,350 megawatts

* Rock Island Dam (Chelan County PUD): 620 megawatts

* Wanapum Dam (Grant County PUD): 1,040 megawatts

* Priest Rapids Dam (Grant County PUD): 910 megawatts

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On the Net:

Grant County PUD: https://www.gcpud.org

Bonneville Power Administration: https://www.bpa.gov