Water released at dam as part of test

Heather Rawlyk and Jean Reid Norman

Friday, Feb. 27, 2004 | 11:28 a.m.

Visitors to Hoover Dam Thursday afternoon witnessed a sight not listed in the tour book, as 130 million gallons of water burst from the Nevada wall of Black Canyon.

A white cloud of mist towered over the canyon as a result of the surge of water knocking against an adjacent canyon wall. A flurry of miniature waterfalls cascaded downward, where they intersected in a collective pool below.

Close to 600 visitors lined up along the wall on top of the dam to witness the water release, which was part of a test the Bureau of Reclamation conducted to "ensure tie rods in the upper Nevada penstock of the dam are structurally sound," according to Bureau of Reclamation spokesman Bob Walsh.

Tie rods provide key structural support to the penstocks, which are large pipes, according to the Bureau of Reclamation.

The upper Nevada penstock is 4,000 feet long and made up of 22-foot sections, each 30 feet in diameter, Walsh said.

The penstocks supply water to the turbines, he said. Releasing a large flow of water through the jet flow gates allows the tie rods to be tested.

"To make it simple to understand, we did this as a way to test the system that carries the water from Lake Mead to generating units," Walsh said. "We had to release the water to test that."

Walsh said it is "crucial to understand" the released water was not wasted or lost.

The water that shot out the penstock would have left Lake Mead anyway, but through the generator, he said.

"The water was going to go anyway," he said. "It just went a different route, some of it anyway.

"We didn't take any extra water out of Lake Mead. People ask me what the impact on Lake Mead was and it was practically not noticeable. (The release) is not going to affect the elevation."

The 130 million gallons of water and 171,000 kilowatt hours of power released Thursday was "small potatoes," he said.

Hoover Dam generates 4.5 billion kilowatt hours per year, Walsh said.

"To put it into perspective, the dam releases 8.7 million acre feet of water every year," he said. "Today we released 400 acre-feet, which translates to 130 million gallons."

The water released will move downstream and be used for agriculture after passing through two more power plants on its way, Walsh said. "It's going to be used," he said.

The last time water was sent through the penstocks in the walls of the Black Canyon was July 1998. Then the Bureau of Reclamation had just finished installing new valves at the end of the penstocks, where they push the water into the generators, Walsh said.

Both releases were part of a regular maintenance program done at the dam to make sure everything is working well, Walsh said. The federal agency has annual maintenance plans, as well as looking as far ahead as five to 10 years to see what work will need to be done, he said.

"It's how we ensure the facility operates the way it was designed to," he said. But, he added, "It's usually not worth looking at."

But maintenance that requires the release of water happens only every three to four years, he said.

"Everybody likes to see it," he said.

Of the 1,700 visitors to Hoover Dam Thursday, about 600 were present in the afternoon to witness the release, which lasted about 30 minutes, according to Steven Leon, Bureau of Reclamation Public Affairs specialist.

"People were just thrilled to see that happening," he said. "Some people had read about it in the paper and came out specifically to see it, but the majority didn't expect it at all.

"It was a real welcome surprise."

The water release was planned for winter, when demand for water and power was lower, he said. "It's a time of year when we can do that," Walsh said.

Walsh said there's no schedule for the next display of water.

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