Las Vegas Sun

October 20, 2017

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Water intake bypass studied

The Southern Nevada Water Authority will bypass its normal low-bidder procedure to find a company to design a project to help keep water flowing to Las Vegas from a dwindling water supply in Lake Mead.

Marc Jensen, water authority engineering director, said the engineering project will more than double the amount of water that can, in an emergency, flow from the second, deeper intake pipe that brings water from the lake to the urban area. The authority is concerned that falling lake levels due to drought and demand will put the older intake, in shallower water, out of business.

The lake now is at about 1,126 feet above sea level. The older intake draws water at 1,050 feet, 76 feet below the current lake level. The newer, deeper intake is 50 feet lower than the old intake, at 1,000 feet.

The drought probably will cause lake levels will continue to fall for years to come, Jensen said. Experts expect the level to bottom out between 2015 and 2025 at about 1,000 feet above sea level.

"This isn't the most pessimistic nor the most optimistic scenario," Jensen told the board.

Water officials are looking at the whole Colorado basin at what could happen as the drought persists.

The water authority played host to technicians and officials from other Colorado River Basin states on the same day that the federal Bureau of Reclamation released its plan detailing how much water those states will receive.

The southern basin states, which are Nevada, California and Arizona, can take their "normal," or basic amount, the bureau is proposing in the Draft Annual Operating Plan. The bureau would release the minimum amount needed from Lake Powell, upstream.

This year's draft plan largely mirrors last year's, local and federal officials said. The discussions in Las Vegas and among the other water users could change those amounts.

The states are working to recommend new rules that would govern which water users get how much water in case if the water levels continue to fall. The upper basin states also are concerned that if water levels continue to fall in Lake Powell, the reservoir for Lake Mead, the hydropower generators will stop working on Powell's Glen Canyon Dam.

Water officials discussed cutting back the amount of water that is released from Lake Powell, which feeds Lake Mead. Cutting back the amount of water would lower the level of Lake Mead under these conditions.

Under the current operating plan, there would be no change in the amount of water released from Lake Mead next year, but if the drought continues, that would likely change in following years.

Vince Alberta, water authority spokesman, said these are only some of the variables facing the users on the river. Until those variables are quantified, he said, questions such as the Las Vegas region's response to the drought also are difficult to answer.

Bob Johnson, regional director for the Bureau of Reclamation's lower basin, said the discussions will continue as the new operating plan is finalized. Any significant changes to the operating plan could come months or years down the road as the drought continues or, officials hope, eases.

"The drought is very worrisome," he said. "This is a significant event. It gets very complex and potentially contentious. Our hope is that the basin states can come together and give us a consensus recommendation on what we should do."

He said that it "is not time for panic on the Colorado River system."

"It's time to be concerned, it's time to start planning for the worst, but it's not time to panic," he said.

Lakes Powell and Mead still hold 31 million acre-feet of water in storage, about three years of drawdown for Las Vegas, Arizona and California, he said.

Johnson said the operating plan should be finalized and signed by Interior Secretary Gale Norton later this year.

For Southern Nevada water officials, the falling level at Lake Mead presents an engineering problem. The older, upper intake feeds its water to the 1971-vintage Alfred Merritt Smith Treatment Facility. The lower intake brings all of its water to the River Mountains Treatment Facility. If the older intake is knocked out, the water authority engineers do not want the Alfred Merritt Smith facility to sit idle.

An existing bypass pipeline can take 235 million gallons a day from the new upper intake to the Alfred Merritt Smith facility. The proposed engineering project will allow an additional capacity of 365 million gallons a day more.

The total summertime consumption is about 450 million to 550 million gallons a day, water authority officials said.

Jensen told the board that building the bypass would improve the water quality coming from the Alfred Merritt Smith facility, because the older intake takes lower quality water from higher in the lake.

What the engineering project will not do, he said, is increase the overall capacity of the system if the lake falls below 1,050 feet. That capacity is about 900 million gallons a day, Jensen said.

Kay Brothers, water authority deputy general manager, said the new pipeline would cost an estimated $15 million to $20 million, and could be in place by the summer of 2006.

Jensen said the board's approval would allow the water authority to pick a firm or consortium that would both design and build the project, a process that would save time and, by eliminating intervening steps, would also likely save money.

Pat Mulroy, water authority general manager, said time is crucial because the falling lake levels need to be addressed as soon as possible.

"We are racing against the clock. We are racing against uncertainty," she said.

Jensen said the water authority board would still have to approve any deal, but this would allow them to find the group best able to do the work quickly. While Nevada law generally requires a competitive bidding process, the water authority can sidestep the rule if the board finds in a public hearing that the alternative will save money and time, he said.

Teams qualified to perform the work have to present their proposals in a public meeting, he said.