Diversion of rivers discussed

Wednesday, May 18, 2005 | 9:42 a.m.

River hearings

The Bureau of Land Management will hold two more hearings on the environmental impact of diversion of Clark County river water to Las Vegas this week. The meetings at the following locations will begin at 5 p.m. with a BLM presentation at 6 p.m.:

The Southern Nevada Water Authority hopes to bring more than 80,000 acre-feet of water -- almost a third of what it now takes from Lake Mead -- from the rivers that move through northeast Clark County and flow into Lake Mead. The agency actually has existing rights on the Virgin River to take up to 190,000 acre-feet, and another 7,100 acre-feet from the Muddy River with plans to buy more, but agency officials say those rights would probably not be fully used.

One acre-foot is about 326,000 gallons, or enough water for several Las Vegas families over the course of a year.

Construction on the $1 billion river diversion project, which would include construction of a plant to take salt and other minerals out of the river water, could begin in 2009.

Before the effort can go forward, potential environmental impacts need to be mitigated, which is why the BLM is holding meetings on the environmental impact this week. The federal agency has to consider any negative environmental impacts before it can give its go-ahead to the project.

While the surface water project has not sparked the opposition that has followed the Water Authority's plans to drill wells and build pipelines to bring groundwater to Las Vegas from rural parts of Nevada, some observers have expressed concerns about the plans.

Jacob Paz, owner of J & L Environmental Services in Las Vegas, said he is concerned that the high mineral content of the Virgin and Muddy flows could introduce potential dangerous materials into the region's drinking water supply.

John Hiatt, conservation chairman for the Red Rock Audubon Society in Las Vegas and a longtime conservationist, said the project could affect people and wildlife on both rivers.

"There are really two phases to the project," Hiatt said. "They have different impacts."

Diversion from the Muddy River, which is often a relative trickle through Moapa Valley, could eventually be about 11,000 acre-feet annually -- about 3.3 billion gallons. The Water Authority already owns rights to 7,100 acre-feet through purchases from agricultural users along the river.

Besides the approval from the BLM, the Nevada State Engineer would have to approve shifting the existing uses for water along the Muddy River from agricultural purposes to urban uses.

Hiatt said the diversion could adversely affect a nearby wildlife sanctuary managed by the Nevada Department of Wildlife.

"One of the things that will happen is that there will be less water for the Overton Wildlife Management Area," he said. "They are sort of at the end of the ditch there."

Another potential problem is that the Muddy River diversion could impact nearby wells.

"There may be people along the Muddy River there and downstream that may have a problem," Hiatt said.

Groundwater pumping is already having an impact on the amount of water in the river bed, he said.

"The groundwater and the surface water are connected," Hiatt said. "It's all basically the same water, but there isn't a very good accounting of how the wells fit into that."

Hiatt said a big issue too is that the city of St. George in southwest Utah also could be using Virgin River water, and that Nevada may not have much water left in the river to take.

Lisa Luptowitz, Water Authority environmental planner, said the issues cited by Hiatt have to be looked at before the agency can get the state and federal permits it needs to draw water from the Muddy River.

The Water Authority will have to leave enough water in the river to sustain the Overton wildlife area, she said. That can be monitored and maintained through the Bowman reservoir on the river, she said.

"The water rights would have to be maintained."

On the Virgin River, which has a relatively stronger flow through Utah and Arizona to Nevada, Hiatt said there are several issues. The plan to store water at a 1,200-acre reservoir would allow the invasive tamarisk, or salt cedar, to colonize a huge area, he warned.

Disposal of brine, a by-product of extensive treatment the Virgin River water would require, would use a similar amount of land and the waste could have more impacts, he said.

Hiatt, who serves as an advisor to the Water Authority through his membership on the agency's Integrated Water Planning Advisory Committee, said using the Virgin River water could be a lot more complicated than is now anticipated. The extreme salinity of the river water means that the Water Authority would have to build a desalination plant.

"The problems with running a large plant of that complexity are really significant," Hiatt said. "This has got huge maintenance costs. There will be huge operations and maintenance problems.

"There are some real technical issues that they have not discussed publicly," he added.

But Hiatt said the surface water is probably the easiest for the Water Authority to develop. Although the agency still has to win approval to develop the resources, it already owns the water rights, he said.

Further, the distance from those sources to Las Vegas is about 65 miles, far shorter than the hundreds of miles anticipated for bringing groundwater from rural areas to the city.

Luptowitz said the issues cited by Hiatt could complicate the development process for the Water Authority but could be overcome. Part of the BLM hearing process is to identify the issues and for the Water Authority to mitigate negative effects, she said.

She agreed that a desalination plant at this point is likely to involve reverse osmosis technology.

"It's not actually technologically difficult, it's just expensive," Luptowitz said.