MARK WAITE / PVT Engineer Donald Allison looks at a map showing the Pahrump drainage and flood control plan. Advertisement

It will cost every property owner in Pahrump an annual assessment of $180 per acre to pay for a complete flood control system, Donald Allison, principal partner of Bureau Veritas, told the Pahrump Regional Planning Commission Wednesday.

RPC member Carrick "Bat" Masterson said however, that would offset the cost of purchasing flood insurance, which could amount to $300 in annual premiums.

Nye County commissioners approved a $386,946 contract for the Bureau Veritas study in 2007 without discussion. The plan was to pay for the study out of the payment equal to taxes received from the U.S. Department of Energy for Yucca Mountain, then reimburse that fund if a general improvement district were established to fund the flood control system.

The GID board would have a lot of powers: the authority to issue bonds to finance and construct public improvements for flood control, exercise eminent domain, set rates, levy assessments and transfer property. But Allison said Clark County commissioners also function as a water reclamation district in Las Vegas.

The establishment of a GID would require county commissioners to pass several ordinances and hold different public hearings, Allison said.

RPC Chairman Mark Kimball said only a few subdivisions in Pahrump are outside a flood zone, like the Artesia subdivision in the south or the Diamond Bar subdivision on the west side.

"You have people who don't want to live here because they are buying a house in the flood plain. So it's truly restricting our growth," Masterson, a real estate agent, said.

Commissioner Gary Hollis wanted to ensure a flood control system would allow recharge into the aquifer, instead of having the water evaporate. He said that could be done by building dams higher up the nearby slopes, for example in Wheeler Wash.

Allison said Wheeler Wash had the biggest flows of any of the 19 drainage basins in Pahrump Valley, concentrating flows from a 93-square-mile watershed.

But Allison said his system didn't incorporate a recreational lake behind a dam on Wheeler Wash, as some county officials have envisioned. The dams would be only three to four feet high, perhaps up to "several feet," he said.

Clark County officials don't have any interest in the Wheeler Wash area and would be content signing an inter-local agreement with Nye County for the dam construction, Allison said. RPC member Nevada Tolladay suggested possibly moving the county line again farther into Clark County, if a recreational facility is constructed on the wash. The Clark County line is reached soon after traveling east from Highway 160.

The Bureau Veritas study does outline a series of nine dams on Wheeler Wash, at a cost of $40 million. The U.S. Army Corps of Engineers could split half that cost.

A system of 18 detention basins could hold 15,806 acre feet of water, according to the Bureau Veritas study. An acre foot is over 320,000 gallons, or enough water to supply two families of five for a year.

Upstream dams can release water at a rate of up to 6,900 cubic feet per second, what Allison said would be an attempt to merely reduce the peak flows during a 100-year flood. A channel along the planned beltway around eastern Pahrump would funnel the water into various retention basins.

RPC members remembered some major flooding events, like September 2003, when streets were heavily damaged in the upscale Winery subdivision.

The report notes the velocity of the water would be low enough to make dirt channels feasible in most places, which would cut down on the cost of cement lining or stone rip-rap. Culverts would need to be constructed under Highway 160, the study estimated crossings under the highway would cost $4.5 million.

Allison suggested issuing bonds rather than paying after fees are collected. Commissioners could then work with developers on flood control infrastructure as they present plans in the future, he said.

Interest rates are currently at 6.1 to 6.5 percent, payable over 20 years, Allison said. Bureau Veritas put a price tag of $315 million on the total project, using a previous Tri-Core Engineering study for the Pahrump master plan in 2003.

"It's cheaper to build things if you pass the bonds now and we can move ahead with the most expensive parts of the project early," Allison said. "You don't get in a position where development is so intense you can't build the project through the development."

Projections show a Pahrump population ranging from 48,660 by 2013 based on a low growth rate of 4 percent, to 64,420 with a 10 percent growth rate. By 2018 those figures range from 59,210 to 103,750. Pahrump has almost 40,000 people now, according to Nye County planning department estimates.

Nye County could pay $220 million for a reduced flood control system just east of Highway 160, but Allison noted, "we can't just build something across 160 and flood everyone else out."

The study however recommends first setting up the GID with an initial $210 million bond to begin constructing improvements east of Highway 160, including the Wheeler Wash dams.

A series of channels are outlined in the report as the second phase, funneling water from the retention basins to the west. The study noted there are 667 parcels abutting the channels.

The study estimates the north, central and south valley channels would cost $75.6 million. The county would have to acquire 251 acres of rights-of-way at an estimated cost of $10.9 million.

The study lists the Irene Street channel, Bannavitch Street channel, Barney Street channel, Basin Avenue channel, Woodchips-Simkins channel, Gamebird-Pahrump channel, Homestead channel, Lakeview Golf Course channel, Manse channel, Malibou channel, Mount Charleston channel, Unicorn channel, Winchester channel, Kellogg Road channel, Thousandaire channel and Turner channel.

"We maximized our facilities to include infiltration into the ground water basin during a flood," Allison said.

He told the RPC much of the flow from flooding would eventually end up in the California dry lake bed on the west side of the valley.

When Kimball asked for a completion date to the entire project, Allison said, "It probably could be completed in about 15 years. It all depends on private development. If a lot of private development occurs we could work out arrangements to de-parcel the project to speed this up."

Representatives of some major developers were sitting in the audience listening and thumbing through the presentation, includingHafen Investments and Focus Property Group, which has plans to develop up to 5,800 homes in the south end along Highway 160.