Thursday, Oct. 20, 2005 | 7:04 a.m.
What: A public hearing on the proposal to change the treated wastewater discharge point to Lake Mead.
When: 6:30-8:30 p.m. today.
Where: Summerlin Library, 1771 Inner Circle Drive.
A proposed $625 million project to change the discharge point for Clark County's treated sewer water would do more harm than good, a handful of critics are charging.
Jim Deacon, a UNLV professor emeritus of environmental studies and biology, testified this week that there are major flaws in the proposal to divert millions of gallons of treated effluent from the Las Vegas Wash to a point at the bottom of Lake Mead, a few miles upstream from Hoover Dam.
The Clean Water Coalition that represents Las Vegas, Henderson and Clark County is proposing the sewer project, which until now has had little criticism.
Deacon said new research shows that changing the discharge point could lead to a buildup of contaminants and degrade the wash, which has become a showcase for biological diversity in the desert. New research also shows the seasonal mixing of water in the lake that project planners are counting on occurs only 60 percent of the time.
The rest of the time the treated effluent simply sticks to the bottom of the lake. If that happened several years in a row, the wastewater could build up to the point where it could enter the Southern Nevada Water Authority's intake pipes, which bring lake water to the valley's population, Deacon said.
He said this week that a better plan would be to take the excess wastewater and pump it into the ground, where it could be "banked" and brought back up for urban needs at some later point.
The Clean Water Coalition proposal is neither "the most cost-effective nor the most environmentally effective" way to handle the growing volume of wastewater, Deacon said.
"The water that is injected into the deep water stays there. It we have two or three years (of that happening) in sequence, that volume simply keeps adding and gets closer and closer and closer to the intake structures," he said. "It probably increases the likelihood of contamination."
Walter Johnson, an engineer with Clark County Water Reclamation District, agrees. Johnson, who was on the Clean Water Coalition's Advisory Committee, has expressed concerns about the project, arguing that treated wastewater should be injected into the Las Vegas aquifer rather than sent back to Lake Mead.
The criticism reverses objections that some, including local environmentalists, had leveled at the local water agencies for bringing water from Lake Mead downstream of the main discharge point. The coalition proposal would move the discharge point closer to Hoover Dam, theoretically preventing contaminants from moving upstream to the Water Authority's intakes.
The coalition is proposing the move because of the increasing volume of wastewater, which officials say will overwhelm the wash.
The trio of municipal sewer agencies currently release about 180 million gallons of treated wastewater every day into the wash. That number could double in the coming decades as the area's population continues to grow. There's a concern that putting that much treated effluent upstream of the water intakes could increase the chance that contaminants reach the intakes.
Deacon said a primary reason that the proposal is no longer necessary is that Clark County's treatment processes have recently reached the point where the water is much cleaner than in the past. Whatever contaminants remain in the water would be removed simply by sending the water down the wash.
Deacon's conclusions are exactly opposite of those planning the change in the discharge point. Clean Water Coalition planners argue that the project will improve the health of the Las Vegas Wash and water quality.
The Clean Water Coalition's Doug Karafa, formerly a reclamation district manager, argues that as the flow increases, the amount of phosphorus and other contaminants will also increase and could pose a threat to the Water Authority's intakes.
He declined to respond in detail to Deacon's arguments, saving a detailed rebuttal for the environmental impact statement that is being prepared under the supervision of the National Park Service and Bureau of Reclamation. The statement must by law discuss potential effects and alternatives to the project before it can get a green light from federal agencies.
"We thoroughly expect that not everyone is going to be in love with our project," Karafa said. "It is part of the process that we look at these comments. We'll address these as best we can."
Launce Rake can be reached at 259-4127 or by e-mail at lrake@ lasvegassun.com.
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