Lake level threatens docks

Friday, March 30, 2001 | 11:18 a.m.

A bad snow season in Colorado, Wyoming and Montana could spell trouble on Lake Mead this summer.

Dry conditions in the West have affected the amount of water flowing down the Colorado River to the lake, and by July water levels could drop 13 feet.

That's part of a usual cycle on the lake -- the water level rises in the winter and falls as the summer heat settles in -- but if the dry conditions persist over several years it could become a costly problem for the rangers of the Lake Mead National Recreation Area.

Lake levels hinge on consumer demand and the weather. Continued population growth has increased demand on the Colorado River, particularly in the Southwest during the past 10 years.

A Southern Nevada Water Authority official said growth experts did a fairly good job until 10 or 15 years ago. "No one estimated this degree of expansion for this period of time," Deputy General Manager Richard Wimmer said.

A drop of 36 feet from the current level would require that the nine docks and boat ramps would have to be moved closer to the water line. Also affected would be water and power lines that connect the docks to the shore supplies.

"Basically, we have nine floating cities plus 1.5 million acres of park to manage," William K. Dickinson, Lake Mead National Recreation superintendent, said.

A drop of 20 feet below 1,180 feet would cost the National Park Service an extra $5 million that is not in its budget. The lake is currently at a level of about 1,196 feet.

If it became necessary, the Park Service would have to ask Congress for emergency funding, which takes an act of Congress.

Failing that, the money would have to come out of the $13.7 million budget for the national recreation area, Dickinson said. The area encompasses 1.5 million acres in Nevada and Arizona. The lake accounts for 13 percent of that.

Services that could face cutbacks include maintaining campgrounds and picnic areas, replacing old docks with new concrete ones and any expansion projects.

It's not something keeping rangers awake at night. They don't think there will be a problem this season.

Neither the Bureau of Reclamation nor the Park Service expects the lake to drop far enough to prompt calls for emergency funding, officials said.

"It's part of a natural cycle for the lake," said Bob Walsh, a spokesman for the Bureau of Reclamation, which is charged with monitoring and managing the Colorado River's water, as he tracked the lake's level at 1,195.7 feet on a recent morning. "It should have little effect this year."

This year the lake is not expected to drop below the 1,180-foot mark, a measure used by the bureau and the National Park Service as a guide for tracking impacts on marina services and activities along the shore.

Each 20-foot drop below 1,180 feet can leave up to 600 feet of shoreline high and dry. Some areas of the shoreline near Las Vegas Bay have dropped 12 feet, marina owners said. When the lake levels drop, they don't necessarily do it in a uniform way.

There is no such thing as a "normal" lake level, Walsh said. The bureau operates the river and its reservoirs, including Lake Mead, as if filling and draining a bathtub. In summer the lakes are depleted as California and Arizona farmers demand more water for crops. Evaporation also takes a toll. In winter, snow and rainfall replenish the river and its reservoirs, Walsh said. Or, as with this winter, sometimes they don't.

This year's late winter rains cooled off the Las Vegas Valley, but they did not rebuild the water supply for the coming months, meaning Lake Mead will continue to drop, Walsh said.

It could become a serious problem if winter snowpacks fail to build in Colorado, Wyoming and Idaho over the next four to six years. The lake in a long dry spell like that could drop 40 to 50 feet, Nevada's chief of the Bureau of Water Quality Planning Tom Porta said.

The lake's level began lowering last July after the last dry season in the mountains. Officials first started noticing the river's flow rate was declining, and slowed the rate of water released from Lake Mead from up to 30,000 cubic feet per second to 8,000 cubic feet per second.

Ironically, even with that reduction, a surplus was declared on the Colorado River last year.

Another surplus of 600,000 acre feet has been declared this year for California, Nevada and Arizona, because the Upper Basin states of Wyoming, Colorado, Utah and New Mexico have not used their full river shares.

But a surplus can't stave off the inevitable if the skies remain dry.

In October 1991, after six years of relatively dry weather, Lake Mead had fallen to 1,171.7 feet. It took three years for the levels to recover to 1,180 feet, according to bureau records.

A dry spell is felt not just in Lake Mead, but downstream as well. Part of the job of the river system's managers is supplying enough water to threatened and endangered species in the river.

It's a concern that has gained prominence, as environmental groups such as the Southwest Center for Biological Diversity and the Grand Canyon Trust, both based in Arizona, have taken on the cause. The groups are pushing for Western states along the Colorado River to allow 1 percent more water to run into the sandy Mexican Delta to restore wetlands and habitat for fish and birds such as the Southwest willow flycatcher and the the Yuma clapper rail.

Not only environmentalists, but Southern Nevada water officials keep an eye on the lake levels.

Southern Nevada Water Authority General Manager Pat Mulroy has said that it is "highly unlikely" that the lake will affect the ability to deliver water to the Las Vegas Valley. The drinking water intake pipes are at 1,050 feet and 1,000 feet, respectively.

But that doesn't stop her from keeping a watchful eye as the levels rise and fall.

The fluctuating water levels can affect the quality of water. With less fresh water running through the lake, concentrations of pollutants such as treated wastewater and untreated surface runoff become stronger.

A dry spell lasting 10 years of longer could affect Lake Mead's level, but officials would have plenty of advance warning about the fluctuations, Mulroy said. Right now the entire river system has enough water to meet downstream deliveries for up to four years.