Lake Mead has dropped to its lowest level in more than 40 years, forcing the closure of several launch ramps and the relocation of at least one marina.
"We have not seen lake levels this low since about 1960," National Park Service planner Jim Holland said.
"It is currently at 1,141 feet elevation, down 80 feet from full pool."
Full pool is the upper elevation limit and is determined by the spillway elevation at Hoover Dam.
Holland said the Bureau of Reclamation has projected that the water level will decrease even further during the next two years to 1,118 feet.
For the past 30 years, the lake level has been held within 40 feet of full pool and recreational facilities were able to expand and operate within the 40-foot fluctuation zone, Holland said.
However, the past three to four years of drought have dropped the lake's level dramatically.
The low water will continue to limit use of launch ramps and marinas, Holland added.
Ramps at Pierce Ferry and Government Wash, near Las Vegas, have closed, and the operation of other ramps may also be in jeopardy if the water continues to drop, he said.
Several marinas and the commercially operated Lake Mead cruises have been temporarily relocated, and other marinas have been reconfigured and moved farther from shore.
Lake Mead is a fluctuating reservoir impounded by Hoover Dam and filled by the Colorado River.
The Bureau of Reclamation, which is part of the Department of Interior, operates the dam.
Lake Mead National Recreation Area is managed by the park service.
During an average year the amount of water flowing out of Lake Mead exceeds the amount flowing into the lake because of snow runoff in upper basin states of Colorado, Utah, New Mexico and Wyoming, Holland explained.
A normal wet year in the upper Colorado River drainage typically replenishes the water supply.
However, the water level is going down because the runoff from the Colorado River drainage for the past four years has been far below normal.
In 2000 the runoff was 56 percent of normal and has been approximately 60 percent normal since.
The park service has set in motion an amendment to the general management plan for Lake Mead National Recreation Area that would address issues related to ramps and marinas affected by the declining water level, and the location of future boat ramps and marinas.
The park service will determine future locations for public and commercial lake access facilities on Lake Mead based, in part, on public input.
The evaluated information will be included in an environmental assessment, which will be available for public review the summer of 2004.
The general management plan amendment will take a minimum of one year put together, Holland said.