Even the section of the straw that pumps water from Lake Mead to nearby Las Vegas might not be deep enough anymore. Last week, the Southern Nevada Water Authority (SNWA) board of directors authorized spending $1.4M to investigate whether or not the intake’s opening needs to be lowered.
A sunken boat still lies where it came to rest—on rocks no longer located at the bottom of Lake Mead (Image: CNN).
This move happened less than a year after the water level at the largest reservoir of the nation reduced drastically, which led SNWA to close and seal off its deepest straw, Intake No. 1, since it isn’t submerged anymore, and to initiate the pumping station at Intake No. 3. This is the most profound and costliest of the three intakes, and it now supplies almost all of Las Vegas’ water, according to the SNWA.
“We are not transferring the intake,” SNWA spokesman Corey Enus told Casino.org. “We are evaluating if the intake opening requires being lowered in its current position, so we can keep drawing water from below the surface.”
It’s About Water Quality, not Quantity
Intake No. 3 presently lies more than 20 feet below the dead-pool elevation of 895 feet above sea level of Lake Mead—the depth at which the Colorado River can no longer flow through Hoover Dam downstream to Arizona, California, or Mexico, and hydroelectric power can no longer be generated.
“We are positive that we can still access our water supply even if Lake Mead drops to a dead-pool elevation,” Enus said. “However, we must comprehend what the water quality effects may be of removing water closer to the lake’s surface, where the water is hotter and may have more dirt suspended in it.”
The third straw intake tunnel is a three-mile, 24-foot diameter tunnel delivering water to more than 2M inhabitants of, and vacationers to, the Las Vegas metropolitan region (Image: nps.gov).
Now, Lake Mead is only 28% full, its surface only about 150 feet above dead pool. Its level has dwindled about 170 feet since drought first struck the American Southwest more than 22 years ago. Even though there were recent rains in the region, the rate of decrease keeps on increasing. According to the most recent forecasts from the US Bureau of Reclamation, Lake Mead is likely to drop another 30 feet in the next two years.
Several alternatives are on the table, in accordance with the SNWA—from shortening the third-intake straw and lowering where its top lies, to constructing settling basins such as those used along the Mississippi River to take out sediment.
“We want to investigate feasible solutions now, so we can make proactive, knowledgeable decisions, and guarantee that our city’s water supply remains high quality,” Enus said.
Jacobs Engineering Group Inc. is expected to start the feasibility study this month. It should take eight months to finish.
