National Park Service
LAKE MEAD NATIONAL RECREATION AREA News Release
NPS RELEASES ENVIRONMENTAL ASSESSMENT FOR PROPOSED FLOW REGULATION IN LOWER LAS VEGAS WASH
BOULDER CITY, Nev. - The National Park Service is seeking public comment for an environmental assessment related to the lower end of Las Vegas Wash.
The park service completed an assessment, analyzing a proposal to regulate flows and reduce erosion in the wash. The assessment describes two alternatives. Under alternative A, no action would be taken. Under alternative B, up to six new grade control structures would be built downstream from the existing structures. Structures would be built as necessary, with the need depending significantly on future water levels of Lake Mead, which influence the rate of degradation in the wash.
The proposal is in response to a study completed by the Federal Highway Administration, suggesting that active management of the channel and additional grade control structures are needed to protect the Northshore Road Bridge and maintain access across the wash to the northern portions of Lake Mead National Recreation Area.
Las Vegas Wash was once only temporary drainage, but beginning in the late 1960s, it transitioned into an enduring stream as a result of the development of the Las Vegas Valley and increased effluent discharge into the Wash.
Greater flows have resulted in channelization of the wash and increased erosion. In 2002, the National Park Service constructed three grade control structures in response to this erosion, but with the drawdown of Lake Mead over the last several years, the Federal Highway Administration suggests additional downstream structures are needed to combat the problem.
The document is available for review at area libraries and online at https://parkplanning.nps.gov/projectHome.cfm?projectID=42094. Comments may be submitted via the website. Written comments should be mailed to Lake Mead NRA, Compliance Office, 601 Nevada Way, Boulder City, NV 89005. Comments must be received by April 4, 2013.
- NPS -
Last updated: February 28, 2015