Owned by the Las Vegas Valley Water District and overseen by the FHWA, the Drop 4 structure was designed to regulate water and minimize silt movement in the Las Vegas wash. The project is located within the Lake Mead National Recreation Area and subject to all relative regulations and restrictions.
Sheet piles were used to create a cofferdam and allow construction in (2) segments while maintaining all run-off from the entire Las Vegas valley, including treated waste-water and storm water flowing into Lake Mead. Water was diverted from one side of the temporary sheets to the opposite side after phase 1 construction was completed. All temporary shoring was removed at the completion of the permanent structure.
Permanent sheet pile cut-off walls were installed across the channel and capped with concrete, at the upper and lower ends of the site, to prevent undercutting and scour during extreme (flood) conditions.