- Project Dates: FEB 2014 - ONGOING
- Contract Amount: $11,640
- Construction Management Services
SBCC was contracted by Wadley Construction to design interim channel shoring and water flow diversion for construction of a drop structure in the Las Vegas Wash channel downstream of the Lake Las Vegas Dam. This structure is the fourth of eight proposed drop structures to control channel erosion within the Las Vegas Wash Outfall Channel due to the lowering of Lake Mead Water levels.
No mechanism exists to completely stop the channel flow, so a flow diversion plan was prepared for approval. The daily base flow was expected to be approximately 350 cubic feet per second (cfs), an average storm event in the area can produce a storm spike from 1,000 to 1,500 cfs, while larger events can produce floods exceeding 10,000 cfs. Protective measures to convey flows from anticipated storm events were incorporated into SBCC's prepared plan. Phasing of construction in the channel was necessary in order to maintain channel flows during construction.
SBCC reviewed new geotechnical condition information and compared it against previously provided information. SBCC analyzed the hydraulic conditions of the channel and prepared sheet pile structural calculations.
Modifications to engineered temporary construction water diversions and supporting calculations were provided to the Federal Highway Administration (FHWA) as a construction submittal. These modifications were required due to encountered changes in subsurface conditions at the site, including the presence of boulders, caliche, and partially consolidated materials that impeded driving of the sheet piles to depths necessary to provide temporary structural support with the applicable factor of safety. Because subsurface conditions did not allow cutoff sheet piles to be driven, SBCC prepared design documentation supporting the construction of an earthen diversion berm, to include culverts and access road.