Performing a Critical Upgrade
to the Upper Las Vegas Wash
By Tony Illia

Flash floods can be devastating to fast- growing desert cities like Las Vegas.

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That's why the Clark County Regional Flood Control District was formed in 1985. Since its inception, the agency has overseen $1 billion worth of design, right-of-way and construction work, including 62 detention basins and 350 mi. of channels and underground storm drains.

But the flood control district anticipates that it will still take another 30 years before all the necessary flood improvements are completed. Las Vegas Paving Corp. is currently aiding that effort by performing a critical upgrade to the Upper Las Vegas Wash.

The $31.7 million, 4-mi.-long undertaking stretches from Craig and Losee roads to Interstate- 215 and Elkhorn Road in North Las Vegas. The multi-faceted job requires a cast-in-place open rectangular channel, up to 56 -ft. -wide and 11- ft. -tall.

Underground pre-cast box culverts, up to 56 -ft. -wide and 290 -ft. -long, must also be installed at eight intersections. And Las Vegas Paving has only eight weeks to complete each locale.

It's a complicated and involved process that requires rerouting traffic, excavating down to 16 -ft. on average, relocating utilities, and placing a total of 988 -ft. of culvert. Las Vegas Paving must then backfill each trench and repave miscellaneous roadway. The project will require 4,500 tons of asphalt paving.

One of the intersections, Centennial Parkway and Lawrence Street, will require regrading as a result of the culvert installation. Las Vegas Paving must import nearly 2,000 cu. yds. of material in order to match street grades for the proper roadway level.

Designed by Las Vegas-based engineering firm VTN Nevada, the wash project will tie into a detention basin near I-215 and Elkhorn Road, enabling a controlled flow of storm water that will avoid flooding at low areas throughout the Las Vegas Valley.

The 4-mi. section of wash will have a rate-of-flow capacity, ranging >> from 2,100 cu. ft. per second up to 6,940 cu. ft. per second.

Although the flood control district funded the job, the city of North Las Vegas is the owner and project manager. Kleinfelder Inc. of Las Vegas is performing quality inspections on behalf of the city.

"This project is going to take the North Las Vegas Detention Basin outflow as well as the Beltway channel, and bring it under the beltway alignment and transfer it 4 mi. downstream to an existing channel at Craig Road," said Jill Reilly, the flood control district's senior civil engineer. "This project will play a critical role in alleviating flooding in North Las Vegas."

Las Vegas Paving is performing most of the work itself, from concrete and excavation to paving and trucking. That enables the firm to set and maintain a brisk project pace and ensure high-quality work, said Josh Mendenhall, the paving firm's project engineer.

Mendenhall added that there will be roughly 70 tradesmen onsite during the height of construction activity.

The wash improvements will entail 400,000 cu. yds. of excavation and 55,000 cu. yds. of concrete.

Because of the area's clay-like soil conditions, nearly 400,000 cu. yds. of material must also be imported. Las Vegas Paving erected a new 120-ton-an-hour batch plant onsite to expedite work progress. It is additionally using a unique metal form and shoring system that enables workers to cast 100 -ft. of worth culvert every three days.

The 22-month project is scheduled to finish by June 2006