Sunbaked Southern Nevada sees a scant 4 in. of rain annually. When a downpour occurs, however, it can be violent, abrupt and torrential. Often, the result is flash-flooding that particularly impacts low-lying northeast Las Vegas, where heavy rains routinely cause water damage to homes, businesses and properties. In 2011, the Federal Emergency Management Agency added 1,700 structures to the area's high-risk flood zone, making insurance premiums nearly five times pricier.

"It meant we needed to meet a 100-year storm event. And we had never looked at the existing channel's capacity or flow rate," says Joe Damiani, Clark County Regional Flood Control District principal civil engineer. "There haven't really been any large capacity improvements—just occasional post-flooding maintenance work."

The Flood Control District, in response, is helping fund four miles of infrastructure improvements through the Clark County Public Works Dept., which is making its first foray into construction manager at-risk (CMAR) project delivery by awarding the project's approximately $145-million guaranteed maximum price, fixed-fee contract to Las Vegas Paving Corp. The Las Vegas-based contractor's size, resources and previous CMAR experience with other several local municipalities all played a role in its selection, project officials say.

Englewood, Colo.-based CH2M-Hill Inc. is the design engineer, with Stanley Consultants Inc., Muscatine, Iowa, as owner's representative.

"This was an ideal job for a CMAR delivery, albeit it's a large project for an owner to cut their teeth on," says Bill Wellman, division and project manager with Las Vegas Paving. "It enables fast-track construction, with early release work occurring while design is still being finalized as opposed to a traditional design-bid-build procurement approach that can be slower and more contentious."

Multiple construction crews

The undertaking calls for upgrading key portions of the Flamingo and Las Vegas washes that flank the 135-acre Desert Rose Golf Course. The work will widen, deepen and line the two flood channels—serving as the region's primary confluence—while improving inlets, replacing bridges and relocating sewer lines.

It additionally revamps the 50-year-old, 18-hole county-owned golf course, including the 4,500-sq-ft clubhouse and accompanying 12,000-sq-ft cart/maintenance building. Project boundaries stretch from Vegas Valley Drive and Sahara Avenue to Sloan Lane and Nellis Boulevard.

Las Vegas Paving is self-forming most of the work, or about 306,000 man-hours, utilizing a 200-person labor force in 10-hour shifts, six days a week. There are roughly 75 dozers, excavators and loaders on site, moving 740,000 cu yd of soil, aided by 30 big-rig trucks each with double side-dump trailers.