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."
