Runoff control projects under way all over Clark County

The soil of our valley is hard and water resistant. As more of the valley has been paved, becoming even harder and more water resistant, the growing population has increasingly come into conflict with raging floodwaters as our summer monsoons drop more water on the valley faster than the land can absorb. For a quarter century, the Clark County Regional Flood Control District has been planning and building structures to control floodwaters in the county.

"We control the floodwaters with a network of detention basins, channels and underground storm drains," said Betty Hollister, public information manager for the Clark County Regional Flood Control District. "We're in charge of flood control for the entire county from Mesquite to Laughlin, but obviously most of what we've done is in the valley."

The majority of the infrastructure is here not just because of the population density, but because of the geography of the valley, a wide plain all but completely surrounded by mountains. It acts as a great tilted bowl, collecting any rain and funneling it down the washes to Lake Mead.

"The valley drops 2,800 feet from Red Rock Canyon to Lake Mead. That's two and a half times the height of the Stratosphere Tower," Hollister said. "That's a huge drop downhill, and the floodwater flows through the valley fast. We've clocked floodwater in channels going as fast as 30 miles per hour."

Although the flood control district has created more than 500 miles of channels and underground storm drains, it's really the detention basins that are the workhorses of the system.

"If it weren't for the detention basins, the channels running through the urban areas would have to be a lot bigger," Hollister said.

The detention basins tend to be at higher elevations nearer the edge of town, although there are a few right in the middle of the valley, as well. The basins collect the water, not unlike a dam, but with an outlet releasing only as much water as the flood control district has determined can be handled downstream. The result is that rather than the rain collecting in a torrent and passing out of town quickly, the rain instead collects in the basins and only releases a river of water down the washes at a slower rate.

The flood control district also builds peaking basins in which the floodwater flows down the wash until it reaches a certain height. Then the excess flows over a low wall of the channel into the basin where, like other basins, it is released slowly.

Although you would be hard-pressed to find someone opposed to flood control, there are those who are not 100 percent behind the exact methods that the flood control district employs. Fred Sigman, a College of Southern Nevada art history instructor, grew up near the washes and has spent extensive amounts of time photographing them. He feels that too much emphasis has been put upon turning the washes into concrete channels.

"It's such a unique environment. It's highly unusual to find this kind of riparian system in the desert," Sigman said. "It certainly isn't what it used to be, but I've got a certain nostalgia because as a kid, it was sort of my Walden Pond."

Sigman said he understands the necessity of re-engineering the wash, but as a member of the Desert Wetlands Conservancy, he keeps an eye on washes being converted to channels and taking water directly to the Clark County Wetlands Park. He sites his concerns as a combination of aesthetic and environmental.

"I have not heard how they're going to treat that water in a way that is superior to the natural filtration system of a wetlands," Sigman said.

Although the flood control district is not primarily concerned with aesthetics or secondary uses for the flood control areas, it has been known to work it into its designs.

"In some cases, the basins are dual use with a recreation field or a soccer or baseball field built into them. The taxpayers are getting both flood protection and recreation," Hollister said. "The Regional Flood Control District doesn't actually build recreation facilities, but we work with the city or county to design it for dual use if that's what they want."

Hollister said that once the flood control district builds a flood control element, it passes it on to the city or county, which becomes responsible for policing, cleaning and maintaining it. Maintenance costs do come from the flood control district's budget, but the actual work is done by the entity concerned.

Funding for the organization comes from a sales tax. The flood control district receives a quarter of a cent of sales tax revenue. This year, due to the foresight of Gale Fraser, the flood control district's general manager and chief engineer, funding also will come from bond sales.

"In mid-June, we were able to bond for 150 million dollars, and that bond fund money combined with our regular revenue source will allow us to move more than 30 projects into construction by the end of the year," Hollister said. "It's historic for the district. We've never had that many projects under construction before."

Although the funding comes partially from the Build America Bond Program, a part of the federal stimulus package, it isn't free money. The bonds still will have to be paid back.

According to Hollister, Fraser had a long-term plan for the bond dating from four years ago. He informed the city and the county, which put the plans on the drawing board.

"We had to have projects that were ready, that were fully designed. If the city and the county hadn't come through with the plans, we couldn't have done the bond," Hollister said. "It's great that we were able to bond in this economy, that we were able to get a good interest rate and we were able to move forward as planned."

Currently 11 of the 30 projects already are under way.

Contact Sunrise and Whitney View reporter F. Andrew Taylor at ataylor@viewnews.com or 380-4532.