Slow going for flood control

For Las Vegas accountant Constance Lentz, Monday dawned with 3 feet of muddy water soaking the file cabinets in her downtown basement office.

It rained less than three hours across the Las Vegas Valley that day, but the storm's consequences cling like the muck on Lentz's floor.

Sorting soggy files on the sidewalk outside her office at Third Street and Coolidge Avenue, Lentz shook her head at the mess.

"We had to pump the water all day," she said, following a storm that dumped almost 2 inches of rain in parts of the valley. Some places got more than an inch of rain in less than two hours.

That's a lot of rain for an area that receives about 4 inches of precipitation annually, but the floods that plagued Las Vegas last week will likely be repeated for many years to come.

The valley tilts downhill from west to east. Floodwaters flow on major east-west streets, probably following old creek beds from artesian springs that have dried up after residents tapped the ground water.

To flood-proof Southern Nevada, it will take another 30 years and another $1.3 billion in today's dollars to complete at least 45 major projects designed to protect the center of the valley.

Across the street from Lentz's office, University Regent Shelley Berkeley, who is running for Congress, had opened her campaign headquarters less than a week before the flood. By noon Monday, she had temporarily moved out of the basement headquarters, leaving an industrial-strength vacuum to suck out the mud.

After the Charleston Boulevard underpass flooded, the water followed the path of least resistance and continued north and east into the Third Street offices.

Flooding in other parts of the valley also created plenty of headaches. Randy Smith recruited his family and a fistful of mops to move the muck from his shop, Time Printing, at 1224 Western Ave. Smith eventually rented a backhoe to clear away the mud piled in front of his office.

While floodwaters were filling basements, cars were floating away. When running water is traveling at 10 mph, its impact can feel like two concrete cinder blocks slamming into a person's knees. Flows after Monday's storm reached 30 mph.

For those who are new to Southern Nevada, the lightning, thunder, wind and rain last week caught many by surprise.

Meteorologist Ron McQueen, who issued the severe-thunderstorm warning for Southern Nevada about 10:30 p.m. last Sunday, had seen trouble brewing northeast of Las Vegas throughout that day.

Killer storms can form northeast of Las Vegas once or twice a year, McQueen said. "When we see it coming from the northeast, batten down the hatches," he said.

Conditions inside the Las Vegas Valley were perfect for Monday's severe storm. The valley's air heated up, brimming with energy. Humid air flowed east into the valley from New Mexico, an unusual development this time of year.

Thunderstorms had clustered over Lincoln County, northeast of Las Vegas, by evening. The storm then slammed across the mountains and into the valley, knocking out power, sweeping cars away and flooding homes and those basement offices.

Four years previously, another killer storm, called a mesoscale convective system, ripped the Las Vegas Hilton's "tallest marquee in the world" to shreds, McQueen said.

But why did the valley flood? Hasn't the quarter-cent sales tax approved by voters in 1987 for flood control built enough protection for the valley? After all, officials have spent $300 million on 20 major flood-control projects.

The answers are not so simple. There is little protection from flash floods when rain falls in the center of the valley, said Gale Fraser, regional flood-control director for Clark County.

The desert environment, combined with paved development, doesn't help protect the valley from floods.

Money collected since 1987 for flood control has been poured into the building of detention basins near Red Rock Canyon, the Las Vegas Creek that runs along Washington Avenue and in Henderson to prevent runoff from the mountains flooding the valley.

Fraser said those basins on the edge of the valley are vital. "The largest flooding threat is from mountain runoff," he said.

Keeping up with explosive growth and the constant landscape changes from development makes flood-protection difficult.

The valley itself sits like a gigantic funnel, geared to gather water from the southern and western mountains, then plunges it into the tip, which is the Las Vegas Wash.

Floodwaters enter Lake Mead during a flash flood at speeds of more than 30 mph.

"We didn't create the mountains. We didn't create the cemented desert soils. We didn't create this valley," Fraser said. Yet the Regional Flood Control District is expected to protect 1.3 million people who live here, plus the valley's more than 30 million visitors a year, from a disaster created by nature.

"And we're expected to do it with a lean and mean budget," he said.

An estimated 5,000 people are moving to Southern Nevada each month. They create a need for more pavement, which creates worse flooding when the rain comes.

"Growth in the Las Vegas Valley by itself does not cause the flooding problem," Fraser said. "However, it does magnify it."

The middle of the valley is not been protected from a sudden deluge, Fraser says. Ditches, channels and barricades either exist only as blueprints or are too fragmented to move the floodwaters from urban areas.

Protecting the developed areas of the valley will require connections. It's like a jigsaw puzzle with the pieces scattered across a basin that drains 2,000 square miles, Fraser said. There are not enough connections in the middle, at least not enough to protect people's lives and property when a storm drops rains over a community.

"This is a real threat," Fraser said, watching a thunderhead build over the Spring Mountains west of the valley. "When a natural disaster strikes, it will probably be major flooding from the mountains."

The district each year reviews its project list with the county, cities and the Army Corps of Engineers. The district also creates a 10-year plan, modified as money becomes available and local approval is granted.

For example, the county is working with the Army Corps of Engineers to protect homes and resorts downstream of the Flamingo, Tropicana, Duck Creek and Blue Diamond washes.

The Regional Flood Control Board, its members representing all Southern Nevada cities and Clark County, on May 17 approved the sale of $150 million in bond money to build more protection projects in the next three years. "They didn't need a flash flood to speed up construction projects," Fraser said.

The district works with individual cities and the county to construct control projects. The annual project list may change with this summer's thunderstorms, if critical needs arise.

Two years ago, Clark County officials accelerated plans to protect a beltway that will one day circle the valley. The county plans to begin building channels and basins to protect the roadway, rather than waiting for the Army Corps of Engineers to do it.

While residents often aren't aware of it, Fraser said, the designs for flood-protection projects for the next 10 years are on the drawing board. A year ago the flood-control district gave Clark County $8 million to buy rights-of-way and easements around the Tropicana and Flamingo washes.

Congress kicked in $10.2 million for designing that project in 1996. For 1999 Sen. Harry Reid, D-Nev., ranking member of the Senate Energy and Water Committee, got $23 million for work on the Tropicana and Flamingo washes. Another $300,000 will help protect the Las Vegas Wash.

But for those living with flooded intersections this summer, hydrologist Dick French doesn't see too much immediate relief.

"This could be a bad year for Southern Nevada," he said. The last stormy flood season came in 1984. Those floods, which covered the valley for weeks, came after the 1983 El Nino season, French noted.

The valley is plagued by small, continuing problems that are tremendously expensive to fix, French said. The Desert Research Institute where French works teamed up with the U.S. Department of Energy to study flooding at the Nevada Test Site, 65 miles northwest of Las Vegas.

Flood experts got a surprise this year when wet weather hit the Test Site.

A rainstorm in February left eight feet of water in a crater, French said. All of that runoff came from a single square mile, not the 13 square miles in the basin.

"Rains like this have made us see that sometimes we don't know anything about flooding," French said. The DOE has approved further studies at the site.

French said people must use common sense in weighing flood risk when buying a home or driving a car. "There's no such thing as zero risk," he said.

When hunting for a house, French said, look at its location, talk to neighbors and study plans filed at the county or cities. "If there's a drainage ditch nearby, you know you'll see water," he said.

Drivers can lose control of their cars or trucks in as little as six inches of water. Whether they're behind the wheel of a four-wheel drive or a sedan, all motorists are in danger. The simplest advice: "Don't drive through running water."

When thunderheads blot out the sun on summer afternoons, French said, he leaves the Desert Research Institute at Flamingo Road and Swenson Avenue to head for his home office to avoid any potential flooding problems. In a Las Vegas flash-flood situation, he said, it's better to stay off the roads.

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