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Scott G Winterton, Deseret News
Thousands of volunteers swarm to help residents in Santa Clara work to clean up after flood waters broke the dike Tuesday, Sept. 11, 2012 and destroyed several homes and businesses.

SANTA CLARA, Washington County — The surge of mud and water that flooded homes and businesses caused $3.7 million in property damage, city officials said Thursday.

That number may rise before the assessment is complete.

Sixty-one homes suffered damage from the flood — double the number of homes that were estimated on Wednesday, said Santa Clara City Manager Edward Dickie.

Sixteen businesses were also damaged when they were caught in the wave of flood waters that tore through an earthen retention basin Tuesday.

In the aftermath of the devastating flood, state officials continued to review the dike Thursday. The middle section breached and was completely washed away.

As they reviewed the damage, state engineers said Utahns shouldn't panic.

Each year, state engineers inspect about 200 Utah dams that could pose the same threat to populations as the Santa Clara dike. They have been classified as "high hazard," based on their proximity to residents and potential for destruction, and are the closest watched of hundreds of dams across state.

In addition, there are about 200 moderate hazard dams, 150 low hazard dams, and more dams that are deemed an even lower hazard.

David Marble, assistant state engineer, helps inspect many of those dams. He has spent most of his career working in dam safety.

Water storage poses a powerful threat, which is why they are carefully monitored. The dams are needed, Marble said. They provide hydropower, recreation, water storage and more, but the risk involved can't be totally eliminated.

"Anytime you're storing something that has that much potential power to it, there is a destructive element to that," he said. "It only takes a minor defect anywhere, and there is a potential for that risk to show up."

Inspectors, engineers and dam owners work diligently to reduce risk of failure so that Utahns living in the shadow of a dam don't need to live in fear, Marble said.

"I don't want everyone to think there is a tremendous danger hanging over everyone's head, I just don't think that's the case," he said. "I think that the work we do provides a great deal of risk protection and risk reduction."

However, the work done to inspect and maintain dams may not be apparent to many.

"The work that we do and the risk reduction we bring to peoples' lives in the state every day are totally invisible until something like this happens," he said. 

The Santa Clara dam is 93 years old and was designed differently than modern dams, Marble pointed out. 

"The challenge with a structure like that is that it was so old," he said. "We would build that dam dramatically differently today."

High hazard dams require an emergency action plan, and Santa Clara officials succeeded in protecting residents' lives.

"The city did a good job of observing the structure when there was water in it, observing that there was a problem developing, and getting people out of the way," Marble said. 

The Utah Division of Water Rights provides a website at www.waterrights.utah.gov/daminfo/default.asp for residents to review state codes governing dams, maps of dams across the state and risk guidelines. 

E-mail: mromero@deseretnews.com, acabrero@ksl.com, Twitter: @McKenzieRomero, ksl_alexcabrero