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Salt Lake prison sites could get hit by tsunami

SALT LAKE CITY — The ground shakes violently and then a wall of salty, brine-shrimp-laden water crashes into the Utah State Prison. The cells of the state’s most dangerous inmates start to flood. Panicked Corrections officers must make a tough choice — hope the waters recede or release murderers and rapists who may escape in the chaos.

This is the doomsday scenario Salt Lake City Mayor Ralph Becker has repeatedly warned about if state leaders decide to build a new prison near the shores of the Great Salt Lake and the airport.

It all sounds far-fetched that a big earthquake could result in tsunami-like waves on the lake, but it is possible, says University of Utah seismology professor James Pechmann.

“Basically I think it is a terrible idea to put a prison there or an industrial park or any other major development because of the hazard from the lake,” he said.

The Prison Relocation Commission is looking at two Salt Lake City sites, one north of the airport and west of 2200 West, and the other west of the airport near Interstate 80 and 7200 west.

Becker flagged his concern about big waves in a technical report he gave earlier this month to the seven commissioners, who are members of the state Legislature. He also brought it up in two public meetings Tuesday, including listing it at No. 5 in his top 10 list of reasons not to build a prison in the city, with No. 1 being a future airport expansion.

“If there is a seismic event, there is not going to be time to do this orderly evacuation of a facility,” Becker said at a gathering at City Hall on Tuesday evening. “It should be a primary factor both for the safety of the prisoners and the employees who are at the prison but also the community around it.”

He pointed to what happened in New Orleans when Hurricane Katrina hit in 2005. A report by the American Civil Liberties Union called the flooding at the Orleans Parish Prison some of the “worst horrors” from that disaster, where some prisoners had to stand in chest-high sewer water, while guards were also trapped at their stations.

At the request of The Salt Lake Tribune, Pechmann reviewed the two sites, the west one owned by the mining giant Rio Tinto and the north site owned by the Swaner family. He said the west site near Interstate 80 may face some flooding under extreme circumstances, but the north site is far more problematic and could face a tsunami-like wave.

“It depends on where the lake level is and how much water you have in the lake,” he said.

Right now, the Great Salt Lake is near a historic low, with the water level at an elevation of about 4,193.4 feet, but that’s cyclical. The lake reached 4,212 feet during the widespread flooding in the 1980s and previously in the 1870s. Experts determined that any building on properties adjacent to the waters and below 4,217 feet would likely face flooding, and Salt Lake City has built that into its master plan.

The elevation of the north site is below 4,217, according to Pechmann and a technical review conducted by Salt Lake City.

If the lake is deep and wide and a 7.0 magnitude earthquake hit, Pechmann said it could send a 10- to 20-foot wave that could come toward a potential prison. What damage such a wave might cause would depend on exactly where the prison was built on the site and how it was configured.

This is not all hypothetical. The 1909 Hansel Valley earthquake was likely below a 6 magnitude and observers saw major waves near Saltair.

“The lake was set in motion to a marked degree, and waves were started rolling over the bathhouse pier,” read a Deseret News story from the time. That story indicated that waves covered a railroad pass. If true, that meant they were 12-feet high. Pechmann is skeptical of that report but says it shows big waves in the Great Salt Lake are possible.

He said a far bigger concern than a massive wave is flooding, either because the lake level would rise or because an earthquake would cause the land to tilt toward the fault line.

A 1998 study looked at six earthquake scenarios at three lake levels. If the lake is at a high, the Swaner land would be flooded in two of the six scenarios.

The Salt Lake City International Airport would see some flooding at the north end of its runways, but in none of the scenarios would it get inundated, Pechmann said.

While each potential disaster is loaded with ifs and uncertainties, Pechmann said looking at the north site for a prison that may stand for 50, or maybe even 100, years, makes little sense.

“It is a very poor choice for a prison or any other critical facility,” he said.

MATT CANHAM, The Salt Lake Tribune