Ahead of approving a resolution for a $150 million bond to build a new high school and replace the Midway Elementary School. Wasatch County School Board heard a presentation regarding the site of the proposed new high school.
At their August 20th meeting the Wasatch School Board unanimously passed a resolution to bring the $150 million bond to election. This November, Wasatch County residents will be able to vote on the bond which would result in the creation of a new high school and replace the current Midway Elementary school.
Engineer Paul Berg presented to the board before they voted on the bond in the meeting. Some local officials have questioned the location of the proposed new high school, worrying it may be in a flood zone area. Berg looked at the 1992 study by the Bureau of Reclamation of the Jordanelle dam. He says the proposed school site is not within the major floodway.
“In fact, we’re 3/4 of a mile from the major floodway,” Berg continued. “The property is on the eastern edge of the overflow limits. So that means as is, the property would have a small amount of water from the overflow on the property. However, the way that the site has been laid out in our proposed elevations for the school building it would be two feet above what was projected back in 1992 as the old flood limits. There’s a red note on the side. It says the inundation areas shown on this map reflect events of extremely remote nature. These results are not in any way intended to reflect on the integrity of the dam.”
According to the Bureau of Reclamation the Jordanelle Dam is built to withstand a 7.5 magnitude earthquake on the Wasatch Fault, which is located on the other side of the Wasatch Mountains.
Although Utah is due for a big earthquake Mike Hylland, Deputy Director of Utah Geological Survey, says that the odds of an earthquake larger than magnitude 7.5 are low.
“For the modeling that we’ve done for the Wasatch Fault, the data support earthquakes as large as about 7.3 on the longest segments of the fault and up to about magnitude 7.4 to 7.5 if more than one segment of the fault were to move at the same time. The chances of an earthquake larger than magnitude 7.5 are very low.”
The dam is also built to withstand a magnitude 6.5 local earthquake. The Bureau of Reclamation confirmed Berg’s assessment saying there is an extremely low risk of this type of seismic activity that would cause a dam failure.
“The only recorded event in Wasatch County that was above 4.5, again this dam was designed for 6.5 local earthquake, was a 4.7 magnitude which is significantly less than 6.5. It happened in 1972,” Berg explained. “If the dam broke, the Bureau of Reclamation has estimated it would take almost an hour for the flood waters to travel 6.5 miles and endanger Heber City. So, in this extreme event that if the dam for some reason was to have the sudden break and completely go, we’d have almost an hour to evacuate the kids. The distance that they would need to be evacuated is less than two blocks from the school building to 600 West where they would now be in a safe area.”
Superintendent Paul Sweat noted that the high school can be evacuated in under 10 minutes. Berg added that a hypothetical dam failure flood is not regulated by Wasatch County ordinances or Heber City codes.
“Typically, their codes are related to FEMA 100-year flood plains which we’ve examined, or other flooding hazards related with streams or ravines,” Berg said. “But a dam breaking is not an event they consider under their code.”
Read the original story at KPCW.org