Jump to Navigation


Our faults ...Researchers find two earthquake faults while studying safety of Martis Creek Dam

By Greyson Howard, Sierra Sun

The Army Corps of Engineers, as part of a study into the safety of Martis Creek Dam, dug two trenches in Waddle Ranch this fall. What they found, two earthquake faults, lends credence to the dam’s ranking of one of the six riskiest in the nation. The dubious ranking, derived by the Corps, came because water is seeping under the dam through a loose glacial till, which in a worst-case scenario could result in failure and flooding in Reno.

“We found a fault in each trench,” said Ron Rose with the Dame Safety Assurance Program of the corps. “They are two separate faults, but probably related, and they do trend towards the dam.” Rose said in a previous interview it could be four years, in a best-case scenario, before the corps can come to a decision, on repairing, rebuilding, or removing the dam.

The Corps did not find any charcoal near the faults for the purpose of carbon dating, which would have indicated when the last earthquake was, and how much of a risk it presents to the dam, Rose said. Other dating options are being pursued.

More trenches will be dug both up and down stream from the dam to further map the faults, and an aerial map will be made of the surrounding landscape, Rose said. Other work around the dam will be slowing down or stopping for the winter, said Veronica Petrovsky with the corps.

For entire article, please visit website.

Fault found under Martis Dam

Sierra Sun staff reports
March 11, 2008

Recent study shows the likely existence of a recently active earthquake fault under the Martis Dam near Truckee.

The 36-year-old earthen-fill dam is located 3 miles east of Truckee in the Martis Valley and has been categorized as an “extremely high risk.”

Officials worry that water seepage could destabilize the dam. It is classified as one of the six riskiest in the nation.

But the Army Corps are keeping the water low to reduce the risks, and the water level as of March 6 was 793 acre-feet, compared to a total 20,400 acre-feet of capacity behind the dam, according to the report.

For entire article, please visit website.

Syndicate content