Piezometers: An Essential Component to Dam Safety

Congress has invested $665,000 from the Bipartisan Infrastructure Law to install new prefabricated staircases for the safety of maintenance workers who use the staircases to inspect the condition of Luck Peak Dam.

These staircases allow access to Lucky Peak’s piezometers, an essential component to dam safety at Lucky Peak Dam. A piezometer is a geotechnical instrument that measures changes of water level or water pressure beneath the surface. There are 25 piezometers specifically arranged at Lucky Peak Dam to gather risk assessment data for engineers. The piezometers extend to different lengths beneath the surface to measure water depth at specific locations.

The piezometers were established and modified between the completion of the dam in 1955 and 2012 to gather the best geological readings. The instruments still provide accurate data for engineers.

The U.S. Army Corps of Engineers conducts weekly and monthly piezometer inspections around Lucky Peak Dam, comparing the data with previous recordings. The piezometer readings benefit USACE by verifying the performance of the dam. They help analysts identify uncommon water levels patterns and to make appropriate decisions for dam safety.

“We use the data to make risk-informed decisions of the performance of the project,” Steven Wyrembelski, Senior Geotechnical Engineer for the Walla Walla District, said.

There is only one way to access three important piezometers: through the staircases on Lucky Peak Dam. The staircases are old and are hazardous for maintenance workers who use them.

“Those three piezometers are the most important ones to tell us about the performance of the dam,” Wyrembelski said. “We are going to have a new system that improves access to those three.”

The BIL funding will allow new prefabricated staircases to be installed so that USACE officials can safely continue to access the piezometers to aid the wellbeing of the project and keep the Treasure Valley safe.

The design contract will be awarded in the fall of 2023 and construction will begin September of 2024.

In addition to weekly and monthly piezometer readings, USACE conducts one-year and five-year inspections of the equipment. The next five-year inspection is scheduled for 2024. Altogether, these inspections help to ensure Lucky Peak Dam remains solid and safe.

In the dam’s almost 70-year history, it has stopped an estimated $2.4 billion in flood damages since 1961.

USACE engineers continue to look for ways to improve piezometer monitoring to maintain dam safety.

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