EM Nevada Well Drilling Underway for Groundwater Analysis at NNSS

An Environmental Management Nevada Program drilling well, ER-20-13-1, is pictured as bits of rock, soil and fluids are discharged into a lined sump on the remote Pahute Mesa at the Nevada National Security Site.

LAS VEGAS — The Environmental Management (EM) Nevada Program has commenced well drilling in a remote stretch of the Nevada National Security Site (NNSS), furthering a decades-long mission to document the nature and extent of groundwater contamination caused by historic nuclear testing at the NNSS.

Crews started drilling the first well, ER-20-13-1, in May on the Pahute Mesa region of the NNSS. They reached a final depth of 2,570 feet below ground surface before moving on to a second well, ER-20-13-2. Drillers will then deepen an already existing third well, ER-20-1, so groundwater from the three wells on the Pahute Mesa can be analyzed for contamination and compared with computer modelings.

“The drilling supports future closure of the final groundwater corrective action unit at the NNSS,” said EM Nevada Program Manager Rob Boehlecke. “To do so, we need hard data. The goal is to demonstrate the reliability of our groundwater contaminant transport model results and provide confidence that the model results can support decisions leading to closure.”

An Environmental Management Nevada Program drilling well, ER-20-13-1, is pictured on the remote Pahute Mesa at the Nevada National Security Site.

The government carried out 928 nuclear tests at the NNSS from 1951 to 1992. Nearly 90% of those tests were detonated underground. The U.S. Department of Energy Office of Environmental Management in 1989 was assigned the job of documenting the extent of the contamination of groundwater stemming from the tests, discerning where the contaminated water is headed and the rate of flow.

In 2016, Frenchman Flat was the first groundwater corrective action unit at the NNSS that EM closed. The Yucca Flat groundwater region was brought to closure in 2020. The same year, the Rainier Mesa and Shoshone Mountain groundwater corrective action unit reached closure three years ahead of schedule to the result of $5 million in federal savings.

In 2023, after extensive scientific analysis, the EM Nevada Program reached what is known as the model evaluation stage for the final groundwater corrective action unit of Pahute Mesa.

The current drilling campaign has required extensive planning carried out by EM Nevada Environmental Program Services contractor Navarro Research and Engineering. Navarro Field Operations Manager Brian Haight said protecting workers has been the top priority for the team since day one.

“There has been a lot of effort focused on both safety and using the newest technology,” Haight said.

Haight said to further safety, Navarro worked with subcontractor Premier Drilling on the use of a top drive drilling rig system, which reduces the need for manual labor on the rig. This minimizes the potential for accidents or injury.

“I no longer have to have a worker required to be up in the tower, which is a very dangerous position,” Haight said.

Safety measures are also in place for workers to avoid heat stress. From noise reduction to pressure points, the engineering of the project has prioritized safety.

“It is built so people don’t have to put their hands on everything, and that eliminates a lot of your typical pinch points and the things where most accidents occur,” Haight said.

If there is any confusion or questions during work, the team pauses to go over everything, Haight said.

He added: “We are extremely happy with the progress made. We are confident that the wells will produce quality data to support closure at Pahute Mesa.”

Through closure activities, the EM Nevada Program is confident that contaminated groundwater will not impact public water supplies.

-Contributor: Glenn Puit