Post-fire environmental monitoring activity will close 'White Rock Y' parking area

Contact: James Rickman, elvis@lanl.gov, (505) 665-9203

Recent News Los Alamos scientist named Asian American Engineer of the Year Los Alamos scientist featured in NASA science update Los Alamos muon detector could thwart nuclear smugglers Wojciech H. Zurek named Phi Beta Kappa visiting scholar Four Los Alamos physicists honored by American Physical Society Los Alamos National Laboratory organizations earn seven out of 13 NNSA Pollution Prevention awards Carter Hydrick returns to the Bradbury Science Museum Feb. 15 Laboratory supports summer science program New NASA IBEX mission to carry Los Alamos instrument Beason takes top threat reduction post at Los Alamos

LOS ALAMOS, N.M., March 21, 2001 -- Attention all "White Rock Y" parking area users: The paved parking area on the north side of N.M. 4 near the junction of N.M. 4 and N.M. 502 becomes unavailable on March 26 as researchers from the U.S. Department of Energy's Los Alamos National Laboratory begin an environmental monitoring activity.

Laboratory researchers are installing three specialized monitoring boreholes in lower Los Alamos Canyon near the parking area to determine whether a flood-mitigation device constructed by the U.S. Army Corps of Engineers in the aftermath of the Cerro Grande Fire is affecting the transfer of water-borne materials from the surface to deep underground. The activity will affect the parking area for several months.

"This project will involve a lot of heavy equipment," said William Stone, technical leader of the project and a member of the Laboratory's Earth and Environmental Sciences Division. "Therefore, we feel that we must close the parking area to ensure that no member of the public is exposed to any safety risk during the course of this project. We are hoping that members of the public who frequently use the parking area will exhibit understanding and patience throughout the closure period."

Two of the boreholes will extend at an angle from the edge of the parking lot to areas beneath lower Los Alamos Canyon upstream of the flood-control structure. The structure, called a weir, is visible from the parking lot, and is constructed of large stones contained within wire baskets. The third borehole will be completed as a long-term monitoring well and extend vertically beside the Los Alamos Canyon stream channel.

By drilling at an angle, researchers will be able to intersect the area below the stream channel and gain insight into how runoff migrates from the surface to the subsurface. Researchers will use a long membrane reminiscent of an inside-out sock to gather information along the boreholes of the two angular wells.

The socks will soak up liquids or vapors and retain them at their relative positions along the borehole. Consequently, by analyzing residue left on the membranes, scientists will gather information about whether contaminants are migrating downward from the surface, how rock layers potentially affect the migration of these contaminants, and how runoff in the canyon affects contaminant flow, transport and chemistry.

Water flow over the surface of some Laboratory property can pick up extremely low concentrations of contaminants left behind from historical Laboratory operations. Los Alamos Canyon is one area where Laboratory researchers have identified residual contaminants.

By constructing the boreholes and monitoring well, Laboratory researchers hope to be able to answer the key question of whether the weir is doing what is was constructed to do: to prevent or greatly decrease the potential migration of contaminants from Los Alamos Canyon to other areas.

The new monitoring site will be located about a quarter mile downstream of two existing monitoring wells in lower Los Alamos Canyon. By comparing the quality of perched groundwater upstream with perched groundwater from the area behind the weir, the researchers hope to document and observe any changes in water chemistry that could be attributed to runoff. These perched groundwater bodies lie above the regional aquifer and are segregated from it by layers of dry rock.

By checking water and vapor chemistry of materials absorbed by the membranes of the two angular wells, the researchers will be able to test whether contaminants are moving downward, and potentially will be able to cross-reference the effects of these contaminants on perched groundwater zones using samples taken from the vertical well.

The shallow perched water zones beneath the Los Alamos Canyon floor are hundreds of feet above the aquifer that supplies Los Alamos with drinking water. Existing test wells located upstream of the weir have not detected contaminant concentrations in the regional aquifer that are above federal drinking water standards.

When drilling the new boreholes, scientists plan to tap two perched groundwater zones, one approximately 150 feet below the surface and the other approximately 270 feet below the surface. Laboratory hydrologists estimate the regional aquifer is located approximately 650 feet below the surface at this location. The vertical well will penetrate both perched zones, and one of the angular boreholes will penetrate the top perched zone. None of the wells will extend into the regional aquifer.

Because scientists will use air-rotary drilling techniques to construct the new test wells, they will not introduce fluids down the well bores. Moreover, the boreholes will be sealed to prevent any surface water from migrating downward. Los Alamos scientists have used similar methods to construct other monitoring and surveillance wells in the Los Alamos area, and have not observed the introduction of surface contaminants into groundwater bodies through well bores.

The monitoring well project will use the expertise of hydrologists and researchers from the Laboratory's Environment, Safety and Health Division and the Environmental Restoration Program Office, as well as from the Earth and Environmental Sciences Division. Funding for the project comes from federal dollars distributed to the Laboratory to help facilitate fire recovery activities in the Los Alamos area.

Stone said he expects the White Rock Y parking lot to reopen in mid to late summer.

Additional news releases from the Earth and Environmental Science (EES) Division