Drilling and Installation of Deep Groundwater Monitoring Wells: Los Alamos National Laboratory, New Mexico
Monday, December 4, 2017: 4:10 p.m.
102 B (Music City Center)
Mark Everett, PG
,
Environmental Management, Los Alamos National Laboratory
Danny Katzman
,
Environmental Programs, Los Alamos National Laboratory, Los Alamos, NM
David Broxton
,
Environmental Programs, Los Alamos National Laboratory, Los Alamos, NM
Steven White
,
Environmental Management, Los Alamos National Laboratory, Los Alamos, NM
Los Alamos National Laboratory (LANL, or the Laboratory) is underlain by a complex basin-fill sequence of alluvial fan deposits, volcanic tuff, basaltic and dacitic lavas, and riverine deposits. On-going drilling and well installation activities have evolved to improve both the quality of hydrogeologic characterization and the performance of groundwater monitoring wells, ensuring they yield representative groundwater samples. Groundwater occurs as canyon-fill alluvial water, perched intermediate-depth water, and as a regional-scale aquifer that is the main water supply for the area. The regional aquifer below LANL is up to 1400 feet below ground surface (bgs). Therefore, monitoring wells at LANL, are among the deepest routinely installed in the US. Cost drivers include logistical challenges, and the variable drilling techniques required to characterize and install wells in this geologic environment.
Major challenges to the characterization approach at LANL are to obtain maximum information during drilling and to meet sample quality requirements while minimizing drilling costs. Current drilling practice makes limited use of fluid additives to supplement air circulation methods to advance through the vadose zone. Starting about 100 feet above the water table, drill casing is advanced to the regional aquifer using only air and municipal water for circulation. The ability to retract casing for video and geophysical logs allows for robust characterization of perched groundwater systems and accurate definition of the top of regional saturation.
Current well design emphasizes a minimal annulus, maximum screen slot size, and thorough well development to mitigate formation damage due to drilling. Careful subsurface characterization at depths ranging up to 1,400 feet bgs, while retaining the ability to collect representative groundwater samples, may have application at a number of sites throughout the environmental industry. Optimizing each well to meet program objectives while reducing total project costs benefits all environmental investigations. (LA-UR-17-23451)
Handout
Mark Everett, PG, Environmental Management, Los Alamos National Laboratory
Mark Everett is a geologist with the Los Alamos National Laboratory Environmental Remediation program. Mr. Everett has been an interdisciplinary technical team and project leader in groundwater related environmental projects for the past 22 years (18 at LANL). His responsibilities include design and implementation of groundwater well installation projects in the complex hydrogeologic setting at LANL. In addition to the installation of new wells, he leads the team maintaining the instrumentation and sampling systems for the network of over 100 wells, some as deep as 2,000 feet with up to nine discrete sampling intervals.
Danny Katzman, Environmental Programs, Los Alamos National Laboratory, Los Alamos, NM
TBA
David Broxton, Environmental Programs, Los Alamos National Laboratory, Los Alamos, NM
David Broxton is a retired employee of the Los Alamos National Laboratory.
Steven White, Environmental Management, Los Alamos National Laboratory, Los Alamos, NM
tba
