Break-out Group Discussion of Indirect Detection Methods
2nd Annual Española Basin Workshop
March 5, 2003
Notes prepared by
Dennis "Woody" Woodward, U.S. Geological Survey, Albuquerque
Answers and Thoughts on the Focus Questions
- What research is ongoing?
- LANL and the USGS both have acquired a lot of magnetotelluric data in the Española Basin. All of the data need to be re-evaluated and re-interpreted so that "shallow" hydrogeologic information could be extracted.
- LANL and the USGS both have collected airborne time-domain electromagnetic surveys over part of the Española Basin.
- LANL will be acquiring micro-gravity surveys throughout the Española Basin (particularly in the Buckman wellfield area); aquifer storage calculations can be determined from these data.
- InSAR interferograms have been prepared for part of the Española Basin; land-surface elevation changes have been detected in the Buckman wellfield area averaging about 1 inch of subsidence per year for the last 4 years.
- What are the major gaps in knowledge?
- Magnetotelluric data need to be revisited and reinterpreted in order to extract "shallow" hydrogeologic data.
- Another airborne time-domain electromagnetic survey needs to be flown to tie the other existing surveys together to get complete coverage of the Basin.
- We need a means to detect and map the water table beneath Cerro del Rio.
- What new data are needed to fill the knowledge gaps or refine what we do know?
- Ground time-domain electromagnetic (TEM) data should be examined; 100-meter loops should be run on experimental basis throughout the Basin. If quality data can be collected, series of TEM profiles should be run in a variety of settings.
- The use of borehole geophysics is to be encouraged; perhaps a recommended suite of logs could be established for future logging.
- The Yates La Mesa #2 well, more than 4,000-ft deep, might be available for work-over investigations - - what should we do to use the well to gain more subsurface information?
- A comprehensive groundwater geochemical assessment should be conducted; this would involve compiling existing data and collected new data. Regional groundwater flow paths, ages, and recharge rates and areas could then be determined.
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