Title: Use of resistance meter to monitor groundwater impacts near wastewater holding ponds-validation report Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: December 22, 2012
Publication Date: March 17, 2013
Citation: Eigenberg, R.A., Woodbury, B.L., Minns, G. 2013. Use of resistance meter to monitor groundwater impacts near wastewater holding ponds-validation report. Presented at The Environmental and Engineering Geophysical Society (EEGS) for the 26th Annual Symposium on the Application of Geophysics to Engineering and Environmental Problems (SAGEEP). March 17-21, 2013, Denver, Colorado. Technical Abstract: Mineral and organic salts from beef manure contained in precipitation runoff from feedyard pen surfaces can alter the conductivity properties of soil and water receiving it. Typically, holding ponds are constructed to control runoff from concentrated animal feeding operations. The integrity of these holding ponds has come under increased scrutiny since leakage has the potential to affect soil and groundwater quality. Traditionally, ponds are monitored by installing monitoring wells at key locations to evaluate the impact of these ponds on the environment. Monitoring wells are expensive to install, costly to sample and the information received is subject to ambiguous interpretation. Researchers from USDA-ARS U.S. Meat Animal Research Center have combined efforts and resources with the Nebraska Cattlemen, the Nebraska Department of Environmental Quality, and AgraTek LLC, to evaluate electronic monitoring of subsurface soils near runoff holding ponds used to contain runoff from beef cattle feedyards. An initial study was conducted that substantiated the need to validate the technology for further development. The objective of this report is to summarize initial findings of the validation study. A subsurface resistivity array was installed at a beef cattle feedyard located at the U.S Meat Animal Research Center, Clay Center, NE (Feedyard A) and at a cattle feeding cooperator site in Central Nebraska (Feedyard B). Array probes were permanently installed at Feedyard A (16 probes spaced 6.1m apart at a depth of 30 cm) and at Feedyard B (32 probes spaced 3.05m apart at a depth of 50 cm). Weekly readings from each site were evaluated to monitor the stability of the zone of hydration near the pond. The low hydraulic conductivity soils at Feedyard A provided in a very quiescent environmental system to evaluate the resistivity array’s inherent measurement stability. This site experienced minimal changes week to week and the changes measured over the season could easily be accounted for by variation in seasonal soil temperatures. The Feedyard B site was typified by coarse textured parent material that had high hydraulic conductivity properties. This site experienced dynamic changes week to week and throughout the season. The resistivity array system was able to adequately measure these dynamics. Additional analysis including soil constituent profiles, weather data, pond level recordings, and soil profile temperature data are included in this initial report summary.