|FRANZ, TRENTON - University Of Nebraska|
Submitted to: Journal of Environmental & Engineering Geophysics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/8/2016
Publication Date: 12/1/2016
Citation: Woodbury, B.L., Eigenberg, R.A., Franz, T.E. 2016. Development of non-collinear arrays for use near wastewater holding ponds. Journal of Environmental & Engineering Geophysics. 21(4):231-236. doi: 10.2113/JEEG21.4.231.
Interpretive Summary: Beef cattle feedlots collect rainwater runoff from the feedlots in holding ponds. The ponds are carefully designed to effectively hold the nutrient-rich liquid until it can be used as a fertilizer for crop production. Traditionally, these ponds are monitored for leaks by collecting water samples from nearby monitoring wells every six months. There are potential problems with monitoring wells since they must be in the correct location, installed properly and must be sampled at the correct time to detect any unintended discharge. An alternative method has been tested using surface probes (arrays) that can establish a monitoring curtain adjacent to these ponds to detect nutrient discharge. These systems are typically installed in straight lines adjacent to holding ponds. However, some holding ponds require installation of arrays with bends to fit the pond profiles or topography at the site. This paper describes methods of correcting the data that is collected from ‘bent’ arrays so that the information can be processed with conventional methods. The calculated corrections were compared with measured corrections from a site with known characteristics. The comparison showed that the calculated corrections would allow installation of arrays with bends and still be able to examine the data with existing analysis methods.
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 strategic 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 (NDEQ), and AgraTek LLC, to evaluate electronic monitoring of subsurface soils near runoff holding ponds used to contain runoff from beef cattle feedyards. A three year study summarized data from two feedyards and concluded that resistivity array systems were able to adequately measure subsurface dynamics and to alert operators of changes that exceeded nominal operation. Subsequently, two NDEQ approved systems were installed at a University of Nebraska research site. Unlike the previous test installations, each of the two new sites required non-collinear installations. This report discusses the theoretical development and testing of non-collinear arrays which proved to be a viable approach to unique array geometries necessitated by feedyard designs.