Engineering Commons^™

A Conceptual Framework For Evaluating Agricultural Economic And Environmental Tradeoffs In The Central Nebraska Basins Using Field-Level Area Study Data, P. G. Lakshminarayan, Bruce A. Babcock, Paul Mitchell

United States Environmental Protection Agency: Staff Publications

The high plains aquifer system, which underlies nearly 85 percent of the state of Nebraska, supplies about 95 percent of all groundwater used in Nebraska. Agricultural activities in the state use most of the groundwater (94 percent), while domestic and commercial users also depend heavily on this groundwater source. About 84 percent of the state's public drinking water supplies are from groundwater (Comfort, Shea, and Roeth 1994; Exner and Spalding 1990). With such high dependence on groundwater preserving groundwater quality is of crucial importance.

Intensive agriculture characterizes this region, especially in the Central Nebraska Basin (CNB), in part because of …

Approximation Of Biodegradation Rate Constants For Monoaromatic Hydrocarbons (Btex) In Ground Water, Todd Weidemeier, Matthew Swanson, John Wilson, Donald Kampbell, Ross Miller, Jerry Hansen

United States Environmental Protection Agency: Staff Publications

Two methods were used to approximate site-specific biodegradation rates of monoaromatic hydrocarbons (benzene, toluene, ethylbenzene, and xylenes [BTEX]) dissolved in ground water. Both use data from monitoring wells and hydrologic properties of the aquifer to estimate a biodegradation rate constant that can be sued in ground water solute fate and transport models. The first method uses a biologically recalcitrant tracer in the ground water, associated with the hydrocarbon plume to normalize changes in concentration of BTEX under anaerobic conditions; attenuation of the tracer is attributed to dilution, sorption, and/or volatilization. Attenuation of BTEX in excess of the attenuation of the …