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[1] Computational capabilities have evolved to a point where it is possible to use multidimensional physically based hydrologic models to study spatial and temporal patterns of water flow in the vadose zone. However, models based on multidimensional governing equations have only received limited attention, in particular because of their computational,(More)
Purpose Up to 90% of antibiotics that are fed to livestock are excreted unaltered or as metabolites and thus are present in manure. By application of manure as fertilizer, veterinary antibiotics can reach soil and groundwater. The aim of this study is to determine the effect of three commonly used (and simultaneously applied) sulfonamide antibiotics on both(More)
Environmental releases of antibiotics from concentrated animal feeding operations (CAFOs) are of increasing regulatory concern. This study investigates the use and occurrence of antibiotics in dairy CAFOs and their potential transport into first-encountered groundwater. On two dairies we conducted four seasonal sampling campaigns, each across 13 animal(More)
Although the spatial variability of water content is expected to be significant in heterogeneous, unsaturated media, its effect on solute transport has been neglected in most stochastic analyses. In this work we develop, evaluate, and numerically verify an analytical model describing the statistical moments of water content, soil water flux, soil water(More)
  • Megan M Mayzelle, Joshua H Viers, Josué Medellín-Azuara, Thomas Harter, Philip A Brunner
  • 2014
Agricultural irrigation leachate is often the largest source for aquifer recharge in semi-arid groundwater basins, but contamination from fertilizers and other agro-chemicals may degrade the quality of groundwater. Affected communities are frequently economically disadvantaged, and water supply alternatives may be too costly. This study aimed to demonstrate(More)
At the regional scale, vadose-zone processes are recognized for controlling both short-term dynamics in watershed hydrology and long-term water balances of hydrologic basins. In this paper we explore the various conceptual and mathematical models that have been proposed or could be considered to represent water fluxes in the vadose zone at the catchment,(More)
This REFERENCE SHEET is part of the Farm Water Quality Planning (FWQP) series, developed for a short course that provides training for growers of irrigated crops who are interested in implementing water quality protection practices. The short course teaches the basic concepts of watersheds , nonpoint source pollution (NPS), self-assessment techniques , and(More)
Domestic wells in North America and elsewhere are typically constructed at relatively shallow depths and with the sand or gravel pack extending far above the intake screen of the well (shallow well seal). The source areas of these domestic wells and the effect of an extended gravel pack on the source area are typically unknown, and few resources exist for(More)