INCORPORATION OF SPATIAL VARIABILITY IN MODELING NONPOINT-SOURCE GROUNDWATER NITRATE POLLUTION

A methodology for incorporation of spatial variability in modeling non -point source groundwater nitrate contamination is presented. The meth odology combines geostatistical simulation and unsaturated zone modeli ng for estimating the amount of nitrate loading to groundwater. Three dimensional soil nitrogen variability and 2-dimensional crop yield var iability are used in quantifying potential benefits of spatially distr ibuted nitrogen input. This technique, in combination with physical an d chemical measurements, is utilized as a means of illustrating how th e spatial statistical properties of nitrate leaching can be obtained f or different scenarios of fixed and variable rate nitrogen application s. Copyright (C) 1996 IAWQ.