Assessing groundwater vulnerability to agrichemical contamination in the Midwest US

Water Science and Technology
By: , and 



Agrichemicals (herbicides and nitrate) are significant sources of diffuse pollution to groundwater. Indirect methods are needed to assess the potential for groundwater contamination by diffuse sources because groundwater monitoring is too costly to adequately define the geographic extent of contamination at a regional or national scale. This paper presents examples of the application of statistical, overlay and index, and process-based modeling methods for groundwater vulnerability assessments to a variety of data from the Midwest U.S. The principles for vulnerability assessment include both intrinsic (pedologic, climatologic, and hydrogeologic factors) and specific (contaminant and other anthropogenic factors) vulnerability of a location. Statistical methods use the frequency of contaminant occurrence, contaminant concentration, or contamination probability as a response variable. Statistical assessments are useful for defining the relations among explanatory and response variables whether they define intrinsic or specific vulnerability. Multivariate statistical analyses are useful for ranking variables critical to estimating water quality responses of interest. Overlay and index methods involve intersecting maps of intrinsic and specific vulnerability properties and indexing the variables by applying appropriate weights. Deterministic models use process-based equations to simulate contaminant transport and are distinguished from the other methods in their potential to predict contaminant transport in both space and time. An example of a one-dimensional leaching model linked to a geographic information system (GIS) to define a regional metamodel for contamination in the Midwest is included.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Assessing groundwater vulnerability to agrichemical contamination in the Midwest US
Series title Water Science and Technology
DOI 10.1016/S0273-1223(99)00042-6
Volume 39
Issue 3
Year Published 1999
Language English
Publisher IWA
Contributing office(s) Iowa Water Science Center, Toxic Substances Hydrology Program
Description 10 p.
First page 103
Last page 112
Country United States
Online Only (Y/N) N
Additional Online Files (Y/N) N
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