New Approach and Methodologies for Characterizing the Hydrogeologic Properties of Aquifers

摘要

In the authors' opinion, the ability of hydrologists to perform field measurements of aquifer hydraulic properties must be enhanced if they are to improve significantly the capacity to solve ground water contamination problems at Superfund and other sites. Therefore, the primary purpose of the report is to provide motivation and new methodology for measuring K(z), the distribution of horizontal hydraulic conductivity in the vertical direction in the vicinity of a test well. Measurements in nearby wells can then be used to build up three-dimensional distributions. For completeness, and to enhance the usefulness of the report as a field manual, existing methodology for the measurement of effective porosity, vertical hydraulic conductivity, storativity and hydraulic head, are presented also. It is argued that dispersion-dominated models, particularly two-dimensional, vertically-averaged (areal) models, have been pushed about as far as they can go, and that two-dimensional vertical profile or fully three-dimensional advection-dominated transport models are necessary if they are to increase significantly the ability to understand and predict contaminant transport, reaction, and degradation in the field. Such models require the measurement of hydraulic conductivity distributions, K(z), rather than vertically averaged values in the form of transmissivities.