Assessing flow systems in carbonate aquifers using scale effects in hydraulic conductivity

Abstract

Counter to intuition, small-scale measurements of hydraulic conductivity do not average to regional values. Instead, mean hydraulic conductivity increases with measurement scale up to a critical distance termed the range, beyond which a constant regional value prevails. Likewise, variance in log hydraulic conductivity increases with separation distance between measurement points as the spatial correlation decreases. As dissolution proceeds in carbonate aquifers, heterogeneity and the volume necessary for an equivalent homogeneous medium (EHM) both increase. As these variables increase, the range of scale increase in both mean hydraulic conductivity and variance increases proportionately. Consequently, the range in scale effects is a reliable measure of the degree of secondary dissolution. By correlating the numeric value of range with independently measured hydraulic properties, the prevalent type of flow system, diffuse, mixed or conduit can be determined.

Department(s)

Geography, Geology, and Planning

Document Type

Article

DOI

https://doi.org/10.1007/bf00767085

Keywords

carbonate aquifers, diffuse flow, conduit flow, karst, scale effects

Publication Date

1994

Journal Title

Environmental Geology

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