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Large-scale natural gradient tracer test in sand and gravel, Cape Cod, Massachusetts: 3. Hydraulic conductivity variability and calculated macrodispersivities

August 1, 1992

Hydraulic conductivity (K) variability in a sand and gravel aquifer on Cape Cod, Massachusetts, was measured and subsequently used in stochastic transport theories to estimate macrodispersivities. Nearly 1500 K measurements were obtained by borehole flowmeter tests and permeameter analyses of cores. The geometric mean for the flowmeter tests (0.11 cm/s) is similar to that estimated from other field tests. The mean for the permeameter tests (0.035 cm/s) is significantly lower, possibly because of compaction of the cores. The variance for the flowmeter (0.24) is also greater than that for the permeameter (0.14). Geostatistical analyses applying negative exponential models with and without nuggets reveal similar spatial correlation structures for the two data sets. Estimated correlation scales range from 2.9 to 8 m in the horizontal and from 0.18 to 0.38 m in the vertical. Estimates of asymptotic longitudinal dispersivity (b.35–0.78 m) are similar in magnitude to that observed in the natural gradient tracer test (0.96 m) previously conducted at this site.

Citation Information

Publication Year 1992
Title Large-scale natural gradient tracer test in sand and gravel, Cape Cod, Massachusetts: 3. Hydraulic conductivity variability and calculated macrodispersivities
DOI 10.1029/92WR00668
Authors Kathryn M. Hess, Steven H. Wolf, Michael A. Celia
Publication Type Article
Publication Subtype Journal Article
Series Title Water Resources Research
Series Number
Index ID 70185473
Record Source USGS Publications Warehouse
USGS Organization Toxic Substances Hydrology Program