Permeability distributions of sedimentary deposits are recognized as an important aspect controlling flow of groundwater and the production of oil and gas. An outcrop coring program was undertaken to estimate the permeability distribution of unconsolidated sediments in the Weber River delta. This information is important because the Weber River delta is a significant groundwater recharge area for the heavily populated Wasatch front. Results from this study can be coupled with the established stratigraphic framework of the delta to serve as springboard for further research on modeling groundwater flow through the delta deposits.

The Weber River delta is a fine-grained (sandy) lacustrine delta deposited along the eastern margin of late Pleistocene Lake Bonneville, near Ogden, Utah. Thirteen lithofacies and five architectural elements (assemblages of lithofacies) are recognized in this delta. Permeabilities were estimated on over 400 minimally disturbed sediment cores from five lithofacies and three architectural elements. Average measured horizontal permeabilities ranged from 0.1 to 18.1 darcys. Average measured vertical permeabilities ranged from 0.07 to 19.0 darcys. Horizontal/vertical anisotropy for core set pairs was less than 2:1, suggesting that sedimentary structures had a small effect on the permeability structure of sampled lithofacies.

The original hypothesis of this project was to quantify the permeability distribution of the delta to test the assumption that the permeability distribution in sedimentary deposits is lognormal. It was initially proposed that the permeability distribution of individual lithofacies (and perhaps architectural elements) would be normal and the permeability distribution of a composite vertical section through the entire delta would be lognormal (reflecting the prevalence of lower permeability sediments/rocks). However, the results were ambiguous. Although the permeability distribution still needs further study, we present the range of permeability data collected to provide comparisons for other geologic engineering models utilizing permeability distributions.