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Due to the recurrence of drought in western Iowa, water users have increasingly been looking for additional sources of water. Buried sand and gravel aquifers associated with three bedrock channels were investigated as potential sources. Due to low data density, two primary study areas were chosen for a more detailed analysis. Point coverage was not sufficient to generate isopach maps or perform statistical analysis, but the production of cross-sections aided in the understanding of the sand and gravel bodies.
Valley fills, where present, are likely to be laterally continuous, but not all valleys will have a significant thickness of sand and gravel. Sand sheets also have the potential to be laterally continuous, but their margins will not be as predictable as a valley fill since they are not bounded by a valley wall. This study demonstrates the complexity of glacial till sequences and predicting the presence of sand and gravel bodies within or between till sheets.
On a local (community or township) scale, it appears that general trends can be established if the data density is sufficient. However, there is less confidence in using this data as a predictive tool on a regional scale. Several areas, such as the Glenwood Chute, have thick and continuous sand and gravel bodies. In many other areas, the data is not sufficient to map the sand and gravel. In many cases, one or two highly productive wells are identified, but their lateral distribution cannot be established.
Iowa Geological Survey, The University of Iowa
44 pages, 11 figures
Water quality, Groundwater, Water-supply, Aquifers, Iowa
Journal Article Version
Version of Record
Publication of the State of Iowa. This publication is a public record.
Kerr, Phillip; Tassier-Surine, Stephanie; Streeter, Matthew; and Gannon, J. Michael. Geologic Evalutation of the Buried Sand and Gravel Aquifers in Western Iowa. Iowa City: Iowa Geological Survey, The University of Iowa, 2015. (Water Resources Investigation Report, 14)