Watch what you drink: Midwestern alluvial-outwash aquifers and the CV Theis Groundwater Observatory
David B. Nash, Amy Townsend-Small, 2018. "Watch what you drink: Midwestern alluvial-outwash aquifers and the CV Theis Groundwater Observatory", Ancient Oceans, Orogenic Uplifts, and Glacial Ice: Geologic Crossroads in America’s Heartland, Lee J. Florea
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The Great Miami Buried Valley Aquifer system (GMBVAS) is a U.S. EPA–designated sole-source aquifer for most of the ~2.3 million residents of the Great Miami River basin. The aquifer system is similar to many of the glacial outwash–alluvial aquifers found throughout the southern Midwestern United States: a valley deeply incised into bedrock by meltwater from repeated glaciations, subsequently aggraded with glacial outwash, lake clays, tills, and post-glacial alluvium. These aquifers are often immediately adjacent to or below modern streams with which they are hydrologically connected. Because of the exchange of water between the aquifer and surface streams, they must be considered two parts of a single hydrogeologic system; anything impacting one part will impact the other.
Because virtually all water is recycled, public water suppliers, agricultural users, and industrial users withdraw water from the GMBVAS, then discharge the used water to the next downstream consumer. For example, agricultural runoff and municipal wastewater enter the Great Miami River. River water recharges the aquifer near well fields through induced infiltration. Municipalities, agriculture, and industry pump groundwater from the aquifer and discharge some of the water back into the river as a return flow. Sound water management requires balancing the needs of these diverse users. Agriculture, particularly in the upper Great Miami basin, is a major source of revenue and jobs but requires heavy application of nutrients and herbicides. Sand and gravel quarrying in the Great Miami basin is critical for construction and infrastructure but also removes vast amounts of aquifer material. Not only is healthy reliable groundwater important for the public water supply, it is also essential to bottling facilities, distilleries, pharmaceutical companies, and other water-dependent industries that have been attracted to the area.
This field trip explores the GMBVAS, its uses, its interaction with Great Miami River, and the contrasting needs of the people and businesses that depend on it.
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This volume, prepared for the 130th Annual Meeting of the Geological Society of America in Indianapolis, includes compelling science and field trips in Indiana, Illinois, Kentucky, Michigan, and Ohio. A wealth of geologic and human history collides in the Midwest, a confluence that led to the growth of America's industry over the past two centuries. Guides in this volume depict this development from the establishment of New Harmony, the birthplace of American geology, through the construction of Indianapolis's modern skyline. Underpinning this growth were the widespread natural resources-limestone, coal, and water-that built, powered, and connected a growing nation. Take a journey through the Heartland to sand dunes, outcrops, quarries, rivers, caves, and springs that connect Paleozoic stratigraphy with the assembly of Gondwana, continental glaciation with Quaternary geomorphology and hydrology, and landscape with the human environment.