TigerStream 17: Beneath The Surface: Characterizing Groundwater Quality and Hydrology in Tennessee.

Описание: ABSTRACT: Groundwater is a critical source of drinking water in Tennessee, serving a substantial portion of the state’s population. Approximately 1.6 million residents receive drinking water from public water systems that rely on groundwater, with an additional 260,000 people served by systems designated as groundwater under the influence of surface water. An estimated 538,000 Tennesseans obtain drinking water from private wells and springs, and in West Tennessee groundwater is the primary drinking water source for most residents.
Much of Tennessee is underlain by Ordovician- to Mississippian-age limestone, with karst terrain covering more than two-thirds of the state. Tennessee has the highest number of documented caves in the United States and is the most biodiverse inland state, with a high degree of endemism. Karst systems host important hydrologic, geologic, biological, cultural, educational, and recreational resources. Understanding groundwater flow and water quality within these systems, particularly where they intersect with sensitive or high-value resources, is essential for effective conservation and resource management.
The U.S. Geological Survey (USGS), in cooperation with the Tennessee Department of Environment and Conservation (TDEC), is conducting several multi-year groundwater investigations across the state. These efforts include groundwater-quality sampling of springs and wells statewide, as well as dye-tracing studies in karst landscapes of Middle and East Tennessee. The groundwater-quality project is focused on developing a monitoring network across Tennessee’s principal aquifers, including the alluvial, Tertiary sand, and Cretaceous sand aquifers in West Tennessee; the Pennsylvanian sandstone, Mississippian carbonate, and Ordovician carbonate aquifers in Middle Tennessee; and the Knox, Cambrian–Ordovician carbonate, and crystalline rock aquifers in East Tennessee.
Multiple dye-tracing investigations have been completed or are currently underway to characterize groundwater flow paths from sink point to points of resurgence and, where possible, to delineate spring recharge areas. These studies have supported a range of resource management efforts, including National Fish and Wildlife endangered species recovery planning, source water protection area delineation for public water systems, and broader conservation initiatives. Fluorescent dyes are injected into sinking features such as sinking streams, and nearby springs and surface waters are monitored for hydrologic connections using charcoal dye receptor packets. Results from these USGS investigations provide critical information to agencies and stakeholders for groundwater protection and management and are published following rigorous review through ScienceBase and the USGS Publications Warehouse.