Proceedings of the 2019 Mississippi Water Resources Conference

Year: 2019 Authors: Arnold A.C.

Using the USGS National Groundwater Monitoring Network (NGWMN) framework document, Geological Survey of Alabama (GSA) staff are currently evaluating observation wells throughout the State to place them into subnetworks of background, suspected or documented changes in water-level elevations. The NGWMN's primary mission is to provide a national online map/data interface to address regional groundwater questions focused on principal aquifers. The GSA staff measure static water levels in observation wells bi-annually. These April and October measurements represent seasonal variation of wet and dry conditions. Many GSA observation wells have recorded water-level elevations for over forty years. The overall approach is to define areas with clusters of high-volume pumping wells. Groundwater use data supplied by the Alabama Office of Water Resources (OWR) provides locations for wells extracting >100,000 gallons per day, chiefly for municipal, agricultural and industrial uses. Within areas of significant groundwater use, GSA will evaluate the observation well network for potential aquifer drawdown. Five areas have tentatively been identified as background that are not affected by intensive groundwater withdrawal. Background areas are situated in low-yielding aquifers of the Cumberland Plateau or Piedmont region, with few major supply wells. The primary areas being evaluated for suspected changes due to groundwater withdrawal are Gulf Coastal Plain, Valley and Ridge, and Highland Rim aquifers. No areas have been classified as documented changes. Future studies will include analyses of available pump test data and delineation of water-level trends in major Alabama aquifers within these areas.