Groundwater quality and age of secondary bedrock aquifers in the glaciated portion of eastern Nebraska, 2016–18

Abstract

Groundwater Quality and Age of Secondary Bedrock Aquifers in the Glaciated Portion of Eastern Nebraska, 2016-18 activities. Future groundwater sampling would be beneficial to characterize groundwater-quality changes within the Niobrara and Paleozoic aquifers over time.

Development of a hydrogeologic visualization model for western Sarpy County, Nebraska

“…Groundwater-recharge dates ranged from older than 1940 in samples from wells screened in the Missouri River Valley alluvial aquifer to as recent as the early 1980s in samples from wells screened in the Dakota aquifer (McGuire and others, 2012). Hobza and Flynn (2021) detected mixed-age (older and modern, post-1950) and modern-age water in the Dakota aquifer in western Sarpy County, which was younger than water from other Dakota aquifer samples taken outside of Sarpy County. During 2012, the USGS, in cooperation with the PMRNRD, sampled domestic wells and determined that many of the wells screened in the Dakota aquifer had elevated nitrate values (greater than 5 milligrams per liter [mg/L]) and some had nitrate values that exceeded the EPA nitrate MCL (10 mg/L) for drinking water (U.S. Geological Survey, 2021b; U.S. Environmental Protection Agency, 2022).…”

“…Several groundwater and geologic studies have been completed in Sarpy County (Verstraeten and Ellis, 1995;Korus and others, 2012;McGuire and others, 2012;Cannia and others, 2017;Hobza and Flynn, 2021). These studies have primarily been groundwater-quality focused.…”

“…They also tested for several pesticides, but none were detected at concentrations greater than the U.S. Environmental Protection Agency (EPA) maximum contaminant level (MCL) for drinking water (U.S. Environmental Protection Agency, 2022). McGuire and others (2012) and Hobza and Flynn (2021) also examined groundwater quality and groundwater age in the primary and secondary bedrock aquifers in the area. Groundwater-recharge dates ranged from older than 1940 in samples from wells screened in the Missouri River Valley alluvial aquifer to as recent as the early 1980s in samples from wells screened in the Dakota aquifer (McGuire and others, 2012).…”