Hydrogeology, Chemical Characteristics, and Transport Processes in the Zone of Contribution of a Public-Supply Well in York, Nebraska

Abstract

The U.S. Geological Survey (USGS) is committed to providing the Nation with credible scientific information that helps to enhance and protect the overall quality of life and that facilitates effective management of water, biological, energy, and mineral resources (http://www.usgs.gov/). Information on the Nation's water resources is critical to ensuring long-term availability of water that is safe for drinking and recreation and is suitable for industry, irrigation, and fish and wildlife. Population growth and increasing demands for water make the availability of that water, now measured in terms of quantity and quality, even more essential to the long-term sustainability of our communities and ecosystems. The USGS implemented the National Water-Quality Assessment (NAWQA) Program in 1991 to support national, regional, State, and local information needs and decisions related to water-quality management and policy (http:// water.usgs.gov/nawqa). The NAWQA Program is designed to answer: What is the condition of our Nation's streams and ground water? How are conditions changing over time? How do natural features and human activities affect the quality of streams and ground water, and where are those effects most pronounced? By combining information on water chemistry, physical characteristics, stream habitat, and aquatic life, the NAWQA Program aims to provide science-based insights for current and emerging water issues and priorities. From 1991-2001, the NAWQA Program completed interdisciplinary assessments and established a baseline understanding of water-quality conditions in 51 of the Nation's river basins and aquifers, referred to as Study Units (http://water.usgs.gov/nawqa/studyu.html). Multiple national and regional assessments are ongoing in the second decade (2001-2012) of the NAWQA Program as 42 of the 51 Study Units are reassessed. These assessments extend the findings in the Study Units by determining status and trends at sites that have been consistently monitored for more than a decade, and filling critical gaps in characterizing the quality of surface water and ground water. For example, increased emphasis has been placed on assessing the quality of source water and finished water associated with many of the Nation's largest community water systems. During the second decade, NAWQA is addressing five national priority topics that build an understanding of how natural features and human activities affect water quality, and establish links between sources of contaminants, the transport of those contaminants through the hydrologic system, and the potential effects of contaminants on humans and aquatic ecosystems. Included are topics on the fate of agricultural chemicals, effects of urbanization on stream ecosystems, bioaccumulation of mercury in stream ecosystems, effects of nutrient enrichment on aquatic ecosystems, and transport of contaminants to public-supply wells. These topical studies are conducted in those Study Units most affected by these issues; they comprise a set of multi-Study-Unit designs fo...

Effects of Seasonal Operation on the Quality of Water Produced by Public‐Supply Wells

“…Multiple investigations have sought to characterize sources of contaminants to public-supply wells by studying observations of groundwater chemistry and age ( Aeschbach-Hertig et al 1998 ; Manning et al 2005 ; Katz et al 2007 ; Jurgens et al 2008 ; Landon et al 2008 ; McMahon et al 2008 ; Plummer et al 2008 ; Brown et al 2009 ; Hinkle et al 2009 ; Katz et al 2009 ; Landon et al 2010b ; Ayotte et al 2011 ; Musgrove et al 2011 ; Bexfield et al 2012 ; Eberts et al 2012 ); however, few studies appear to have used these observational data to explore whether seasonal variability in well operations can have important effects on water quality. Seasonal to multi-year variability has been described for public-supply wells in karst systems dominated by relatively young water (commonly less than about 50 years) ( Katz et al 2007 ; Musgrove et al 2011 ), where the quality of water from supply wells could be expected to respond to even short-term changes in hydrologic conditions.…”

Modeling the Potential Impact of Seasonal and Inactive Multi-Aquifer Wells on Contaminant Movement to Public Water-Supply Wells1

“…To demonstrate that simple models can be used to assess the potential impact of multi‐aquifer wells on confined‐aquifer PWS wells, we use a well‐studied example from York, Nebraska (Clark et al. , 2008; Landon et al. , 2008).…”

Processes affecting geochemistry and contaminant movement in the middle Claiborne aquifer of the Mississippi embayment aquifer system

“…The higher number of pesticide detections in a developed area could originate from their use for weed control along rights-of-way in urban areas in the study area. Well SPRT-26 is a relatively high capacity supply well, and the land use inventory for the 500-m buffer area may not reflect land uses in the contributing area of this well, as has been shown for public-supply wells in other areas (Landon et al 2008). Agricultural land use in the 500-m buffer areas for the other five wells ranged from 31-75%.…”

“…Well SPRT-26 is located in the east part of the study area in the outcrop area of the MCA where the aquifer is unconfined and this well is relatively shallow with a screened interval from 61 to 91 m. The relatively high pumping rate for this publicsupply well (about 3,800 L/min) likely induces the movement of groundwater from shallow zones into the screen. A similar pumping rate for a public supply well in the northern High Plains aquifer (an aquifer with similar lithology to the MCA) drew contaminants from shallow unconfined parts into the deeper confined parts of the aquifer (Landon et al 2008). Two other wells, SPRT-14 (domestic well) and SPRT-24 (public supply well) also are located in the east part of the study area where the MCA crops out (Fig.…”