Large Data Bases and Regional Ground‐Water Quality Assessments ‐ An Iowa Case Study

Abstract

ABSTRACTMany state and federal agencies routinely collect ground‐water quality data to meet a variety of objectives. The WATSTORE (Water Data Storage and Retrieval System) data files of the U.S. Geological Survey containing raw ground‐water quality data from 4,388 wells and the MSIS (Model State Information System) data files of the U.S. EPA containing finished (blended and/or treated) ground‐water quality data from 2,137 public water‐supply sources are the only two large computer‐coded data files on Iowa ground‐water quality. These two data bases, by themselves, provide significant insights regarding the distribution of chemicals in different hydrogeological environments and the compliance status of PWS sources with reference to drinking‐water quality standards in Iowa. With minor modifications, these two data bases can be integrated to: (a) provide statistical, spatial, temporal, and geological summaries of observed ground‐water quality; (b) determine the extent of exposed populations to various contaminants in their different concentrations; (c) provide necessary information to reduce the existing list of contaminants and include some of those that are not being monitored now; (d) identify gaps in current data‐gathering efforts and prioritize the various components of future monitoring programs; (e) identify potential linkages for the combined use of ground‐water quantity and quality, socioeconomic, land‐use, and public health data; and (f) alert policy makers to potential ground‐water quality problems facing the state. Some of the limitations of the two data bases and the need for integrating them is demonstrated by a comparative analysis and evaluation.