A ground-water-quality monitoring network has been designed to collect data to describe the long-term chemical quality of major bedrock and Quaternary aquifer systems in Iowa. The network was designed because of data needs expressed by several State and Federal agencies. Areas where new or additional data are needed are nitrate and bacteria concentrations in alluvial and glacial drift aquifers, fluoride and radionuclides in deep bedrock aquifers, general quality of water in the Missouri River alluvium, changes in water quality of deep bedrock aquifers caused by large withdrawal, effects of land use on shallow aquifers, and the impact of agricultural injection wells on receiving aquifers.
Most of the ground-water-quality monitoring in the State has been directed at compliance or ambient monitoring of municipal water supplies. Some site-specific monitoring has occurred. More recently several special studies or research monitoring activities have been completed or begun.
The monitoring program utilizes a strategy that includes low frequency and sparse distribution of samples from Cambrian-Ordovician, Silurian-Devonian, Mississippian,Pennsylvanian, and Dakota aquifers. A larger density and greater frequency of samples will be obtained from shallow bedrock wells and from wells penetrating Quaternary aquifers suck as alluvial, buried channel, and other drift aquifers.
More than 1,200 wells are available and acceptable for the network. From these and newly completed wells, 200 samples will be collected and analyzed annually. Analyses will be made for common anions and cations, trace metals, nutrients, and radionuclides. One out of ten samples will be analyzed for priority pollutants and pesticides. Data from this program will be published annually in Water Resources Data, Iowa, U.S. Geological Survey Water-Data Report.
