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IGS - Water Resources Management

Water Resources Management Program

Iowa Geological and Water Survey’s Role in the 2008 Water Resources Management program

The Iowa Geological and Water Survey (IGWS) plans and implements programs that result in the acquisition of comprehensive information on the mineral and water resources of Iowa, with emphasis on water supply developments and monitoring the effects of environmental impacts on water quality.

Some of the most frequently asked questions of the IGWS are about groundwater, and since groundwater supplies 80 percent of Iowans their drinking water, an understanding of the geologic and hydrologic framework that contains Iowa’s groundwater is in the best interest of Iowans and is essential when planning for better and sustainable use, protection, and management of Iowa’s most valuable natural resource.

The last comprehensive state water plan for Iowa was completed in 1978 by the Iowa Natural Resources Council (1978 Water Plan). This plan was funded by the state legislature and took three years to complete. It addressed major water problems of the time and recommended policies and programs to solve and prevent current and future problems. While some portions of the plan were implemented, the plan did not provide a mechanism for ongoing water planning. Additional plans and programs have been developed since 1978, however, these efforts were never integrated into a comprehensive plan for water management and have not created the public awareness needed to prevent degradation of groundwater and surface water resources in Iowa. The last update of the state water plan occurred in 1985. (1985 Water Plan)

The ability to protect and improve Iowa’s natural resources, while utilizing them to benefit society, requires proactive long-range planning, based on accurate and current geologic and hydrologic information. In the past, most funding for water planning issues has come from the state general fund. However, continued reductions in general fund revenues and geologic and hydrologic staffing over the last 20 years have made it difficult for the IGWS to conduct the preemptive investigation and research necessary to create and maintain a forward looking, integrated, and comprehensive Water Resources Management program.

Recently, concerns about the availability of groundwater in Iowa have come to light because of increasing demand for large quantities of water from various industries, as well as increases in demand from agricultural, municipal, and domestic uses. While Iowa is probably not facing an immediate water shortage, we currently do not have the information or resources available at the state level to answer basic questions regarding how much water can be withdrawn from Iowa’s aquifers on a sustainable basis, without significantly lowering water levels and depleting very long-term groundwater storage.

Following a proposal in 2007 from the Iowa Geological and Water Survey for annual funding to characterize the availability, quality, use, and sustainability of Iowa’s surface water and groundwater resources, the Iowa legislature approved funding to support a comprehensive Water Resource Management program for Iowa (www.iaenvironment.org/documents/11-27-07FinalStateWaterPlan.pdf). Currently efforts are underway to secure sustainable funding for continued study and management of Iowa’s water resources through an improved water resource permitting system.

Iowa’s Geologic Framework

Iowa’s groundwater resources are stored in shallow unconsolidated aquifers and in five deeper bedrock aquifers that are generally separated by widespread confining beds, or aquitards, that slow the movement of water between the aquifers (Figure 1). The unconsolidated aquifers include alluvial sand and gravel deposits found along stream valleys and in ancient buried river valleys, and sand and gravel deposits found within glacial drift. The bedrock aquifers are usually sandstone, siltstone, limestone, or dolomite, and sometimes are a combination of all of these rock types. The major bedrock aquifers in Iowa were deposited between 75 to 550 million years ago (mya), and include, from shallow to deep: the Cretaceous (Dakota), Mississippian, Silurian-Devonian, Cambrian-Ordovician (Jordan), and Dresbach (Mt. Simon).

Figure 1. Cross-sectional view of Iowa’s major aquifers and aquitards from northwest to southeast (modified from Iowa’s Groundwater Basics by Jean C. Prior, et al., 2003, Iowa Dept. of Natural Resources, Iowa Geological Survey Educational Series 6, 83 pages).

The Major Aquifers to be Studied

The Dakota Aquifer is the first major aquifer to be studied by Iowa Geological and Water Survey under the auspices of the 2008 Water Resources Management program. The study is part of the work in progress to delineate the occurrence, movement, availability, use, and chemical quality of groundwater from Iowa’s major aquifers for better and sustainable management of Iowa’s groundwater resources. In the future, the IGWS will also be evaluating and updating information for the Mississippian, Silurian-Devonian, and Cambiran-Ordovician bedrock aquifers, and possibly some of the larger alluvial aquifers in Iowa as time and funding allow. As more wells are completed in these aquifers and more stratigraphic, construction, and water-quality data are interpreted and entered into our databases, our knowledge of these valuable resources will improve and our evaluation of them will be refined.

Our website materials for the 2008 Water Resources Management program are currently under development and will also be improved and refined as more water resource information is collected and interpreted.

Major Bedrock Aquifer Studies  

Regional Alluvial Aquifer Studies