A study of the water resources of the Springfield, Missouri, area in the 1970s determined that a cone of depression, formed by ground-water pumping, had developed in the Ozark aquifer beneath the city. Continued ground-water usage in the 1970s and 1980s caused concern that ground-water resources would not be sufficient to meet the future needs of Springfield during periods of drought. As a result, a ground-water flow model of the Springfield area was developed by the U. S. Geological Survey (USGS) in 1987 to assess the future role of ground water as a water source for the area. Results of the USGS model led to a decision by the City Utilities of Springfield to primarily rely on surface water from Stockton Lake as a source of water. Population growth has continued to be rapid in the area and has caused commercial, industrial, and domestic water use to increase. Population growth has been especially rapid in Nixa, Ozark, and Republic, and water use in the vicinity of these cities has grown an estimated 39 percent since 1990. Unlike Springfield, ground water is the primary source of water for these cities.

In 2006, the USGS, in cooperation with Greene County, Missouri, the Missouri Department of Natural Resources, and the U. S. Army Corps of Engineers, began a study to investigate the changes in the potentiometric surface of the Ozark aquifer since the 1980s. The USGS collected water-level data in 2006 and 2007 to produce an updated Ozark aquifer potentiometric surface map. This potentiometric surface will be compared to previously produced potentiometric surfaces and to the predicted results of the USGS ground-water flow model completed in 1987. The current water-level data also will be used to calibrate an updated ground-water flow model based on a finer resolution grid that covers a larger area than the previous USGS model.

The updated ground-water flow model will be used to predict how the potentiometric surface in the Ozark aquifer might respond under different pumping stress scenarios. Results from the ground-water flow model will be a tool that resource managers can use to optimize ground-water use in the area.