The U.S. Geological Survey (USGS) will present findings from a multi-year groundwater study of the Silurian aquifer during a public work session of the Johnson County Board of Supervisors on Wednesday, May 14, at 9 a.m.
Leading the presentation titled “Simulation of Groundwater Flow in the Silurian Aquifer, Eastern Iowa (2020–2045)” will be USGS hydrologist Jude Thomas, who is currently the section chief for Groundwater and Geophysics in the Central Midwest Water Science Center. The study evaluates future groundwater availability across Johnson County and neighboring areas, which depend heavily on the Silurian aquifer for municipal, industrial and agricultural use. The findings will provide important information and analytical tools to support Johnson County and surrounding communities in making informed decisions about planning for long-term access to clean, reliable groundwater.
Since 2022, a contracted team of hydrogeologists has collected data and studied the Silurian aquifer in the target area, an area spanning over 1500 square miles and reaching eight counties: Johnson, Linn, Benton, Iowa, Washington, Louisa, Muscatine, and Cedar. The data was then used to construct three-dimensional groundwater flow models to characterize and simulate the Silurian aquifer. The predictive model can be adjusted to show projected long-term effects based on water-use activity and climate scenarios.
“The Silurian aquifer is one of our region’s most important water sources,” said Josh Busard, director of Johnson County Planning, Development and Sustainability. “Protecting it requires thoughtful, strategic decision-making across communities. This study gives us a clear picture of where we stand today, and more importantly, it provides a forecasting tool that helps us plan responsibly for the future.”
The study and its development were made possible through a cost-sharing partnership between Johnson County and several Eastern Iowa municipalities. Participating cities include Coralville, North Liberty, Tiffin, Solon, West Branch, Mount Vernon, Fairfax, Lisbon, Swisher, Shueyville, Riverside and Atkins.
The work session will take place in the third-floor boardroom in the Johnson County Health and Human Services Building, 855 S. Dubuque St., Iowa City, and is open to the public. A link to access a live viewing of the meeting will be available at http://bit.ly/jocomeeting.
The findings being presented are part of a full report anticipated to be published soon by the U.S. Geological Survey. Once finalized and approved for release, the full report will be available to the public on the Johnson County website.