ISGS Helps Lead Groundwater Workshops in McHenry County, Illinois

Visualization of a 3-D geologic map in McHenry County, Illinois. The base map is courtesy of Google Earth.

The ISGS has recently completed a major 3-D geologic mapping study in McHenry County, Illinois. Initiated in 2008, this project has helped the county in its aggressive approach to understanding and protecting the county’s vital groundwater resources. Approximately 60% of municipal water supplies in the county, and an even larger percentage of domestic water supplies, are derived from shallow sand and gravel aquifers (generally less than 200 feet deep). The ISGS has developed a detailed 3-D geologic model that shows the current and best understanding of the underground distribution of the sand and gravel aquifer systems in that area. At the scale of a county, the result is arguably one of the highest resolution 3-D geologic maps in the world. Similar projects are ongoing in Lake County and Will County, Illinois. The 3-D geologic map of McHenry County was the framework that was necessary for predictive groundwater-flow modeling conducted by the Illinois State Water Survey (ISWS). The results of the ISWS project indicate current groundwater levels within aquifers and estimate long-term scenarios of groundwater withdrawal to the year 2050.

Jason Thomason (ISGS) speaks to attendees of the groundwater workshops on March 14 in McHenry County, Illinois.

On March 14, in cooperation with county staff, Jason Thomason (ISGS) and Scott Meyer (ISWS) led public workshops to unveil the results of the 3-D mapping and groundwater modeling studies. The workshops focused on the regional distribution of the aquifer systems and long-term groundwater supply planning and protection. Discussions were wide ranging and included topics such as geologic history, groundwater withdrawal predictions, wetland conservation, and water supply planning for the future. The workshops were attended by approximately 75 people and included elected government officials, local environmental groups, county and municipal employees, consultants, educators, and others from the public. The full day of workshops also included a special presentation to municipal government leaders (McHenry County Council of Governments) to discuss local implementation of these projects.

Scott Meyer (ISWS) presenting at the groundwater workshops in McHenry County on March 14