Tools for Groundwater Protection Planning: An Example from McHenry County, Illinois, USA

Area of Science:

• Hydrogeology
• Environmental Geology
• Geographic Information Systems (GIS)

Background:

• Rapid population growth necessitates informed land-use planning to protect vulnerable groundwater resources.
• Aquifers, particularly shallow sand and gravel types, are susceptible to contamination in rapidly developing regions.
• Effective groundwater resource management requires understanding aquifer vulnerability to potential contaminants.

Purpose of the Study:

• To develop and demonstrate an approach for generating aquifer sensitivity maps using three-dimensional geologic (stack-unit) maps.
• To provide a tool for land-use planners, public health officials, and developers to make informed decisions regarding land use and groundwater protection.
• To assess aquifer sensitivity in McHenry County, Illinois, a rapidly growing area with extensive shallow aquifers.

Main Methods:

• Construction of three-dimensional geologic maps (stack-unit maps) detailing the succession of earth materials to a specific depth.
• Interpretation of geologic successions to create aquifer sensitivity maps, classifying areas based on their potential to transmit contaminants.
• Application of the methodology in McHenry County, Illinois, as a case study for practical implementation.

Main Results:

• Development of aquifer sensitivity maps for McHenry County, Illinois.
• Identification of areas with highly vulnerable sand and gravel aquifers located near the ground surface.
• Demonstration of the utility of stack-unit maps in interpreting aquifer sensitivity for land-use planning.

Conclusions:

• The developed approach effectively translates geologic mapping data into actionable aquifer sensitivity information.
• Aquifer sensitivity maps are crucial for guiding land-use decisions, protecting groundwater resources, and mitigating potential environmental liabilities in growing communities.
• This methodology offers a valuable framework for groundwater resource management and regulatory guidance, particularly in areas with vulnerable aquifers.