Michigan Statewide Data Examples

This map illustrates the vulnerability of the uppermost groundwater (water table aquifer) to becoming contaminated from surface sources such as leaks and spills of hazardous materials, inappropriate application of pesticides or nutrients, septic leachate, etc. This 1980 map was based on a cursory evaluation of water well records which mapped the amount of clayey material in the sediments above the water table. Areas exhibiting little or no clayey sediments were classified as unprotected, while regions commonly underlaid by clayey materials were called protected. This was a somewhat misleading choice of terms because no place in Michigan provides perfect, long-lasting, natural protection for groundwater.