HYDROGEOLOGIC CHARACTERISTICS

Several hydrologic properties of water bearing geologic materials govern the ability of saturated sediments and rocks to transmit water under a hydrostatic or pumping induced pressure gradient.

Hydrogeologists commonly use the terms transmissivity, hydraulic conductivity and storativity to describe and compare the interstitial flow and water yielding capabilities of aquifers to supply groundwater to wells. The values of these properties are determined by analyzing and evaluating the changes in water levels that occur in an aquifer during an aquifer test.

The transmissivity and storativity of the aquifers in Minnesota vary widely throughout the state having values that commonly differ by one to two orders of magnitude.

NWATS has conducted over 20 aquifer tests throughout the state in an area that comprises Brown County in the south to Lake of the Woods County in the north, bounded from Meeker to Cass County in the east, to Wilkin and Polk County in the west.

The figure below shows the location of each of these tests along with the resulting transmissivity and storativity values of the respective aquifers.