Ground penetrating radar and spring formation in a groundwater dominated peat wetland

Ground penetrating radar (GPR) was used to identify the thickness and geometry of peat in a groundwater fed wetland in Northern Wisconsin. The low electrical conductivity of the water-saturated peat permitted high resolution imaging to a depth of 16 m. The GPR survey results delineated a break in slope in the interface between peat and the underlying sand/gravel. Springs and ponds are located above the break in slope suggesting that thinning of the sand and gravel may focus groundwater flow upward to the wetland surface with emergence as springs. The results of the GPR surveys suggests a potential mechanism that controls the formation of large springs and pools above the break in slope. (C) 2009 Elsevier B.V. All rights reserved.