The movement of water from peatland into surrounding groundwater

Abstract

The flow of groundwater between and out of two adjacent bogs in southwest Michigan was investigated. Both wetlands are kettlelike depressions located in a complex upland covered by glacial outwash and till. Neither bog has an inlet or outlet stream. Their vegetation is typical of bogs, dominated by Sphagnum spp., Chamaedaphne calyculata, and Vaccinium corymbosum; however, only the south bog is forested with Larix lancina. The water table within the study area slopes through the north bog to the south bog. Both wetland surfaces are somewhat elevated above the surrounding groundwater and surrounded by "lagg" zones. The groundwater table around the bogs is only slightly affected by heavy precipitation, and water table fluctuations are least on the downslope side of each bog. Alkalinity, pH, and Ca²⁺ generally decrease from north of the north bog to the south end of the south bog. This is evidence that groundwater is moving down gradient through both bogs and that waters seeping out of the wetlands locally change the chemical nature of surrounding groundwater.