Abstract
Geophysical and temperature measurements were used to identify hydrostratigraphicfeatures that control groundwater/surface water interactions in a peat-dominated wetland/stream complex. Using these combined measurement techniques, we identified features that control the distribution of springs, ponds, and stream discharge zones within the wetland. Ground penetrating radar (GPR) surveys were used to image the distribution of peat within the wetland. A fiber optic-based distributed temperature sensor was used to measure changes in streambed temperature along the length of the stream. Variations between groundwater and surface water temperature were used to identify focused zones of groundwater discharge as well as larger gaining and losing reaches. Variations in the thickness of the peat, especially abrupt changes in slope, appear to correspond to the location of springs and ponds at the wetland surface. Based on these observations we propose a conceptual model to explain the relation between the changes in hydrostratigraphiclayers and the position of springs and ponds. Hypothesis testing using numerical groundwater flow simulations shows potential groundwater flow paths that may support the formation of springs and ponds.
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