A wetland-aquifer interaction test

An understanding of the hydraulic connectivity between an isolated wetland and its underlying groundwater is required to help assess the ecological im pact that changes in the groundwater level may induce. Literature values fo r the hydraulic conductivity of peat vary up to ten orders of magnitude, in dicating the absolute necessity of obtaining site-specific information. Hor izontal and vertical variability in peat layers makes the process of extrap olating point-based measurements to predict system-level behavior difficult . By inducing or augmenting a flow up from the underlying aquifer into the wetland through a rapid lowering of wetland water level, the system-level h ydraulic connectivity of a wetland to the groundwater may be directly measu red. At a study site, a small, seasonally flooded depression mash wetland i n Florida, the method and subsequent analysis yielded a value for the hydra ulic resistance of the organic layer of 6 days, indicating a significant co nnection between the wetland and the aquifer. (C) 2000 Elsevier Science B.V . All nights reserved.