DETERMINING THE HYDROLOGIC PROCESSES AND PHYSICAL PARAMETERS OF RIDGE-TOP WETLANDS IN THE DANIEL BOONE NATIONAL FOREST

Most constructed ridge-top wetlands in the Daniel Boone National Forest have hydroperiods that are longer than natural wetlands. The hydrologic function of the natural wetlands needs to be further studied in order to provide a well-quantified standard for future constructed ridge-top wetlands to replicate natural ridge-top wetlands. In this research we gathered physical and hydrological data from five ridge-top wetlands (2 constructed, 3 natural), in order to develop a conceptual model of wetland hydrologic function. Weather stations equipped with a rain gage, soil moisture sensors, and groundwater level sensors were placed in the watersheds of these wetlands to gather hydrologic data. We inserted wells inside of the pool and another within the catchment area of each wetland to take water levels. Soil samples were taken in the lab where specific yield and porosity were estimated with grain size analysis and loss on ignition testing. Aquifer bail and recovery tests were conducted to measure the hydraulic conductivity of the aquifer. A double ring infiltrometer was used to estimate infiltration rates and runoff. The White [1932] method was used to estimate the evapotranspiration rate of the groundwater. Results show that the natural wetlands are connected to perched groundwater that is directly recharged from the wetland depression. Evapotranspiration rates of groundwater were close to estimated values of recharge, indicating that natural wetlands were drained mainly by vegetation. Infiltration in ridge-top soils was higher than precipitation rates indicating that overland recharge of the wetland depression during rainfall is small.