APPLICATION OF SOIL WATER BUDGETS TO LANDSCAPE HYRDOLOGY ANALYSIS

Water budgets compare inputs and outputs of water to determine how the amount of water stored in a soil changes over time. This study developed a water budget to evaluate a wetland restoration plan as well as to predict off-site impacts of the restoration. The site is a Carolina Bay in NC that was drained for agriculture. Precipitation, potential evapotranspiration, surface outflow, and soil water storage were measured on site. No surface inflow entered the Bay. Net groundwater inflow was estimated by difference. The water budgets done to-date show that groundwater supplies approximately 20% of total water input to the Bay. Estimates of evapotranspiration represent the largest single source of error in the water budget. We assumed that actual Et was approximately 70% of PET. At this time the drained Bay acts as a discharge wetland. Most of the groundwater that enters the Bay leaves as surface outflow through the existing ditch network. The restoration plan will convert the Bay into a flowthrough wetland and may raise water tables in the surrounding region.