Hydrologic Budget Analysis of a Small Natural Wetland in Southeast USA

Temporal variability and linkages among hydrologic components of a natural riparian wetland in the southeast USA were examined using two years of measured data. Rainfall was the dominant inflow and evapotranspiration (ET) the dominant outflow for the wetland. The wetland response factor, defined as the ratio of runoff to rainfall volume, was small and surface runoff accounted for only 9% of the total rainfall. ET was significantly different for wetland vegetation types and was significantly less than Class A Pan evaporation for most part of the year. Water losses through groundwater discharge accounted for 20% of the annual water budget. On an annual scale, very little water was added to storage within the wetland. Because of its shallow nature the wetland did not have a large capacity for flood storage and did not always attenuate floods. The results obtained from this research should be applicable to other natural riparian wetlands in temperate/subtropical climates. Also, the data should be useful to developing and validating hydrologic models of natural and constructed wetlands.