G. M. Chescheir, D. M. Amatya, R. W. Skaggs 2
Water balance components were monitored over a 22 month period on a natural forested wetland near Plymouth NC. The monitored components were surface runoff, lateral seepage, soil air volume, rainfall, and evapotranspiration. A wide range of soil water conditions were observed during the study period including two winter and spring seasons with water ponded on the soil surface and two summer and fall seasons with the water table as much as 1.9 m below the soil surface. Surface runoff accounted for 16% of the rainfall while lateral seepage accounted for less than 1% of the rainfall. Evapotranspiration accounted for 87% of the rainfall. Closure error over the 22 month period was 5.7%. Water balance calculations were subject to the largest errors when the water table dropped below the soil surface in the spring. These errors may have been caused by uncertainties in estimating porosities near the soil surface or by errors in estimating evapotranspiration. Errors in the water balance also occurred during the time of high ET and convective storms during the summer. These errors may have been at least partially caused by the spatial variation of the rainfall.
