Tuesday, November 14, 2006

Soil Matric Potential and Subsurface Flow in a Forested Catchment.

Xiaobo Zhou, The Pennsylvinia State University, University Park, PA 16802 and Henry Lin, Pennsylvania State Univ., University Park, PA 16802.

The subsurface water flow (lateral and vertical) plays a critical role on areal soil moisture redistribution. A systematic and dynamic monitoring of soil matric potential status and water moisture content in spatial and temporal scales is essential for understanding water flow as well as other hydrological processes. The objective of this study is to characterize the soil matric potential and moisture content distribution and subsurface water flow at a forested catchment in central Pennsylvania. Tensiometers were installed at various depths (10-, 20-, 40-, 60-, 80-, and 100-cm or deepest) to measure soil matric potential at sites with different soil types and landscapes. Soil moisture content was also measured simultaneously at those sites using Time Domain Reflectometry (TDR) probes. The results showed that different soils and landforms exhibited different temporal patterns of soil moisture and matric potential change. Ernest soil was relatively temporally stable among the soil types, while Weikert and Berks soil had higher variation of soil moisture and matric potential over time. The soil moisture and matric potential status were also investigated at hillslope scale.