Analyzing the Influence of Preferential Flow on Hydraulic Properties in Various Land Use and Land Covers Along the Brazos River Basin in Texas

Abstract:

Watersheds serve not only as a large-scale representation of pertinent information to the water cycle and budget, but also as a representation of how water moves and responds to various geological, biological and hydrological intricacies as well as regional climate. While the impact of land use and land cover on soil hydraulic properties have been studied earlier, the influence of preferential flow on hydraulic conductivity on a watershed scale has yet to be thoroughly investigated. In this study, we conducted field experiments to measure in-situ (saturated and unsaturated) soil hydraulic conductivity at five strategically placed Texas Water Observatory sites (http://two.tamu.edu). A total of 100 measurements were taken during the Summer 2020. Data was acquired by using disc infiltrometers to measure soil hydraulic conductivity at different matrix potentials near saturation (0-20 cm). For hydraulic conductivity at matrix potentials higher than 20 cm, tempe cells and pressure plates up to 5 bar were used. All hydraulic conductivity and water retention data were juxtaposed reflecting multi-modal behavior in which preferential flow is dominating the infiltration process. Our results showed that preferential flow dominated infiltration in areas where the swelling-shrinking phenomena prevailed, and agricultural management practices were present.