HR: 09:30h
AN: H21E-05    [Abstracts]
TI: Hillslope Scale Rainfall Simulation for Understanding Water Fluxes on Rangelands
AU: * Wilcox, B P
EM: bwilcox@tamu.edu
AF: Texas A&M University, 2126 TAMU, College Station, TX 77843 United States
AU: Munster, C
EM: cmunster@tamu.edu
AF: Texas A&M University, 2126 TAMU, College Station, TX 77843 United States
AU: Owens, K
EM: kowens@ag.tamu.eud
AF: Texas A&M University, 2126 TAMU, College Station, TX 77843 United States
AU: Mohanty, B
EM: bmohanty@tamu.edu
AF: Texas A&M University, 2126 TAMU, College Station, TX 77843 United States
AB: A variety of approaches are available for understanding runoff processes on rangelands but generally these approaches will involve measurements during natural precipitation events or take advantage of rainfall simulation. Rainfall simulation has many advantages but one persistent disadvantage is that scale of observation is often quite small-several square meters or less. Alternatively, runoff from natural rainfall events can be monitored at larger scales but for rangelands, runoff producing events may be few and far between. A potential compromise is to conduct rainfall simulation at the hillslope scale. In this paper we describe a methodology and approach that has been applied with considerable success on shrublands in central Texas. To date we have simulated rainfall above tree canopies at a height of over 10 meters and on an area that is 20 x 26 square meters in size. The simulator is modular and composed of individual masts that support a set of four nozzles each. An advantage of this approach is that rainfall is applied on an area sufficiently large as to incorporate processes and factors that influence runoff at the hillslope scale. During rainfall simulation experiments we make detailed measurements of the major components of the water budget including interception, stem flow, transpiration by woody plants, soil water storage, surface runoff and interflow. Since the system is modular, there is the option of expanding it and applying water on even larger scales. The major limitation is transporting and storing sufficient water for rainfall simulations on such a large scale.
DE: 1815 Erosion and sedimentation
DE: 1860 Runoff and streamflow
SC: Hydrology [H]
MN: 2005 Joint Assembly