HR: 0800h
AN: H21C-1364    [Abstracts]
TI: Up-scaling the Effects of Small Scale Spatially Variable Hydraulic Conductivity on Hortonian Runoff
AU: * Sheldon, S
EM: shane@uidaho.edu
AF: Department of Civil Engineering, University of Idaho, P.O. Box 441022, Moscow, ID 83844-1022
AU: Fielder, F
EM: fritz@uidaho.edu
AF: Department of Civil Engineering, University of Idaho, P.O. Box 441022, Moscow, ID 83844-1022
AB: Several models have studied the effects of spatially variable hydraulic conductivity on hillslope scale runoff processes. While these models have greatly enhanced our understanding of small scale infiltration interactions they are most often computationally impractical for larger scale runoff event. For such applications these small scale interactions are generally ignored. Using a detailed hillslope scale model a broad set of numerical simulations was initiated to investigate the role of interactive infiltration on runoff processes taking into account correlation length scale, initial moisture content, and dimensionless rainfall rate. By explicitly taking into account the dynamic interactions of small scale random lognormal distributed saturated hydraulic conductivity fields the model is able to account for variable infiltration from overland flow intersecting previously unsaturated soil, the run-on process. The results indicate spatially variable hydraulic conductivity can exert significant control either increasing or decreasing runoff generation depending on the conditions present, eg. rain duration, rainfall rate, and correlation length scale. After identifying the conditions where interactive infiltration heavily influenced the amount and trend of runoff these conditions were parameterized using an effective hydraulic conductivity and put into a simple larger scale model to see if the small scale effects of spatially variable hydraulic conductivity could be reproduced.
DE: 1838 Infiltration
SC: Hydrology [H]
MN: Fall Meeting 2005