HR: 11:55h
AN: H12C-07    [Abstracts]
TI: Assessing model and data uncertainty by combing a tracer experiment with process modeling
AU: McGuire, K
EM: kevin.mcguire@oregonstate.edu
AF: Oregon State University, 004 Peavy Hall Department of Forest Engineering, Corvallis, OR 97331 United States
AU: * Weiler, M
EM: markus.weiler@ubc.ca
AF: University of British Columbia, 2Department of Forest Resources Management and Geography, Vancouver, BC V6T 1Z Canada
AB: While field studies of hillslopes often result in complex hydrological descriptions reflecting the spatial and temporal variability of water source and flow path, most modeling efforts find it challenging to incorporate this information directly into model structures. This is frequently due to the disparity between the scale of field observations and model sub-units and natural hillslope heterogeneity. Thus, parameters are usually estimated through a calibration-validation exercise with measured runoff even if the runoff information content limits the identifiability of model parameters. We approach this problem on a well-studied hillslope (WS10, H.J. Andrews, Oregon, USA) by combining the merits of a simple physically-based model with applied line source tracers (Amino G acid and bromide) and detailed soil property measurements (i.e., based on a database containing values of hydraulic conductivity, porosity, and water retention characteristics determined from $>$400 soil cores collected at the WS10 hillslope). We parameterized a relatively simple model structure that represents the dominant runoff generation processes in forested hillslopes by performing a multi-criteria calibration (runoff, tracer, and groundwater levels) over the range of measured soil properties. We were able to demonstrate that acceptable simulations with an improved parameter uncertainty can be found within the parameter range determined by the measured field data. We attributed the success our study to the limited model complexity used to structure our model that was largely field data driven, but constrained by both tracer and runoff.
DE: 1860 Runoff and streamflow
DE: 1866 Soil moisture
DE: 1875 Unsaturated zone
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting