HR: 1330h
AN: H42G-1154    [PDF]
TI: Parameterization and Assessment of a Distributed Hydrologic Model
AU: * Brooks, E S
EM: broo2789@uidaho.edu
AF: University of Idaho, Dept. of Bio. and Ag. Eng. JML 81C, Moscow, ID 83844-2060 United States
AU: Boll, J
EM: jboll@uidaho.edu
AF: University of Idaho, Dept. of Bio. and Ag. Eng. JML 81C, Moscow, ID 83844-2060 United States
AB: Verification of distributed hydrologic models is rare due to the lack of spatially detailed field measurements and a common mismatch between the scale at which soil hydraulic properties are measured and the scale of a single modeling unit. In this study two of the most commonly calibrated parameters, soil depth and the vertical distribution of lateral saturated hydraulic conductivity (Ks), were eliminated by a spatially detailed soil characterization and results of a hillslope-scale field experiment. The soil moisture routing (SMR) model, a simple distributed hydrologic model, was modified to represent the dominant hydrologic processes for the Palouse region of northern Idaho. The model was applied to a 2 ha catchment without calibration to measured data. Distributed responses were compared to perched water depth measurements made every 12 hours over a three year period on a 10 x 15 m grid. The modified SMR model simulated the perched water table fluctuations across the catchment during the hydrologically active season remarkably well especially given that one mm of error in the water balance would result in an error of 20 mm in water table depth. Simulations also captured water table fluctuations during a year with high spatial variability of snow accumulation and snowmelt rates at up-slope, mid-slope, and toe-slope positions with Nash-Sutcliffe efficiencies as high as 0.79, 0.70, and 0.52, respectively. In one location in the catchment, consistent over-prediction of perched water table heights indicated a localized recharge zone which was not identified by the soil morphological survey. Our detailed data set with its spatial variability in soil properties and dynamic hydrologic measurements is ideal for verification of distributed hydrologic models. Modeling results in this paper show that the simple GIS-based SMR model is physically sound.
DE: 1829 Groundwater hydrology
DE: 1833 Hydroclimatology
DE: 1860 Runoff and streamflow
DE: 1866 Soil moisture
SC: Hydrology [H]
MN: 2003 Fall Meeting