Parameter estimation in semi‐distributed hydrological catchment modelling using a multi‐criteria objective function |
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| Authors: | Hamed Rouhani Patrick Willems Guido Wyseure Jan Feyen |
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| Institution: | 1. Department of Land Management and Economics, K.U.Leuven, Celestijnenlaan 200E, B‐3001 Heverlee, Belgium;2. Gonbad Faculty of Agriculture, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran;3. Department of Civil Engineering, K.U.Leuven, Kasteelpark Arenberg 40, B‐3001 Heverlee, Belgium |
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| Abstract: | Output generated by hydrologic simulation models is traditionally calibrated and validated using split‐samples of observed time series of total water flow, measured at the drainage outlet of the river basin. Although this approach might yield an optimal set of model parameters, capable of reproducing the total flow, it has been observed that the flow components making up the total flow are often poorly reproduced. Previous research suggests that notwithstanding the underlying physical processes are often poorly mimicked through calibration of a set of parameters hydrologic models most of the time acceptably estimates the total flow. The objective of this study was to calibrate and validate a computer‐based hydrologic model with respect to the total and slow flow. The quick flow component used in this study was taken as the difference between the total and slow flow. Model calibrations were pursued on the basis of comparing the simulated output with the observed total and slow flow using qualitative (graphical) assessments and quantitative (statistical) indicators. The study was conducted using the Soil and Water Assessment Tool (SWAT) model and a 10‐year historical record (1986–1995) of the daily flow components of the Grote Nete River basin (Belgium). The data of the period 1986–1989 were used for model calibration and data of the period 1990–1995 for model validation. The predicted daily average total flow matched the observed values with a Nash–Sutcliff coefficient of 0·67 during calibration and 0·66 during validation. The Nash–Sutcliff coefficient for slow flow was 0·72 during calibration and 0·61 during validation. Analysis of high and low flows indicated that the model is unbiased. A sensitivity analysis revealed that for the modelling of the daily total flow, accurate estimation of all 10 calibration parameters in the SWAT model is justified, while for the slow flow processes only 4 out of the set of 10 parameters were identified as most sensitive. Copyright © 2007 John Wiley & Sons, Ltd. |
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| Keywords: | semi‐distributed hydrological catchment modelling multi‐criteria objective function |
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