Keywords
rainfall-runoff modelling, regionalisation, parameter values
Start Date
1-7-2008 12:00 AM
Abstract
The majority of catchment water balance studies use conceptual rainfall-runoff models to estimate total daily runoff at the catchment outlet. In most applications, the observed runoff used to calibrate these rainfall-runoff models is only available at the catchment outlet and thus represents an aggregated response of spatially variable rainfall across the catchment. In many applications, the input climate data (rainfall and PET) used to calibrate the models is available only at limited locations within the catchment or even somewhere close to the catchment. Only in some applications is spatially variable climate data used to drive the models either as a lumped or distributed model. Many regionalisation studies over the last decade have focussed on the transfer of rainfall-runoff model parameters from gauged to ungauged catchments with the intention of deriving a rainfall-runoff model for an ungauged catchment (i.e. one with no streamflow records). Sometimes this is done through the transfer of calibrated models from ‘similar’ or nearby catchments, and sometimes it is done through the transfer of model parameters based on their relationships with measurablecatchment attributes. Where the latter technique has been used, it is based on the assumption that rainfall-runoff model parameters are representative of the hydrologic response of the catchment and are thus largely independent of each other and of errors in the rainfall inputs.
Effect of Rainfall Data Quality on Rainfall-Runoff Model Calibration and Regionalisation
The majority of catchment water balance studies use conceptual rainfall-runoff models to estimate total daily runoff at the catchment outlet. In most applications, the observed runoff used to calibrate these rainfall-runoff models is only available at the catchment outlet and thus represents an aggregated response of spatially variable rainfall across the catchment. In many applications, the input climate data (rainfall and PET) used to calibrate the models is available only at limited locations within the catchment or even somewhere close to the catchment. Only in some applications is spatially variable climate data used to drive the models either as a lumped or distributed model. Many regionalisation studies over the last decade have focussed on the transfer of rainfall-runoff model parameters from gauged to ungauged catchments with the intention of deriving a rainfall-runoff model for an ungauged catchment (i.e. one with no streamflow records). Sometimes this is done through the transfer of calibrated models from ‘similar’ or nearby catchments, and sometimes it is done through the transfer of model parameters based on their relationships with measurablecatchment attributes. Where the latter technique has been used, it is based on the assumption that rainfall-runoff model parameters are representative of the hydrologic response of the catchment and are thus largely independent of each other and of errors in the rainfall inputs.
