Large Sample Basin Experiments for Hydrological Model Parameterization: Results of the Model Parameter Experiment–MOPEX. IAHS Publ. 307, 2006, 237–245.

 

Characterization of flow regimes for three French rivers using a 6-parameter continuous simulation rainfall–streamflow model: the importance of the parameter selection procedure

 

Ian G. Littlewood

 

Centre for Ecology and Hydrology, Wallingford, Oxfordshire OX10 8BB, UK

igl@ceh.ac.uk

 

Abstract An established 6-parameter rainfall–streamflow modelling package (PC-IHACRES) is applied to three French catchments using daily data sets made available to participants of a Model Parameter Estimation Experiment (MOPEX) workshop held in Paris, 2004. For one catchment, Le Loupe at Villeneuve-Loubet, the main aim is to characterize the flow regime over as wide a range of flows as possible, using a single set of model parameters selected by a multi-objective model parameter selection procedure. Using a more restricted, twin-objective, parameter selection procedure, a subsidiary aim for each of the three catchments (additionally Le Guillec at Trézilidé and Le Toulourenc at Malaucène), is to investigate how well a model calibrated on a sub-period of the available record performs on a different sub-period not used for model calibration. For Le Loupe at Villeneuve-Loubet, the 6-param­eter model structure, with a single set of parameters calibrated over almost the entire available record, characterizes the flow regime between 5 percentile and 80 percentile flows. Split-sample analyses for Le Guillec at Trézilidé and Le Loupe at Villeneuve-Loubet, using two sub-periods of the available record in each case, demonstrate the difficulty of capturing a time-invariant characteris­tic response for those two catchments. A similar split-sample analysis suggests that Le Toulourenc at Malaucène has an essentially time-invariant characteris­tic response to rainfall. The results are discussed in the context of similar analyses reported in the literature, and with respect to the potential of the
6-parameter model for some aspects of regionalizing model parameters against physical catchment descriptors to enable flow simulation at ungauged sites.

 

Key words  flow regime characterization; rainfall–streamflow modelling; regionalization; ungauged catchments