APPLICATION OF A GROUPED RESPONSE UNIT HYDROLOGICAL MODEL TO A NORTHERN WETLAND REGION

Applications of hydrological models to northern wetland-dominated regi ons have been limited in the past to a few case studies on small basin s employing 'lumped' models. Only recently have there been attempts to apply the grouped response unit (GRU) distributed modelling approach using terrain classifications to these same basins. This study summari zes recent efforts in applying such a model. For the purposes of imple menting the GRU approach, terrain types that are hydrologically signif icant and characteristic to the wetland-dominated regime were successf ully discriminated using a principal component analysis and a hybrid u nsupervised/supervised classification technique on Landsat-Thematic Ma pper imagery. The terrain classifications were then used as input into a distributed hydrological model for calibration and validation using recorded spring runoff events. Preliminary model applications, and re sults are described. Calibration to a historic spring runoff event yie lded an r(2) value of 0.86. Model validation, however, yielded much po orer results. The problems of model applicability to this region and l imitations of sparse data networks are highlighted. The need for more held research in this type of hydrological regime, and associated impr ovements to the model parameter set are also identified.