Climate Variability and Change—Hydrological Impacts (Proceedings of the Fifth FRIEND World Conference held at Havana, Cuba, November 2006), IAHS Publ. 308, 2006, 134–138.

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Predicting low flows in ungauged basins: a hydrological response unit approach to continuous simulation

ANDREW R. YOUNG, VIRGINIE KELLER & JIM GRIFFITHS

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

ary@ceh.ac.uk

Abstract An alternative approach to the problem of the regionalization of a rainfall–runoff model is explored in which the concepts of Hydrological Response Units (HRU) are used to define a flexible model structure where catchment descriptors are used to define relatively complex, specific model structures within each catchment from one generic structure. This model structure has been simultaneously calibrated, and hence regionalized across a large set of catchments within the UK. The simulation results obtained with this approach have been compared with those from a simple lumped model regionalized by relating prior calibrated model parameters to catchment descriptors. The paper concludes by suggesting that model structure and regionalization strategy may not be significant in limiting the performance of regionalized models and that they can be improved by incorporating sparse, at-site measurements.

Key words rainfall–runoff models; continuous simulation; hydrological response units; regionalization; water resources

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