River Flow Simulation within Ungauged Catchments; the Utility of Regionalised Models

The extraction of information from hydrological data has been increased by the use of multiple objective functions which lead to trade off strategies during model calibration. Uncertainty within input data, model calibration and structure and parameter regionalisation schemes all led to uncertainty within model simulations when used as predictive tools. However, model success and failure is commonly determined not by abstract fit statistics but by the sensitivity of subsequent analyses to the uncertainty in the simulated stream flow data. This paper will explore some of these issues in the context of the assessment of potential impacts of climate change on river flows using the results from a UK case study on regionalising model parameters for a rainfall runoff model. The paper will comment on the utility of regionalised hydrological models for evaluating the impact of potential climate change scenarios using the specific example of a study from the United Kingdom and will conclude by outlining some current research directions in the regionalisation of rainfall runoff models and climate change impact assessment.