Appropriate modeling of climate changes impacts on river flooding

Background and objectives

The research deals with the determination of the appropriate model complexity dependent on modelling objective and research area, and the assessment of the climate change impact on river flooding with the obtained, appropriate model. The Meuse basin in Belgium and France serves as an application area. A model appropriateness framework is introduced comprising the determination of the dominant processes and variables, the appropriate scales and the associated appropriate process formulations. Important part of this framework is a reduction methodology to assess the appropriate scale for a particular variable dependent on the correlation length of that variable. The application of this methodology resulted in an appropriate scale for extreme precipitation of 20 km with a temporal scale of 1 day and appropriate scales for other key variables between 0.1 and 5 km. The final appropriate model scale was found to be about 10 km. The issue of appropriate scales is further explored by considering the effect of different spatial and temporal scales of the rainfall input and river basin model on extreme river discharges. The main conclusion is that the effect of the model scale on extreme river discharge is of major importance as compared with the effect of the input scale. An appropriate river basin model has been constructed by implementing the appropriate model components into an existing modelling framework. Additionally, two river basin models of differing complexities have been set up to evaluate the sensitivity of the model results to model complexity. The average and extreme discharge behaviour is well reproduced by the three models, and the results become somewhat better with increasing model complexity. The small differences between the two most complex models are due to the small differences in spatial model scales and the fact that no additional calibration data have been used. The increase of extreme discharges with climate change is much smaller than the associated uncertainty. However, it has been argued that the changes have a systematic rather than a stochastic character and therefore are not completely cancelled out by the uncertainties.

Publications

Booij, M.J., 2000. Model appropriateness for simulation of climate change and river flooding. In: L.R. Bentley, J.F. Sykes, C.A. Brebbia, W.C. Gray and G.F. Pinder (Eds.), Proc. XIII International Conference on Computational Methods in Water Resources, 25-29 June 2000, Calgary, Canada. Balkema, Rotterdam, 1169-1176.

Booij, M.J., 2001. Appropriate river basin modelling to assess the impact of climate change on river flooding. In: E.E. van Loon and P.A. Troch (Eds.), Book of Abstracts International Workshop on Catchment-scale Hydrologic Modeling and Data Assimilation, 3-5 September 2001, Wageningen, the Netherlands, 27-28.

Booij, M.J., 2002. Appropriate modelling of climate change impacts on river flooding. PhD-thesis. University of Twente, Enschede, 207 + xii pp., ISBN 90-365-1711-7.

Booij, M.J., 2002. Extreme daily precipitation in Western Europe with climate change at appropriate spatial scales. International Journal of Climatology, 22, 69-85.

Booij, M.J., 2002. Modelling the effects of spatial and temporal resolution of rainfall and basin model on extreme river discharge. Hydrological Sciences Journal, 47, 307-320.

Booij, M.J., 2002. Appropriate hydrological modelling of climate change impacts on river flooding. In: A.E. Rizzoli and A.J. Jakeman (Eds.), Integrated Assessment and Decision Support. Proc. First Biennial Meeting of the International Environmental Modelling and Software Society (Vol. I), 24-27 June 2002, Lugano, Switzerland, 446-451.

Booij, M.J., 2003. Determination and integration of appropriate spatial scales for river basin modelling. Hydrological Processes, 17, 2581-2598.

Booij, M.J., 2005. Impact of climate change on river flooding assessed with different spatial model resolutions. Journal of Hydrology, 303, 176-198.

Booij, M.J. and Vreugdenhil, C.B., 1999. Impacts of trends and uncertainties in river flooding due to climate change. In: P. Balabanis, A. Bronstert, R. Casale and P. Samuels (Eds.), The impact of climate change on flooding and sustainable river management. Proc. Second RIBAMOD Workshop, 26-27 February 1998, Wallingford, UK, 297-308.

Van der Wal, K.U., 2001. Meuse model moulding. On the effect of spatial resolution. MSc-thesis. University of Twente, Enschede.