Journal of Flood Engineering vol:1 issue:2 pages:93-108
Changes in the hydrological systems are expected due to climate change resulting from enhanced greenhouse effect. The impact of climate change on the hydrological systems is needed to assess at local and regional scales since these changes are not uniform over the globe. The present study
focuses on climate change impact on the hydrological extremes (e.g., high and low flows) during the 2050s over the region of the Kaidu River basin, Bayinbuluke, China. The high flow extreme determines the flooding event while the low flow extreme determines the drought event.
In this study, the future climate variables (e.g., precipitation, temperature and potential evapotranspiration)
were estimated based on the results from the General Circulation Models (GCMs) for A2 and B1 IPCC (2007) emission scenarios. A statistical downscaling technique was applied to transfer the climate change signal from the grid-based climate model to the point-based meteorological station site. Downscaling of precipitation was performed in two steps. The first step was to apply wet-day frequency signal which signifies the number of wet-days and the second step was to apply wet-day intensity signal which signifies the changes in the magnitude of precipitation intensity on a wet-day. Since inter annual variabilities of the temperature and potential evapotranspiration are low, downscaling of these two parameters was performed by applying delta change approach. The projections of climate change impacts on the hydrological extremes were analysed with the generalised lump conceptual hydrological model, Veralemeend conceptual Hydrologisch Model (VHM) for the period of 2046 to 2065. The results were compared with a baseline period of 1979 to 1998. The simulation results show a significant increase of the daily high flow peaks
(15 to 30%) during the 2050s whereas the daily low flow peaks show a decrease of 15 to 45% over the same period. The results indicate that the severity of flood and drought will significantly increase due to climate change in this region. The paper describes the different steps to estimate future climate variables towards an assessment of climate change impact on the hydrological systems of the case study area with the aid of a lump conceptual model.