Regionalisation of flow duration curves on global scale and lessons learned

Abstract:

Flow duration curves (FDCs) summarise information of the hydrological characteristics of rivers and the shape of the FDC depends both on climatic and physical factors. FDCs are used for a variety of applications such as water resources estimation, hydropower planning and evaluation of hydrological models. Given the lack of discharge data in many areas in the world, a technique to estimate FDCs in ungauged or poorly gauged basins is desirable. There exist plenty of examples of regionalisation of FDCs within relatively limited areas (e.g. for local sub-basins or at national or regional scale), but to our knowledge it has not been done on global scale. The large variety of shapes of the flow duration curves and uncertainty in data complicates the process of regionalisation on this large scale. In this study, several methodologies are used to construct FDCs in basins assumed to be ungauged and the results are compared and discussed.