Model-based assessment of flash flood potential in ungauged
tropical basins (MAFFPO TROPIC)
Flash floods are one of the most destructive and dangerous natural disasters in tropical regions. They cause loss of human life and infrastructures. These events are related with extreme rainfall events and usually take place in small-ungauged or poorly gauged basins. One of the major challenges for flash flood assessment in the poorly gauged basins is the lack of reliable runoff records and high-resolution rainfall data in both spatial and temporal scales. It refers to rural and urban areas in northern Thailand, which are severely exposed to flash floods. A combination of a hydrological model (PANTA RHEI), which allows high spatial and temporal resolution and a 2D hydrodynamic model (MEADFLOW) is applied to map the potential flash flood hazards.
The two main objectives of this ongoing project are: (i) to develop a framework of the integrated hydrological and hydrodynamic modelling for flash flood assessment in the poorly gauged tropical basins and (ii) to develop a new spatial approach for investigating the role of the morphometric characteristics of the basins in the generation of flash floods.
Since flash floods occur in a short-period, high-resolution rainfall data are necessary. Thus, daily rainfall data are disaggregated with hourly rainfall data from neighboring stations and radar-rainfall observation before they are provided to a model. PANTA RHEI, a hydrological model developed at the LWI of TU Braunschweig, is used to reconstruct flash floods which occurred in the upper Nan River basin in August 2008 and June 2011. The simulated hydrographs computed by PANTA RHEI are fed into MEADFLOW, a hydrodynamic model. On the parallel approach, the analysis of basin characteristics; namely, area, drainage density, relief ration and basin shape, is carried out with ArcGIS10. The results from the integrated hydrological and hydrodynamic models are correlated with morphometric parameters of basins. Finally, hazard maps of flash flood potential of the pilot and other regions will be produced based on this research results.
German Academic Exchange Service (DAAD)
Lohpaisankrit, W., Meon, G., Tingsanchali, T. (2015). Flash flood modeling for the assessment of flash flood potential in ungauged tropical basins. Conference Tag der Hydrologie 2015, Bonn, 19.-20.03.2015.