Date: Thursday, October 8, 2009 4:30 PM
Location: 366 Hollister
Flood generation in headwater catchments are governed by rainfall intensities and its distribution and by the pre-event state of the catchment, e.g. by the spatial pattern of the soil moisture, groundwater conditions, and possibly snow. Therefore, flood simulations in headwater catchments might be improved by enhancing the spatial precision of rainfall and by adding prior-rainfall soil moisture information. We explored the limits and potentials of measuring soil moisture by different methods and in different scales. These measurements were obtained in 2007 and 2008 within a comprehensive multi-scale experiment in the Weisseritz headwater catchment in the Ore-Mountains, Germany. The following technologies have been applied jointly: gravimetric method, FDR, Spatial-TDR cluster, ground penetrating radar, airborne polarimetric-SAR and satellite-based Envisat-ASAR. For possible use in flood forecasting, the observation of soil moisture at multiple scales has to be combined with suitable hydrological modelling. Therefore, several simulation experiments have been conducted in order to test both the usability of the recorded soil moisture data and the suitability of a distributed hydrological model to make use of this information.
There are still a variety of limitations, such as the need for parallel ground measurements (Envisat ASAR), uncertainties in polarimetric decomposition techniques (Polarimetric-SAR), very limited information from remote sensing methods about vegetated surfaces, and the non-availability of continuous measurements. The model experiments showed the importance of soil moisture as an initial condition for a physically based flood modelling. However, available soil moisture data reflect the surface or near-surface soil moisture only, why certain flood generation processes such as subsurface stormflow or quick groundwater drainage cannot be assessed by these data at catchment scale.
Refreshments will be served at 4:15 PM
