Geoscience Reference
In-Depth Information
Model Requirements
The 1D2D flood simulation tool SOBEK requires four input parameters: a
Digital Elevation Model (DEM), surface roughness coecients of the flood-
plain, the river network with cross-sections and hydrological input data.
The DEM was generated from interpolation of spot heights and contour
lines obtained from different sources and scales (see Fig. 3). The hydrolog-
ical data consisted of discharge and water level time series derived from a
MIKE-11 Model by Nippon Koei
4
and NEDA,
5
for the upper boundaries
(Bicol, Naga, and Libmanan River) and water level at the lower boundary
(San Miguel Bay) for the return periods of 1.25, 5, 10, and 25 years. Values
forreturnperiodof2and50yearsarederivedthroughinterpolationand
extrapolation of the available data. The software generates maps of water
depth and flow velocity at predefined intervals, as well as time series of
certain parameters (water level, discharge, etc.) at predefined locations.
Results
Figure 4 shows the maximum water depth and flow velocity for the scenario
flood with a return period of 10 years. The output maps can also be used to
Fig. 3. Overview of the study area; scale varies in this perspective view. Elevation data
are in meters above sea level (m.a.s.l.).
