| Abstract | Bangkok is located on the lowland near the estuary of Chao Phraya River,
approximately 1.5 meters above mean sea level. Bangkok is known as one of a high
flooding risk city. This is because of several reasons namely i) the rapid urbanization
(runoff increase), ii) inflow from the north part of Thailand, iii) inadequate of
drainage capacity, and iv) backwater from the tidal and withdrawal of groundwater.
Floods cause enormous economic losses to urban. Flood damage to increase and the
potential for damage to property will escalated if flood loss prevention and
management are not developed and implemented.
Modeling of urban drainage flooding in Sukhumvit area, Bangkok, Thailand is
conducted by application on a hydrodynamic model, MOUSE, built with three
exchangeable networks, pipe, street flows and terrain layer. The application of
mention model is further improved by the model calibration technique which is
conducted using the field experiment data. The water level and rainfall data is
collected in the field and provides good result. The analysis shows that the observed
rainfall data express 10 years return period characteristic.
Modeling of urban drainage in Sukhumvit area is calibrated and verified to
find out an appropriate model parameter set for this specific area. The calibration
reveals fairly agreement between model calculation and observed data. The field
observed data conduct on October 5, 2002. The results of the calibration provide
impervious area 30-40%, time of concentration 12-16 minutes (it should be noted that
there are some areas of railway and high building in Sukhumvit) and Manning's
number 0.018-0.022. However this set of parameter does not provide satisfaction
result in the verification which is done on October 7, 2002. The main causes suspect
to be lost of water volume in Sukhumvit street sewer. Therefore, the further
improvement is needed in the verification state.
The real time system of urban drainage system is successfully established in
the present study. The real time system is an automatic monitoring procedure for
tracing the flooding situation. This system provides continuously monitoring system
of rainfall data coupling with urban drainage model's simulation. The result of
simulated flooding situation is openly reported to the public during the actual process.
The analysis and presentation processes are conducted in two forms. The first form is
done by reporting MOUSE model's simulation results via DIMS in time series of
water level within various considered nodes. The second, the inundation map
presentation has benefits on easy understanding and convenient implementation of all
urban flooding. This procedure is tested and studied including database size, range of
data to simulate, loop of simulation, advantage and disadvantage of this system etc.
Lastly, the application of both Digital Elevation Model (DEM) and ArcView GIS
computer program is conducted to obtain the inundation map. This map is more
advance and improvement in the present work aims to obtain higher accuracy and
easier demonstration. |