| Author | Tanit Boonpan |
| Call Number | AIT Thesis no.WM-98-1 |
| Subject(s) | Storm sewers--Thailand--Bangkok--Mathematical models
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering. School of Civil Engineering |
| Publisher | Asian Institute of Technology |
| Abstract | Bangkok, the capital of Thailand, is located in the Chao Phraya River delta. In the
past decade, land use of Bangkok has changed. Rapidly developing or urbanizing regions are
exposed to growing environmental pressures as the effects of uncontrolled land
development, which causes frequently flooding. Densities of land uses are increasing and
hence causing higher storm runoff. Bangkok always faces with the problems of flooding
during heavy rainfall. The flooding problem in Bangkok Metropolitan Administration (BMA)
is well known and difficult to solve. The flood damages losses of both life and properties are
enormous. Due to the complexities of the system, how to improve storm water management
to avoid losses, there is a need for more through understanding of the hydrologic process.
The study area is located on the east bank of Chao Phraya River, which covers about
650 km2
. In this study, Storm Water Management Model (SWMM) was used and also
rainfall data especially in September 1998, which was one of the heaviest rainy seasons, were
analyzed in order to determine the pattern, spatial distribution of rainfall. The annual rainfalls
in El Nino and La Nina years were analyzed to determine their effect to distribution of
rainfall in BMA. The distribution of annual rainfall for EL Nino and La Nina years were
presented and found that mean value of La Nina increased. The amounts of rainfall in the
years of El Nino have the same chance to be more or less than the average value. The
amounts of rainfall in La Nina have 70% chance to be more than the average one.
SWMM was applied to simulate the flow discharge in channel and flow depth at
junctions at any time. The channel network was schematized into 15 8 number of nodes, 179
number of branches with 7 outlet boundary nodes located along the Chao Phraya River. The
calibration was carried out with the recent 15 minutes rainfall in September 1998.
The simulated water levels from calibration matched well with observed data with
calibrated Manning' coefficient equals to 0.05 for impervious area and 0.3 for pervious one,
and the channel Manning's roughness coefficient values in klongs are between 0.015 to 0.08.
The model was applied for two cases to improve drainage capability. The result
showed that the water level in case 1, which was the tunnel from K.Lat Phrao to Chao Praya
River about 6 km, decreased about 10 cm. In case 2, the water level decreased less than case
1. However, the flood volume and flood time for case 2 decreased more than case 1. The
average flood time and flood volume were remarkably increased 1 % and reduced 15% for
case 1. For case 2, average flood time reduced 44% and 46% for flood volume respectively. |
| Year | 1999 |
| Type | Thesis |
| School | School of Engineering and Technology |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Water Engineering and Management (WM) |
| Chairperson(s) | Sutat Weesakul; |
| Examination Committee(s) | Tawatchai Tingsanchali;Kazama, So; |
| Scholarship Donor(s) | Royal Thai Government (RTG); |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1999 |