| Author | Dinh Cong San |
| Call Number | AIT Thesis no.WM-99-7 |
| Subject(s) | Floods--Vietnam--Mekong River
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of
Engineering. |
| Publisher | Asian Institute of Technology |
| Abstract | Channel forming discharge (CFD) and hydraulic geometry are investigated at five river
reaches of the Lower Mekong River, Viet Nam for flood seasons from 1978 to 1998. Five
methods defining CFD are considered at each reach to find the suitable ones. These are
Leopold et al., William, Maccaveev, Blench and bank-full methods. Utilizing hourly
discharge-water level and discharge-water surface slope relations of each flood season, a
modified William method and modified Maccaveev methods are introduced for CFD
calculation under semi-diurnal tidal influenced river reaches. The difference in CFD for each
method is compared to the average CFD value of the various methods. For the Tan Chau,
Chau Doc and Varn Nao reaches, the tidal influences are negligible during flood seasons. It is
found that William method gives the best result with the difference less than 7% and followed
by Leopold method. For My Thuan and Can Tho reaches, the tidal influences are not
negligible during flood seasons. It is found that the Blench method gives the best result with
the difference less than 5% compared to average value of the four methods.
By statistical approach, hydraulic geometry relationships are examined for the only
Chau Doc reach, which is the stable reach under non-tidal influences during flood seasons.
The width and mean depth relationships of cross-section are presented with their standard
errors and correlation coefficients between field and calculated data. The results show that the
constants in regime formulae are locally applicable. Based on the magnitudes of correlation
coefficients between field and calculated data, the suitable form of equation is according to
Przedwojski formula but with different coefficients (followed by Grisin and Leopold et al.) for
determining stable width of the channel at Chau Doc. For stable mean depth calculation, the
most suitable form of equation is according to Grisin (followed by are Brownlie, Leopold et
al., and Przedwojski).
The median bed material grain size is found to reduce downstream and the width-depth
ratios at stable reaches are found to increase downstream of the Lower Mekong River are also
presented. |
| Year | 2000 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Water Engineering and Management (WM) |
| Chairperson(s) | Tawatchai Tingsanchali; |
| Examination Committee(s) | Izumi, Norihiro;Sutat Weesakul; |
| Scholarship Donor(s) | Sida Mekong; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2000 |