Verification of GSTARS 2.0 river morphological model | |
| Author | Qing, Xi |
| Call Number | AIT Thesis no.WM-01-03 |
| Subject(s) | Sediment transport--Mekong River River sediments--Mekong River Streamflow velocity--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 | Most of the sediment and water routing models, such as the HEC-6 (U.S.Army Corps of Engineers, 1977,1993)model were developed for solving one dimensional alluvial river problems. Although there are truly two-dimensional and three-dimensional models for alluvial river simulation, they are too computationally intensive for engineering applications. Molinas and Yang (1985) simulate flow conditions in a semi-two-dimensional manner and the change of channel geometry by using the first version of GSTARS. The model was then mostly used in-house for small projects due to its limited features and research status. The GSTARS model was revised and enhanced by Yang et al. (1998) and released by the U.S. Bureau of Reclamation. GSTARS 2.0 is a stream tube model for alluvial river simulation. Backwater computations are carried out using the standard step method based on the conjunctive use of the energy and momentum equations. Stream tubes are used for hydraulics and sediment transport calculations to achieve a lateral variation within a cross section. Sediment routing, and bed sorting and armoring computations are performed independently for each stream tube. In this study, The predictions of the cross sectional area of Nong Khai station in Mekong river were done. The Gstars 2.0 model was applied to simulate the measured data at Nong Khai station in Mekong River, the model is calibrated using the flow and cross-section data of Mekong river at Nong Khai gaging station, Thailand in the years of 1986-1987, 1987- 1988 and verified using the flow and cross section data in the year 1985-1986. The model simulated the quasi-steady flow condition of the Mekong River on daily basis and the sediment transport and changes in cross sectional geometry using a 1/8 day time step for numerical stability and accuracy. The calibration yields the optional set of the model parameters namely Manning's n=0.030, number of stream tube=5, the best sediment transport formula is the Toffaleti's total load equation. It is found that the GSTARS 2.0 model yields very satisfactory results for model calibration and verification. Furthermore, the effects of each individual model parameter or the selected sediment transport function are investigated on the calculated changes in the cross section. From the analysis, the effect of significant model parameters are identified. With such information, the model calibration, verification, and application can be done effectively. Gstars 2.0 shows good ability in simulating and predicting the changes of cross sectional geometry of the Mekong River, simulating and predicting the hydraulic and sediment variations both in the longitudinal and in the transverse directions, computing hydraulic parameters for open channels with movable boundaries. |
| Year | 2002 |
| 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) | Clemente, Roberto S. ;Sutat Weesakul |
| Scholarship Donor(s) | Government of Japan |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2002 |