| Author | Janejira Tospornsampan |
| Call Number | AIT Thesis no.WM-99-19 |
| Subject(s) | Watershed management--Thailand--Rayong
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of
Engineering. |
| Publisher | Asian Institute of Technology |
| Abstract | The present study aims at evaluating the Water Erosion Prediction Project (WEPP)
model applicability and prediction accuracy for a small watershed in the East of Thailand.
Three 5 by 22.1 m plots with 5% slope from seventeen runoff and erosion experimental plots
established by the Land Development Department in the Rayong Research Station were
selected for the study to simulate three different land use treatments. Runoff and soil loss data
were collected over a period of 3 months (August-October 1999). Observed rainfall and
observed runoff and soil loss data were analyzed for their relationships. The WEPP model was
run in a continuous simulation mode for 4 months from July 1999 to October 1999 for each
plot and the results were compared with the observed data. The USLE model was also applied
in the study for soil loss prediction and the results were compared with the observed data and
WEPP predicted results.
The runoff amount and runoff coefficients from the traditional plot (Plot 1) were higher
than the conservation plots (Plot 2 and Plot 3). WEPP produced slightly acceptable results for
runoff prediction though it overpredicted total runoff for all plots. Considering the existing
observed soil loss data, WEPP overpredicted total soil loss for all plots as well as USLE.
From the regression results, USLE tended to predict soil loss less than WEPP in Plot 1 but it
tended to predict soil loss more than WEPP in Plot 2 and 3. It is not explicitly addressed in
this study that how the models gave the predictions for soil loss as a number of observed data
were not enough. Application of WEPP to a sub-watershed of Dokkrai Watershed in the
eastern part of Thailand showed the close prediction of runoff for one available observed event
though it could not be concluded that how was the model ability in prediction for the
watershed. The results of sensitivity analysis showed that rill erodibility, critical shear, rill
cover, precipitation amount and duration, slope length and slope gradient are major factors in
terms of model response to detachment. |
| 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) | Loof, Rainer;Babel, Mukand Singh |
| Examination Committee(s) | Gupta, Ashim Das;Izumi, Norihiro |
| Scholarship Donor(s) | Japan Government Schorlarship |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2000 |