A mathematical model for locating flooding area in the lower Maeklong river basin

Abstract

The propose of this study was to develope a mathematical model to predict flooding. The model calculates flood elevation at Banpong, Photharam, Ratchaburi and Bangkhonthi. Terrain elevation (Digital Elevation Model: DEM) was constructed to apply along with flood elevation from model. Flooding area was generated using Geographic Information Systems (GIS). The study found that the model shows good prediction of flooding areas compared to those that actually occurred. The model can predict the time that the maximum flood elevation will occur elevation at downstream sites (Banpong, Photharam, Ratchaburi nd Bangkhonthi). In addition, the model is easier to use than other hydrologic models because the model only requires the water elevation instead of the quantity of water (Q) at Maeklong Dam. The water elevation can be read directly from a gage measurement, so the official government at Maeklong Dam can able to warn people who live at downstream sites as to when and where flooding will occur. However, due to the limitation of this investigation, the numbers of used control points in generating DEM are quite few which may cause generated flood map errors. The recommendation from the study is that an alternative method using a computing lag time procedure calculating water travel time between downstream sites be used.