Flood study around and downstream of nonghan, Kumpawapi

Abstract

Bi-dimensional Flood Flow Model has been used for flood study around and downstream of Nonghan, Kumpawapi. Dike system had been constructed around Nonghan which is the low area and was also extended to high area on both banks of main streams which drain into Nonghan Kumpawapi. It is an unsteady flow model which flood can be calculated both in river channel and on flood plain area. The effect on tidal water downstream can be included in this model. The study area is divided into smaller one which is corresponded to the topography and it is called “Cell” or “Mesh” . In this study the area is divided into 118 meshes. Flow throuh main regulator of the project is controlled by the channel topography downstream, therefore the calculation starts at the point which is a distance of 2 kilometers downstream of Sritat bridge. RID rating curve at this bridge which is free flow to Lam Pao revervoir is used as the startting point. The results of the study are:

1. Construction more dikes along both banks of theexisting main channel from Nonghan dike backward to higher area is recommended.

2. More culverts are recommemded to be onstructed along Nonghan dike.

3. The result of the study with 10 river cross sections for a length of 40 km. (2 km downstream of sritat bridge to downstream of project regulator) con be concluded as follows: