Abstract
Recently, the simulation by numerical model is growingly employed in the analysis of runoff mechanisms. This paper deals with the important aspects to be considered in applying this method to runoff practice of low-lying basins.
Firstly, a runoff system from fields to downstream facilities was set up hydraulically; then the numerical model for this area was established, and the solution procedure was illustrated. Secondly, after applying the above method to the Hachiro-gata Polder, the calculations were compared with the measured vatues of this area. Through this study, the primary points to be considered in applying this method to the practical problems have been listed as follows:
1. Tributary canals show high roughness, which requires careful consideration in employing difference equations;
1. Tributary canals show high roughness, which requires careful consideration in employing difference equations;
3. For basins involving many branch drain channels of short lengths, calculation points should be distributed at small intervals sufficient for accurate water level determination.
4. Therefore, in order to obtain the knowledge of waterlevel over a low-lying basin correctly, one must consider the whole status concerned on the basis of available measurement records.
