A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology

Thesis (M.Eng.) - Asian Institute of Technology, 1988

Flocy model . The model is developed to calculate the flood frequency at any station along the study reach from Bangsai to the river mouth at Fort Chula using theod frequencies in the Chao Phraya River have been studied by means of a coincident flood frequen total probability theorem. The frequency and duration relations of the upstream and downstream water levels are used as the boundary conditions. The Single Reach with Loop Model is applied to calculate a relationship of maximum flood level at any station as a function of the Bangsai flood peak level and the tides at Fort Chula. The calibration is made by adjusting the duration curve to allow it to represent very large flood events. Good agreement between the computed flood-stage frequency curves and the observed one are obtained. After calibration, the model is applied to determine the effects of a flood control diversion channel which diverts flood discharge at Pak Kret on the we s t bank of the Chao Phraya River. This measure is found to reduce the flood level frequency in the upper reach efficiently. For the lower reach , it is found not capable enough to reduce the flood level frequency effectively .