The optimal design method which the flood diversion for the construction period can be reduced for construction of the downstream cascade reservoirs by changing reservoir operation for regulation reservoir on the upper reaches of cascade reservoir was presented in the paper.

Construction diversion tunnel design for Naen HPP;

Application of Galerkin meshless method to two-dimensional numerical simulation of construction diversion;

Integrated risk of construction diversion system based on the Monte-Carlo method;

Essential problems in the process of construction planning for LHP are discussed in this paper, such as the pre_stage engineering design, bid preparation for main structures, river diversion, controlling construction schedule and methods for RCC dam constrction, etc.

The effects of various hydraulic factors on river diversion risk are analyzed.

Consequently, research works must be done not only on stability of cofferdam feet, channel scour, protection of the bank and so on, but also on navigation problems and salvation of downstream river during river diversion construction.

To solve the problems existed in construction diversion and closure system simulation at present such as hard modeling of simulation computation, poor transplantablity of program, separation between computation and data results, and difficult realization of simulation visualization, structural drawing-oriented simulation theory and method is presented in this thesis.