The Regulation Project Of Nansi Lake The Effect Evaluation Of Phase â…  Project And The Plan Determination Of Phase â…¡ Project

The regulation project of Nansi lake is an important component of the project to divert water from east to south in Huaihe River Basin. It is the key project to solve the flood discharge and to lower the flood level effectively.The regulation project of Nansi lake have been planned and controlled many times (from clearing reed away in early times to the enlargement of the small lake waist, the big lake waist and the establishment of the new river in the west of Nansi lake)since the founding of the PRC. The enlargement of the lake waist and the establishment of new river in the west of Nansi lake have the disadvantage of project investment excessive and engross lots of arable land. The experience tells us that the project is not easy to carry out. The shallow groove project in Nansi lake is a prioritization scheme on the fundament of reed cleaning program, with the deep understanding to manage Nansi lake and paying more attention to protect the environment. The shallow groove project in Nansi lake is consist of two construction. The first-stage construction has started in 1998,and has finished in 2001. The primary mission of first-stage construction is to clear away the hider of flood such as reed,tree fishpond coffer spoil of channel. This project designs the flood control standard according to twenty years face once flood. It will dig three shallow grooves inside the west and east of the lake and subordinate Nansi lake to speed up the flood down.The main research contents in this paper are analysis and effect evaluation of the first-stage, the necessity and feasibility of the second-stage construction. Compared with different proposals to choose the optimal case, the Nansi lake's comprehensive treatment was founded sciencetifically.The main achievements in this paper are:(1)according to the consistency principle of underlying surface condition, engineering conditions and current conditions of the lake, we make the Post-Implementation flood as the typical flood and the pre-implementation flood as the contrast flood, we selected some typical floods and contrast floods before and after Implementation of Phaseâ… Project. We use the evolution of the level of lake, time of propagation in the lake, the time of flood becoming normal, the gradient of flood surface as index. Analyze the effect of the first-stage construction about the project of inside management of Nansi lake. (2)We review the planning and control program of the project inside management of Nansi lake previously.analysis the effect of the first-stage construction about the project of inside management of Nansi lake and analysis the problems in prevent or control flood at present, we raise the necessity and feasibility of second-stage construction on the project of inside management of Nansi lake. (3)We combine the first-stage construction, study out many programs with different indexes, unit and contrast them, analyze and optimize them. Then the optimal project of the second-stage construction was decided.