Research On Flood Routing Model Of Nansi Lake

Nansi Lake is locate at southwest of Shandong province. As a famous shallow water fluviatile dam lake, it consists of a series lake as Nanyang Lake, Zhaoyang Lake, Dushan Lake and Weishan Lake which all of has no clear dividing line.It is a important transmission channel of water and pondage action lake in South-to-North water diversion. In recent years, along with the social economy of the valley continuously expanding, economic aggregate increasing, the loss caused by flood is serious increasing, therefore it extremely has the necessity to renew the result of Flood Routing in time and master the process of flood routing totally, which provided scientific base for flood control decision and programme and designing of Nansi Lake. It has great theoretical significance and practical advantages to research on the flood routing model of Nansi Lake.Base on knowing well of general situation and the characteristic of nansi lake valley, the paper analyzes and made a comparison between various kinds method of flood routine .then research on model of Nansi lake flood routine is made from the hydrology and the hydraulics The present paper main content includes:1. The paper advanced the necessity of research on the model of Nansi lake flood routing through analyzing the flood problem of Nansi Lake. The flood rooting model of "Three Lakes Two Rivers" and finite-difference method is put forward through comprehensive reviewing advancement in methodology for research on flood routing, and contrasting the hydrology and hydraulics flood calculation method.2. The paper expounds the the derivation of the flood routing fundamental equation and the conditions for determining on solution and the basic principle of finite difference method, introduces the astringency, compatibility and stability of format of difference together with related characteristic, four differences format in common application, and analyzing the format of Preissmann in detail, finally, produces several special boundary conditions processing method.3. The auxiliary curve is drawn according to the characteristic of "Three Lakes Two Rivers" model. The program is work out base on two kinds of curves combinations plan, which runs in response to a 50-year design flood. The difference between the results of the two kinds of curve combinations is small. So the model is nonsensitive to the combinations of the auxiliary curve, the model is reasonable and stable.4. An unsteady flow model is established, based on generalizing Nasi Lake reasonably, according to the narrow and long shape and the characteristic of river-type reservoir, which simulates the flood process in response to a 50-year design flood. Analyses and comparison is made between non-steady flow and "three lakes two rivers" model. Overall, the evolution of flood in the entire Nansi Lake is well simulated by the one dimension unsteady flow model. As an exploratory research, unsteady flow model is feasible and potential.5. The paper sum up the achievements of the paper, and point out the orientation of further study.