Exploration In Several Hydrological Problems For Hydraulic Engineering

In the planning, design and management of hydraulic engineering, to fix and check the scale of the project, it is necessary to carry out hydrological calculations. And utilizable fixed number of years of hydrolaulic engineering, could be beyond a hundred years. It's hard to use the present hydrological forecast by analyzing factors to forecast the runoff in such a long future period. So it is common to select hydrological data of a certain period for calculation and analysis, to figure out the situation, which would probably happen in the river where the project is located on, and to put forward a reasonable plan for the engineering. But because of the complexity of the hydrologic ally effective factors and the inadequateness of the observation data, the hydrology science still in the developing stage at present, the shortcomings of some calculation theories and methods which need to be improved increasingly along the development of science and technology, the variety of calculation methods and difference in technological level and experience of different technologists also cause a certain difference in calculation outcomes of identical hydrological feature value for the same project. So based on different types of actural hydraulic engineering, some hydrological calculation probles are discussed in this paper, and the main achievements are as follows:(1) Taking the Er Longshan Reservoir as an example, the designed flood hydrograph and routing was carried out on the bases of different typical hydrographs. The calculation shows that the typical graphs have a certain effect on the routing resoults.(2) In the case study of flood routing and check for a group of small-size reservoirs in Qixing river basin, considering the influence of storage and dam break of upstream reservoirs, the inflow and flood routing are calculated for downstream reservoirs. The resoults show that if the upstream reservoirs keep the present capacity of flood prevention, the outlet reservoir, Baijiayao Reservoir will be not safe in flood control.(3) Considering the special problems in Fugu section of Yellow River, such as the influences of branch river, scouring and silting, and bridges on flood, the water surface profile was carried out and discussed. The resoults show that the branch river and scouring and silting have great influence on the profile.(4) With the case study of flood regulation for Shiquan reservoir in south Shaanxi, the enlargement of hydropower plant can increase the utilization rate of surplus water and generate much more energy, especially for the middle- or small-floods. At same time, the analysis shows that it is feasible taking different initial regulating stages for different magnitudes of floods.(5) Considering the actural conditions of Malan Water Diversion Project, the reasonable diversion flow was analyzed first. Then the designed flow and check flow of the. diversion tunnel were figured out, they are 3 m3/s and 4 m /s respectively.