Integration Application Research Of Hydrological Analysis System

The South-to-North Water Diversion Project for solving the water shortage problem in Beijing-Tianjin region plays an important role. The source areas and receiving areas of the middle route of South-to-North Water Diversion Project has very complex characteristics of precipitation and runoff. The analysis process is also very complex, and the workload is very heavy for calculating. Hydrological Analysis System which uses the theories of system analysis and integration is developed to facilitate management of the mass of hydrological data, and to achieve the analysis of area rainfall calculation, the frequency characteristics and runoff encounter quickly and efficiently.Hydrological Analysis System consists of basin mean annual precipitation subsystem; frequency calculation subsystem and rainfall encounter subsystem. And it includes a series of processes from data acquisition to data processing. Data acquisition uses basin mean annual precipitation subsystem which is developed on Arc Engine and the subsystem calculate basin mean annual precipitation through the Thiessen polygon method. The data processing carries out frequency calculation and Portfolio analysis.Basin Mean Annual Precipitation Subsystem calculates the average precipitation of a particular region with several hydrological stations. It is calculated using the Thiessen polygon method and based on the Arc Engine platform. And it integrates many modules, such as map browsing, layer control, map registration, spatial database operations, attributes table operations, add hydrological stations and region, query properties and create Thiessen Polygon, and so on.The frequency analysis subsystem uses the Pearson Typeâ…¢frequency curve, which is the one of most widely used in hydrological analysis in China. And the curve parameters are estimated with Genetic Algorithms. In order to improve the accuracy, the integration combines the Simpson's rule with dichotomy. The Genetic Algorithm is a package of tool box of Matlab platform, and the COM component is used to carry out the combination of the Visual Studio platform and Matlab platform. The frequency calculation can get the design value through the input data.The rainfall encounter subsystem is mainly used in water diversion project, such as South-to-North Water Diversion Project, which involves a number of watersheds. And different watershed shows different hydrological characteristics. The change of water volume will directly affect the economic benefits of water diversion project. This system includes the division of the site rainfall, site rainfall statistics, rainfall-cycle statistics, continuous rainfall statistics, portfolio statistics and composition of the state statistics.