Research Of Flood Forecasting And Early Warning System At Small And Middle Watershed: The Shuangji River As Example

Flood is one of the frequent natural disasters in our country. With thedevelopment of society and economy, higher requirements for the construction offlood protection have been put forward. Though, we have built a lot of engineeringfacilities and non-engineering facilities with advanced technology in the great river inour country. the effect of flood protection is very good, the small basins are facing asituation of "heavy rain cause big disaster, and light rain cause small disaster". Inrecent years, the medium and small basins start to strengthen engineering facilitiesconstruction of flood protection, and propose to improve non-engineering facilitiesincluding hydrological monitoring, flood forecasting and warning, which will providedecision-making basis for flood protection. This study is to establish a system of floodforecasting and warning to strengthen flood protection capacity and improveprediction accuracy and strengthen the ability of early warning and preventingdisaster in the small and medium basins. This system take the C/S model based onGIS component, which fuses the display and spacial analysis ability of GIS to theflood forecasting and early warning service. It improves the efficiency of processingwater and rainfall data, and enhance the ability of prediction and early warning of thesmall watershed. It can achieve visual and interactive operation in the whole businessprocess. It solve the problem that the information level is not high about the floodforecasting and early warning in the medium and small basins, which can provide fastand accurate basis for this basin flood protection and provide data support for thedownstream flood protection.This study analyses the characteristics of small basin flood control. we select therainfall runoff correlation method in the flood forecasting, and select the regionmethod to select or transplant parameter in the protecting mold. We select the voronoidiagram to calculate average rainfall. In the early warning method, we present themethod for determining the warning value, and the submerged three-dimensionaldynamic analysis based on DEM, and the flood early warning management methodbased on grid. The c/s model system for development based on the GIS component has been used. Then, we make the whole design and the logic design and the functionmodule on the system; make the conceptual design and the logic design for the spatialdatabase and the attribute database.The main results of the research are that we select the Shuangji River Basin inthe Zhengzhou as the study area, we obtain the data about the engineering facilitiesdistribution and the attribute information and the hydrology and rainfall from theZhengzhou Bureau of Hydrology and the websites, we vectorize the graphic andorganize the attribute data in accordance with the design to establish Geodatabase andthe attribute database based on the SQL Server2005. We use the C#language todevelop the medium and the small basin flood forecasting and early warning systembased on the ArcGIS Engine9.3components in the Visual Studio2008platform.This system can realize the map scan about the whole valley, and realize the overallstatistical data of rainfall and the water level, and realize the spatial query about thestation network and the reservoirs based on the map. It can realize the real-timedisplay about the hydrology and the rainfall information and can display the real-timeisohyetal line. It can realize the visual and the interactive flood forecasting, andrealize the submerged three-dimensional dynamic analysis based on DEM and theflood early warning management based on grid.This study has improved the level of information management in the small andmedium basins, which improves the flood forecasting and warning capabilities. It canprovide more accurate, quick information for the medium and small basins toprevent flood disaster.