Study On The Application Of Urban Drainage Networks Modeling Based On GeoDatabase

With the development of computer technology and the acceleration of urbanization, the theories as well as computational methods of urban drainage system have been progressing steadily nowadays. It has become an indispensable way to use the Geographical Information System (GIS) technique as well as hydraulic & hydrological model to aid the plan, design and rehabilitation of the urban drainage networks. Moreover, it is an advisable step to bridge the gap between China and the developed countries in this field via introducing the advanced theories and software to the related domestic projects. In this paper, with the software of Arcgis and InfoWorks CS, the hydraulic simulation of storm water drainage networks in Mohekou industrial park, Bengbu, Anhui Province was performed based on the construction of geographical database for the urban drainage system. Its results not only offer suggestions to the design of the drainage networks in this area but also provide experiences and consultations for the design, management and operation of similar drainage networks in other cities.Currently, the popular DBMS platform, namely, the conventional database or CAD with attributes database has such disadvantages as lack of spatial analysis, poor user interface, long-term advanced programming etc. In chapter 2 of this paper, under the guidance of spatial data model named GeoDatabase which is regarded as the third version of geographical data model, the urban drainage system model was established by adopting object-oriented modeling technique. It has superiority over the two former versions and ordinary relational database in data management, extensibility, user-defined function, seamless storage and graphic display, thus closer to the real world.The traditional theory and computational method of urban drainage networks bear the deficiency of lack of precision & reliability as well as tough work. In chapter 3 & 4 of this paper, by virtue of the established GeoDatabase, the networks structure and background data are imported into the InfoWorks database directly to facilitate the simulation. During the calculation, the network operational state was analyzed and diagnosed to improve the efficiency and reliability of the design. As we know, the rainfall-runoff model plays a key role in the computation and its solution remarkably influences the accuracy of the whole model. Therefore, under the condition of domestic application, the parameters definition of the rainfall-runoff model commonly used in developed countries is a key issue in this paper. By comparison, we found that the combination of Chicago design rainfall model and local stormwater equations can generate suitable stormwater parameters. Then by employing fixed runoff coefficient runoff volume model and Wallingford runoff routing model we gained the preferable simulation results.Conclusion regarding the establishment and application of GeoDatabse as well as hydraulic model to urban drainage networks is made in the last chapter. It can be anticipated that further research and practice is desired in order to apply this method to complex drainage networks successfully because it takes some time for the software to adapt itself to the situation of China.