The Study And Application On The Methematical Model Of Urban Rainstorm Flood Waterlogging

With the development of economy, urbanization is speeding up gradually.Urbanpopulation and assets density is expanding rapidly. The ratio of impervious areas continuesto increase due to urban cement buildings and hardened pavement with suburban placesbeing used for urban development and water bodies surrounding the cities such as theoriginal rivers and lakes etc. continuously squeezed or simply filled up, which causes seriousatrophy of urban flood storage capacity. The rapid development of cities brings abouteconomic boom, but also associated with a series of problems, of which urban storm floodwaterlogging is one.Aiming at the severity of Chinese urban flood disaster, this paper proposes urbanizationis the main factor of intensifying it. Firstly, the basic theory and the present developmentsituation of urban stormwater runoff and flood model are introduced. And then the basicequation of the shallow2-d unsteady flow is deduced detailedly. In addition, it also presentsthe principle and procedure of the establishment of a mathematic2-d flow model by thefinite element method. Finally, along with the knowledge and data of meteorology,hydrology, hydraulics, drainage etc. of Fuzhou University City, we come up with amathematics model of storm flood waterlogging in university city.The model simulates urban surface runoff and river confluence by employing2-dunsteady flow equations as basic control equations, and establishes a triangularcomputational grid by the use of basic ideas of the finite element method and unstructuredirregular modeling techniques. And then after decorating variables in computing gridreasonably,it will discrete control equations and execute the solution and programming. Onthe one hand, a mathematical model of river flood has been established,which mainlysimulate the change processes of river’s flood capacity, water level, and flow. And the otherhand, a mathematical model of inrush waterlogging has been established,which mainlysimulate urban water duing to stagnation of river passage and overflowing of part of riverembankment to assess the flood hazards and losses.A mathematical model of storm, flood and waterlogging of Fuzhou University City isestablished by the use of the basic theories and methods above, which is debugged and validated by heavy rains and flooding materials of typhoon “Sepat” on August18th~19th,2007,and typhoon “Longwang” on October2nd~3th,2005, and shows high precision.Using this model to calculate and analyze flood disasters of university city,this paperanalyzes and compares renovation shemes of flood and water-logging control minutely bythe comparison of regional flood process, water distribution, water depth and time, whichprovides a certain theoretical basis for formulation and further execution of schemes and hasa certain directive significance.