Water Resources and Power

Taking Haidian Island in Hainan Province for an example,on the basis of urban fine partitioning runoff method for calculating runoff and rainwater drainage capacity curve fitted by piecewise linearization,the function relation of the drainage capacity and the tidal level was established by using high precision DEM terrain grid with surface attribution. Water land boundary condition was processed to allow water flow in both directions. Eventually waterlogging model of coastal city based encounter of rainstorm and tide was established by coupling flow concentration module with hydrodynamics of underground pipe network and tidal floodplain submergence. The characteristics of urban water regimen and waterlogging were discussed. The results show that the encountering of the tide and rain will make urban waterlogging situation worse,and water-logged area increased; deteriorative causes of urban waterlogging are not the same for different area,coastal area was mainly caused by the tidal water flow backward and the urban interior zone did not drain off water owing to high tidal level. Compared to independent rainfall case,water-logged depth of the typical representative points increase 0.22 m averagely,water-logged durations increase 7.7 hours averagely as well as the time of duration for deep waterlogging prolong obviously.