A Numerical Prediction Study Of Storm Surge And Floodplain On The Delta Of Oujiang

Storm surge is one of the severest natural disasters that leading to global loss of lives and properties. Located along the Northwest Pacific coast, China is frequently hit by storm surge. Storm surge has become the primary ocean disaster of China. Therefore, it is significant to accurately simulate storm surge and inundation for coastal cities. As one of the most suffering regions, the southern part of Wenzhou in Zhejian is chosen to study the storm surge. Using the two dimensional (PARALLEL) ADVANCED CIRCULATION MODEL(ADCIRC,v47.31), a high resolution unstructured triangular grid is established in Wenzhou(the horizontal resolution is 70m‐150m). Simulations of storm surge and inundation in Wenzhou under Typhoon 9417 are carried out considering the effect of river runoff, waves, land discription and sea level rising.The influence of runoff is added based on the traditional storm surge simulation which just coupled the tide and typhoone ,and SWAN wave model is coupled with the ADCIRC model too. It is demonstrated that the consideration of runoff improved the simulation of the storm surge at tidal stations in the river courses , which successfully reproduced the second and third peak value of storm surge after Typhoon 9417; the contribution of ocean waves to elevation rising is not obvious, only about 0.2m.The effects of land discription, sea level rising, river runoff and waves are studied respectively in the simulation of inundation, focusing on the former two aspects. On the one side, the simulated area of inundation is greatly reduced after considering the spacial distribution of bottom friction, especially in the southern bank of Oujiang, which is more realistic comparing to the measurements. However, the influence of land discription is not significant though the wind speed experiences a distinct decrease due to the hindering of the buildings. There is only slightly improvement. On the other side, experiments with different sea level rise are conducted. As sea level rising up to 0.25m, the inundation has nearly doubled; as the aspect of 0.5m, the simulated area is 2.96 times of the original. Thus, sea level rising plays an important role on the numerical simulation of inundation. As for the affect of river runoff and waves, they increase the floodplain to some extent, but not remarkable.In a word, the runoff of river should be considered when simulating the storm surge at tidal stations in the river courses which makes great improvement,while the distribution of bottom friction cannot be ignored in the simulation of flood plain.