基于情景模拟的滨海平原河网区复合洪涝淹没特征分析与风险评估OA

Coastal areas are prone to experiencing the combined effects of rainfall,tidal levels,and storm surges,which can lead to complex flood disasters with intricate mechanisms.To deeply reveal the evolutionary characteristics and driving mechanisms of complex flood disasters in coastal plain river networks,the Qianshan River Basin in Guangdong Province was selected as the research object.Based on the conditional risk probability model,eight typical combinations of rainfall and tide encounters were identified and constructed.A one-dimensional and two-dimensional hydrological and hydrodynamic coupling model was built using basic data such as DEM and land use types.The model was validated by combining runoff coefficients and historical flood area data.The results showed that the model could accurately reflect the hydrological response and waterlogging characteristics of the study area,and the overall accuracy met the research requirements.Based on this,numerical simulations were conducted for eight typical scenarios involving rain and tide encounters.Flood grade classification standards were introduced to grade flood risks,systematically analyzing and revealing the characteristics of flood inundation and the spatial distribution patterns of risks in coastal plain river networks under rain and tide encounters.The research results indicate that under different scenarios of rain and tide encounters,the inundated areas are primarily distributed in Tanzhou Town,Sanxiang Town,and the surrounding areas of the Hongwanyong water outlet.As the tide level and rainfall recurrence period increase,both the total inundated area and the inundated areas of various water depth levels in the study area show a continuous growth trend.Moreover,the newly inundated areas are mainly concentrated in Tanzhou Town,indicating that this area has a high sensitivity to changes in rain and tide.The flood risk distribution is dominated by low and high risk levels,with medium risk areas accounting for a relatively small proportion.The high-risk areas are primarily concentrated in Tanzhou Town and significantly expand as the intensity of rain and tide increases.It is worth noting that seawater inundation will significantly expand the flood inundation range and have a pronounced amplification effect on the expansion of high-risk areas,which is one of the key factors affecting the spatial pattern of regional flood risk.In summary,this study reveals the driving mechanism of tidal level and rainfall variation on the evolution of compound floods in coastal plain river networks,and provides important scientific basis and technical support for flood disaster risk assessment and flood control and drainage engineering planning in such areas.