基于数值模拟的山前蓄滞洪区减灾成效量化分析与评估OA

Mountain river floods pose a serious threat to the safety of foothill urban areas.Constructing flood deten-tion and storage zones in front of mountainous regions can retain floodwater,reduce flow velocity,attenuate flood peaks,and effectively mitigate the impact of floods on developed areas.Taking the Beisha River in the Wenyu River Basin,Beijing,as a case study,this research employs a numerical simulation method based on hydrodynamic prin-ciples to simulate the flood evolution processes under two scenarios:free flood discharge and discharge regulated by flood detention zones.By comparing the flood risks and spatial distributions under different return-period floods before and after the construction of detention zones,the effectiveness of flood control and disaster mitigation was evaluated.The results indicate that:under various return-period flood scenarios,the foothill detention zones along the Beisha River can significantly reduce downstream flood peaks,inundation extent,and water depth,thereby lowering regional flood risk;the overall mitigation effect is constrained by the scale of the detention zones—under the 20-year flood scenario,the Beisha River detention zone achieves the highest mitigation benefit,reducing GDP losses by 27.55%,followed by 22.45%under the 50-year design flood;numerical simulation of flood processes provides an effective means to quantitatively analyze and assess the mitigation performance of planned or ongoing flood control projects,through comparative analysis of flood risks before and after project implementation.