基于MIKE FLOOD模型的小流域山洪内涝协同治理研究

Research on Synergistic Governance of Mountain Floods and Waterlogging in Small Watersheds Based on MIKE FLOOD Model

摘要:

针对小流域山洪成灾快、强度高、破坏大并易进一步引发城市内涝的问题，以杭州市半山小流域为研究对象，开展内涝风险评估与山洪内涝协同治理方案研究。基于MIKE FLOOD构建一、二维耦合水动力学模型，利用实测降雨数据对模型进行验证，评估内涝风险等级；针对不同类型内涝成因，提出协同治理方案，并考虑超标降雨的应对措施。结果表明：在50年一遇工况下，半山小流域因截洪沟系统不完善、雨水管渠排水能力不足、部分地块地势低洼等因素，内涝风险较为严重。通过新建截洪沟、改造雨水管道、抬高地势等治理措施，可有效降低洪涝风险；针对超标降雨，需构建涝水行泄通道，并完善灾前预防、灾时抢险与灾后恢复的全过程应急管理。

Abstract:

In view of the problems that mountain floods in small watersheds cause disasters quickly, have high intensity, cause great damage and are prone to further trigger urban waterlogging, taking the Banhan Small Watersheds in Hangzhou City as the research object, the research on the risk assessment of urban waterlogging and the synergistic governance scheme of mountain floods and waterlogging is carried out. The one-dimensional and two-dimensional coupled hydrodynamic models are established based on MIKE FLOOD, and are validated using the measured rainfall data to assess the risk levels of waterlogging. The synergistic governance schemes are proposed according to different causes of waterlogging, and the countermeasures for excessive rainfall are considered. Results show that under the once-in-50-year condition, the Banshan Small Watershed is at a relatively serious risk of waterlogging due to factors such as an incomplete flood interception ditch system, insufficient drainage capacity of rainwater pipes and channels, and low-lying terrain in some plots. Implementing measures such as constructing new flood interception ditches, upgrading rainwater pipelines, and elevating terrain can effectively reduce flood and waterlogging risks. Aiming at the excessive rainfall, it is necessary to build waterlogging drainage channels and perfect the full-process emergency management covering pre-disaster prevention, emergency rescue during disasters and post-disaster recovery.