This study proposes a novel comprehensive hydrodynamic flood modelling framework over Mithi river watershed in Mumbai, India, a coastal urban area, to reduce the inundation extent by incorporation of different inland hydraulic scenarios. First, the study addresses the issue of data scarcity by adapting alternate robust techniques to estimate design rainfall, tidal elevation and discharge, the key inputs for a flood model. Following that, a three-way linked flood model has been developed in the MIKE FLOOD platform, considering river, stormwater, overland flow and tidal influence to generate flood inundation and subsequently hazard maps for various inland hydraulic scenarios, by incorporating different feasible cross-sections and lining materials. The flood inundation and hazard maps have been derived for 10-, 50and 200-year return periods of design rainfall, discharge and tide to identify the best possible flood-reducing hydraulic scenario. It is observed that a ‘trapezoidal river cross-section lined with concrete’ relatively maximizes the reduction in flooding extent. The proposed framework can be implemented as an effective flood mitigation strategy in data-scarce, densely populated and space-constrained areas.

中文翻译：

---

通过沿海城市流域的三向关联水动力建模框架对潜在的内陆洪水管理方案进行绩效评估

本研究在印度孟买沿海城市地区 Mithi 河流域提出了一种新的综合水动力洪水建模框架，以通过结合不同的内陆水力情景来减少淹没程度。首先，该研究通过采用替代稳健技术来估算设计降雨量、潮汐高程和流量（洪水模型的关键输入）来解决数据稀缺问题。随后，在 MIKE FLOOD 平台中开发了三向关联洪水模型，考虑河流、雨水、地表流和潮汐影响，通过结合不同的可行横截面，产生洪水淹没以及随后的各种内陆水力情景的灾害图和衬里材料。洪水淹没和灾害图已导出为 10-，设计降雨、流量和潮汐的 50 年和 200 年重现期，以确定可能的最佳减洪水力方案。据观察，“用混凝土衬砌的梯形河流横截面”相对最大程度地减少了洪水泛滥程度。在数据稀缺、人口稠密和空间受限的地区，提议的框架可以作为一种有效的洪水缓解策略来实施。