Due to the increasing frequency and severity of storm events, driven by the escalation of anthropogenic climate change and urban expansion, there is a requirement for increasingly efficient flood risk management strategies. While Blue-Green Infrastructure (BGI) offers a sustainable solution for managing flood risk, optimal implementation is challenging. To help overcome this challenge, this study presents a novel multi-objective optimisation tool that couples a state-of-the-art hydrodynamic model with a bespoke evolutionary algorithm. The use of a fully dynamic hydrodynamic model enables the tool to accurately evaluate the effectiveness of proposed BGI features with respect to property scale flood vulnerability and hazard analysis. This contrasts with alternative approaches which utilise simplified models, which can only reliably predict inundation extents, thus the proposed optimisation tool provides greater certainty regarding the optimality of the solutions. As a hydrodynamic simulation is required to evaluate each candidate solution, the bespoke evolutionary algorithm is specifically designed to minimise the number of simulations required, ensuring the tool is computationally practical. The effectiveness of the tool in this regard is validated via the derivation of exact convergence measures, for a tractable search space, and via comparisons with benchmark algorithms, for an intractable search space. Compared with traditional design practices, the proposed tool offers an automated approach capable of efficiently exploring a wide range of solutions, providing decision-makers with a set of optimal solutions from which they can make informed investment decisions. The presented methods provide a robust framework for optimising a variety of BGI features in complex urban environments.

翻译：鉴于人为气候变化加剧和城市扩张导致暴雨事件频率和强度持续上升，亟需更为高效的洪水风险管理策略。尽管蓝绿基础设施（BGI）为洪水风险管理提供了可持续解决方案，但其优化实施仍面临挑战。为应对这一难题，本研究提出了一种新型多目标优化工具，该工具将最先进的水动力学模型与定制化进化算法相结合。通过采用全动态水动力学模型，该工具能够从建筑尺度的洪水脆弱性和危险性分析角度，准确评估拟建BGI措施的有效性。这与采用简化模型（仅能可靠预测淹没范围）的替代方案形成鲜明对比，因此本优化工具能为解决方案的最优性提供更强确定性。由于需通过水动力学模拟评估每个候选方案，定制化进化算法专门设计用于最大限度减少所需模拟次数，从而确保工具的计算可行性。通过可解搜索空间中精确收敛指标的推导，以及不可解搜索空间中与基准算法的对比验证，该工具的有效性得到确认。相较于传统设计方法，本工具提供了一种能高效探索广泛解决方案的自动化方法，为决策者提供一系列最优方案，助力其制定明智的投资决策。所提出的方法为复杂城市环境中各类BGI措施的优化提供了稳健框架。