Griffith_Aerodrome Overland Flow Flood Study

#INTRODUCTION#\r\n\r\nIn recent years, small duration heavy intensity rainfall events associated with thunder storms have shown that the Griffith Aerodrome and associated infrastructure are exposed to some potentially destructive, and certainly disruptive, flood risk. In order to quantify the flood risk and then to propose measures which may protect the aerodrome and associated facilities in the event of a flood, Griffith City Council (GCC) have appointed WMAwater to carry out a flood study. The Department of Environment, Climate Change and Water (DECCW) is providing financial assistance towards the flood study.\r\n\r\nThe main objective of this study is to:\r\n\r\n* Define the overland flow flood behaviour within the aerodrome catchment (refer to Figure 1 for the location of the study area). The principle focus is on those buildings that adjoin the aerodrome facility, i.e. hangers and administrative buildings, as well as the runway itself, and\r\n* Preliminary assessment of mitigation measures.\r\n\r\nThe study seeks to establish suitable hydrologic and hydraulic model tools, demonstrate their capacity to emulate local flood behaviour via calibration/validation (as data allows) and then apply these tools to establish the existing flood risk for a range of design flood event probabilities in conjunction with a range of event durations. Following design flood modelling for the existing conditions, a damages assessment for the aerodrome will be carried out. The above work will establish the flood liability of the aerodrome under exisiting conditions.\r\n\r\nThe model will then be utilised to test preliminary mitigation measures. Mitigation measures will seek to reduce the degree of inundation of the aerodrome and associated infrastructure and therefore reduce the flood damages associated with an extreme event. Mitigation options could potentially be quite varied however two that spring to mind in this case are detaining flood water upstream of the aerodrome or diverting it prior to its entry into the aerodrome area.\r\n\r\nThis report details the investigations, results and findings of the Flood Study. The key elements of which include:\r\n* a summary of available data;\r\n* model development;\r\n* calibration of the hydraulic model;\r\n* definition of the design flood behaviour for existing conditions through the analysis and interpretation of model results; and\r\n* testing limited mitigation options.\r\n

#引言#

近年来，与雷暴相关的短历时强降雨事件频发，已凸显出格里菲斯机场（Griffith Aerodrome）及其配套基础设施面临着潜在破坏性且无疑会造成严重干扰的洪水风险。为量化该洪水风险并提出可在洪水事件中保护机场及配套设施的应对措施，格里菲斯市议会（GCC）委托WMAwater开展本次洪水研究，环境、气候变迁与水利部（DECCW）为该研究提供资金支持。

本研究的核心目标如下：

* 明确机场汇水区内的坡面洪水演进特性（研究区域位置参见图1），主要关注点为毗邻机场设施的建筑（即机库与行政办公楼）以及跑道本体；
* 对防洪减灾措施开展初步评估。

本研究旨在构建适配的水文与水力学模型工具，通过率定与验证（在数据允许范围内）验证其模拟本地洪水演进特性的能力，随后运用这些工具，针对一系列设计洪水事件概率及对应历时场景，确定现状条件下的洪水风险水平。在完成现状条件下的设计洪水模拟后，本研究将开展机场洪水损失评估，上述工作将明确现状条件下机场面临的洪水风险责任。

随后，本研究将运用该模型对初步拟定的防洪减灾措施进行测试。减灾措施的目标是降低机场及配套基础设施的淹没程度，从而降低极端洪水事件带来的损失。减灾方案类型多样，本研究初步考虑的两类方案为：在机场上游拦蓄洪水，或在洪水进入机场区域前将其导流改道。

本报告详细阐述了本次洪水研究的调研过程、成果与结论，其核心内容包括：
* 现有可用数据汇总；
* 模型构建；
* 水力学模型率定；
* 通过分析与解读模型结果，明确现状条件下的设计洪水演进特性；
* 对有限的减灾方案开展测试。