Institute for Technology and Resources Management in the Tropics and Subtropics (ITT), Technische Hochschule Köln, Betzdorferstr. 2, 50679 Cologne, Germany; Higher Council for Environment and Urban and Rural Promotion, Khartoum State, Sudan.
Institute for Technology and Resources Management in the Tropics and Subtropics (ITT), Technische Hochschule Köln, Betzdorferstr. 2, 50679 Cologne, Germany.
Sci Total Environ. 2017 Dec 1;601-602:1031-1045. doi: 10.1016/j.scitotenv.2017.05.260. Epub 2017 Jun 9.
This study aims at enabling the compilation of key lessons for decision makers and urban planners in rapidly urbanizing cities regarding the identification of representative, chief causal natural and human factors for the increased level of flash flood risk. To achieve this, the impacts of flash flood events of 2013 and 2014 in the capital of Sudan, Khartoum, were assessed using seven integrated approaches, i.e. rainfall data analysis, document analysis of affected people and houses, observational fieldwork in the worst flood affected areas, people's perception of causes and mitigation measures through household interviews, reported drinking water quality, reported water-related diseases and social risk assessment. Several lessons have been developed as follows. Urban planners must recognize the devastating risks of building within natural pathways of ephemeral watercourses. They must also ensure effective drainage infrastructures and physio-geographical investigations prior to developing urban areas. The existing urban drainage systems become ineffective due to blockage by urban waste. Building of unauthorized drainage and embankment structures by locals often cause greater flood problems than normal. The urban runoff is especially problematic for residential areas built within low-lying areas having naturally low infiltration capacity, as surface water can rapidly collect within hollows and depressions, or beside elevated roads that preclude the free flow of floodwater. Weak housing and infrastructure quality are especially vulnerable to flash flooding and even to rainfall directly. Establishment of services infrastructure is imperative for flash flood disaster risk reduction. Water supply should be from lower aquifers to avoid contaminant groundwater. Regular monitoring of water quality and archiving of its indicators help identify water-related diseases and sources of water contamination in the event of environmental disasters such as floods. Though the understanding of risk perception by the locals is an important aspect of the decision making and planning processes, it should be advanced enough for proper awareness.
本研究旨在为决策者和城市规划者在快速城市化城市中提供关键经验，以确定导致突发洪水风险增加的代表性主要自然和人为因素。为了实现这一目标，利用七种综合方法评估了 2013 年和 2014 年苏丹首都喀土穆的突发洪水事件的影响，这些方法包括：降雨数据分析、受影响人群和房屋的文件分析、在受灾最严重的洪水地区进行观测实地工作、通过家庭访谈了解人们对原因和缓解措施的看法、报告的饮用水质量、报告的与水有关的疾病以及社会风险评估。以下是得出的一些经验：城市规划者必须认识到在短暂水道的自然通道内建造房屋所带来的破坏性风险。他们还必须在开发城市地区之前确保有效的排水基础设施和地形学调查。现有的城市排水系统因被城市废物堵塞而变得无效。当地居民未经授权建造排水和堤坝结构经常会导致比正常情况下更大的洪水问题。城市径流对建在自然渗透能力低的低洼地区的住宅区特别成问题，因为地表水可以迅速在洼地和凹陷处收集，或者在抬高的道路旁收集，这些道路阻止了洪水的自由流动。薄弱的住房和基础设施质量特别容易受到突发洪水和甚至直接降雨的影响。建立服务基础设施对于减少突发洪水灾害风险至关重要。供水应来自较低的含水层，以避免受污染的地下水。定期监测水质并归档其指标有助于在发生洪水等环境灾害时识别与水有关的疾病和水污染来源。尽管当地人对风险的理解是决策和规划过程的一个重要方面，但为了提高认识，还需要有足够的了解。
