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A lot to lose

Hong Kong’s economic success story could be swiftly undone if the government fails to respond to growing flood risks, argue Faith Chan, Adrian MacDonald and Gordon Mitchell.

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In July, a torrential rainstorm linked to Typhoon Chanthu slammed into Hong Kong. More than 150 millimetres of hammering rain fell in an hour, causing flash floods that killed three people and damaged 3,000 houses. Such events are likely to become more common. Climate change is making many of the world’s coastal cities increasingly vulnerable to flooding from the effects of sea-level rise, intensified typhoons, storm surges and rapid urbanisation. Hong Kong, located on the South China Sea, is one of these. The flooding this summer served as a reminder that the government’s heavy engineering-led approach to managing the risks needs revamping.

Since the 1960s, the city has seen 136 severe storms, with six to seven typhoon cyclones affecting the region every year, often causing flooding. Over the last three decades, more than 380 people have died in floods, and there have been major financial losses. A single storm in May 1992 caused more than 100 million HKD (US$12.9 million) worth of damage to properties, fish ponds, farmlands and telecommunication utilities.

After this event, the Hong Kong government established the Drainage Services Department (DSD), with the primary purpose of overseeing flood management. So far, the DSD has invested over 20 billion HKD (US$2.6 billion) in improving flood infrastructure, and engineering technological solutions. But, as Typhoon Chanthu has shown, this engineering-led approach is inadequate. Sustainable flood risk management, using concepts such as “living with floods” or “making space for water”, being applied in countries including the United Kingdom, offers more options for achieving a win-win strategy on flood mitigation, socio-economic development and the environment. These strategies may provide Hong Kong and the wider Pearl River Delta with useful insights. 

Hong Kong, often dubbed Asia’s world city, is one of the most important global financial centres. In 2009, its per capita GDP was US$42,800 – the fifteenth largest in the world. It was also ranked as the fifth most expensive big city on the planet in 2008. But this high-value property faces increasing risks. About 424,000 people and 100 billion HKD (US$12.9 billion) are currently vulnerable to storms in Hong Kong – the seventh highest economic exposure level to such weather events in the world, according to the World Health Organization Collaborating Centre for Research on the Epidemiology of Disasters (CRED).

Much of Hong Kong’s landscape is hilly, which limits urban development in many places and has led planners to create more space through land reclamation in flood-prone districts. A population of over 7 million is settled along the lower-lying costal area. There is a tension here: while the Hong Kong Government has realised the region’s vulnerability to flooding, it is keen to develop the area most in danger – and attempts to ameliorate the flood risk have so far been poor.

The tragic loss of life this July was a wake-up call – and a reminder that more challenging future is on its way. Storms, along with sea level rise and heavy rain will be more frequent in light of climate change. The Hong Kong observatory (HKO) reports that total annual rainfall in Hong Kong has risen in the last 50 years from 226.5 centimetres in the 1950s to 251.8 centimetres between in the 1990s. Moreover, the return period for torrential rainstorms shortened between 1900 and 2008. In this context, and despite the red-hot property market, planners must stop building in Hong Kong’s flood-prone area. We should accept the fact that flooding is hard to control and be prepared to “live with floods” and provide more space for flood storage.

The United Kingdom offers useful lessons here. The country has had some serious flood events in the past century and its flood-management policies are worthy of note. Importantly, the country’s strategies recognise that future climatic change is unpredictable; that flooding is a part of nature; and that we are no longer only using hard engineering to control floods, but also need to apply adaptation to enable communities to cope with risks.

The United Kingdom’s overarching policy statement on this issue (Planning Policy Statement 25, or PPS25) offers more options on flood mitigation. It includes the concept of “making space for water”, aiming to give more space for flood restoration and restricting development plans in high-risk areas. The best approach is to plan before building, hence the PPS25 ensures that the assessment process and sustainability appraisal consider social, economic and environmental aspects in all development projects. It then further appraises the cost-benefits, with broad engagement from all stakeholders through public participation.

Public participation is key to progress. The Coastal Flood Management Plan (CFMP) in England’s Humber Estuary is a good example. The CFMP has welcomed members of the local community and NGOs onto the committee that assesses the project’s progress. There is no doubt that this level of public participation in the decision-making process can increase the time it takes to take a project forward. On the other hand, it provides dynamic, open and interactive approaches that ensure a scheme really engages with local concerns surrounding flood management and helps to minimise any bias on the perception of flood-management processes. The authorities can also learn from the process, for example using residents’ knowledge of local flood history to supplement their computational models.

Back in Hong Kong, most of the work carried out under the DSD’s core strategy – the 1996 Drainage Master Plan (DMP) – has been engineering-led. Its projects have included widening and straightening the main river streams, such as the Shenzhen River and Kam Tin River, in the New Territories, one of Hong Kong’s three main regions; building underground sewerage; restoring ponds for collecting flood water; and monitoring the hydraulic conditions of main urban drainage.

As a result of this narrow focus on technological solutions, today it is almost impossible to find any "natural streams" in Hong Kong as nearly all the rivers have been converted into artificial channels. The sustainability implications of these engineering projects are often not fully considered and research has already shown that river regulation works have caused negative ecological impacts. For example, following 1997 flood-engineering works in the Deep Bay area – a wetland area of high ecological value and an important habitat for birds – 346,000 square metres of fishponds were found to be at risk of disappearing. In addition, as a result of 1990s river regulation, 11 out of a total of 32 local freshwater fish species are now threatened with extinction.

The DSD has, to an extent, realised its mistakes and has started to experiment with ecological restoration in concrete channels located in the Yuen Long floodway. The main idea is to compensate environmental loss and rebuild the wetland habitat by, for example, installing reed-beds and building water ponds for birds, freshwater fish, frogs and dragonflies. This might point towards a more sustainable approach to flood management, but progress is relatively slow – and there are no other restoration projects on concrete channels currently being undertaken.

The DSD’s approach to information sharing also raises concerns. The organisation has conducted flood-risk modelling and mapping of intensive rainfall in highly populated areas since the early 2000s, and has released information on flooding black spots to the public. But, collectively, the spots only cover a small area and vital information is not made available. The DSD needs to provide more transparent flood-risk data to enable the public to prepare for floods. This happens elsewhere in the world, for instance in Australia, where flood mapping provides detailed risk data by location.

Furthermore, the DSD’s focus is largely limited to urban and rural issues, even though Hong Kong is also exposed to coastal inundations, as flooding in the fishing town of Tao O has shown. Monitoring sea and tide level falls to the HKO, while the Civil Engineering and Development Department (CEDD) deals with seawall maintenance and beach improvement. Governance of coastal-flood management in Hong Kong remains blurred and adequate strategies and policies are still lacking, even as the dangers increase. Here, and at every level of Hong Kong’s flood-risk management, a more coherent approach is needed. Now, more than ever, it is necessary to formulate a long term and sustainable flood-management strategy for Hong Kong and the wider Pearl River Delta.

Faith Chan is a research cluster associate, Gordon Mitchell senior lecturer and Adrian MacDonald professor, all at the School of Geography, University of Leeds.

Homepage image from Marc Oh!


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Better late than never

Ten years ago I saw a commercial about the dangers of landslides continuously broadcasted on a Hong Kong TV station, and it was shown for many years. But it only told people not to go out when there was flooding. Although we say it's not too late to "fix the pen after a sheep has been lost", but we are always fixing the pen when sheep are lost and it's been ten years and no lessons for defensive measures have been learned. There is no use fixing the pen when all the sheep have been lost.

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Reply to the comment

Hi, many thanks for your comment. I am not having any bias to defend with the Drainage Service Department, but somehow we need to give some credits to them. They have done a lot of engineering works on flood protection over two decades from 1989. We are yet to know the flood risk in Hong Kong due to lack of the open flood risk information, such as flood map for the public access. However, I do believe the inland and urban flood risk are largely reduced after many flood mitigation projects have been completed.

However, I would like to emphasis the flood management strategies based on the hard engineering approach has been expired, evidences have been well-proved globally, i.e. 1993 Mississippi flood in the USA.

As you mentioned, we really need a comprehensive, long term and sustainable flood risk management strategy to be prepared for the future, i.e. climate change. It is because we may no longer afford to be flooded in light of the huge economic growth and rapid urbanisation process in the Pearl River Delta. We may need to PLAN for the flood risk before the disaster comes. Otherwise, it will be too little too late.





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文章不错,但最好换一个角度思考。从别人的角度,政府的角度,中国传统文化的思考。文章把Civil Society的概念,在洪水防范这个题材上表现出来,力图追求一个经济,社会,生态三赢的解决洪水模式。想法不错。但是洪水防范是牵一发动全身的事情。应该多从政府和现实的角度出发,才有实用性。香港地太少人太多,跟英国很难相比。给水留空间就是给人少留空间。有我没你。更关键的是留多少空间才够。当然空间越多越好,但是人住哪里?现在排水渠有的也非常大,花费大量人力物力。这说明政府想解决问题,也可以花钱。排水渠再大,它也有限。而且简单易行,十米不够,二十米,二十米不够,五十米。排水渠占用面积而造成的直接和间接成本,可以简单计算,方便规划。如果采用“给水留空间”的模式,需要非常多的技术支持,如细致的洪水基础数据,可靠的数据模型等。再加上公众参与和讨论,众说纷纭。决策过程长不说,也不一定有一致的最终结论。在一个精英文化流行的香港社会,掌权的精英,政府的精英当然不会容忍上面的情况发生。因为这代表低效率和侮辱精英专家智慧。如何解决上述问题和情况,作者应该多想想。公众参与是否应有一个相对固定的流程,如果最后众说纷纭,如何裁判和得出最终结果。更关键是多考虑本地实际情况和政府考虑。不然作者的文章就象洪水一样,来的时候雷霆万钧,走的时候踪影全无。

Nice article, but too westernized

Such a good article, but it would be better if we adopt the perspective of others, of the government, or of the traditional Chinese culture to ponder over the issue. The article applies the concept of “Civil Society” to flood prevention for the purpose of formulating a flood solution model which brings about a win-win situation for economy, society and ecology. It’s a great idea. Nevertheless, flood prevention is a matter where one move will introduce a chain reaction. Practicality cannot be achieved until a realistic governmental perspective is employed. Hong Kong is hardly comparable to Great Britain due to its huge population over limited land. Leaving more space for the water means less space for people. It’s a neither-you-nor-me situation. And a more important issue is how much space is enough. Definitely more space, the better. Then another problem pops up----where should the people live? At present, some drainage channels are pretty big in size, consuming tremendous manpower and materials. It demonstrates the government’s decisiveness to solve the problem and willingness to spend. Drainage channels are still limited no matter how big they are. But it’s easy and feasible to make adjustments. If ten meters are not enough, twenty meters will do; if twenty meters do not work, then fifty meters. The direct and indirect cost caused by land appropriation for the channels can be easily calculated and is easy to be planned. If the model “More Space for Water” is adopted, a lot of technological support is needed, such as detailed basic statistics of floods, reliable data model etc. Meanwhile, opinions are widely divided because of the participation of the public in the discussion. As a result, the decision process will be time consuming. Besides, a final agreed conclusion might also be up in the air. In Hong Kong, a society where elite culture prevails, elite in power and the government certainly won’t allow the situation mentioned above, happen. Otherwise it will be an indicator for low efficiency and an insult to the wisdom of those elites. The author should ponder more over how to solve these problems and situations mentioned above. Is there any necessity for a comparably stable procedure to regulate the participation of the public? Given that opinions are varied, how to make a judgment so as to achieve the final conclusion? It is more important to give more attention to the local reality and government. Otherwise this article will be like a flood: Come and roar like a thunderbolt while leave and go with nothing left.

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Firstly, Your comments is so good, but don’t forget this is a very short article mainly aim to voice out the flooding problems in Hong Kong and the Pearl River Delta Region. I have no intention to provide any further options, strategies and ideas. However, that is nice to re-think of your idea. To response of your feedback, it has a few points to reply as follow:

1. The concept of civil society and the importance of planning in flood management practice

Yes, civil society is a big concept to follow, you have to consider the principle of environmental justice as well if we are talking about the long term flood risk management strategy coping with sustainable development.

" As pressure from civil society to address perceived environmental inequalities is growing, it is important to understand the nature and extent of any such inequalities" (Walker et al., 2003).

In fact, your view is correct the land use distribution in Hong Kong is stressed, it thus need a comprehensive planning system including flood management. Limitation on land area is surely a matter, but we are suggesting the government and policy maker not to build on the flood plain which is a feasible option, as it is harder to predict the emerging flood risk. Most of the natural or human induced wetland buffer areas in the new territories have been functioned like this for most of the time, the Planning Department of Hong Kong has followed the Outline Zoning Plan (OZP) and clearly identified the restriction of development on the rural area. We are basically asking the government to keep such this kind of land for the concern of the pressure of drainage system and consideration of the natural services (i.e. birds and biodiversity). To achieve a better life wellbeing, a substantial of green space is essential in the city. Then, to conserve the natural wetland or wetland buffer area in Hong Kong can lead to carry out the win-win strategy for the socio-environmental aspects. That is the reason why the article suggested we may have to think about a comprehensive planning and flood risk appraisal (FRA) system may help us to achieve the sustainable and long term flood management practice with social, ecological and economical considerations by referring the UK case (e.g. Planning Policy Statement 25 in England).






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Point of penetration

This is a very long article which talks of many things. If we begin according to the author's meaning, then this is a large-scale, comprehensive project which necessitates joint efforts by many experts in the fields of economics, the environment, planning, meteorology, geology, and so on. You can imagine the degree of difficulty. Because the issue relates to so many different things, it would be unrealistic to attempt to undertake everything together, at the same. Selecting a point of penetration is very important and I believe that mass participation is a good motivational force. Not all Hong Kong ministers, from the period of British colonialism to the present day, have been democratically elected, however every important minister has had an outstanding CV, has been highly educated and has been an elite model (not excluding the impact of the political intention of the central government on some people's positions). They have good grounds for proposing this approach to overcoming floods - it is reasonable and is based upon careful consideration of prior events. But why are people not necessarily supportive, or even in fierce opposition to this method? Let's not talk about who is right and who is wrong, what we need to do first of all is communicate. We can only begin discussions once both parties understand each other's opinion. There is a huge need for a mechanism and platform for mass participation. This platform not only gives governments and the people a means of communication, but also gives academic experts on either side an opportunity to voice their expert opinion. This won't undermining the government or create difficulties, it will make sure that the people better understand the ideas behind government policies whilst also giving the government a better insight into their citizens' experiences. Under the guidance of academic experts, a scientifically rational, unanimous conclusion will be reached with relative ease.

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Reply to the comment (cont.)

2. Limitation from hard engineering flood protection approach and FRA system

Moreover, most of the urbanised cities in the world are suffering from the urban flooding by the effectiveness and efficiency by their land drainage system, for example, urban drainage system will be affected by the waste or pollution matters for the dust and litters block the inlet of manholes. It then implies the core problems are not due to the techniques of stormwater or drainage engineering, i.e. enlargement of drainage culvert and flood storage system; or the level of flood protection infrastructure e.g. flood wall installation, etc. Such the similar problems has experienced from Sao Paolo in Brazil. It has been noticed that Hong Kong has spent over 20 billion Hong Kong Dollars on flood infrastructure projects, i.e. river channelization, urban drainage and various flood engineering approaches. I understand some flood-plain areas in Hong Kong that have been well developed with properties, then it has to rely on hard engineering FRA approaches for flood mitigation. But as I mention in the article, the Drainage Service Department has started to adapt the sustainable options such as applying Sustainable Urban Drainage System (SUDs) in their latest flood management practice.

In light of climate change, the future climatic regime is difficult to be predicted, i.e. sea-level rise, land subsidence, frequencies and intensities of storm, precipitation rate, etc. For the long term flood management strategy, we need to seek for a variety of adaptation options on flood management practice. Through the appraisal system such as Strategic Environmental Assessment, Biodiversity Action Plan, Ecosystem Services assessment, etc.

Actually, I agree with your comments on penetration point, we may need to enhance the engagement and consultation process for a good communication between stakeholders in the Flood risk Appraisal. That is certainly including the public as you have mentioned. After the consultation process, it will then helpful to transform all outcomes in the flood risk appraisal into the provisional plans and policies on improving the current flood management practice.

The flood risk appraisal approach provides options, legislative guidance and policy outcomes Therefore, We can deliver a wide range of criteria and concerns from social, economical and ecological aspects after the appraisal process coping with the planning policy to achieve sustainable flood risk management in the PRD region.