Floods and typhoons are two of the greatest water disasters affecting South East Asia, causing misery and death to people, damaging properties, infrastructure and crops, and causing disruption to commerce and industry. In many cases the impact can be widespread, affecting not only individual households but also large parts of a country including agriculture areas, towns and cities, and sometimes even beyond national borders. The rapid pace of development has resulted in a disproportionate increase in runoff and a many-fold increase in river discharges leading to more frequent and more intense flooding. This situation is expected to be further aggravated due to the impact of global warming and climate change. To cope with such challenges, countries in South East Asia are developing their policy responses tailored to suit their local conditions and environment. This paper looks at the water disaster situation and the policy responses in three cities in South East Asia: Bangkok, Kuala Lumpur and Metro Manila, the capital cities of the Kingdom of Thailand, the Federation of Malaysia and the Republic of the Philippines, respectively. Although all three countries are in the same climatic zone, due to their geographical locations, water disasters impact differently on them and the remedial measures also differ.

Introduction

Floods and typhoons are two of the greatest natural disasters affecting mankind, causing misery and death to people, damaging properties, infrastructure and crops, and causing disruption to commerce and industry. In many cases the impacts can be widespread, affecting not only individual households but also large parts of a country including agriculture areas, towns and cities, and sometimes even beyond national borders. As an example, the Great Flood of Bangkok in 2011 affected the global supply chains for automobiles and computer hard disks. Floods are also a threat to a country or region achieving its full economic development potential, as investors are deterred from venturing into flood-prone areas.

The rapid pace of development in the ASEAN1 region has resulted in a disproportionate increase in runoff (that portion of rain that flows overland to a river) and a halving of the time of concentration (the time it takes for the runoff to reach the river). The consequence of this is a many-fold increase in river discharge leading to more frequent and more intense flooding (Figure 1). This situation is expected to be further aggravated due to the impact of global warming and climate change. The Intergovernmental Panel on Climate Change (IPCC) has assessed that there will be possible intensification of the hydrological cycle on a global basis, leading to increased frequencies and intensities of extreme weather events, i.e. floods and droughts will occur more frequently and will be larger and more intense and last longer. In the words of the UN Secretary General, Ban Ki-Moon, ‘The abnormal is the new normal.’

Fig. 1.

A three-fold increase in the mean annual flood of Klang River as a result of development of the upper catchment (Abdullah, 2006).

Fig. 1.

A three-fold increase in the mean annual flood of Klang River as a result of development of the upper catchment (Abdullah, 2006).

The traditional engineering approach to managing floods has been to try to ‘control’ the flood through structural measures. These have included the construction of flood storage dams and flood attenuation ponds, the deepening and widening of rivers to increase their capacities, and the protection of low-lying areas through the provision of river levees. Such an approach tends to be problem driven, where projects are implemented to reduce the risk of flooding in an area without giving much consideration to the impact of the projects on upstream or downstream areas. In many cases, such piecemeal solutions end up transferring the flood problem to another area.

In recent years, flood engineers have modified the approach to ‘mitigate’ (reduce the impact) rather than attempting to ‘control’ floods. This approach involves a combination of structural and non-structural measures. Non-structural or ‘soft’ measures include flood zoning, flood forecasting and warning, flood risk mapping and flood insurance. However, such measures have proven to be inadequate as flood mitigation works have been unable to keep pace with the rapidly increasing flood volumes arising from development and urbanization.

The challenge now is to focus on ‘adaptation’ (adjusting to changing situations), i.e. flood solutions have to be innovative, flexible and adaptable to changing situations. At the same time the solutions have to be viewed at a macro level and in the context of a river basin, so as to promote a holistic and integrated approach rather than being localized and fragmented. Such an approach integrates land and water resources development in a river basin and aims at maximizing the benefits to society while minimizing the damage from flooding.

Three cities, one region

The Association of South East Asian Nations (ASEAN) is a political and economic grouping of 10 countries located in Southeast Asia, and was formed on 8 August 1967 by Indonesia, Malaysia, the Philippines, Singapore and Thailand. Since then, membership has expanded to include Brunei, Cambodia, Laos, Myanmar and Vietnam (Figure 2). Its objectives include accelerating economic growth, social progress, socio-cultural evolution among its members, protection of regional peace and stability, and opportunities for member countries to discuss differences peacefully.

Fig. 2.

The 10 countries of ASEAN (see http://www.asean.org/).

Fig. 2.

The 10 countries of ASEAN (see http://www.asean.org/).

ASEAN covers a land area of 4.46 million km2, which is 3% of the total land area of the Earth, and has a population of approximately 600 million people, which is 8.8% of the world's population. In 2012, its combined nominal gross domestic product (GDP) had grown to more than US$2.3 trillion, which if ASEAN was a single entity, would rank it as the sixth largest economy in the world.

Bangkok, Kuala Lumpur and Metro Manila are the capital cities of Thailand, Malaysia and the Philippines, respectively. The city of Bangkok is located in the estuary of the Chao Phraya River which flows 372 km through the central plains of Thailand into the Gulf of Thailand, draining an area of 160,400 km2. The city of Kuala Lumpur was founded in the late 19th century as a tin mining settlement and is situated in the middle reach of the Klang River which originates from the central mountain range at an elevation of 1,330 m and traverses a distance of nearly 120 km before discharging into the Straits of Malacca, draining a catchment of about 1,288km2. Both cities suffer from flooding due to overflow of the Chao Phraya and the Klang rivers, respectively. Metro Manila which is located on the island of Luzon, sits astride the typhoon belt and experiences heavy torrential rains during the typhoon season from July to October.

Policy response to water disasters

Climate-wise, ASEAN lies in the humid tropics, defined as a zone located between latitude 23.5° north and 23.5° south and having monthly precipitation exceeding 100 mm per month for at least 4½ months. In fact, most of ASEAN lies in the monsoonal humid tropics, where more than half the year is wet and the annual rainfall ranges from 1,500 to 5,000 mm. As a result, floods are common during the monsoonal wet months.

Policy response – Bangkok

Bangkok is located in the estuary of the Chao Phraya River. The Chao Phraya begins at the confluence of the Ping and Nan rivers and flows south for 372 km from the central plains to Bangkok and into the Gulf of Thailand, draining an area of 160,400 km2. In the past, floods were a common occurrence especially during the monsoon season between May and October.

The policy response to deal with the floods was very much structural (or engineering) based, i.e. to store the flood waters upstream and release them for use during the dry season. As part of the flood management plan, three large dams were constructed: the King Bhumibol Dam (1964), the Queen Sirikit Dam (1972) and the Pasak Chonlasit Dam (1998). On completion, the three dams provided sufficient storage capacity to substantially reduce flooding in the central plain and the city of Bangkok. With the floods considered under ‘control’, less attention was given to improving the capacity of the Chao Phraya River downstream. In addition, many drainage channels in the city were deemed superfluous and converted into roads.

The monsoon of 2011 was unusually wet with accumulated precipitation exceeding the historical average by more than two-fold in some areas. The situation was further exacerbated by four tropical storms and one typhoon that hit the north and northeast late in the rainy season when normally there would be only two to three tropical storms. This resulted in the total amount of rainfall in the upper Chao Phraya River Basin being 30–60% higher than average. Consequently, the water levels in the three reservoirs not only reached historical highs but peaked some 2 months early, resulting in the need to release the excess flood waters downstream. This huge volume of water created a flood wave downstream which lasted for over 2 months.

The weakness in the flood management plan was that it could not cope with the very extreme series of hydrological events that occurred, and when the storage capacities of the three dams were exceeded, there was no back-up plan downstream. In the light of the IPCC's assessment that there will be possible intensification of the hydrological cycle leading to increased frequencies and intensities of extreme weather events, the ‘abnormal’ flood of 2011 may become the new ‘normal’ in the future.

Subsequent to the 2011 floods, the policy response of the Thai government has been to focus on three areas: infrastructure, management and climate change. In the area of water infrastructure, existing design concepts and criteria are being reviewed and upgraded, while the government has begun a huge programme estimated to cost around 100 billion2 bahts to repair, rehabilitate and upgrade the flood infrastructure. In terms of management, nature can no longer be taken for granted and ‘business as usual’ is no longer tenable. The planning process will now consider the entire spectrum of upstream to downstream factors and include consultations with all stakeholders to produce an over-arching flood and water management plan that mitigates, as far as possible, a recurrence of the 2011 catastrophic flooding.

To cope with changing climatic conditions, Thailand is looking to develop technologies in predicting/forecasting weather more precisely so that there will be sufficient time to take preventive and protective measures, and provide early warning to the population. For the long-term, people will have to learn to live under extreme hydrological events and adjust by building resilience capabilities in their communities and infrastructure.

Policy response – Kuala Lumpur

Kuala Lumpur is situated at the confluence of two tributaries of the Klang River and has, from the earliest days, been subjected to flooding, with the 1926 flood being the worst ever recorded. The Klang River is small by global standards, having a length of 120 km and a catchment area of only 1,288 km2. The river's headwaters comprise mountainous and steep terrain and, coupled with the intense level of precipitation, this results in large volumes of storm runoff even from small sub-catchments, which often leads to the river systems in the localized areas being completely overloaded. This causes what is termed as ‘flash’ flooding which is quick to manifest and equally swift to subside. This form of flooding is frequently experienced and can occur several times in a year. In addition, as a result of the extensive urbanization of the catchment up to the hill slopes, the severity and frequency of floods have increased over the years.

In the early days, the policy response was to ‘control’ floods through structural (engineering) measures, and a programme to channelize and dredge the river system was undertaken. However, from the 1970s, as Kuala Lumpur continued to transform into the ultra-modern metropolis it is today and as development kept changing the face of the city, the existing infrastructures came regularly under pressure to cope with flood flows beyond their design limits. This urbanization of the catchments in and around the city has resulted in flood runoffs increasing many fold, bringing with it challenges for the flood planners to come up with more innovative solutions.

One such solution was to construct a flood bypass to divert the flood flows away from the city centre. However, the topography of the land was such that a bypass alignment would cut through high ground as well as areas which were densely built-up, making the use of an open channel (open cut) prohibitive in terms of land acquisition and compensation costs. It was thus decided that the bypass should be a tunnel as this was more competitive in terms of pricing and would offer the least disturbance during construction. At the same time, it was realized that a flood bypass tunnel would be in use infrequently and hence by incorporating a road into the flood tunnel, value could be added to the project by introducing an additional function of helping to reduce the traffic congestion at the southern gateway of the city into the city centre.

The resulting Stormwater Management and Road Tunnel (SMART) project is the first project in Malaysia (and possibly in the world) to combine two contradicting uses in one tunnel, i.e. to pass flood waters and traffic through the same tunnel, albeit at different points in time. It was also funded through a new financing mechanism whereby the costs were shared between the government and the private sector, with public funds paying for the flood component and the private sector funding the motorway component. The private sector was given a concession to recover costs by charging a toll on motorway users and, in the process, help to defray public costs in operation and maintenance.

Policy response – Metro Manila

Sitting astride the typhoon belt and having a long coastline of 36,289 km, the Philippines archipelago is particularly vulnerable to tropical storms and typhoons. On average, up to 20 tropical storms enter Filipino waters annually, with about half of them making landfall. The most frequently impacted areas are Luzon Island and the eastern Visayas. The capital, Metro Manila, is situated on the island of Luzon and is ranked by the USA as the third most vulnerable metropolitan area on earth with the second most number of people at risk.

To some extent, Metro Manila is fortunate because of its geographical positioning whereby the rugged terrain surrounding the city has, in the past, effectively served as a windbreak. Two previous typhoons with wind speeds of more than 110 knots (200 km/h) fell to 75 knots (140 km/h) by the time they reached the city.

Typhoons bring heavy rainfall which, when combined with the strong winds and storm surges, can cause large-scale flooding and result in enormous destruction and loss of life. In the face of such daunting factors, it would be prohibitively costly to invest in the necessary defensive infrastructure to protect Metro Manila from typhoons. Instead, the policy response has been to focus on improving disaster preparedness and management.

Unfortunately, so far, city officials have shown a disheartening inability to cope with such disasters. In 2012, torrential rains hovered over the city for 8 days, causing citywide flooding, leaving 63 people dead and nearly 84,500 homes destroyed completely. Despite the fact that the storm hit the centre of government, it was weeks before the city could recover from the damage and destruction.

In the aftermath of Super Typhoon Haiyan, funding for disaster preparedness and management was increased by nearly 100 billion Pesos, or about 5% of the total national budget. However, while a portion has been spent wisely on more proactive and innovative disaster mitigation programmes such as hazard mapping, the bulk of the funds is earmarked for cleaning up, repairs and rehabilitation of the damage from Haiyan.

Case studies

The 2011 flood: Thailand's worst flood

Introduction

The Kingdom of Thailand is a country at the centre of the Indochina peninsula. It is bordered to the west by Myanmar, to the east by Cambodia and Laos, and to the south by Malaysia. Located in the humid tropics, Thailand has a total land area of approximately 513,000 km2 and a population of around 65 million people. The capital and largest city is Bangkok, which is Thailand's political, commercial, industrial and cultural hub. Over the past three decades, Thailand has experienced rapid economic growth and is now considered as a newly industrialized country.

The average annual rainfall in Thailand ranges from a high of almost 4,000 mm in the south to a low of 1,000 mm in the northern and central plains. The monsoon season takes place between May and October and the heavy rainfall during this period is a result of low pressure cells, depression storms, tropical storms and typhoons originating in the South China Sea and moving towards the Indochina region.

In the Chao Phraya River Basin, the average annual rainfall ranges from 966 to 1,259 mm per year (based on the past 30 years’ record). In 2011, the accumulated rainfall from January to November was 1,781 mm, which was approximately 30% higher than the average value. Table 1 gives the annual rainfall accumulation in Chao Phraya River Basin since 1978.

Table 1.

Average annual rainfall in Chao Phraya River Basin since 1978 (in descending order of magnitude) (Source:Anukularmphai, 2014).

Year 2011 1980 1995 1978 1983 
Average annual rainfall (mm) 1,781 1,145 1,161 1,151 1,129 
Year 2011 1980 1995 1978 1983 
Average annual rainfall (mm) 1,781 1,145 1,161 1,151 1,129 

The 2011 floods

The 2011 floods were the worst to ever hit Thailand. The flooding of the central plains of Thailand started in the month of June and progressed downwards towards Bangkok in the following sequence of events. During the months of March and May, Thailand had experienced a heavy monsoon season which was characterized by high rainfall. At the end of June, tropical storm Haima brought heavy and widespread rainfall to the northern part of Thailand causing flash flooding in five provinces including Chiang Rai, Phayao, Nan, Tak and Sukhothai.

In early August, tropical storm Nock-Ten hit the northern region bringing heavy rainfall to Nan, Uttaradit, Phrae and Pitsanulok provinces. By mid-August, the floods had reached Nakhon Sawan Province while the flooding situation remained critical in the provinces of Chiang Rai, Lamphun, Lampang, Sukhothai, Pitchit, Phitsanulok, Kamphaeng Phet and Nakhon Sawan.

By early September, the floods had reached Sing Buri, Chainat and Lopburi. Two weeks later the floods reached Ayutthaya. By early October, all of Ayutthaya province including Wat Chai Wattahanaram (a World Heritage site) was declared as a disaster area. The flood wave next reached Nonthaburi, causing breaches in the Hitech Industrial Estate dyke. A week later, the flood waters reached the Bangpa-In Industrial Estate and the Nava Nakhon Industrial Estate. On 25 October, the flood waters reached Don Muang Airport and the Flood Relief Operation Centre (FROC) which had to be evacuated and relocated to the Energy Centre. By early November, the flood waters had advanced to Lad Prao intersection, Lad Prao Road, Rama II Road and Ratchadapisek Road (near Bangkok's Ratchadapisek Metropolitan Rapid Transit (MRT) station).

Finally, on 17 November, the flood waters on Lad Prao Road, Ratchadapisek Road and near-by areas began to recede and by 28 November, the Inner Bangkok area was back to normal, with businesses and shopping malls reopened, except in the Lak Si, Don Muang, Phasi Chareon, Tawiwattana and Bangplad areas. Figure 3 shows the flood wave at various points along the Chao Phraya River.

Fig. 3.

Water level record along Chao Phraya River (Anukularmphai, 2014).

Fig. 3.

Water level record along Chao Phraya River (Anukularmphai, 2014).

From Radarsat images captured in the Chao Phraya Basin, it can be seen that at the early stages of flooding in July, the flooded areas were localized and scattered. Then, as flooding progressed towards the end of September, most of the flood waters were concentrated in the upper and lower Chao Phraya. Finally, it moved downwards as a huge mass of flood water towards Bangkok. It has been estimated that about 15,260 million m3 of flood waters were accumulated above Bangkok in October. This huge volume of water had to be drained into the Gulf of Thailand, mainly through the Chao Phraya River and its flood plain. The maximum combined outflow of the Chao Phraya river (300 million m3/day at the estuary) and the estimated drainage system capacity located on both sides of Chao Phraya (200 million m3/day) was only 500 million m3/day, which was relatively small in comparison to the total volume of flooded water. This was the basic reason why the flooding situation was prolonged for months in some of the most severely flooded areas.

The main cause of the floods was an unusually wet monsoon exacerbated by four tropical storms (Haima in June, Nock-Ten in August, Haitang in September and Nalkae in October) and one typhoon (Nasat in September) that reached the north and northeast of Thailand late in the rainy season. These storm events were unusual as normally there would be only two to three tropical storms per year. Preceding the floods, Thailand had already experienced a monsoon season which was characterized by high rainfall during the months of March and May, with accumulated precipitation exceeding the historical average value by 277% and 45%, respectively. Coupled with the precipitation from the four storms and typhoon Nasat, the total amount of rainfall in the upper Chao Phraya River Basin was 30–60% higher than the average (Figure 4). In the Bangkok area, the accumulated precipitation up to 1 December 2011 was 2,257.5 mm, while in comparison, in the past 50 years, the highest precipitation level recorded was only 1,973.5 mm.

Fig. 4.

Accumulated rainfall and major storm events in Thailand in 2011 (Anukularmphai, 2014).

Fig. 4.

Accumulated rainfall and major storm events in Thailand in 2011 (Anukularmphai, 2014).

The floods of 2011 affected 65 of the 76 provinces, 684 districts, 4,920 tambon and 43,636 villages and left heavy extensive damage along their path. In terms of population, 13,595,192 people from 4,086,138 households were affected, with 693 persons confirmed dead and 3 missing. The causes of death were drowning (580 persons), electric shock (48 persons), washed away by the floods (26 persons), boat sinking (23 persons) and others (16 persons). In an effort to cope with the flood-affected population, 1,739 evacuation shelters and stations were opened.

The negative impact on agriculture was significant with some 12.61 million hectares of farm land flooded. For the industrial sectors, 9,859 manufacturing plants with 600,000 factory workers were affected, with the flood damage estimated at 800,000 million baht. At least seven industrial estates were flooded, damaging 838 factories, affecting 382,693 factory workers and resulting in an estimated flood related cost of 403,784 million baht. The floods’ impact on academic institutions such as schools and universities was unprecedented with 3,088 schools disrupted and approximately 700,000 students affected.

In terms of culture and tourism, 313 historical ancient monuments and sites were damaged. In Ayutthaya province, home to numerous world heritage sites, 130 locations were affected. The economic losses for the tourism sector were estimated at 50,000 million baht, due to a 10% decline in tourist arrivals during and after the floods. The World Bank estimated the total economic damage at 1.4 trillion baht (approximately US$44.5 billion), slashing economic growth by 2.4% and making the 2011 Thailand floods the world's fourth costliest disaster, surpassed only by the 2011 earthquake and tsunami in Japan, the 1995 Kobe earthquake and Hurricane Katrina in 2005.

In addition, the impact of the floods was felt beyond the national borders, causing disruption to the global supply chain. Two particularly hard hit sectors were the automobile and computer manufacturing industries. In the automobile industry, two of the world's largest car manufacturers, Honda and Toyota, had severe disruption to their manufacturing processes, not just in Thailand but worldwide, due to a lack of parts. In the computer industry, Thailand was responsible for the manufacturing of about a quarter of all hard disk drives produced for the global market and the flooding of the factories resulted in a global supply shortage.

Policy response: pre-2011 floods

Being in the humid tropics, the need to deal with floods especially during the wet monsoon season, has long been recognized in Thailand. The policy response beginning in the 1950s was very much engineering biased, i.e. to construct three large dams: the King Bhumibol, the Queen Sirikit and the Pasak Chonlasit, to store the flood waters and release them for use during the dry season.

The Bhumibol Dam is a concrete arch-gravity dam on the Ping River, a main tributary of the Chao Phraya River. The dam is 154 m high, 486 m long and 8 m wide at its crest, and has an active storage capacity of 9,762 million m3. Construction began in 1958 and was finished in 1964 while the reservoir was completely filled in 1970. Located about 480 km north of Bangkok, the dam was built for the purposes of water supply and irrigation, hydroelectric power production, flood control, fisheries and saltwater intrusion management, and was Thailand's first multi-purpose dam project.

The Sirikit Dam, completed in 1972, is an embankment dam on the Nan River, the other main tributary of the Chao Phraya River. Built for the purpose of irrigation, flood control and hydroelectric power production, the dam is 113.6 m high, 800 m long 12 m wide at the crest and 630 m wide at the base. Covering a surface area of 259 km2, the dam reservoir has an active storage capacity of 6,666 million m3. Together, the Bhumibol and Sirikit Dams control 22% of the Chao Phraya's annual runoff and both dams also help provide for the irrigation of 1,200,000 ha of farmland in the wet season and 480,000 ha in the dry season.

The Pasak Chonlasit Dam is a 36.5 m high and 4,860 m long earthfill embankment dam with an impervious core, impounding the Parsak River. With a storage capacity of 785 million m3 at normal water level, and a maximum capacity of 960 million m3, it is the biggest reservoir in Central Thailand. Commissioned in 1998, the Pasak Chonlasit Dam project is one of Thailand's major irrigation projects, providing water to the plantations in the Pasak valley and the lower Chao Phraya valley. The dam also helps to decrease the problems of water management in Bangkok by allowing more flood control, as the Pasak River is one of the main sources of flooding in the Bangkok metropolitan area.

Collectively, the three dams act together to prevent or reduce the flooding of the lower Chao Phraya flood plain, including the city of Bangkok. Hence, the procedures and operations of the dams during the raining season are of paramount importance for reducing the flood risk to Bangkok. Over the years, a set of operation rule curves have been developed and prior to 2011, these rule curves managed to control the peak inflows within the capacities of the dams. However, the heavy rainfall and the unusual rainfall pattern of 2011 resulted in the dams reaching their maximum capacities some 2 months early, resulting in the need to release the excess flood waters downstream. Figure 5 shows the situation for Bhumibol Dam.

Fig. 5.

Operation rule curve of Bhumibol Dam (Anukularmphai, 2014).

Fig. 5.

Operation rule curve of Bhumibol Dam (Anukularmphai, 2014).

Policy response: during the 2011 floods

As the magnitude of the floods worsened, the government set up a Centre for Emergency Management and mobilized flood monitoring and relief operations. On 7 October 2011, a FROC was established to coordinate the delivery of aid. The FROC included all Ministries, the Bangkok Metropolitan Administration, the Army and other government agencies. It was led by the Minister of Justice who reported directly to the Prime Minister. The FROC administration consisted of two units, an operation team under the Minister of Science and Technology, and a planning and prevention team under the Minister of Transportation. After the FROC had successfully operated within Bangkok, similar organizations were established at the local level, led by the Provincial Governor.

On 20 October 2011, the Prime Minister ordered measures for a designated disaster area, as empowered under the Public Disaster Prevention and Mitigation Act (2007), for 21 provinces that were designated as disaster areas. On 25 November 2011, the government declared natural disaster mitigation and relief areas representing 58 provinces and Bangkok. In all, eight committees were established and charged with the various responsibilities for disaster relief and mitigation, as indicated in Table 2.

Table 2.

Establishment of committees and their responsibilities (Source:Anukularmphai, 2014).

Name of committee Responsibility Date of establishment 
1. National committee on floods, tropical storm and mudslides Oversee and manage national disasters due to floods, tropical storms and mudslides 25 August 2011 
Preparedness, prevention, response and recovery of all the major phases of disaster management 
2. Twenty-five river basin national joint-committee Support national water management and flood warning system 11 September 2011 
3. Flood Relief Operation Centre (FROC) Oversee all flood management effort focussing on the lower Chao Phraya plain 7 October 2011 
4. Flood relief committee (structural, economic, social subcommittee) Assist the population affected by flood disaster 12 October 2011 
5. Flood recovery and restoration committee Replacement of the flood recovery and restoration committee 4 November 2011 
To coordinate the flood relief management for structural, economic and industrial issues, and people's livelihoods and quality of life 
6. Public communication committee To improve public information of flood disaster to people 4 November 2011 
7. Strategic committee for reconstruction and future development Prepare strategies for reconstruction and national future of sustainable development 10 November 2011 
8. Strategic committee for water resources management Manage water resources with principles of sustainability 10 November 2011 
Name of committee Responsibility Date of establishment 
1. National committee on floods, tropical storm and mudslides Oversee and manage national disasters due to floods, tropical storms and mudslides 25 August 2011 
Preparedness, prevention, response and recovery of all the major phases of disaster management 
2. Twenty-five river basin national joint-committee Support national water management and flood warning system 11 September 2011 
3. Flood Relief Operation Centre (FROC) Oversee all flood management effort focussing on the lower Chao Phraya plain 7 October 2011 
4. Flood relief committee (structural, economic, social subcommittee) Assist the population affected by flood disaster 12 October 2011 
5. Flood recovery and restoration committee Replacement of the flood recovery and restoration committee 4 November 2011 
To coordinate the flood relief management for structural, economic and industrial issues, and people's livelihoods and quality of life 
6. Public communication committee To improve public information of flood disaster to people 4 November 2011 
7. Strategic committee for reconstruction and future development Prepare strategies for reconstruction and national future of sustainable development 10 November 2011 
8. Strategic committee for water resources management Manage water resources with principles of sustainability 10 November 2011 

In general, the government response during the floods could be characterized as somewhat adequate though some of the actions and decisions were reactive rather than proactive. The authority and roles of the numerous committees and working groups varied greatly due to timing, political forces and public responses. A significant gap was the lack of system integration and unity of command, as the various committees and working groups followed their traditional roles and responsibilities according to the legal framework under normal circumstances or non-disaster operating environments.

External and internal public communication were observed to be seriously challenged, especially when flood information requests became more complicated and increasingly area specific. Conflicting, and at times misleading, flood information was a normal occurrence with various agencies offering technical information that was either inaccurate or simply not given in a timely fashion. Consequently, there were several conflicts and incidents of protest in different forms including violence as the public took matters into their own hands to handle the floods in the best possible way that they thought was correct.

Overall, a lack of awareness and preparedness for natural disasters such as floods appeared to be one of the core challenges cutting across government, the private sector and civil society as a whole. As a result of this general lack of public awareness, housing and businesses had encroached into the flood plains at an unprecedented rate with little preparation or preventive thought for flooding or the effects thereof.

Policy response: post 2011 floods

The flooding of the central plains of Thailand, including Bangkok, began in late July 2011 and finally reached Bangkok in October 2011. Over this 3-month period, the flood wave left heavy extensive damage along its path. While the flooding was massive and the resultant disaster the worst in modern Thai history, the floods did provide an opportunity to review, analyse and assess the planning, response and actions at various stages so that valuable lessons could be learned for improving future flood prevention and water management for the country.

A major policy response is that flooding is no longer considered as just a natural occurrence, but one which is closely linked to human activities and socio-economic developments to meet the food, energy and infrastructure needs of an ever growing and demanding population. Unfortunately, in the haste to develop, the infrastructure designs have sometimes overlooked the impact of natural water flow and runoff, and their effects upon river and canal flows. One key observation of the 2011 floods was that the drainage canal systems in the central plain of Thailand could not handle the huge volume of flood waters. There is also greater recognition that many flood management infrastructures were simply inadequate in their engineering design parameters, outdated construction practices, and lack of regular operation and maintenance procedures towards flood protection. As a response, the government has now begun a huge programme estimated to cost around 100 billion bahts (US$3.3 billion) to repair, rehabilitate and upgrade the flood infrastructure.

In more general terms, the main causes for the recent floods were climate (namely rainfall), management and infrastructure. Therefore, flood management will now focus on approaches to better address these three main causes. Firstly, in the area of climate change, there is now greater awareness that extreme hydrological events will become more frequent and the perceptions, practices and policies of all concerned agencies, including decision makers and the decision-making cycle, should be reviewed and reassessed. To cope with such changing climatic conditions, Thailand needs to develop technologies to predict/forecast more precisely and in advance, the occurrence of rain storms and typhoons, and their intensities and expected impacts, so that there will be sufficient time to take preventive and protective measures and provide early warning to the population.

Secondly, in terms of management, nature can no longer be taken for granted and ‘business as usual’ is no longer tenable. With flooding becoming an ever greater challenge and the economic and social costs mounting, it is imperative that sound and timely flood management planning be undertaken. The planning process should consider the entire spectrum of upstream to downstream factors and include consultations with all stakeholders who are affected by flooding, with a view to preparing an over-arching flood and water management plan that mitigates, as far as possible, catastrophic flooding such as that witnessed in 2011. Moreover, it is essential that any plan strikes a balance between hard and soft engineering, and also recognizes the critical role that economic and urbanization influences will contribute to flood discharges, and the measures that the government should take to manage in a responsive way.

A policy response being considered is to pay greater attention to land use and watershed management. For decades, the rural population in remote areas have engaged in deforestation activities both for timber as well as to open up new areas for agriculture. In recent years, such practices have increased significantly due to the practice of mono-culture cash crops such as orchard, corn, rubber and palm oil. This problem is further compounded as the destruction of forests in the watershed area has not only increased the runoff leading to more frequent flash floods, but also caused heavy soil erosion and landslides leading to increased siltation of the reservoirs. Post 2011, there have been calls for an urgent national policy review on future agricultural watershed development to more adequately address the watershed land use challenge. At the same time, a comprehensive and more holistic flood water diversion management plan (which uses flood simulation extensively), combined with consultations with local stake holders, is being considered.

Henceforth, the principle of risk management will be the key to reduce the damage from extreme climatic events. Decision makers will need to set priorities with respect to social and economic sectors as well as potential affected areas so as to reduce overall damage. Furthermore, water resources will have to be managed in integration with other natural resources, and the principle of Integrated Water Resource Management should be applied and well understood.

Thirdly, with respect to the water infrastructures, the recent water-related disasters have highlighted the need to review engineering design concepts and design criteria by focussing more on flood protection and flood control. This is because many of the existing structures were designed and constructed based on normal hydrological conditions, while some did not take into consideration hydraulic conditions as well as the livelihoods of people around the affected areas. As such, it will be necessary to review and reset standards in response to climate change which will result in extreme hydrological events with which the old designs cannot cope. In addition, a review of town planning and zoning will also be necessary due to the fact that some communities or even industrial estates were wrongly located in the flood plain, as the planners had overlooked the risk of flooding. For the long term, people will have to learn to live under extreme hydrological events and adjust by building resilience capabilities in their communities.

In summary, living with floods in Thailand is not a new phenomenon and it is likely that the 2011 floods could be a good catalyst to remind government and communities that the time is now right to develop sound flood preparedness and mitigation measures that encompass a balanced use of structural and non-structural measures. Nature possesses powerful forces that are at times difficult to deal with. Perhaps a philosophy of learning to live with nature is an option to consider, whereby future flood management planning and preparedness recognizes and strikes a better balance between nature and engineering.

The SMART Tunnel: an underground approach to flood mitigation

Introduction

Malaysia is located between latitude 1° and 7° north, and longitude 100° and 119° east. The country comprises two regions, Peninsular Malaysia and the States of Sabah and Sarawak, separat­ed by 640 km of the South China Sea. Peninsular Malaysia adjoins Thailand in the north and stretches down to Singapore in the south. Sabah and Sarawak are situated, respectively, in the north and northwest of the island of Borneo. Together, the two regions cover an area of 330,000 km2. Located in the humid tropics, Malaysia has an average annual rainfall of 3,000 mm.

The city of Kuala Lumpur, the capital, was founded in the late 19th century as a tin mining settlement and, over the years, has grown to become Malaysia's largest and most important city. Kuala Lumpur is situated at the confluence of two tributaries of the Klang River which originates from the central mountain range at an elevation of 1,330 m and traverses a distance of nearly 120 km before discharging into the Straits of Malacca, draining a catchment of about 1,288 km2.

The river's headwaters comprise mountainous and steep terrain covered almost entirely by a thick canopy of tropical jungle. The mid upper reaches where Kuala Lumpur is situated is generally less steep and lies between 30 and 60 m above mean sea level. Downstream of the city, the river flows through gently rolling lands and a flat coastal plain before discharging into the sea. The rolling grounds which were earlier opened up for agriculture, have in recent times been developed into new townships and residential areas, and this process of land use conversion is expected to continue into the foreseeable future.

Flooding situation

Topographically, Kuala Lumpur was built along the flood plains of the Klang River and thus, from the earliest days, had been subjected to flooding. The 1926 flood, the so called ‘Bah Merah’ (Red Flood) is believed to be the worst in living memory but the most notable and extensive flood event on record was the flood of January 1971. This flood lasted for 5 days, cut off the city from the rest of the country, and resulted in extensive damage to property, infrastructure, agricultural land and crops, and in some loss of lives. About 445 ha of land in the city were inundated to depths up to 2 m causing widespread damage and huge losses to infrastructure and property. Since then, the city has experienced a number of major flood incidents (Table 3). A major flood event is defined as one when an area of >100 ha of built up area is submerged to 0.5 m or more.

Table 3.

Major flood events in Kuala Lumpur (Abdullah, 2007).

Period No. of times Year 
1970s 1971 (often referred to as the ‘Great Flood’). 
1980s 1982, 1986, 1988 
1990s 1993, 1995, 1996, 1997 
2000–2010 30 April 2000, 26 April 2001, 29 October 2001, 11 June 2002, 10 June 2003, 10 June 2007 
Period No. of times Year 
1970s 1971 (often referred to as the ‘Great Flood’). 
1980s 1982, 1986, 1988 
1990s 1993, 1995, 1996, 1997 
2000–2010 30 April 2000, 26 April 2001, 29 October 2001, 11 June 2002, 10 June 2003, 10 June 2007 

There are two basic types of floods which occur in the Klang River basin. The first is the monsoonal type flooding caused by a long duration (3–10 days) of low intensity rainfall (>20 mm/h) precipitating over a large area, resulting in the major river systems over-spilling the banks and causing widespread flooding. The flood of 1971 was a monsoon type flooding. Flooding of the second type is caused by thunderstorms which are localized rainfall of very high intensities (>180 mm/h) and short durations (2–5 h). The intense level of precipitation causes large volumes of storm runoff even from small catchments, which often leads to drainage and river systems in the localized areas being completely overloaded. This causes what is termed as ‘flash’ flooding. As the name suggests, flash floods are quick to manifest and equally swift to subside. This form of flooding is frequently experienced in Kuala Lumpur and it can happen several times in a year.

The frequency of flood events (both monsoon type and flash floods) has increased over the years. The main causes of this can be attributed to the extensive urbanization of the catchment up to the hill slopes, while the capacity of the tributaries are at the same time greatly reduced by the heavy siltation due to the uncontrolled land clearing activities and wanton disposal of solid wastes in the rivers. This disturbance to the eco-balance by converting forests into townships has greatly increased the area of impervious surfaces and consequently reduced the flood detention capacity. Studies in Malaysia have shown that forested catchments capable of absorbing 100 mm of rainfall in the 1st hour of a storm can only absorb 20 mm of rainfall when converted to urban conditions. The increasing trend of the flood magnitudes is best illustrated in the measurement of annual flood discharges taken at Sulaiman Bridge (near the city centre). From the mid-1980s there has been a 300% increase in the mean annual flood discharges from 148 to 440 m3/s (see Figure 1).

As a result, over the past three decades, the incidence of major flooding has become more frequent (see Table 3). In addition to these major flood events, there have been numerous occurrences of flash floods in the city. These descend with very little warning and totally upset city routine, disrupting commerce and traffic. Overall, the situation is expected to be further aggravated due to the impact of global warming and climate change.

Policy responses

In the aftermath of the 1926 flood, the then colonial government initiated steps to resolve the flood issue. The policy response was to ‘control’ floods through structural (engineering) measures. The early flood control works were carried out by the Hydraulic Branch of the Public Works Department. In 1932 the Department of Irrigation and Drainage (DID) was formed and it took over this function. Some of the early works were:

  • channelization and protective works of the Klang River, completed in 1933;

  • dredging of the Klang River between 1937 and 1941;

  • improvement of the Klang River through the city, completed in 1960;

  • improvement of the Gombak River, completed in 1969.

Nevertheless, as the level of development in the pre-war years was not significant, there was no major flood in the ensuing two to three decades, though the problem of localized flooding due to inadequate drainage continued to persist. However, as Kuala Lumpur continued to transform into the ultra-modern metropolis it is today and as development kept changing the face of the city, the existing infrastructures came regularly under pressure to cope with flood flows beyond their design limits. This urbanization of the catchments in and around the city has resulted in much upheaval to the hydrological regime and has increased flood runoffs many fold, overstraining the drainage capacity of the river system, and bringing with it challenges for the engineers to come up with innovative engineering solutions.

After the disastrous flood of 1971, the policy response was to entrust hydrology and flood mitigation as additional functions of the DID. The DID then modified the approach to ‘mitigate’ (reduce the impact) rather than attempt to ‘control’ floods. This approach involves a combination of structural and non-structural measures. Non-structural or ‘soft’ measures include flood zoning, flood forecasting and warning, flood risk mapping and flood insurance. Using this approach, the DID developed the Kuala Lumpur Flood Mitigation Project (KLFMP). The main project features consisted of three dams located upstream of the city and urban drainage works on the main tributaries. The project consisted of the following measures:

  • Channel improvement: this involved the straightening, widening and deepening of 47.2 km of river channel and the removal of the Puchong Drop Structure. Within the city, where space is restricted, the river sections were deepened and concrete lined.

  • Klang Gates Dam modification: the height of the existing Klang Gates gravity arch concrete dam completed in 1959 was raised by 3 m to create a new active capacity of 28.8 million m3, i.e. 76% over the 16.3 million m3 previous capacity. An additional land area of 71 ha of forest reserve was required for the reservoir impoundment. New spillway piers, gate hoists and four radial gates were installed in the spillway. All the works were completed in 1981.

  • Batu Dam and reservoir: the construction of a new earthfill embankment dam with a reservoir capacity of 36.6 million m3 to control surface runoff from a catchment of 50.2 km2. This multi-purpose flood control and water supply dam was completed in 1987 and provided an additional 1.34 m3/s (25 million gallons per day) of domestic and industrial water supply to the city.

  • Gombak Dam and reservoir: this was a proposed multiple-arch concrete structure of 25 m height and a reservoir capacity of 42.6 million m3 covering an area of 82.3 ha. However, as it required an additional 411 ha of land for roads, services and other project functions, there was much social opposition from the 1,110 families residing in the proposed reservoir area, and the Gombak Dam project was eventually shelved.

  • Batu Retention Pond: the Batu Retention Pond was proposed as a partial replacement for the Gombak Dam. The Batu Pond has since been completed (in 1993) and the Gombak River Diversion (3.4 km) was completed in 2003. The Pond is designed to carry a flood discharge (100 years return period) of 60 m3/s from the Gombak River via a diversion channel, and 40 m3/s from the Batu River.

  • Pumped Drainage: Kampung Baru is an inner-city area of about 90 ha located on the right bank of the Klang River about 2 km upstream of the Klang/Gombak confluence. About 35 ha of this area is below the designed level of the Klang River and, of this, 15 ha suffers from flooding due to internal water inundation as the area is relatively low. To mitigate the flooding, the area was ‘poldered’ and a pump house and a storage basin was constructed alongside the embankment of the river in 1993.

Work on the KLFMP commenced in the mid-1970s, but the pace of implementation was limited by the availability of funding. In the meantime, the rate of development of Kuala Lumpur and the surrounding environs picked up at a much higher level and consequently increases in flood discharges began to outpace the improvement to the river capacity through the flood mitigation works. After the series of floods that hit Kuala Lumpur from 2000, it became apparent that a completely new approach was necessary to alleviate the flood problem in the city. Among the options considered was the possibility of providing additional upstream storage for the excess flows, increasing the capacity of the rivers and creating flood bypasses to divert flood flows away from the city centre.

Detailed studies indicated that for the northern part of the catchment, a number of disused tin mining ponds could be converted into flood detention ponds, while for the southern part, the only viable alternative was to construct a flood bypass. Here, the topography of the land was such that a bypass alignment would cut through high ground as well as areas which were densely built up, making the use of an open channel (open cut) prohibitive in terms of land acquisition and compensation costs. It was thus decided that the bypass should be a tunnel as this was a more competitive alternative in terms of pricing and would offer the least disturbance during construction.

At the same time, it was realized that a flood bypass tunnel would be in use very infrequently and hence, by incorporating a road into the tunnel, the project could be value added by helping to reduce the traffic congestion at the southern gateway of the city to the city centre. Thus was born the idea of the SMART project.

The SMART Tunnel3 project

The SMART Tunnel project comprised two components; a stormwater component consisting of a tunnel flood bypass to mitigate the flooding problems in Kuala Lumpur city centre and a motorway component using the same tunnel to provide an alternative traffic dispersal scheme to ease the traffic congestion at the southern main gateway into the city. The project was designed to provide Kuala Lumpur with a Q100 protection and this required the use of a very large bore tunnel for the bypass.

The stormwater component was designed to reduce the storm flow through the city centre to a manageable quantity within the capacity of the river. A total of 280 m3/s of flood discharge would be diverted into a holding pond with an area of 8 ha and having a capacity of 600,000 m3. The water would then flow into a bypass tunnel 9.8 km long and with an internal diameter measuring 11.8 m. The total storage provided by the tunnel during diversion is 1 million m3 and it discharges into a storage reservoir of 23 ha, having a capacity of 1.4 million m3. The effect of the bypass and the storage that can be contained within the system is to reduce both the flow through the city centre as well as the subsequent discharge back into the river system downstream of the city.

The motorway component comprises a 3 km stretch at the middle of the tunnel which offers motorists from the south a speedy alternative to the central business district. To ensure safer traffic operations, this portion of the tunnel was constructed with two decks: one for motorists entering and the other for exiting the city centre. Owing to the limitation of headroom in the double deck configuration, only cars and other light vehicles are allowed to use the tunnel. Figure 6 shows a cross-sectional view through the motorway component.

Fig. 6.

Typical cross section of motorway tunnel (Abdullah, 2007).

Fig. 6.

Typical cross section of motorway tunnel (Abdullah, 2007).

The SMART Tunnel is operated in three modes based on the relationship between flood discharge and the operation status of the motorway (Figure 7). In mode I (no storm), which is the normal condition, the tunnel is kept dry, as no water is diverted into the system. Twin floodgates are installed at either end of the traffic section to isolate this part of the tunnel from the other sections.

Fig. 7.

Operation of SMART Tunnel (Abdullah, 2007).

Fig. 7.

Operation of SMART Tunnel (Abdullah, 2007).

In mode II, (minor storms) some water is diverted into the tunnel but is confined to the lowest drainage chamber provided in the traffic tunnel. During such times, the set of twin floodgates at either end of the traffic tunnel are kept shut, to ensure safety for the traffic in the tunnel. Each gate in the twin set is, by design, capable of sealing the traffic compartment. Nevertheless, for additional safety reasons, a second set was provided for backup.

In mode III (major storms), a much larger discharge has to pass through the tunnel, for which the full section of the traffic compartment is required. During this operation, the tunnel is closed to traffic and secured for flooding. Road gates placed at either end of the traffic compartment prevent water in the tunnel from reaching the ground surface at the ingress/egress.

Financing mechanism for the SMART Tunnel project

Traditionally, flood infrastructure is funded by the government social project and there is no attempt to recover cost from the beneficiaries. Capex funding is procured under the 5-year National Development Plans, while O&M funding has to be sourced through the annual operating budget. While there has been private sector involvement in numerous infrastructure projects under the build-operate-transfer (BOT) concept, there have been no takers for flood projects due to the lack of political will to institute a viable cost recovery mechanism, e.g. through local or property tax.

The SMART Tunnel project was funded through a new financing mechanism whereby the capex costs were shared between the government and the private sector, with public funds paying for the flood component and private funds for the motorway component. The private sector was given a concession to recover their costs by charging a toll on motorway users under the BOT concept and was responsible for operating and maintaining the tunnel, thereby relieving the government of its obligations for O&M. However, the government retained control of the operation during floods.

Super Typhoon Haiyan (Yolanda)

Introduction

The Republic of the Philippines is an archipelago of 7,107 islands located between latitude 4° and 21° north, and longitude 116° and 126° east. To the north lies Taiwan, to the west is Vietnam and to the south and south west sit Indonesia and Malaysia. Including inland bodies of water, the Philippines has a total land area of approximately 300,000 km2, while its 36,289 km of coastline makes it the country with the fifth longest coastline in the world. Its location on the Pacific Ring of Fire and close to the equator makes the Philippines prone to earthquakes and typhoons.

According to the official count, the population hit 100 million in July 2014, making the Philippines the seventh most populated country in Asia. It is estimated that half of the population resides on the island of Luzon. A newly industrialized country, the Philippine economy has been transitioning from one based on agriculture to one based more on services and manufacturing.

Located on the island of Luzon, Metro Manila, the capital of the Philippines, is a huge urban mass of 16 cities, the most populous of which is Quezon City. Metro Manila is the most populous metropolitan area in the Philippines with a population of over 16 million, while Greater Manila, which includes the suburbs in the adjacent provinces (Bulacan, Cavite, Laguna and Rizal) has a population of around 21 million. Metro Manila's gross regional product is estimated (as of July 2009) to be 468.4 billion pesos (at constant 1985 prices) and accounts for 33% of the nation's GDP.

Flooding situation

Sitting astride the typhoon belt, the Philippine archipelago experiences annual torrential rains and thunderstorms from July to October, with around 20 tropical cyclones entering Filipino waters in a typical year and 8 or 9 making landfall. A tropical cyclone is categorized according to its wind speed. The lowest category is a ‘tropical depression’ which has wind speeds not exceeding 33 knots (61 km/h). A tropical depression is upgraded to a ‘tropical storm’ should its sustained wind speed exceed 34 knots (63 km/h); and should the storm intensify further and reach sustained wind speeds of 48 knots (89 km/h), then it is classified as a ‘severe tropical storm’. Once the cyclone's maximum sustained winds reach 64 knots (119 km/h) it is designated as a ‘typhoon’.

In recent years, tropical cyclones have been increasing in frequency and intensity and as a result, in 2009, typhoons were further divided into three sub-categories: ‘typhoon’, ‘severe typhoon’ and ‘super typhoon’. A typhoon has wind speeds of 64–79 knots (119–149 km/h), a severe typhoon has winds of at least 80 knots (150 km/h), and a super typhoon has winds of at least 100 knots (190 km/h).

Nearly one-third of the world's tropical cyclones form within the western Pacific with the area just northeast of the Philippines being the most active place. Within the Philippines, the areas most frequently impacted by tropical cyclones are northern and central Luzon and eastern Visayas. These tropical cyclones contribute at least 30% of the annual rainfall in the northern Philippines, while for the southern islands it is under 10%. While the percentage may look small, the precipitation is generally delivered over a few days, resulting in very high rainfall intensities. This rainfall, coupled with the strong winds, invariably culminates in severe flooding. The wettest known tropical cyclone to impact the Philippines archipelago was a 1911 cyclone, which dropped over 1,168 mm of rainfall within a 24-hour period in Baguio.

Typhoons also cause storm surges inland. Historical records between 1897 and 2013 indicate that many typhoons hit the Visayas area near Tacloban City, Leyte, but the five worst storm surges are as shown in Table 4.

Table 4.

Historical records of storm surge (Source:Nepomuceno, 2014).

Date of typhoon occurrence Fatalities Station pressure (hPa) Storm surge 
12 October 1897 1,300 925 7.3 m (Hernani) 
24 November 1912 52 924 7 m (Santa Rita) 
27 October 1952 444 930 Not recorded 
04 November 1984 1,167 925 3.5 m (coastal areas of Leyte) 
08 November 2013 6,241 + 910 6–7 m (Leyte & Samar areas) 
Date of typhoon occurrence Fatalities Station pressure (hPa) Storm surge 
12 October 1897 1,300 925 7.3 m (Hernani) 
24 November 1912 52 924 7 m (Santa Rita) 
27 October 1952 444 930 Not recorded 
04 November 1984 1,167 925 3.5 m (coastal areas of Leyte) 
08 November 2013 6,241 + 910 6–7 m (Leyte & Samar areas) 

The vulnerability of the Philippines is best illustrated by two very severe typhoons that have recently struck. In December 2012, Typhoon Bopha (known in the Philippines as Pablo), was the strongest tropical cyclone to ever hit the southern island of Mindanao, making landfall as a super typhoon with winds of 280 km/h. Bopha caused widespread destruction on Mindanao, leaving thousands homeless, causing 1,146 fatalities, with another 834 missing and more than 170,000 people moved to evacuation centres. Total damage was estimated at US$1.04 billion.

Almost a year later, in November 2013, Super Typhoon Haiyan slammed into the Visayas region of the Philippines, killing more than 6,300 people and resulting in US$9.7 billion in losses and damage.

Super Typhoon Haiyan (Yolanda)

Super Typhoon Haiyan (known in the Philippines as Yolanda), was the 23rd tropical cyclone to hit the Philippines in 2013 and the 9th that made landfall. Haiyan is believed to have been the strongest typhoon ever to strike land anywhere in the world, and the strongest typhoon ever recorded in terms of wind speed, with wind gusts of up to 200 knots (380 km/h). It is the deadliest Philippine typhoon on record, killing at least 6,300 people in the Philippines alone. More than 2 months later, bodies were still being found.

Haiyan originated from an area of low pressure about 425 km east-southeast of Pohnpei, one of the states in the Federated States of Micronesia, on 2 November 2013. Moving westward, the system encountered environmental conditions favouring tropical cyclogenesis (i.e. the development and strengthening of a tropical cyclone in the atmosphere) and developed into a tropical depression by the following day. After becoming a tropical storm and being assigned the name ‘Haiyan’ on 4 November, the system began a period of rapid intensification that brought it to typhoon intensity the next day.

On 6 November, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) assigned the storm the local name ‘Yolanda’ as it approached their area of responsibility (PAR). Over the same day, Haiyan attained super typhoon status as the eye of the typhoon passed over the island of Kayangel in Palau with sustained winds of up to 230 km/h. Prior to landfall in the central Philippines, Haiyan reached its maximum intensity on 7 November in the early evening, with 1-minute maximum sustained wind speeds of 314 km/h, unofficially making Haiyan the strongest tropical cyclone ever observed based on wind speed.

Haiyan entered the Philippine PAR at midnight of 6 November and made its first out of six landfalls on 8 November (4:40 a.m.) in Guiuan, Samar. At landfall, it had maximum sustained winds of 235 km/h with gusts of 275 km/h near the centre. From there, it moved west-northwest crossing Northern Leyte at 7:00 a.m., then to Northern Cebu (9:40 a.m.), Northern Panay (12:00 noon) and Busuanga in Northern Palawan (8:00 p.m.). It exited the PAR on the following day, 9 November at 1:40 p.m. Owing to its massive destruction, the Philippine Government declared a National State of Emergency on 11 November 2013.

Haiyan also brought storm surges which were recorded in several locations along the eastern coastline. According to the 8 November situational report of the United Nations Office for the Coordination of Humanitarian Affairs (OCHA), the storm surge created 5–6 m waves that wiped out most infrastructure, health facilities, schools, basic public services, homes and commercial buildings in several coastal towns/barangays in the islands of Samar and Leyte. Based on a PAGASA-DOST4 survey of storm surge heights, Tacloban City in Leyte (population 221,000 people), bore the most severe damage, with a storm surge of 5–6 m that also resulted in inundation of 600–800 m and which smashed through coastal communities. From Guiuan to Hernani in Samar, a storm surge was recorded at 6–7 m high with 800–1,000 m inundation.

Super Typhoon Haiyan brought so much destruction, particularly in central Philippines. The affected areas consisted of 12,139 barangays in 591 municipalities and 57 cities in 44 provinces, and more than 16 million people were affected, as shown in Table 5.

Table 5.

Humanitarian costs (as of 3 April 2014) (Source:NDRRMC, 2014).

Population affected 3,434,593 families (16,078,181 persons) 
Population displaced 890,895 families (4,095,280 persons) 
Number of reported deaths 6,293 
Number of reported injuries 28,689 
Number of missing persons 1,061 
Population affected 3,434,593 families (16,078,181 persons) 
Population displaced 890,895 families (4,095,280 persons) 
Number of reported deaths 6,293 
Number of reported injuries 28,689 
Number of missing persons 1,061 

Some 70–80% of the houses on the island of Leyte were destroyed, with the low-lying areas of Tacloban City the worst affected. The terminal buildings of Tacloban Airport were destroyed, along with almost all of Tacloban's infrastructure. Over 20,000 houses in the city were damaged, with a large part totally destroyed. Ships were washed inland, cars piled up and trees uprooted. Overall, along the 100 km path of Haiyan, some 1,140,332 houses were damaged, 550,928 totally and 589,404 partially. Most of the damage was caused by storm surges, strong winds and heavy rains that resulted in loss of life, property and infrastructure. Based on the results of a joint Asian Development Bank and OCHA rapid assessment of Tacloban and other locations, and on the data provided by the National Disaster Risk Reduction and Management Council (NDRRMC), more than half of the estimated damage and loss was private property.

The total direct losses in the Philippines are estimated to have reached US$9.7 billion and even though on the global scale these losses appear low (e.g. Hurricane Katrina caused an estimated US$125 billion of direct losses), they made a deep dent in the Philippine economy. Property valued at around 4% of the country's GDP was destroyed. Only about 7% of the losses were insured and the balance cannot be recovered without placing a huge additional burden on the country's population or the national budget. The disaster brought about by Haiyan also illustrated well the large loss amplification factor, whereby a big disaster can result in secondary catastrophes such as prolonged periods of non-accessibility to affected places due to infrastructure destruction, and a strong regional economic downturn leading to a population drain and migration outflow from the disaster zone.

Policy responses

The Philippines is a country where massive natural disasters including typhoons, earthquakes and volcanic eruptions are a way of life. Sitting astride the typhoon belt and having a long coastline of 36,289 km, the Philippines archipelago is particularly vulnerable to tropical storms and typhoons. On average, up to 20 tropical storms enter Filipino waters annually, with about half of them making landfall. The most frequently impacted areas are northern and central Luzon and the eastern Visayas. The capital, Metro Manila, is located on the island of Luzon.

Typhoons bring heavy rainfall which, when combined with the strong winds and storm surges, can cause large-scale flooding and result in enormous destruction and loss of life. In 2013, the Philippines was struck by Super Typhoon Haiyan, the strongest typhoon ever to strike land anywhere in the world, with wind gusts of up to 200 knots (380 km/h) and creating a storm surge 6 m high and extending 1 km inland.

In the face of such daunting climatic factors, it would be prohibitively costly for the Philippines to invest in the necessary defensive infrastructure to protect the country or even to try to mitigate the impacts from typhoons. Instead, the policy response has been to focus on improving disaster preparedness and management. In 2010, the Philippine Government enacted Republic Act No. 101211 on Disaster Risk Reduction and Management (DRRM Act 2010). This Act provided for the development of policies and plans and the implementation of actions and measures pertaining to all aspects of DRRM, including: (i) good governance; (ii) risk assessment and early warning; (iii) knowledge building and awareness raising; (iv) reducing underlying risk factors; and (v) preparedness for effective response and early recovery.

Significantly, the law enabled the government to review and finalize its landmark plan on DRRM ‘Strengthening Disaster Risk Reduction in the Philippines: Strategic National Action Plan (SNAP) 2009–2019’ based on its global commitment to disaster risk reduction (DRR), as embodied in the Hyogo Framework for Action. The SNAP has been institutionalized through Executive Order No. 888 signed on 7 June 2010. The SNAP recognizes the paradigm shift from a mostly reactive disaster response approach to a proactive DRR orientation.

Further, Administrative Order No. 1 directed all government units, particularly provinces, to adopt (in their planning activities) the guidelines on mainstreaming disaster risk reduction, in sub-national development and land use/physical planning. As the Philippines is considered one of the countries most prone to events triggered by natural hazards, the country's vulnerability to such hazards will continue to hinder socio-economic development unless practical solutions are found to avert potential damage from them. The Medium-Term Philippine Development Plan has identified disaster mitigation as a priority thrust, and achievement of such thrust includes the integration of a disaster management strategy in the development planning process at all levels.

The DRRM Act called for the development of a National DRRM Framework which shall provide for a comprehensive, integrated, multi-sectoral and inter-agency and community-based approach to DRR. The framework shows that mitigating the potential impacts of existing disaster and climate risks, preventing hazards and small emergencies from becoming disasters, and being prepared for disasters, will substantially reduce loss of life and damage to social, economic and environmental assets. It also points out the need for effective and coordinated humanitarian assistance and disaster response to save and protect the more vulnerable groups during and immediately after a disaster. Further, building back better after a disaster will lead to sustainable development after the recovery and reconstruction. To ensure its relevance to the times, the DRRM Framework will be reviewed every 5 years, or as may be deemed necessary.

Inherent in the DRRM Act of 2010 is the transformation of the National Disaster Coordinating Council into the NDRRMC. This Council is made up of 33 representatives from various government agencies, and seven representatives from non-government, civil and private sector organizations. It is chaired by the Secretary of the Department of National Defence and administered by the Office of Civil Defence under the Department of National Defence. The Council is responsible for ensuring the protection and welfare of the people during disasters or emergencies within the framework of DRRM as expounded under the law.

In the aftermath of Super Typhoon Haiyan, disaster preparedness and management has justifiably received major government attention, with funding increased by nearly 100 billion Pesos, or about 5% of the total national budget. However, while a portion has been spent wisely on more proactive and innovative disaster mitigation programmes such as hazard mapping, the bulk of the funds is earmarked for cleaning up, repairs and rehabilitation of the damage from Haiyan.

What would happen if such a super typhoon were to strike Metro Manila? Simulation studies indicate that at least 4,000 people would be killed and 13,000 would be injured. Nearly all commercial and residential structures would experience some degree of damage and total estimated damage would probably exceed US$3 billion. Power generation systems and distribution lines would be downed, leaving millions of homes without electricity for long periods. All telecommunications systems would experience extensive outages. Transportation infrastructure damage would cause major disruptions. The vulnerability of a large portion of the city population, particularly the urban poor, would result in a humanitarian crisis. Not surprisingly, Metro Manila is ranked by the USA as the third most vulnerable metropolitan area on earth with the second most number of people at risk. There are also serious concerns about what such a storm would do to the national economy, as the city accounts for 40% of the country's gross national product.

Conclusion

This is a tale of three capital cities in South East Asia. Although all three cities are situated in the same climatic zone, due to their geographical locations, water disasters impact differently on them, whilst policy responses also differ.

Bangkok is located in the estuary of the Chao Phraya River, which has a drainage area of 160,400 km² (or almost half the total land area of Malaysia or the Philippines). The policy response to the flooding problem was to ‘control’ the floods through upstream storage. However, in the light of the unprecedented 2011 floods, the policy response has been modified to learning to live under extreme hydrological events and to adjust by building resilience capabilities in the communities and flood infrastructure.

Kuala Lumpur is situated at the middle reach of the Klang River, a comparatively small but steep river. In the early days, the policy response was to ‘control’ floods through structural measures and regular investments in flood infrastructure were made. However, the continuing urbanization of the catchments in and around the city has resulted in flood runoffs increasing many fold, bringing with it challenges for the flood planners to come up with more innovative solutions, from both the engineering as well as the financial perspectives.

Metro Manila sits astride the typhoon belt and is particularly vulnerable to tropical storms and typhoons. Typhoons bring heavy rainfall which, when combined with strong winds and storm surges, can cause large-scale flooding and result in enormous destruction and loss of life. In the face of such daunting factors, it would be prohibitively costly to invest in the necessary defensive infrastructure to protect Metro Manila from typhoons. Instead, the policy response has been to focus on improving disaster preparedness and management.

Policy conclusions

Climate change is already impacting on the hydrological cycle, leading to increased frequencies and intensities of extreme weather events, i.e. floods, typhoons and droughts are occurring more frequently, and are larger and more intense and last longer. In recent years, three large-scale water disasters have occurred in South East Asia. In 2011, the worst floods in Thailand occurred from August to November, and the Philippines was hit by two of the worst typhoons ever recorded: Typhoon Bopha in December 2012 and Super Typhoon Haiyan in November 2013.

Structural measures are still needed to mitigate the impact of such extreme events but the existing water infrastructure will not be able to handle storms which are likely to be several times larger than designed for. Concerted action is needed to repair, rehabilitate and upgrade the flood infrastructure and make it more adaptable and flexible. The design process will have to consider the entire spectrum of upstream to downstream factors, include a balanced use of structural and non-structural measures and involve consultations with all stakeholders to produce an over-arching flood and water management plan that will mitigate, as far as possible, the worst case scenario.

Zero risk does not exist (i.e. engineering works cannot offer complete protection) and in planning for the future, one should expect the unexpected. In terms of management, nature can no longer be taken for granted and ‘business as usual’ is no longer tenable. Investments in DRR, preparation and prevention will pay off in terms of reduced loss of life, avoided damage, and long-term economic growth and stability.

1

Association of South East Asia Nations.

2

Billion = 109.

3

Although the term SMART Tunnel is a misnomer since the ‘T’ in ‘SMART’ already stands for tunnel, this term was the official name of the project to highlight that it was a unique and innovative use of a tunnel.

4

A term frequently used as PAGASA is an agency under the Department of Science and Technology (DOST) of the Philippines.

References

References
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Stormwater Management and Road Tunnel (SMART): A Unique Flood and Motorway Solution in the City of Kuala Lumpur
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