The 2011 Thailand flood

Background Information

• Thailand normally experiences its rainy season during the period of June to October.

• As Thailand is geographically sloped, all the rainwater collected from the North will flow southward and into the Gulf of Thailand.

• However, due to the increase in human activities, it resulted in 100 000 000 000 cubic metres of water to be accumulated behind the dams.

• Currently, there are only 3 routes left for the water to flow into the Gulf of Thailand, namely, the Jeen River, the Bang Pakong River and the Chao Praya River.

• These rivers can only bring 2 000 000 000 cubic metres of water into the Gulf of Thailand which means that it will take 50 days for the water to be completely drained away.

• The 2011 Thailand flood is by far the worst flood that had struck Thailand.

Climatic Conditions in Bangkok, Thailand 2011

Causes of the flood

Natural Causes• La Niña phenomenon

Human Causes• Deforestation• Urban Development

La Niña phenomenon

• La Niña refers to the abnormal warming of the water surface at the southwestern part of the Pacific Ocean. 

• It usually follows after an El Niño process.

La Niña phenomenon

• During La Niña, cold waters rising from the east chill the air above it, bringing drought to countries at the eastern Pacific since the wind will blow from the east (a region of high pressure) to the west (a region of low pressure).

• On the other hand, as the trade wind blows toward the west, it will bring heavy rains to the western Pacific, increasing the likelihood of flooding in that area.

• Coincidentally, Thailand is located in the western Pacific. Henceforth, flooding will eventually occur due to the La Niña process.

Urban development

• As Thailand is a developing country, the government has to build various infrastructures in the major cities and urban areas.

• In these urban areas, concrete pavements and tarred roads prevent rainwater from seeping into the ground.

• Besides that, with the rise of high density buildings, it prevents water from draining away more efficiently.

• This is reflected in the case of Big C Department Store located in Hat Yai, which prevented water from being drained via the Utapoa canal.

Deforestation

• Ten years ago, Thailand was a home to many natural vegetation and forests.

• However, due to illegal logging and the government’s agricultural policy, it had resulted in the loss of many forests.

Deforestation

• Without these forests, there will be no vegetation to intercept the rainwater.• Besides that, since Thailand is geographically sloped at an angle, without

trees to secure the soil together, it will increase the chances of soil erosion.• As such, soil and mud will be washed into rivers, causing them to be

shallower.• Furthermore, the bare slopes that remained will result in increased surface

runoff.• All these will then result in flooding in Thailand.

Effects of the flood

1. Damage to industrial estates and global supply shortages

2. Sanitation concerns

3. Loss of lives and economic damages

Damage to industrial estates and global supply shortages

• On 8 October 2011, the flood had caused the collapse of a 10 metre high water blockage in Nikom Rojna industrial estate which housed many manufacturing plants.

• The strong currents interfered with reconstruction efforts and resulted in the whole area being non-operational.

• Thailand is also responsible for approximately 25% of the world’s production of hard disk drives.

• However, numerous factories, including Western Digital’s, that are in charge of the production of hard disk drives were flooded, leading to some industry analysts to predict future worldwide shortages of hard disk drives.

• Nonetheless, the problem was alleviated when Western Digital managed to re-operate one of their plants.

Sanitation concerns

• As the flood water subsides, it will leave behind stagnant pools of water which may cause the effects of trash and sewage within them to peak.

• In addition, since a household sanitation system is unable to operate under flood water, individuals that remained in flooded areas exposed themselves to risks and also increased the risks for those living downstream by continuing to produce more sewage and trash in the waters.

• As a result of these stagnant water and water pollution, it will encourage the growth of bacteria and mosquitoes which will result in the spread of dengue fever, malaria, cholera and other diseases which are detrimental to our health.

Loss of lives and economic damages

• As of 6 November 2011, the flooding has affected 3,151,224 people from 1,154,576 families, with 506 deaths and 2 missing persons.

• The total damages summed up to approximately 185 billion baht. • 930 factories in 28 provinces were flooded, causing many industrial

processes to halt.• It is estimated that the flood will result in a decrease of 0.6 to 0.9% in

Thailand’s economic growth.

Solutions

1. Building of dykes

2. Building of dams

3. Building of new underground canal

4. Watershed management

Building of dykes

• Dykes were already being built in Bangkok to prevent floods.• Dykes are made up of sand, stone and concrete and are built along river

banks which are prone to flooding.• These dykes increase the capacity of the river to hold water and hence

reducing the chances of flooding.• Through the building of more dykes, the Thailand government hopes to

reduce the effects of flood significantly.

Dykes

Building of dams

• Building of dams is another way in which the Thailand government implemented to reduce floods.

• The main purpose of a dam is to control the amount of water that flows downstream in a river.

• Gates are being installed in the walls of the dams to hold back or release water from the man-made reservoir behind it.

• The reservoir also serves a purpose in preventing flood simply by increasing the amount of water that a river system can hold upstream.

• Currently, dams had already been constructed on the Ping river (the Bhumibol Dam) and on the Nan River ( the Sirikit Dam).

A bird’s eye view of the Bhumibol Dam.

Other than preventing floods, it is also used for hydroelectric production.

The man-made reservoir

The Dam

Building of new underground canal

• The Engineering Institute of Thailand came up with a proposal to build a underground tunnel that stretches 100km with a diameter of 24 meter and a depth of 10km in order to reduce the impact of floods.

• The construction will take at least 2 years and it will cost about 200 billion baht.

• This underground tunnel will be connected to existing canals and will act as an expressway to allow water to flow directly and quickly into the sea without any impact to the communities.

• With this new tunnel, it will boost the drainage capacity of the city to 130 million cubic metres a day.

Watershed management

• New ways to deal with floods include managing the entire water shed. • The Royal Forest Department(RFD) in Thailand is an example where it has

developed a watershed management programme to prevent floods from occurring.

• This programme comprises detailed plans on conserving the natural vegetation in watersheds.

• By conserving vegetation cover, surface runoff and the amount of sediments washed into rivers are reduced.

• This in turn reduces the occurrence of floods. • The RFD programme also includes re-planting trees in areas where they

were previously cut down. • The planting of trees and grass on slopes reduces surface runoff and soil

erosion, thereby decreasing the chances of flooding.

Evaluation of the 4 solutions

Solutions Advantages Disadvantages

Building of dykes

• Able to increase the holding capacity of the river, thus, reducing floods.

• May erode over time due to the currents of the river, hence, checks had to be conducted on a timely basis to ensure that it’s still in working conditions.

Building of dams

• Compared to dykes, it is able to increase the holding capacity of the river more.

• Dams are able to produce hydroelectricity at the same time,

• Dams are costly to build.

• Dams may be damaged as a result of too much water pressure.

Evaluation of the 4 solutions

Solutions Advantages Disadvantages

Building of new underground canal

• Allow water to flow directly and quickly to the sea without any impact to the communities.

• Boost the drainage capacity of the current canals.

• Like the construction of dams, it involves a great amount of money.

• It is time consuming to construct.

Watershed management

• It helps to solve the problems of deforestation in Thailand at the same time.

• Illegal logging may still take place when the trees are grown.

Our opinion

• Out of the 4 solutions, we feel that building of the new underground canal is the most effective solution.

Why?• The building of dykes can only prevent floods for a short period of time. • As time goes by, the dykes will be eroded by the water which may cause it

to collapse and thus, the government will have to carry out checks on a timely basis to ensure that it is still in working conditions.

• This will require a huge planning process and would not be cost effective as it needs to make use of large amount of manpower to carry out the checks.

Our opinion

• Out of the 4 solutions, we feel that building of the new underground canal is the most effective solution.

Why?• Managing a watershed environment for the prevention of floods is a perfect example of

"Prevention rather than Cure".• It emphasizes on how we can make preparations before the flood comes instead of

trying to salvage the remains and aftermath later. • However, we feel that even if this project is successful, it would be extremely costly to

continue funding this project and to sustain it. • The vegetation might not be suitable to grow in that area and often, external factors such

as heavy thunderstorms and droughts might cause the plans to wither away or to collapse and fall.

• Plants are also weak, vulnerable and susceptible by nature. Thus, they  can only rely on circumstantial factors to survive.

• In conclusion, this is not a good suggestion.

Our opinion

• Out of the 4 solutions, we feel that building of the new underground canal is the most effective solution.

Why?• As for the construction of dams, without an efficient draining system, floods

will still occur.• Dams only allow about 2 billion cubic metres of water to flow into the Gulf of

Thailand via the three rivers.• During the rainy season in Thailand, there will be about 100billion cubic

metres of water to be accumulated. • This will definitely mean that it will take 50 days for the water to be

completely drained away. • Therefore, it is not time-efficient enough to be considered the best strategy.

Our opinion

• Out of the 4 solutions, we feel that building of the new underground canal is the most effective solution.

Why?• With the construction of more underground canals, it will allow more water

to flow directly and quickly to the Gulf of Thailand.• Hence, the time taken for the water to be drained away will decrease

significantly, causing the chances of flood occurrence to drop.• Therefore, we feel that building of the new underground canal is the most

effective solution.

Thank you for your kind attention and good bye!

Our wiki: http://geography-project-floods.blogspot.com/