Adaptation of land use and houses in the upper mekong deltas deep flooding area 2

Adaptation of land use: Infrastructure development dealing with floods This section studies the flood control planning and infrastructure in the studied area and its impacts on floods

This chapter studies current flood adaptation strategies in land use planning

and housing practices in the studied area This is obtained through literature review

on adaptation of land use and houses, site visits, sketches, and interviews of 47

households in the Mekong Delta Figure 43 and Figure 44 present the location of the

studied area and houses in the administrative and flood maps

Section 4.1 studies infrastructure development and its impact on floods while

Section 4.2 examines the community in the studied area Then, Section 4.3 explores

adaptation of houses by analyzing houses from different aspects that have impacts

on adaptation Based on these analyses and evaluation criteria of safe shelter,

ensuring connectivity, and supporting livelihoods, Section 4.4 discusses the

limitations of current adaptation strategies

Figure 43. Location of the studied area and houses  

Source: NAGECCO (1998) 

Source: Author (based on maps of SIWRP) 

4.1 Adaptation of land use: Infrastructure development

dealing with floods

This section studies the flood control planning and infrastructure in the

studied area and its impacts on floods, socio-economic development and the

environment

4.1.1 Flood control infrastructure development

Infrastructure in the Mekong Delta has been developed for flood control and

agriculture intensification, especially since 1990s In the studied area, year-round

flood protection is provided in the urban areas, for main transportation systems, and

the fruit tree areas This is achieved by constructing full dykes9, main roads or landfills higher than flood peak levels in 1996 and 2000 (Figure 45, Figure 46 and

Figure 47) Full dykes protect the farms from floods completely, with the control of

sluice gates and pumps, enabling three rice crops per year Outside the above areas,

9 Full dykes (high dykes) are dykes constructed higher than peak flood levels, protecting the areas from floods all year round They are usually combined with roads and residential dykes

partial flood control solution, which protects the rice crops from early floods in

August and late floods in November-December, is possible with semi-dyke systems

(Figure 48) At the end of July and beginning of August, rice crops are ready for

harvest, if floods happened early and there are no dykes, crops would be damaged

Therefore, semi-dykes are constructed around the level of floods in this time,

protecting the areas from early floods After harvesting, floods overflow semi-dykes

into the fields The semi-dykes also protect the farms from late floods in November

– December, so that farmers can start cultivating the next crop Semi-dyke systems

help decrease the flood duration for agricultural production, ensuring two crops of

rice (SIWRP 1998b; To 1998) In the studied area, 67% of the dykes are semi-dykes

with an average level of about 2.5 m.a.s.l, and the rest are full dykes with an average

level of about 4.5 m.a.s.l Moreover, there are more than 1000 man-made canals in

the Mekong Delta, which have been used for flood drainage, irrigation, and

transportation (Le et al 2008)

Figure 45. Preliminary design of dykes in Tam Nong District  

Source: MRC (2009) 

Figure 46. A main road  combined with dyke in Tam  Nong District  

Source: Author (Tam Nong  District, November 11, 2009) 

Figure 47. Local road combined with semi‐dyke, canal system, and high elevated area in the  studied area  

Source: Author (Tam Nong District, December 01, 2009)  

Figure 48. Flood control infrastructure of the studied area in 2004 

Source: SIWRP (2010) 

In the studied area, during 1996-2000, early flood prevention embankments

were constructed, and the Tan Thanh – Lo Gach canal was dredged (Figure 49)

After 2000, major changes in infrastructure include further dredging of canals, and

the expansion and raising of Road No 30 to exceed the peak flood levels in 2000

(5.23 meters amsl at Tan Chau) (Figure 50) Soil obtained from dredging canals is

used to elevate the roads, and to build embankments along canals and along

residential areas (Le et al 2008)

Source: Le et al. (2008) 

Figure 50. Infrastructural change in the Mekong Delta: (b) after 2000 

Source: Le et al. (2008) 

Figure 51, Figure 52, Figure 53, and Figure 54 illustrate average elevations

of dykes in Tam Nong and Tan Hong districts, with simulated water levels in the

historical 97 years under current infrastructure in the Mekong Delta The average

elevations of dykes in Tam Nong and Tan Hong are about 2.4 meters and 3 meters,

respectively These dykes can protect the area from the early floods in August, for

roughly 90 percent of flood water levels simulated This also implies that

semi-dykes account for the majority of semi-dykes in the studied area

Figure 51. Average elevations of dykes in Tam Nong District and simulated max water levels in the  historical 97 years under current infrastructure situation  

Source: MRC (2009) 

Figure 52. Average elevations of dykes in Tam Nong District and simulated water levels in August 

in the historical 97 years under current infrastructure situation 

Source: MRC (2009) 

Source: MRC (2009) 

Figure 55 illustrates the flood control infrastructure in a nice flood11 in sections12 of the studied area It shows high elevated roads, elevated residential or urban areas, and areas protected by full dykes, which are higher than flood peak

trans-levels in 1996 or 2000, hence they are not affected by floods It also shows that areas

protected by semi dykes areas with low elevation of the roads and ground, and areas

not protected are inundated by peak levels of a nice flood Section 4.3.2.1 further

discusses how houses in these areas are affected by floods

Le et al (2008) examined the impacts of infrastructure on floods in the

Mekong Delta based on the analysis of flood variation from 1961 to 2004 and

effects of infrastructure changes from 1996 to 2001 using hydraulic model

HydroGIS It is suggested that these engineering structures make the flood duration

approximately 5–10 days longer and water level 0.2–0.3 m deeper in some areas

near or between the high embankment systems Floods are reduced in areas

protected by embankments and increased in water level and duration in other areas

such as downstream of Dong Thap Muoi towards the Vam Co River, because the

engineering structures make changes to the flow and obstruct drainage Another

impact is overbank inflow to Vietnam is decreased and water flow in the canals is

increased, resulting in a trend of increase with progression in flood peaks

downstream (Le et al 2008)

or “serious” damage properties and infrastructure The “dreadful” floods cause heavy human

casualties and severe damage to infrastructure In the “light” floods, fishery production decreases, the soil is less fertile, and salinity increases (Please refer to Section 2.3.1.1 for more details)

12 The trans-section is combined from typical sections of houses in the studied area

Positive impacts

Changes in infrastructure mentioned above have significant impacts on

agricultural practices and flooding in the Mekong Delta Flood control infrastructure

in the studied area has benefited socio-economic development, protected people,

infrastructure and houses, and supplied fresh water Thanks to dyke systems and

hydraulic constructions, rice production has almost quadrupled from 1974 to 2005

(Nguyen 2007a), and damages caused by floods have reduced substantially

Elevated roads ensure convenient transportation and connections of inhabitants to

public services in the flooding season

Negative impacts

Although the current strategy dealing with flood in the Mekong Delta is a

combination of “Living with floods” and flood control, the numerous measures of

flood control and underestimation of the complexity of the Mekong Delta’s ecology

have resulted in numerous drawbacks and challenges to the area’s environment and

flood regime These measures have brought about a decrease in fishery resources

and sediments in the flood control area (To 1998), as well as soil acidification, water

pollution, and increase in insects and vermin in the rice fields Recently, yields have

decreased, in some cases to 25-50 kg per 1000 m2 Due to decrease in sedimentation, more chemical fertilizers and insecticides were used, leading to higher production

cost and harm to the environment In addition, full dyke protection may constrain

water transportation (Le and Chu et al 2007)

In conclusion, the main strategies for coping with flood in the studied area

are building semi-dyke systems to control early floods, and using canals for quick

flood water drainage These may be good adaptive measures to deal with floods in

the studied area as they have benefited agriculture development and reduced

damages and loss of human lives, and damage to infrastructure and properties

Development of semi-dykes in the studied area is a better solution compared to

full-dykes because it can both reduce damages and receive benefits from floods, which is

critical to people’s livelihoods While drawbacks of full-dykes such as degradation

of soil and water quality and fishery resources depletion result in difficulties for

agriculture activities in the long term, semi-dykes cause these drawbacks to a lesser

extent Therefore, even with more pressure on agricultural production, full-dykes

may not be an efficient solution for this specific area and any proposal to build full

dykes should be carefully examined

4.2 Adaptation of community

4.2.1 Characteristics

Unlike villages in the Red River Delta in Northern Vietnam which are closed

by bamboos and walls, villages in the Mekong Delta are open Villages are along the

roads or the rivers, usually with one layer of houses and about 7 – 8 kilometers long,

but the density is not high Historically, when the farm land was not enough for the

population, a part of the population moved to fresh land for cultivating and formed

new villages (Figure 56 and Figure 57) (Phan 2004)

Figure  56.  The  formation  of  new  village:  when 

there  was  not  enough  land  for  farming,  people 

Communities in the Mekong Delta are not affected crucially by

blood-relationship However, family relatives support each other and respect the hierarchy

People in the neighborhood have a close relationship as they share the same

experiences of traveling to fresh ground to cultivate and establish a new settlement

People in a village may have the same career, such as handicrafts

4.2.2 The role of community in adapting to floods

In the event of large floods that cause severe damage, the community plays

an important role in the recovery of affected families and individuals As new

settlers who have changed fresh land into cultivated area, Mekong Delta dwellers

have great empathy for each other’s difficulties They are generous and value

friendship through mutual affection and a willingness to help each other overcome

difficulties People help in the dry season activities such as harvesting fishes,

building and repairing houses In adaptation to flooding, people help each other in

preparation before the arrival of the next flood, during inundation, and after flood

has receded They may share food and houses, donate money, help repair and

rebuild the houses People also cooperate in work which benefits the community

such as building and repairing dykes, village paths or bridges There are also

programs in which the government and people in communities cooperate to build

public infrastructure such as roads and hydraulic works, according to the motto

“Both the government and people work together” (Le 2006a)

In conclusion, communities in the studied area are open and settle along

roads and canals People have mutual affection and are helpful to each other,

especially in hard times Therefore, people are willing to support flood victims with

whatever resources they have, including settlement, food, money, and labour to

rebuild or repair houses This spirit and practice of cooperation has contributed to

the people's survival in the studied area

4.3 Adaptation of houses in the studied area

This section explores the adaptation of houses in the studied area First, it

examines housing characteristics, including the general layout of houses and types

of houses (Section 4.3.1) Then, current adaptation of houses is analyzed from

different aspects to figure out adaptation strategies of houses in the studied area

(Section 4.3.2)

Criteria to evaluate adaptation of houses to floods

As stated by UN ESCAP (2011), the physical components of settlement

comprise shelter, infrastructure and services The house needs to satisfy the role of a

shelter and connectivity to infrastructure and services In the studied area, the house

not only provides shelter, but being integral with infrastructure, form the basis of

socio economic and communed activity These functions are thus used as criteria to

evaluate adaptation of houses in the studied area to floods First, houses need to be

safe shelters, protecting people from floods Second, connectivity of houses to roads,

canals, farms, and services such as schools, markets, and healthcare centres needs to

be secure in dry and flooding seasons Third, the settlement has to collectively

function as an entity to sustain and support all activities, including those relating to

livelihoods

4.3.1 Characteristics of houses in the studied area

4.3.1.1 Layout of houses in the studied area

The following provides an overview of houses in the upper Mekong Delta’s

deep flooding area Elements of the typical layout of houses in the studied area

include (Figure 58, Figure 59, and Figure 60):

 Main area (nhà chính/nhà trên): worship and living room (1) (Figure 61)

 Water floor (sàn nước), bathroom and WC (2) (Figure 65)

 Bridge area (nhà cầu) (3) (Figure 64) and/or ancillary area (nhà phụ) (5)

(Figure 66): family room, sleeping area, rice storage area, kitchen

 Back area (nhà sau/nhà dưới) (Figure 63): kitchen, sleeping area (4)

 Verandah: the large front verandah is the space to relax, meet neighbours and

guests, and also to work (Figure 62) There can also be side verandahs These

form the interstitial space between the house and outside environment, for

cultural and climatic reasons

In addition, there are ancillary spaces outside the house to support people’s

activities and livelihoods, including small jetty, yard, garden, farm, pond, pigsty,

hen-coop, and storehouse, etc

Source: Author 

Figure 59. Plan of a house in the Mekong Delta’s deep flooding area 

Source: Author

Source: Author 

Figure 65. The water  floor, bathroom and WC 

Source: Author (Phu Cuong  Village, Tam Nong District,  November 28, 2009)

Figure 68. A store house 

Source: Author (Phu Duc  Village,Tam Nong District,  November 28, 2009)

a Type A ‐ traditional house on stilts

This type of house is popular in the upper Mekong Delta’s deep flooding

area due to several advantages First, the floor level of these houses is raised high on

stilts to avoid the floods Second, the houses are convenient for farming and fishing

activities in dry and flooding seasons The ground floor can be used for storing

farming and fishing tools; in some cases, this space can also be used as living space

in the dry season Other spaces used for storing harvested rice are the bridge area,

ancillary area and back area Third, the local culture is integrated with this

traditional layout There are spaces like the altar in the center of the large living

room, the large verandah as a space for informal guests, the bridge area for family

activities, and the water floor for washing activities

Figure 69. Type A houses 

Source: Author (Phu Duc Village, Tam Nong District, November 28, 2009 (left) and Long Khanh Village, Hong 

Ngu District, December 05, 2009 (right))  Figure 70 shows photos of a traditional house on stilt in the studied area The

house has a small jetty connected to canals The ground floor is used to store

farming and fishing tools The elevated front ground ensures connectivity of the

house to the roads and can be used for drying husks and fishes The house includes

the main area with living and sleeping rooms, the bridge area for family activities

and storing harvest, the back area for kitchen, water floor and toilet, and a large

verandah with a tea table for informal guests

Figure 71 and Figure 72 illustrate activities of a Type A house in the plan in

the dry and flooding seasons Figure 73 and Figure 74 illustrate its activities in the

section in the dry and flooding seasons It can be observed that there are changes of

livelihood activities between the dry and flooding seasons

Source: Author 

Figure 72. The plan of a Type A house in flooding season  

Source: Author 

Source: Author 

Figure 74. The section of a Type A house in a nice flood 

Source: Author 

b Type B ‐ temporary house on stilts

This type of house is popular in the upper Mekong Delta’s deep flooding

area They are temporary houses on stilts which have quite similar advantages like

Type A houses, but they are less durable and spacious, although more economical

The houses are built of low quality wood and temporary materials such as thatch and

metal panels The durability of this type of house is a concern in dealing with storm

surges and strong winds, especially during the flooding season

Figure 75. Type B houses 

Source: Author (Phu Tho Village, Tam Nong District, December 01, 2009 (upper left and lower right), Binh  Thanh Village, Hong Ngu District, December 04, 2009 (upper right), and Tam Nong District, November 27, 2009  (lower left) 

Source: Author 

Figure 77. Section of a temporary house on stilts in Phu Tho village, Tam Nong in a nice flood 

Source: Author 

c Type C ‐ old house

This type of house can be found at Long Khanh Island in the upper Mekong

Delta’s deep flooding area Due to the fertile soil in this area (natural levee) and

higher level of land, many houses are garden houses and the level of the houses on

stilts is low compared to houses in other areas These houses have been built for a

long time, with several houses aged over 50 years These houses were built by

wealthy people, using high quality wood such as Xylia xylocarpa (căm xe),

Lagerstroemia calyculata (thao lao), “cà chất”13, Pterocarpus macrocarpus (giáng hương)

Figure 78. Type C houses 

Source: Author (Long Khanh Village, Hong Ngu District, December 04, 2009) 

d Type D ‐ houses on elevated ground

Houses built on elevated ground are quite similar to houses in the Mekong

Delta’s non-flooding area They are usually connected directly to elevated roads or

elevated front ground, hence they are almost not affected by flood

13 Vietnamese name of the wood

Source: Author (Phu Tho Village, Tam Nong District, December 01, 2009 (left) and National Road 30, November 

27, 2009 (right) 

e Type E ‐ floating house

Floating houses are used for fishing homesteads and for people who do not

own land However, most families living in floating houses prefer to live on the

land This type of house may be an option for future adaptation Below are some

characteristics of these houses

 Water pipes, barrels and bamboos are put into a frame to keep the houses

floating Light materials are used for other components of the houses

 In the flooding season, people move the houses towards the river banks

as the water flows swiftly in the flooding season

 People travel by boats For houses near the river banks, they have a small

wooden path on barrels connecting them to the land

Source: Author (Da Phuoc Village, An Phu District, An Giang Province, December 07, 2009) 

Figure 81. Section of a floating house in Chau Doc 

Source: Author 

Source: Author 

f Type F ‐ houses in residential dykes and clusters

The government provides these houses to resettle inhabitants from the deep

flooding areas that are vulnerable to flood This type of house and its advantages and

disadvantages are discussed in detail in Section 3.1.1.2

Houses in residential dykes are preferred to houses in residential clusters

because the quality of infrastructure is better and people’s lifestyles are less affected

People may engage in animal husbandry (illegally) and gain direct access to the

canals The residential dykes are usually nearer to people’s former habitats, so they

can better sustain livelihoods If they have some land, it is convenient for them to

connect to their farms If they are landless, it is easier to sustain relationships for

their hired on-farm and off-farm jobs

In summary, in order to raise floor levels to adapt to floods, houses on stilts

or elevated grounds are built Houses built by the people also support livelihoods

activities in the dry and flooding seasons For all of these types, people flexibly

arrange spaces in and around the houses for livelihood activities such as spaces for

working, storing tools and harvests, and drying yards Floating house is an

interesting type because their floating characteristics can be applied as an adaptation

measure to floods in the future

4.3.2 Current adaptation strategies of houses

This section analyzes how houses adapt to floods in terms of location and

settlement patterns, elevation, durability and housing construction, flexibility,

landscape, and other criteria (land ownership, main source of income and wealth),

which are the issues that affect adaptation of houses to floods

4.3.2.1 Location and settlement patterns

This part describes locations of houses and their connections to roads, canals

and farms and how houses are affected by floods

a Relative location of houses to roads and dykes

In the studied area, houses settle along high elevated roads, low elevated

roads, in flooded areas, in protected areas (full-dyke and semi-dyke), and in

residential dykes and clusters Figure 86 illustrates houses in different location with

different flood levels in history It shows that location has critical impact on houses

in the flooding season, mainly due to impact of floods on transportation and the

connectivity of houses to public services The followings discuss in detail how

location affects the impacts of floods on houses

or 2000)

The levels of main roads were constructed over the peak flood level in 1996

or 2000 Since then, houses along high elevation roads have not been affected

substantially by floods These houses have good connections to infrastructure and

public services such as schools, markets and healthcare centres, and facilities such as

electricity and piped water, as these facilities are usually provided together with the

main transport system In addition, their daily activities, except agriculture

production, are not considerably influenced by floods

Houses along low elevated roads (lower than the peak flood levels in 1996

or 2000)

Low elevated roads may be inundated in the flooding season As a result,

people may encounter difficulties in connecting to infrastructure and facilities to

some extent In the case that the road is inundated deeply, water transportation

becomes predominant in the flooding season However, most roads in the studied

area are relatively high compared to the average flood level, so houses have not been

significantly affected in recent years

Houses in areas protected by dykes

Majority of dykes in the studied area are semi dykes (Section 4.1) Houses in

semi-dyke protected areas are protected from early (August) and late (November

and December) floods Meanwhile, houses in full-dyke protected areas are not

affected by floods, but in the long term, agriculture production may be negatively

affected due to loss of sediments, increase of vermin, and reduction of fishery

resources

For houses that are surrounded by floodwater, water transportation becomes

predominant Houses in these areas have difficulties connecting to infrastructure and

facilities, and may have limited access to electricity and piped water However,

these houses are the minority in the studied area, due to their inconvenience and

danger, and resettlement in residential dykes and clusters

Houses resettled in residential dykes or clusters

People who have resettled in residential dykes and clusters are not affected

by floods because the level of houses and roads is higher than the highest flood level

in history However, these houses have a poor quality of construction The

infrastructure, including the drainage systems and piped water supply systems, is

inadequate The people may also have difficulties in sustaining and improving their

livelihoods

In summary, the location of houses considerably affects the extent of impacts

of floods on houses, especially the connectivity of houses to the transportation

system and public facilities, and the livelihood activities of the inhabitants Houses

in flooded areas, areas protected by semi-dykes, and houses along low elevated

roads are most affected by floods

Source: Author 

  Figure 87. Settlement patterns in dry season, nice flood and flood in 2000 

Source: Author 

b Settlement patterns

Settlement patterns represent the connections among houses, roads, canals

and farms, which means the connections of houses, infrastructure system, and

livelihoods Therefore, it determines the extent of impact of floods on access to

transportation and services, people’s daily activities and livelihood activities such as

farming and fishing In the studied area, most houses and buildings are along the

roads, canals and rivers due to travelling convenience, especially in the flooding

season Figure 87 shows different settlement patterns in the dry season, and a nice

flood and the flood in 2000 It can be interpreted that houses with access to both

roads and canals have the most advantageous connections to transportation, and also

farms Meanwhile, houses in the infield areas are most affected by flood due to

limited connections to transportation, but have easy access to surrounding farms for

farming and fishing activities Houses in infield areas are the minority in the studied

area

Settlement patterns in the studied area are examined in greater detail below

Group 1: Houses that are directly connected to roads and canals

This group of houses has both access to land and water transportation in dry

and flooding seasons It is convenient for them to access farms and transport heavy

things such as farming tools, fertilizer and harvests Connectivity of these houses to

services and facilities is also advantageous (Table 7)