SEMINAR ON RESULTS MANAGEMENT FOR
PUBLIC SECTOR EXCELLENCE
16 - 20 April, 2012
RECENT DAMAGES ON ROADS FROM NATURAL DISASTERS
AND PREVENT MEASURES TO MITIGATE THE DAMAGES
IN VIET NAM
By Eng. Cao Thi Mai Lan
Science Technology, Environment & International
Cooperation Department
Directorate for Roads of Vietnam
1. About natural conditions - impacts to road infrastructures
Viet Nam located in South- East Asia under the condition of tropical monsoon
climate.
Viet Nam is set apart from the other countries of the Indo-Chinese Peninsula by
the length of its coast, thousands kilometer of seashore, exposed to the typhoons of
South China Sea from June to December.
Table 1 shows climate characters of several locations in Viet and in the region.
Table 1. Data of climate conditions
Ha Noi
Ho Chi
Minh
City
Phnom
Penh
Vientiane
Total Temperature per year (C)
8560
10000
10100
9250
Total Heat Radiation (kcal/cm2.year)
111.3
136.4
155.3
140.5
Yearly average Temperature (C)
23.4
27.6
28.0
25.7
Temperature of most cold month (C)
16.6
26.2
26.4
21.7
Temperature of most warmth month
(C)
28.8
29.8
29.8
28.5
Yearly Rainfall (C)
1600
1984
1400
1670
Climate Character
Rainy season
Yearly average Humidity (%)
May - Oct May - Oct May - Oct May - Oct
84.0
1
82.0
73.0
80.0
Geotechnical and geographical condition for construction and management of
road infrastructures in Viet Nam is extremely complicated.
Viet Nam located on the long and narrow peninsula with 80% land area of
mountainous characters, perilous terrain and strongly separate geomorphology.
Mountainous terrain not to high but obstacle, strongly divided, enough thick but so
deep, so much mountain slopes… all that created a dense network of rivers. In some
region reached river density up to 1.5 - 2.0 km river/km2. That means in the rainy
season flooding water concentrates and so quickly and aggressively flows.
Road network distributed in mountain, highland and level morphology. Common
Geological of Viet Nam’s terrain are the stratification of sedimentary rock under
hardly evolved environment of tropical climate influences. So much geotechnical –
engineering technologies would find necessary application in building and
maintenance of bridge and road in Viet Nam.
Viet Nam seashore of over 3,200 km confronts mostly the West Part of East Sea
(3,447,000 km2 and nearly 4,106 km Seawater). Along this there are sea-currents
northwards (Summer) and southwards (Winter). That dominates the tropical-monsoon
climate of Viet Nam. It brings rains to the whole country. In the rainy season, rain
water get till 70% of total rain water in an year, in some localities up to 90%. And the
concentrated rainwater often brings strong flood (in mountainous area high water
speed up to 2-3m/h).
Viet Nam seashore is also bordering the East Sea including the Bac Bo Bay where
is the so called “homeland” of West Pacific Typhoon/Hurricane Nest - one of the 5
biggest Nest on the Earth. In this region 37% of Hurricanes on the Earth appear and
destroy all things on their way.
Table 2 presents the data of Typhoon distribution got by long year statistic (1884 1989) on the region of Viet Nam.
Table 2. Distribution of Typhoon to Viet Nam (1884 - 1989)
Region of Viet Nam
Number of typhoon Distribution (%)
Bac Bo (North part)
148
30
Bac Trung Bo (North of Central Part)
182
37
Da Nang to Binh Dinh
118
24
Deo Ca (Ca Bypass- Southwards)
45
9
Total
493
100
It is remarkable that the appearance frequency of typhoon/cyclone in Viet Nam
increases. It causes by the increasing of the Earth Average Temperature. In the past
time from 1884 till the end of last century the number is 5.5 typhoon/year, in the 80’ 6.0 typhoon/year and the 90’ - 7.2 typhoon/year.
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In Viet Nam the typhoon/strong rainy system has also special character. That is
the very terrible rain in typhoon. Some typhoons brought together with the strong and
daily-lasting rain of high intensity 700 - 1100 mm/24h. In fact, typhoon/strong
rain/flooding can appear at the same time in catastrophe of some regions.
2. A general view of the Vietnamese Road Network
Road transport plays an important role in the socio-economic and cultural
development, national defense and security and expansion of international exchanges.
The transport infrastructure including road infrastructure is a critical part of the
socio - economic infrastructure. That is why it needs first investment development to
create precondition and main force for the socio-economic development, serving the
cause of national, industrialization and modernization and the country’s course of
economic integration with the region and the world as well.
A general view of the Viet Nam road network is presented in Table 3, table 4 and
figure 1.
Table 3. Road Network of Viet Nam
Road Category
Length (Km)
%
National Highway
16,839
6.014
Provincial Highway
25,449
9.089
Urban Highway
17,025
6.08
District and Village Road
212,857
76.02
7,837
2.799
280,007
100
Specialized Roads
Total Length
.
Road density: 24,06 km/100 km2 and more than 28,000 small, medium and big
bridges with total length of 223,818 meter long on the road network.
3
RRMU.
2
RRMU.
4
RRMU.
5
B¶o Léc
§ång Xoµi
Hßn R¸ i
RRMU.
7
Sãc Tr ¨ ng
0
100
200
Kilometers
Figure 1. Map of main road network of Viet Nam
During the recent years, the Government has paid special attention to the
construction and improvement of the road network. Investments including domestic
funds and foreign loans are increasing day by day. The road infrastructure has
gradually been improved and quality of roads and bridges has increased.
Together with the development investments, investment in the management and
maintenance of the existing national highways should be paid due attention in order to
enhance their operation efficiency. However, budget allocation to the work of road
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management and maintenance remains low, only meeting about 30 - 40% of the
demand.
Table 4. Annual Road Maintenance Allocation
Maintenance
Program
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
Routine
Maintenance
190
180.548
182.677
243.99
284.2
326.175
433
469.797
524.307
551.959
655.072
749.035
Periodic
Maintenance
308
329.452
416.483
621.63
662.33
661.665
938.46
1 405.02
1 381.74
1 438.38 1 847.33
1 836.14
Total Km
15 425
15 425
15 425
17 295
17 295
17 295
17 295
17 002
16 839
16 763
16 747
As impacts of natural disasters to the road infrastructures in Viet Nam every year
road users and especially Road Engineers, workers as well as Road Managers have to
confront with all the dangers of flooding and landslide, road pavement, road
embankment, destruction of any sizes, destructions on bridge and culverts …. on road
network of Viet Nam (see figure…..)
Figure 2. Images from damages on Viet Nam’s road by typhoon, strong rain and
flooding
2. Information about Land Infrastructure Damages from Viet
Nam Natural Disasters during the period 2001 - 2011
2.1. Natural Disaster 2001 - 2005
Only in the last five years on every rainy season, the natural disasters with
typhoon/strong rain/flooding eradicates scandalously region of country with very
larges losses including frightful destruction of transport infrastructures. In the table 4
are showing the outstanding natural disasters, location meet with typhoon…. Table 4
listed great losses from these disasters in whole sector transportation at that time.
5
16 700
Table 4. Natural disaster (2001 - 2005) in Viet Nam
Year
Number of
Typhoon
Regions meet with
natural disaster
Losses
2001
9
North West , Red River
Delta, Along Central Area,
Mekong Delta ….
2002
10
The North, Central Area, 335 Deaths, 34 lots, 275
East of the South. Many injuries, heavy damages on
sweep floodings
roads
2003
11
Red River Delta, Central Landslide, great deformation
Area….. Strong - long rain on many highways (1a, 6, 10,
700 - 1000mm
14D, 14B, 14E, 15, 32, 37,
39, 279
2004
4
Seashore province
Railway section Quang Binh
- Quang Ngai
2005
8
Strong typhoon attacked
together with high tide in
seashore area, strong rain
in Central area with sweep
flooding and landslide
Landslides
on
national
highway No. 2, 3, 4, 12, 14E,
32, 37, 279 ……
Destruction on
dyke, 4 deaths
seashore,
In 2001 prolonged flooding (August - November, 2001) overflowed 9 provinces
and destroyed bridges, culverts embankments section, pavement ……. and specially
on the rural road network.
In 2002 there were strong sweep flooding in mountainous areas of the North and
in the Eastern South of Viet Nam. For example, the prolonged and strong rain in
August 2002 destroyed and stopped traffic on the National highway (NH) No. 6, 12,
37, 279 etc; created landslides of total 216,179 m3/soil; deformed 4,537m2 road
pavement; damaged 1 bridge and 67 culverts, all with total loss of 62 billion VND.
In 2003 strong rain and flooding created destruction on NH No. 32, 37, so much
road sections overflowed by flooding and cut traffic flow for some days. In rainy
season on the Thong Nhat railway main line from Ha Noi to Ho Chi Minh, from Km
1228+150 to Km 1663+050, there were 29 sections overflowed and damaged. Traffic
stopped for two days (13 - 14 November).
In 2004 typhoon and strong rain in Central area brought enormous damages and
destruction on Thong Nhat railway line (from Quang Binh to Quang Ngai) and on the
rural road network. Traffic on railway must be stopped for 3 days, and so 49 trains had
to be cancelled… In 2005 on 27 and 28 September, strong rain brought about powerful
sweep flooding in several provinces as Lao Cai, Hoa Binh, Phu Tho, Nghe An and
especially in Yen Bai. It ravaged all kind of infrastructures. There were 64 deaths in
Yen Bai. Strong rain in other area of the country brought also damages in all kind as
landslide, embankment destroyed……
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It was already estimated the big loss from these Natural Disaster for whole
transport sector in five years 2001 - 2005 with amount of 2,577,840 billion VND
including:
- Road: 631,350 billion;
- Rain: 72,354 billion;
- Inland waterway: 12,677 billion;
- Maritime: 5,274 billion;
- Aviation: 0,9 billion;
- Construction corporations: 65,168 billion;
- Rural Road and Inland waterway: 1,790,117 billion.
Remarkable is that total amount compared the half of estimated cost for the
construction of Ho Chi Minh Trial of first stage.
In five year 2001 - 2005 are following damages registered and repaired:
12,550,948 m3 of earth works from landslides, 2,791,412 m2 of pavement deformation
and destruction, 4,258 damaged bridges and 1,777 damaged culverts.
2.2. Natural Disaster 2006 - 2011
There was another year of complicated and severe weather in 2010 in which many
opposite weather phenomena have been observed over Viet Nam. From the beginning
of the year, water level in many rivers all over the country were historical low; early
hot weather accompanied with many severe events and above average temperature and
historical maximum temperature in Hoa Binh (41.8C), Ha Noi (40.4C), Tinh Gia
(42.2C), Con Cuong (42.2C), Quynh Nhai (42.0C)…. In the Central: During flood
season of 2010, in rivers in Central Region, from the late September to late November,
it is occurred 4 large rainfall and floods. Large flood occurred on rivers from Ha Tinh
to Thua Thien Hue provinces. Historical flood and extreme floods occurred on some
rivers from Ha Tinh to Quang Tri Provinces, flood peak in most of rivers in the area
exceed the alarm level 3 from 0.3 to 1.5m, except Nhat Le river occurred historical
flood and two medium and small floods. Two highest floods are described in main
national report. In the North, Central Highlands and South of Viet Nam: There is not
any big flood.
During rainfall season of 2010, in the North, Central and Highland of Viet Nam, it
is occurred 17 heavy rains in which 7 serious rains were occurred in Central Viet Nam
and on the main rivers of Viet Nam, it is occurred 6 floods, in which 4 serious floods
were occurred in main rivers in Central, Highland of Viet Nam. Two historical flood
events were occurred on some rivers of Ha Tinh and Quang Binh provinces. These
floods caused extreme damages on human lives and properties to these provinces.
In 2011, most part of the Central are likely to experience slightly below normal
condition, separately in March and April, the average temperature is below normal.
The heat wave (the highest temperature during the day upper 35C). The heat wave is
less and shorter than heat waves occurred in 2010. The heat waves period occurred in
May and June and was effect mainly in the North and Middle of Central.
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During rainfall season of 2011, in the North, Central and Highland of Viet Nam, it
is occurred 7 floods, in which 4 serious floods were occurred in main rivers in Central,
Highland of Viet Nam. These floods caused extreme damages on human lives and
properties.
It was already estimated the damages since 1990 - 2009:
- Dead and missing: 12,915 persons, average 646 per year.
- Damaged and Collapsed houses: 11,334,436 houses, average 556,722 per year.
- Sunk and damaged boats: 14,597 boats, average 730 per year.
- Crops: 6,458,836 ha, average 322,941ha per year.
- Total economic loss estimated: 115,063 million USD.
3. Causes to large, prolonged flood
- In the flood, there were weaknesses and unsuitability due to limited resources
from the government and local public infrastructure does not meet the requirements for
flood and storm prevention; besides there are also some unsuitabilities in the planning
and development of infrastructure, industrial and residential areas.
- The connections between National Highway No. 1A and Ho Chi Minh Trial,
which were built to help reduce traffic jam due to flood in National Highway No. 1A
and roads to mountainous districts, have been flooded and were not effective.
- National Highway No.1A, Ho Chi Minh Trial and North-South Railway, which
have been built in higher elevation, have become a west-east flood barrier. However,
the bridge and sluice system has not yet met the flood drainage requirement which led
to longer flooding time and destruction at some railway and national road locations
and caused extreme traffic jam.
- Due to urbanization, some towns have leveled low-landing areas, areas along
floods drainage, estuarine areas, flood drainage corridor etc. to build industrial areas,
residential areas and housing. Moreover, the foundation is not high enough, so in large
flood, many residential areas are still inundated, which makes flooding more serious
and causes many accidents in the area during the period.
- Most of irrigation and hydropower reservoirs are designed in order to reduce
flood level for downstream areas. However, examination results in 2009, 2010 in
Central Provinces and Central Highland Provinces have shown that most of reservoirs
have no flood volume for downstream areas.
- Reservoir operation, especially multi-reservoir operation, still has many issues
that need to be considered and researched in order to help reduce flood and mitigate
damage for downstream areas.
4. Proactive and prevent measures to mitigate damages on Road
Network of Viet Nam
Positioned to the place where every year the life and people impacted by
numerous natural disasters, Viet Nam - the country in general - and specially the
transport sector have to make more and more efforts to “live peacefully” with these
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disasters. It means also good measures as well as effective technology must be found
for that struggle.
1. At national level, the Environment Protection Law and Policy already set up.
Forest Protection and Cultivation Program, and other Rural Development Projects
steps by steps realizing. All these would contribute basically to our task “Protection of
Transport Infrastructures from natural disasters”.
- Implementing orientations of the National Strategy in Disaster Prevention and
Mitigation by 2020.
- Review land-use planning, residential areas, transportation, irrigation, river and
ocean dykes, electricity systems, communications, industrial zones, tourism areas and
disaster prevention and mitigation work, especially areas prone to flooding to ensure
harmony cooperation between socio-economic development, disaster risk reduction.
- Checking bridges, culverts, dykes in road system, railway, industrial areas,
services, residential areas.
- Increasing investment funding on infrastructure for flood and storm prevention,
rescue equipments, training on capacity building for staff, local residents, meeting the
requirements step by step.
- Increasing international cooperation in disaster prevention, especially with
countries in the region and countries with rich experience in the field.
- Mobilizing, calling for ODA funding, capital grant support to develop resources
in disaster prevention activities in the whole country.
2. At (transportation) sector level, there are policy in detail to be set up.
- Policy of transportation infrastructure quality including all activities of
construction works such as: survey and testing for project, designing, constructing,
managing the built works etc. The survey and testing procedures must be more
invested in the meaning of more money input, and especially of the proactive survey
and testing techniques. On the results of survey are numerous economy-technological
issues depending (size, special treatment measures, size of investment, super
technology etc.)
- Policy of development and using of proactive technologies in whole transport
sector such as planning, transport construction with Quality control system,
management and traffic organization, maintenance policy and activities etc.
3. Some proactive and protection technologies applied in Viet Nam transport
infrastructure:
- Study and using optimal design of water drainage structure system for roads on
mountainous area of Viet Nam.
- Using new technology of road slope stabilization by using pre-stressing
anchorage technique.
This proactive technology has brilliant future for using in Viet Nam Road
Network development and especially in maintenance.
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Figure 3. Road slope stabilization
- On the sections of National highway along Central Area and Seashore where
every year overflowed daily-long in rainy season, the proactive technology of cement
concrete pavement continued reinforced can be used successfully.
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Figure 4. Expansion joint installation
5. Conclusion
Natural disaster (Typhoon - strong rain - flooding) always bring great difficulties
to Viet Nam. This report concentrated to present main data of tropical climate
conditions in Viet Nam with rainy season and tropical hurricane, of the size of road
network, of the losses in transport every year by natural disasters.
Proposals for setting up some necessary policies in national level and sector level
would make the community and road users more awaken to these problems.
Proactive technologies (landslide protection, concrete pavement continuous
reinforced, ….) were presented as prevent measures to mitigate damages of transport
infrastructures in Viet Nam under hard condition of natural disaster.
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