UNITED NATIONS ECONOMIC AND SOCIAL

COMMISSION FOR ASIA AND THE PACIFIC

South-East Asia Flood Risk

Reduction Forum

By: By: TES SopharithTES SopharithSenior HydrologistSenior HydrologistDepartment of Hydrology and Department of Hydrology and River Works, CambodiaRiver Works, CambodiaEmail: sopharith01@yahoo.comEmail: sopharith01@yahoo.com

20 February 2012, Bangkok, Thailand

Contents� Brief of river systems and flood characteristics in

Cambodia;

� The 2011 flood damage

� The flood response by the Royal Government and � The flood response by the Royal Government and International countries and Agencies.

� Flood monitoring by the DHRW, MOWRAM.

� Gaps, Challenges and efforts

River Systems:River Systems:• 500 km of Mekong

River bisects Cambodia.

• Tonle Sap Great Lake is

connected to the Mekong

river by the Tonle Sap

river at Chaktomuk

junction in Phnom Penh,

some 120 km to

3

some 120 km to

southwest of the outlet of

the Lake.• At Phnom Penh - Chaktomuk junction, after meeting the Tonle

Sap river, the Mekong then splits into two rivers namely the

lower Mekong and the Bassac rivers. Both rivers flow

parallelly and discharge into the South China Sea.

• About 86% of Cambodia’s territory is the basin of the

Mekong, the Bassac and the Tonle Sap rivers and the Tonle

Sap Great Lake with its tributaries

Flooding in CambodiaFlooding in CambodiaTwo main types of floods can be identified:

� Mekong flood which caused by cumulative of rainfall in the

upper catchments throughout the rainy season and most severe

floods are the results of tropical storms and tropical depression.

The Mekong flood is slowly but steady built in rising level.

• Flash Flood: The flash flood mostly

occurs in the mountainous areas with

4

occurs in the mountainous areas with

high rainfall intensity and affected by

Typhoon or storm in the region.

those floods are swift and could last

only for a few days but often caused

severe damage to crops and

infrastructure especially for

tributaries around the Great Lake

and eastern tributaries of the

Mekong.

2011 Flood2011 Flood A series of heavy monsoon rains caused by tropical storms and low pressure combined to make 2011 the worst flood season in Cambodia since 2000. It was as a combination of Flash flood + the Mekong flood.The flood started on 8/10/2011 and ended on 11/15/2011, with a duration of 98 days.of 98 days.

Source: Weather Chart issued at 12:00 UTC

on September 23, 2011 by Thai

Meteorological Department Source: NASA on October 18, 2011

Comparison between 2000 (white) and 2011 (light blue) max. flood extent in Cambodia and Viet Nam

Max. flood extent Year 2011smaller than max. flood extent Year 2000, especially in Viet Nam

2011 2011 Flood: Impact on Social Flood: Impact on Social Based on official statistics issued by NCDM on 3 Nov 2011:

� hit many parts of 18 cities and provinces (Kampong Thom, Battambang, Banteay Meanchey, and Siem Reap, home to marvelous Angkor Wat, are the most affected);

� Dead 250; 1,593,976 persons of 354,217 families affected; More than 23,000 families evacuated to higher ground.

• 268,631 houses flooded, and 1297 houses were swept away ;

• 491 pagodas, 115 health centers and 1360 schools were submerged in the floods;

2011 Flood: 2011 Flood: impact impact on on

Agricultural production Agricultural production

� Submerged 432,020 ha of grown rice paddies, 66 % of which were destroyed;

� Submerged other crops of 21,929 ha;

� 1675 animals dead.� 1675 animals dead.

2011 Flood: 2011 Flood: Impact on InfrastructuresImpact on Infrastructures

� National and provincial roads: 922 km.

� Rural roads: 4,400 km

� Bridges Inundated: 177 locationslocations

• Irrigation dams submerged: 496,745 m

• River bank collapsed:11,789 m

2011 2011 Flood Flood response� On 22 September 2011, the Prime

Minister, Samdech Techo Hun Sencalled and ordered the responsive agencies, such as National Committee for Disaster Management, Cambodian Red Cross, to take proper mitigating Red Cross, to take proper mitigating measures for rescuing the flood victims.

� Cambodia's Council of Ministers held a special meeting on 26th September 2011 to take measures dealing with the Mekong River and flash floods inundating most parts of the country.

Government, Several humanitarian organizations and international donor organizations were assessing the situation in flooded areas and were beginning distributing of food and non food items to affected population. There is an immediate need for shelter, food and safe drinking water as well as education for safety.

Aid Aid to flood to flood relief in Cambodiarelief in Cambodia

� The government had set aside more than $100 million to help repair damages.

� Besides, Cambodia ,till 3 November 2011, received � Besides, Cambodia ,till 3 November 2011, received humanitarian aids from various international organizations and countries, such as, ADB, UNDP, WFP, FAO, Singapore Red Cross, ASEAN, Japan, China, Republic of Korea, Thailand, Vietnam, Myanmar, France, Australia and USA.

Flood monitoringFlood monitoring� Flood levels along the Mekong, Tonle Sap

and Bassac mainstreams are monitored by the Department of Hydrology and River Works (DHRW) of the Ministry of Water Resources and Meteorology (MOWRAM).

� All flood monitoring and forecasts are � All flood monitoring and forecasts are daily distributed to the government institutions, Prime Minister office, line agencies, NGO and other organizations and mass media.

� In case of severe flooding, warning is also issued by the Minister to the above-mentioned receivers.

� Flood level monitoring on the Mekong mainstream in Cambodia is also put in the DHRW website: http://www.dhrw-cam.org

2011 Maximum flood levels on the 2011 Maximum flood levels on the

Mekong mainstreamsMekong mainstreams

Warning level Date Flooded Flood level

1 Stung Treng 10.7 23-Sep-11 11.25 12

2 Kratie 22 23-Sep-11 22.88 23

3 Kampong Cham 15.2 25-Sep-11 16.02 16.2

Station

3 Kampong Cham 15.2 25-Sep-11 16.02 16.2

4 Chaktomuk 10.5 28-Sep-11 10.85 12

5 Nak loeung 7.5 28-Sep-11 8.06 8

6 Koh Khel 7.4 28-Sep-11 7.89 7.9

7 Prek Kdam 9.5 29-Sep-11 9.98 10

Flash Flood Detection System� Under support of the MRC, the DHRW can access the

MRCFFG system, developed by the U.S. Hydrologic Research Center (HRC) through a USAID/OFDA funded program , to obtain real-time information on flash flood guidance (FFG), flash flood thread (FFT), mean areal precipitation (MAP) and average soil moisture (ASM) occur for 1, 3, 6, and 24 hour on a small basin scale (ASM) occur for 1, 3, 6, and 24 hour on a small basin scale across the country. However, in 2011 we just used this FFGS as trial and haven’t applied this information for Warning yet.

� The MRCFFG is a diagnostic system for flash floods to produce forecasts and ultimately warnings for flash floods. It is not a predictive system.

Example: flash flood in Siem Reap

on 22 September 2011 09:00 UTC

The flash flood occurred in some areas in Siem Reap city at noon time was detected by MRCFFG.

The 24-h observed

rainfall was about 200 mmrainfall was about 200 mm

24-h accumulated rainfall by hydroestimator

Daily rainfall at Banteay Srey(1 August to 1 November 2011)

0

50

100

150

200

250

1-Au

g4-

Aug

7-Au

g10

-Aug

13-A

ug16

-Aug

19-A

ug22

-Aug

25-A

ug28

-Aug

31-A

ug3-

Sep

6-Se

p9-

Sep

12-S

ep15

-Sep

18-S

ep21

-Sep

24-S

ep27

-Sep

30-S

ep3-

Oct

6-O

ct9-

Oct

12-O

ct15

-Oct

18-O

ct21

-Oct

24-O

ct27

-Oct

30-O

ct

date

m

Banteay Srey

Flooding in Siem Reap, 22-24 Sep 2011

Gaps, Challenges and efforts � So far only flood information on the Mekong mainstream is

monitored. The accuracy of short-term forecast of these flood levels are acceptable.

� Sometimes flood information could not reach to the remote and rural people who live in the flood vulnerable area. This caused loss of many lives, especially children.

� Monitoring of flash flood is still not efficiently and is relied on the � Monitoring of flash flood is still not efficiently and is relied on the MRCFFG. Moreover, an accuracy of flash flood forecasting model need to be improved. To improve the issue, this year, the MOWRAM will install a Doppler Radar , which will be completed before May 2012

� Besides, through a series of trainings on space technology application for flood risk reduction provided by ESCAP, ICHARM and JAXA we expect to be capable to make use of the JAXA reliable satellite information for flood risk reduction in our country.

Doppler Radar system

� This doppler rada is build in the MOWRAM head quarter.

� Provides real time rainfall cover area with diameter of cover area with diameter of 400 km.

� Synergy product – ARP05 for short-term and long-term forecasts

� Meteo-factory for issuing warning

Thank you for your kind

attention!