Flood Risk Management in Chindwin River Basin (Myanmar)

Ms. Htay Htay Than Director

Hydrological Division Department of Meteorology and Hydrology

Myanmar

Contents of Presentation

• Introduction

• Study Area

• Causes of river floods

• Flood Forecasting System

• Flood Early Warning System

• Dissemination of forecasts and warnings

• Flood Management

• Gaps and Need

Introduction

Annual Normal Rainfall in Myanmar

Introduction

Catchment Area in Myanmar

No. River Basin Area (km2) 1. Ayeyarwady 348064 (upto Zalun) 2. Chindwin 110350 (up to Monywa) 3. Sittoung 26758 (up to Madauk) 4. Bago 2580 (up to Bago) 5. Dokehtawady 45792 (up to Myitnge) 6. Thanlwin 295270 (up to Hpaan) 7. Shwegyin 1747 (up to Shwegyin) 8. Ngawun -

Stations Lag Time

Hkamti to Homalin 1 day and 12 hrs

Homalin to Mawlaik 1 day and 18 hr Mawlaik to Kalewa 1 day

Kalewa to Monywa 1 day and 18 hrs

Ayeyarwady - 15 Stations

Chindwin - 5 Stations

Sittaung - 2 Stations

Thanlwin - 1 Station

Dokethawaddy - 2 Stations

Bago - 2 Stations

Shwegyin - 1 Station

Ngawun - 2 Stations

Total - 30 Stations

Myanmar has eight major rivers which generally flow from North to South. Ayeyarwady - 1789 km Chindwin - 901 km Thanlwin - 1223 km Sittoung - 407 km Bago River - 331 km

Warnings/Forecasts/Bulletins and News

Warning

• Cyclone Warning • Storm Surge

Warning • Flood Warning • Untimely Rainfall

Warning • Fog Warning • Heavy Rain

Warning • Aviation weather

warning • Low flow water

level • Tsunami • Port Warning • Strong wind

Warning

Forecast

• Daily Weather/water level

• Monthly Weather/Flood

• Seasonal Weather/River Flood Forecast

• Aviation Weather Forecast

• Marine Weather Forecast

• Special Forecast

Bulletin

• Agro-meteorological Bulletin

• Bay Bulletin • Flood Bulletin • Special Weather

Bulletin • Significant Water

Level • Low Flow Bulletin

News

• Earthquake News • Rainfall/Temperat

ure Records • Cyclone News

Daily water level forecast

Dekad Forecast (10 days advance FC)

Monthly Forecast

Significant Water level Bulletin

Flood Warning and Bulletin

Minimum Alert Water Level and Bulletin (for low flow)

Seasonal water level forecast

General Long Range flood Forecast

Flood Forecast for early monsoon

Flood Forecast for Peak-monsoon

Flood Forecast for Late-monsoon

STATIONS CATCHMENT AREA (km2)

HKAMTI 27420

HOMALIN 43124

MAWLAIK 69339

KALEWA 72848

MONYWA 110350

Receives very high rainfall at upper part of basin and high discharges

Annual Rainfall varies from 800 mm to 4000 mm.

Total catchment area is 110350 km2

Study Area

Hkamti

Homalin

Mawlaik

Kalewa

Monywa

Elevation (m)

India

Chindwin River Basis - Intense heavy rain due to pronounced monsoon trough

persisting for at least 3 days over Northern Myanmar areas

- Heavy rainfall due to cyclonic storm crossing Myanmar and Bangladesh coasts during pre-monsoon and post-monsoon

Causes of River Floods

Manual Observation to Automatic WL Observation

Status of Hydrological Observation System for Discharge Measurement

Discharge Measurement by Moving Boat Method

Discharge and Cross section Measuring by M9 (River Surveyor)

Preparation of Forecast and Warning

The river forecasting methods such as river stage correlation and empirical model are used for computing daily water level forecasts as well as flood forecasts

Whenever heavy rainfall condition arises due to occurrence of strong monsoon, presence of tropical cyclone near Myanmar coast, formation of trough near part of Myanmar for 3 to 4 days and crossing the remnant of Typhoon from the south china sea to Myanmar, alert is taken for watching flood along those rivers

03.2716.017.016.012.084.0 )(1 +++++=+ changeMCBPTtMKtMCBtMKtMKt HRFRFHHH

Multiple Linear Regression Approach for 1 day ahead for Ayeyarwady River

FC for Myitkyina

Used parameters WL and RF of Forecasting Station, WL and RF of upstream station, 24 hr Change WLs

10:29 am (MST)

Early Warning Dissemination

Phone

Fax

SSB

Early Warning

President office

Chief Ministry State & Region

Ministry of MSWRR

Related Ministries

Media

Television

Radio/ FM

Website/ newspaper

INGO, NGO

4.11

2.07

3.78 3.7

0.99 0

0.51

1.52

2.53

3.54

4.5

Hka

mti

Hom

alin

Maw

laik

Kal

ewa

Mon

ywa

flood

mag

nitu

de (m

) Highest Flood Magnitude of Chindwin basin by meters since 1966

18.25 18.5 18.5 18.5

16.5

15.5

16

16.5

17

17.5

18

18.5

19

Hka

mti

Hom

alin

Maw

laik

Kal

ewa

Mon

ywa

flood

dur

atio

n (d

ays)

Highest Flood Duration of Chindwin basin by days since 1966

Flood Disaster in Myanmar Chindwin Catchment

June 1%

July 41%

August 33%

Sep 11%

Oct 2%

Monthly Flood Percentage at Lower Chindwin River

0

10

20

1967

1968

1969

1969

1970

1971

1972

1973

1974

1975

1976

1977

1977

1978

1979

1980

1980

1981

1982

1983

1984

1984

1984

1985

1985

1986

1987

1987

1988

1988

1989

1990

1990

1990

1991

1991

1992

1993

1994

1995

1995

1996

1997

1997

1998

1998

1998

1999

1999

2000

2000

2000

2001

2002

2002

2003

2004

2004

2005

2006

2007

2007

2008

2008

2009

2010

2011

2011

2012

2013

Day

s

Flood Duration at Kalewa (Chindwin River)

2009 Flood View at Kalay

Flood duration : 2 to 15 days

1 ft to 12.1 ft above danger level

Flood Duration 7-7-2008 to 16-7-2008 ( 9 days) Flood Peak 1840 cm (9.5 ft above danger Level)

Flood Management

Heavy machines at works for strengthening the embankments before the flood water arrives.

Strong Embankment after reenforcement works - ready to combat against flood water.

Protection from erosion by using low coast local bamboos.

During the entire flood period, more than 35 000 people, comprising of Government employees, local residents, police & fire service staffs, red cross Volunteers, students, etc, watched the river water conditions and the stability of the river embankments day and night, for immediate response.

Flood Management

Dept. of Meteorology and Hydrology (DMH)

Early Warning

Dept. of Irrigation Special repairs to be done on embankment system using

machine and manpower to fill up where the embankment is low and strengthening weak portions of the embankment by resectioning them

Directorate of Water Resources and Improvement of River System (DWIR)

River Training (Bed Regulation Method)

Dept. of Relief and Resettlement

Flood mitigation and preparedness

Relief Items to the Flood Victims

Workshop and Training Courses at DMH

Lectures to University/college/High School about weather and disaster mitigation and prevention

Radio Talks and Television News for Public Education

Distribution of pamphlets

Articles in the Newspapers and Journals

Public Awareness Programs

Gaps/Needs and Challenges

Lack of instruments for real time data observation such as rainfall, water level, etc

Lack of real time data for utilization of flood forecasting No mobile Doppler Radar Lack of communication system No information from dam, reservoir and weir, etc, Lack of co-ordination among government departments / organizations Insufficient flood related data and network No automatic flood related data collection Network Insufficient knowledge about flood hydrology (rainfall runoff

estimation, flood volume estimation, flood routing etc.) in flood related departments.

Lack of developing the early warning system for dangerous hydrometeorological phenomena

Lack of developing the flood risk maps