2009/2/23

Water induced disasters, Flood Hazard Mapping &Koshi flood disaster of epal

Presentation atEast & Southeast Asia Regional Seminar on Flood Hazard Mapping(17-19 Feb, 2009 at Manila, Philippines)

Presented By: Mitra Baral (Engineer, DWIDP, +epal )Outline of Presentation








Introduction
Disaster Mitigation Acts & Policies in Nepal
Water Induced Disasters
Concerned Organizations & Situation of FHM
Essential FHM Data Situation
Present Problems of FHM
Types of FHM Necessary for Nepal
Koshi Flood Disaster of NepalConclusion1

2009/2/23+EPAL
 Complex geographic feature About 75% mountains & hills, 25% plain.
 Area 147,181 sq. km
 Population 27 million. (Growth rate 2.13%,)
 6000 rivers and rivulets.
 Average annual rainfall 1700 mm (95%; June-Sept.) Average annual surface flow7,125 m3/sec
 Annual deforestation rate 1.8%.
 Sediment discharge about 353 million tones/yr Average rise in temp.0.50 C/decade (Global Warming ??)Surface Water
Perennial sources of water originating from

Mountains

Water flowing throughHills

Passes through plain

Terrains22009/2/23

Disaster Mitigation Acts & Policies in Nepal Natural Calamity Relief Act 1982
 Water Resources Act 1992
 National Action Plan on Disaster Reduction 1996
 Environmental Protection Act 1996
 Local self Governance Act (LSGA, 1999)
 National Water Resource Strategy, 2002
 National Water Plan, 2005
 Three Year Interim Plan (2008-2010 )Natural Calamity Relief Act (+CRA, 1982 ) Amended, 1989 A.D. and 1992 A.D
 Ministry of Home Affairs: Nodal Agency
 Chief District Officers :Crisis Managers at
the time of Natural Disasters.
Central Natural Disaster
Relief Committee

Relief & Treatment
Sub-Committee

Regional Natural Disaster
Relief Committee

Supply, Shelter & Rehabilitation
Sub-Committee

District Natural Disaster
Relief Committee

Local Natural Disaster
Relief Committee

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Water Induced Disasters
 Flood Landslide Land erosion
 Debris flow Glacier lake outburst
 Drought Epidemic
Average annual loss of 309 lives andaffects 27654 families

Concerned Organizations of FHM
 Ministry of Home Affairs: Nodal body Disaster Management Section under MoHA
 Water Induced Disaster Prevention Technical Centre(DPTC): Estd. 1991; JICA
 Department of Water Induced Disaster Prevention(DWIDP) : Lead agency (Estd. 2000; JICA)
 Different INGO like Red Cross Society, JICA,ICIMOD, UNESCO etc.

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Situation of FHM
 Started in 1999 (DMSP:JICA)
 So far FHM of nine river basins.
National Water Plan By 2007 : Potential disasters zones are identified
by type and located on map; Not completed
 By 2017 : Water induced hazard warning systems inall over the country.

Integrated water-induced map of Ranugn river basin ( Area 495.8 sq km mainly
the Dandeldhura District )5

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Flood hazard map of Rupandehi districtOthers
1. Tinau River Basin
4. Rapti River Basin
7. Trijuga River Basin

2. Bagmati River Basin
5. Aandhi Khola River Basin

3. Kamala River Basin
6. Kankai River Basin.

Essential FHM data situation
Hydro meteorological data: Department of Hydrology and Meteorology (DHM) Many measuring stations throughout the country.
 Due to lack of resources, advance techniques, equipments and accountability on datacollection they are not reliable and consistent.
Satellite images, Land-use and topographic maps:
 Survey Department
 Collects, preserve and revised the satellite images, land-use and topographic maps.
 High quality satellite images, precise land- use and topographic maps are notavailable Topographic maps are prepared in 1995
Digital elevation model (DEM):
 Survey department is also providing DEM
 Generally GIS based DEM of the study area are freely downloaded from internet.
 Not precise as available in the market.
 Do not have trend to invest for precise data.
 Problem to develop accurate flood hazard map of the study area.

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Present problems of Flood Hazard Mapping Concept of FHM is somewhat new.
 Developed maps are not complete for dissemination.
 Not aware about the benefit of FHM
 FHM is not taken as development activity andsufficient budget is not allocated for it.
 No trend and culture to invest on observation, datacollection and research activity which are essentialfor FHM
 Lack of availability of precise data and softwares forinundation analysis and flood hazard mapping.

Types of FHM necessary for Nepal
Further improving the data collecting system, wecan manage more precise hydro-meteorological data.
Rainfall runoff modeling can be performed.
If we will be able to manage precise GIS based data
We can produce Flood Hazard Maps based oninundation analysis as described by ICHARM

Type E : Past inundation area based on simulation.
Type F : Inundation area based on design flood.
Type G : Inundation forecast by real time analysis.

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Other information’s about FHM
 Good communication system for information dissemination
 Privatization policy in communication system.
 Many private Television and FM radio stations.
 Telecommunication and internet system are established inmany districts.
 Newspapers are published even at regional and local level DHM provides information and forecast about weather andrainfall.
 Ministry of Home and Chief District Officer issues
evacuation order.
 Red Cross Society, UNOCHA, JICA, UNICEF, Rotary,Save the Children etc are assisting in awareness raising,rescue operation, relief activity and evacuation order at thetime of water induced disasters.

Koshi River & it’s Disaster in +epal
o Largest river basin of Nepalo It originates from the Tibetan Plateau of Chinao Tran boundary river (Nepal & India)
 Total length 729 km. (534 km in Nepal)
 Catchment area 60,400 Sq.Km.
 Average annual flow 1590 m3/sec.
 River width: Up to 11km in Nepal and up to 18 km in India.
 Horizontally changed its course as much as 120 km in the last
250 years
 Average annual sediment volume: 118 million cubic meter.
 Past maximum flood : 913,000 cusec (25849 m3/sec ;5th Oct.1968)
 Recent Flood: 168,500 cusec ( 4770 m3/sec; 18th August, 2008)

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Koshi Project Treaty
Signed between India and Nepal in 1954
Objective: Flood control, Irrigation and Hydropower generation“Sorrow of Bihar”“Pride of India” (Bihar) after completion of the project
Barrage has a discharge capacity of 950,000 cusecs ( 26896 m3/sec) in a peak flood.

Koshi project• Agreement in April, 1954.
• 1150 m long barrage with 56 gates.
• Two head regulator for canals (Eastern: 612,500ha & Western 356,610 ha).
• Power generation of 20 MW ( 11 km d/s of Barrage at eastern canal).
• Earthen Left embankment 144 km (32 km with 57 numbers of spurs in Nepal).
• Earthen Right embankment 125 km (25 km with 51 numbers of spurs in Nepal).
• Length of spur; 150 – 300 m.
• Nepal territory leased for 199 years.

Some clauses of Koshi Project treaty:•The Government of India (GoI) shall be authorized to conduct necessary
investigation for storage or detention for dams on the Koshi or its
tributaries - soil conservation, check dams, forestation, etc. forprevention of future problems (Art. 2.2).
•Nepal shall provide necessary lands to execute the said project (Art. 3.1)
and compensation of land to be provided by India to Nepal (Art. 3.2).
India shall execute all necessary repair work and maintenance, and if
incident occurs, compensation for every damage case shall be provided
to Nepal (Art. 3.3).
•India shall be the owner of all lands acquired from Nepal. The
sovereignty rights and territorial jurisdiction of the Government inrespect of such lands shall continue unimpaired by such transfer (Art.5).
•Nepal shall be responsible for ensuring security in the project areas (Art.
14).

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Koshi Flood Disaster of 18th August 2008
 Breaching of embankment (12.6 km U/S of barrage)
 Breached at 12:50 PM, Discharge at Barrage 168850 cusec 1.7 Km Embankment Breached @ 100m/ hour About 85% flow passed through new channel.
 No such early warning No FHM
 Self evacuated

Schematic View of Koshi River & Flooded Area

Breach Point ZeroChatara
Barrage
Koshi River

LaukahiEmbankment

East West
HighwayBihar
Kosi flowing
in new course

Ganga
Schematic View Courtesy : Ajaya Dixit

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Embankment

Spurs

Koshi River

Koshi Flood ( August 2008)85 % Flow

Photo Courtesy: Basistha Raj Adhikari
Adhikari,,SDE, DWIDP, +epal

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Koshi River

Photo Courtesy: Basistha Raj Adhikari
Adhikari,,SDE, DWIDP, +epal

Map & Photo : UNOCHA

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Dry Barrage

Photo Courtesy: Basistha Raj Adhikari
Adhikari,,SDE, DWIDP, +epal

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Map: German Aerospace Centre (DLR)

Photo Courtesy: Basistha Raj Adhikari
Adhikari,,SDE, DWIDP, +epal

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Disaster Scenario
Country
Affected People
Affected
Displaced People/ Family
RescuedRescued By
Human Casuality (During/ After Disaster)
Relief Camps
Human sufferings

Affected Animals
Displaced Animals
Animal Casuality
Damage+epal

India

107,200
30,65,000
8 VDC of Sunsari District
1704 villages of 16 district
56752 / 7995
1,14,278/+A
5500
3.78.826 evacuated
3 Helicopters, 10 rafting boats, 3 ordinary
2036 boats (Other +A)
boats, 4 elephants etc
1/7
7/47
28
182
Cholera, diarrhea, pneumonia, eye
6 mobile health team,158 Health centre
conjunctivitis, fever etc.
established (Other about sufferings +A)
55000 +A except 96 cattle camps about 6764
20000 animals have been treated.
14571
Agricultural land, Infrastructures, 2/3 of2,83,797 Houses damaged (OtherHouses of the area, Road +etwork,information +A)
Irrigation System, Telecommunications,Transmission line, Wildlife Reserved Area

Data Source: MoHA, Nepal & MoHA, India

Daily life after disaster15

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Reasons of Koshi flood disaster• Unequal Koshi project treaty.
• Rise of bed level (0.05m/year) due to excess sediment load.
• Concentration of flow towards eastern embankment and striking sincelast 8 years• Lack of regular monitoring mechanism and maintenance activity.
• Over confidence about the strength of structures• Yearly havoc about breaching, but not• Problem of security at the site.
• Lack of good coordination between Nepal & India. Trend of blaming
each other• No proper emergency response activity• Lack of nonstructural countermeasure works like rising of awareness,development of early warning system and flood hazard mapping.
• No experience about the extent of flood damage.

Conclusions
 Flood risk reduction is possible with rainfall runoff
modeling, inundation analysis & FHM
Effects of hazards can be tremendously minimized with anapplication of hazard mapping and early warning system.
Present practice of flood hazard mapping is not reliable.
Flood Hazard Maps developed by departments are notcomplete for dissemination.
We should improve our policy & practice to develop
hazard maps and early warning system considering it as adevelopment activity (rather than humanitarian) withpeople’s participation.
Bilateral coordination and co-operation should be set up
with neighboring country to solve transboundary water
induced disasters problem.

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Thank you for your kind attention

Additional

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Flood Damage

Daily Activity

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Evacuation

Damage of structures19

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Post Disaster Activity

Flooded Area

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Satellite image of Koshi Barrage

325,000 ha

712,000 ha
Slashed Down (1975)
374,000 ha
20 MW Hydropower Plant

Flood Control Benefits 214,000 ha

Koshi Barrage

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Koshi River
Flooded Area
Embankment
Breach Point22