Local flood early warning with low-tech approaches and community

Community involvement and local
flood early warning with low-tech
approaches for small rivers in the
Philippines
Hilton Hernando
Philippine Atmospheric, Geophysical & Astronomical Services Administration
Olaf Neussner
Deutsche Gesellschaft fuer Internationale Zusammenarbeit (GIZ)
28 May 2013, Seoul, Republic of Korea
10/23/11
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Philippines: average of about 30 flood events per year!!
T. Marce - SW (Aug. 2004)
Ondoy (Sept. 2009)
SW Monsoon (Aug. 2012)
T. Pedring (Sept. 2011)
T.S. Sendong (Dec. 2011)
T. Frank (June 2008)
Ormoc Flood 1991
Hilton Hernando, Olaf Neussner
Typhoon Pablo (Dec. 2012)
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Only 5 river basins
with telemetered Flood
Forecasting & Warning
System
For other smaller basin / watershed areas:
CBFEWS (LFEWS) is still the best and
preferred alternative. (innovative, inexpensive yet
robust, strong community participation)
Hilton Hernando, Olaf Neussner
10/23/11
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The Community-Based or Local Flood Early Warning
System (CBFEWS/LFEWS)
Key elements of an LFEWS:
1. Risk knowledge
2. Monitoring & Warning
3. Info Dissemination & Communication
4. Response capability
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10/23/11
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Binahaan Flood Early Warning System
Example of LFEWS program
in the Philippines
Data
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Warning to
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Warnin
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ain
Flood-prone
Area
Binahaan
Watershed
Data gathering
Warning to municipalities
Warning to villages
Warning to households
Evacuation
Hilton Hernando, Olaf Neussner
10/23/11
Tanauan
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1.
2.
3.
4.
5.
ation
Evacu
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Warning to Munic
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Operation
Center
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RISK KNOWLEDGE
Community-based Participatory risk
mapping:
- People know frequently occurring
hazard events well (e.g. floods).
- Location of households and other
assets
- Encoded in GIS for overlaying with
existing (scientific and topographic)
maps.
Community-based mapping in GIS
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MONITORING & WARNING
Manual and an automatic (radio linked) rain gauges
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MONITORING & WARNING
Manual and automatic (radio linked) water level gauges
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MONITORING & WARNING
Community volunteer with display of rain sensor on the roof;
below student volunteers doing rainfall observations
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INFO DISSEMINATION & COMMUNICATION
Flood Warning Levels
Flood Level 1
Alert / Stand By
Three stages
Prepare / Get set
Flood Level 2
Preparation
Ready
Flood Level 3
Evacuation
Go
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INFO DISSEMINATION & COMMUNICATION
Flood Warning Levels
Flood is inevitable
within some hours
High probability of flood
Flood coming any time
?
Condition (Binahaan River)
WL >= 2.5m @ LMWD Flood
WL >= 1.5m @ LMWD,
WL >= 2.0m @ LMWD Flood
or RG >= 80mm/h @ LMWD. will be at San Benito Bridge in is past San Benito Bridge and
will reach other barangays
<5 hours.
any time.
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10/23/11
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INFO DISSEMINATION & COMMUNICATION
Who needs to do what at the three warning levels?
MDRRMO
(Operation Centre)
Radio, telephone (landline, mobile)
Barangay Dev. Council
(DRRM Committee)
Bells, megaphone,
SMS, messenger
Households
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10/23/11
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INFO DISSEMINATION & COMMUNICATION
Municipal DRRM Office
•
•
•
•
•
•
Warn all BDRRMCs in flood-prone
area. Inform about flood, advice
to start slow preparatory
activities, gather children,
animals
Alert MDRRMO staff and ask
them to go on standby
Alert Search and Rescue Teams
and ask them to go on standby
Inform PNP
Check status of/access to and
prepare municipal Evacuation
Center
Listen to status report on DYMP
•


•
•
Warn all BDRRMCs in flood-prone
area . Advice households to
prepare for evacuation:
Prepare Emergency Pack for five
days (water and food, cloth, etc.)
Secure vulnerable items in
household
Prepare and open municipal
evacuation Centers (e.g. lights,
water, food, toilets, beds,
blankets, medicine, etc.)
Listen to status report on DYMP
Hilton Hernando, Olaf Neussner
•


•
Advice all BDRRCs in flood-prone
area. Order households to
evacuate and bring emergency
pack for at least 5 days
Check evacuated houses
Head count at evacuation center
Listen to status report on DYMP
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RESPONSE CAPABILITY
Drills
Active participation of locals in
providing warnings, e.g. Bells, etc.
Evacuation Drill in St. Bernard,
Southern Leyte
Evacuation drills strengthen LFEWS
ownership of communities
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RESPONSE CAPABILITY
Improved Evacuation Centres
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RESPONSE CAPABILITY
Search & Rescue Capacity Training
Strong Participation of Community Members
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LFEWS in action
Alert Level 3
lifted
Water level [m]
Alert Level 2
issued
Alert Level 3
issued
Flood starts
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10/23/11
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Community members and governmental rescue professionals work hand in
hand
Ormoc, Leyte, 27/28 Dec. 2011
Bulacan, Sept. 2011
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10/23/11
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Summary
How is the Local Flood Early Warning System
established and how does it perform?



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LFEWS costs 30,000 – 40,000 US$ in the Philippines
Cost Benefit Analysis says this is “profitable” after eight years (less
damages than costs)
Run by “non professionals” but with guidance from professionals
Many successful warnings were issued by eight LFEWS
Very low failure rate (one false alarm only)
Population has more time to prepare for floods; damages reduced
Can be replicated in other countries without a problem
Involvement of volunteers in response strong but weak in data
transmittal
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Way forward...
Flood modelling
Simulation of situations that did not happen
yet in order to be able to prepare for them
Replication in the Philippines:
PAGASA and GIZ currently supports the
establishment of eight more LFEWS in
different parts of the country
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Flood model
Ormoc City
525mm/ 24h
(Theory)
“Juan”
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