2009/2/23

East & Southeast Asia Regional Seminar on Flood Hazard Mapping, 2009EDSA Shangri-La Hotel, Mandaluyong City, Metro Manila, Philippines
17-19 February 2009

Community-Based
Early Warning System
Susan R. Espinueva
Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA)
Department of Science and Technology (DOST)PAGASADOST

Outline of Presentation:
1. Introduction
2. Definition of EWS
3. The community based EWS
4. Challenges and opportunities

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1. Introduction

Hazard impacts and vulnerabilityHazards:• quick-onset or slow-onset, long-term, low grade
and cumulative
Risk Assessment

NaturalHazards

Exposure
EventVulnerability

Expected
Loss

Consequences
CostBenefits

PolicyAdoption

Schematic illustration of the science, technology, & fundamental
knowledge needed for risk assessment (Hays, 1999).

Should there be an EWS for
vulnerability andvulnerability changes?
Cabiao Floodway, 2006

PAGASADOST

1. Introduction

EWS Definition“I may not know how to define accurately an early warning
system, but I’ll know one when I see it” (Anon.).
“A rose by any other name is still a rose” (M.H. Glantz).
“ EWS is a social process for generating maximally accurate
information about possible future events” (Early Warning
Systems: Do’s and Don’t’s, Shanghai, China, 2003).

Candaba swamp, Pampanga River basin,Ty Marce 2004

How early is early?
What constitutes a warning?
What is meant by a system?
What are to be its official functions?
What else might it do?
What are the levels of warning?

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1. Introduction

Do we need early warning systems?
“To live is very dangerous” (Brazilian author, Joao
Guimaraes Rosa, 1963)Fact is: EWSs exist in every society.
EWS can be:
1.Formal – with visible structures
2.Informal – local and cultural in naturePart of the human nature – to seek
insights into the future through:- Looking at trends & making projections,forecasts & scenarios; andMystical and astrological means.
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1. Introduction

EWS - provides an effective solution to thisby giving people sufficient time toevacuate and protect their property
from an impending hazard.
EWS solutions
conflicting requirements
including cost andreliability
factors:
technological, social, and political
maintainable and accessible
by nontechnical personnel
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3. The community based EWSRISK KNOWLEDGE

Key elements of People-Centered EWS
MONITORING & WARNING DEVICE

Systematically collect data andundertake risk assessments

Develop hazard monitoring & early
warning devices

Are the hazards & the vulnerabilities
well known?
What are the patterns & trends
in these factors?
Are the risk maps & data widely
available?

Are the right parameters being
monitored?
Is there a sound scientific basis
for making forecasts?
Can accurate & timely warnings
to be generated?

DISSEMINATION &COMMUNICATIONRESPONSE CAPABILITY

Communicate risk information &early warnings
Do warnings reach all of those at risk?
Are the risks & warnings understood?
Is the warning information clear & usable?

PAGASADOST

Build national & community
response capabilities
Are response plans up to date and tested?
Are local capacities & knowledge
made use of?
Are people prepared & ready to react
to warnings?

Adapted from Developing Early Warning Systems: A Checklist, EWC III, March 2003

Background &Evolution of Flood
Early Warning System(FEWS) in thePhilippines

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The climate of the Philippines is influenced by thecomplex interactions of various factors such as :Philippine Geographyand Topography

Ocean currentsSemi-permanentcyclones and anticyclones

Principal Air Streams

Linear systems



Tropical Cyclones

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Tracks of tropical cyclones (1148 entered PAR)
that formed in the Western North Pacific (WNP)- 1948 - 2006

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FREQUENCY OF FLOOD IN CITIES &MUNICIPALITIESTHE STUDY ON THE NATIONWIDEFLOOD RISK ASSESSMENT AND THE
FLOOD MITIGATION PLAN FOR THESELECTED AREAS IN THE REPUBLIC
OF THE PHILIPPINES:: JICA, 2004

River Basins in the Philippines

18 – Majors
420 principal rivers

Monitored river basins
4 – fully automatic
2 – combination ofautomatic & manual
Several – manual orcommunity based
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A community based flood early
warning system :• involves institutions,instrumentation & community• people centered• cheap, non-structural flood
mitigating measure

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3. The community based EWS

Why pursue a CBFEWS?
•It empowers local government units(LGU’s) and the communities to protect
themselves against floods.

•The community and LGUs are in thebest position to undertake
preparedness measures against floods.

•It promotes a sense of ownership on
the part of the LGUs, hence it is easier
to sustain.

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3. The community based EWS

Objectives and Activities
under CBFEWSCBFEWS - mechanism for monitoring andregistering rain data and river
behavior upstream to provide
timely warnings to downstream
communities from a possible
flood.

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3. The community based EWS

River basin approachAt riskcommunities
Network Design is basedon river basin approach.
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3. The community based EWSPartners:
1. Community
2. Local government units (LGUs)
3. National government (OCD, DOST,academe, etc.)
4. Scientific institutions
5. NGOs6. Foreign donors
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3. The community based EWS

Activities of CBFEWS

A. Implementation Phase
1. Consultation
with LGUs & otherinstitutions

6. IEC, Dry run/flood drill & turn
over
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2. Data gathering,survey & designof network

5. On-site Trainingof observers(members ofcommunity)

3. Procurement /fabrication &installation ofequipment

4. Setting ofhydromet
parameters forobservation

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3. The community based EWS

Activities of CBFEWS

B. Operational Phase
7. Data Observation and analysis
8. Formulation and issuance of warnings
9. Documentation
10. Maintenance of early warning system
11. Evaluation after a flood event (for updating)
12. Conduct of IEC and flood drills

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3. The community based EWS

Activities ofCBFEWSPAGASA
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3. The community based EWS

Criteria for the issuance of warnings:
1. Threshold values of rainfall

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Note: Threshold values of rainfall are based on previous studies,
hence these are arbitrary. These values will be modified
when sufficient data are available in the locality or area(based on observation of LGUs).

3. The community based EWS

Criteria for the issuance of warnings:
2. Assessment water levels
321

GO

Water LevelPAGASADOST

Meaning

Flood Warning

Level 1

Awareness

READY

Level 2

Preparedness

GET SETLevel 3

ResponseGO

Note: Assessment water levels are based on surveys onthe river at a particular cross section. Again, thesevalues will be modified when sufficient observations
are available.

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Schematic of a Community Based
Flood EWS in the Philippines

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Challenges & Opportunities
1. Objectives and Activities - clear
2. Network Design – upstream & downstream
issues
3. Communication – which is the mostapproppriate?
4. Warning dissemination & notification
mechanism
5. Operation & maintenance
6. Stakeholder network & volunteer management
7. Funding & sustainability issues –mainstreaming EWS in local contingency plan
PAGASA
DOST122009/2/23The success of an EWS
is implicit in theoperative capability andthe response of thecommunity which
operates it.
PAGASADOST

East & Southeast Asia Regional Seminar on Flood Hazard Mapping, 2009EDSA Shangri-La Hotel, Mandaluyong City, Metro Manila, Philippines
17-19 February 2009

Thank you.
shenry112293@yahoo.com

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DOST13