coastal protection for the coastline of the philippines · preliminary emergency plans generally in...

Coastal Protection for the

Coastline of the Philippines

A case Study for Tacloban and

outlook for Metro-Manila

Wouter de Hamer

25 April 2017

Coastal protection strategy for Tacloban and Palo | 2 June 2016

Typhoon Yolanda

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November 2013 the largest typhoon ever recorded Yolanda.

NDRRMC confirmed 6,201 identified fatalities, 5,803 of which in Visayas.

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Typhoon Yolanda

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Coastal Defense Masterplan Tacloban and

Palo Municipality

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Coastal Protection Strategy

Objectives:

to develop a coastal protection strategy to:

minimize flood risks (loss of life and damage to properties) due to

natural coastal hazards (surge and typhoon waves);

enhance the sustainable development of the coastal zone (develop

natural ecosystems, sustain livelihoods, etc)

Taking into account:

Extreme typhoon events

Expected climate change

Future urban development

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Coastal Protection Strategy

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Multi-level Safety Approach:

Level 3, resilience and emergency response

Level 2, planning and zoning

Level 1, flood protection, prevention of inundation

Level 3

Level 2

Level 1


Flood hazards for different Return

Periods

Damages ($/m2) - using damage

functions)

Economic risk ($/m2/year) – area

under the damage probability

curve

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Basis: Flood Risk Damage

Assessment

Coastal protection strategy for Tacloban and Palo | 2 June 2016 10

Strategy: Non-structural

Strategy: Structural & Non-structural


Translation of Risk to Strategy


Project area – North Tacloban

No “expensive” structural measures

due to limited marco-economic benefit

Invest in emergency shelters and early

warning to ensure safety of the people

Invest in mangrove expansion and

conversion of fish ponds to improve

resilience.

Only future urban development in flood

free areas

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Strategy: Non-structural


Project area – Central Tacloban

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Invest in structural measures due to high marco-economic benefit Offshore seawall in the bay area to

minimize social impact Dike along provincial road alignment to the

south to minimize environmental impact Dike along ocean-side of airport to protect

essential infrastructure

Maintain proper drainage from the urban areas and wetlands to the ocean

Design for low maintenance for the dike (no concrete, but earthen dike and armour rock)

Create mangrove education park north-west of airport for education of DRR function soft measures.

Offshore Seawall

Elevated road

Coastal Sea wall

Stru

ctu

ral &

N

on

-str

uct

ura

l Coastal Sea wall


Mid North - MCA

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A B C

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Mid South - MCA

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weight factor elevated road sea wall

Technical 10 76% 56%

Socio-economic 70 54% 47%

Environmental 20 80% 20%

61,6 42,8

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Bird’s Eye Impression


Project area – Palo Municipality

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Only targeted investments in structural

measures to protect urban areas of Palo

Municipality

Invest in emergency shelters and early

warning to ensure safety of the people

Maintain wide openings for the rivers to

freely discharge into the ocean

Invest in mangrove expansion and

conversion of fish ponds to improve

resilience.



Bird’s Eye Impression


The proposed strategy is….

A strategy built up from hard measures where necessary and soft

measures where possible, creating a healthy ecosystem and a

protective landscape for the people in and around Tacloban and Palo.

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Assessment Flood Risk Philippines

Quick Assessment done for LGUs along the eastern

shoreline: over 2500km coastline (158 LGUs) .

Using open source data:

Population density

Flood risk maps (DOST, NAMRIA)

Typhoon tracks (probability)

Conclusions:

Three regions (V, VIII and XIII) at high risk

10 cities (>65,000 people) at high risk

Preliminary emergency plans generally in place

No actual coastal protection strategy exist…

Landuse planning along the coast is key!

For this analysis risk is defined as: “the probability of a flood to occur

multiplied by the damage caused by this flood scenario”.

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Assessment Flood Risk Philippines

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Typhoon Pedring (2011)

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Typhoon Modelling Pedring (Cat. 3)

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Typhoon Modelling Pedring

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Manila Bay - Multi-level Safety Approach

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Level 3, resilience and emergency response

Most cities have emergency plans in place (mainly

focussing on riverine flooding)

Special/more attention needs to be given to the

most vulnerable people living along the coastline

Level 2, planning and zoning

Overall Masterplan for Manila Bay is lacking

Recent promising initiatives:

NEDA: Manila Bay Sustainable Masterplan

PRA: Programmatic EIA and DSS Manila Bay

Level 1, flood protection, prevention of inundation

Hard measures: implemented on LGU level

(questionable if these are all “future proof”)

Soft measures: non-existing (mangrove and

wetlands areas degraded in most parts)


Manila Bay’s Issues on Planning (Level 2)

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High pressures on ecosystem due to rapidly increasing

population / urban sprawl :

Untreated wastewater discharges in Manila Bay

Overload of solid waste dumped in Manila Bay

Overfishing / Uncontrolled development of fishponds

Unregulated/illegal (land) developments


Manila Bay: modern example of “Tragedy

of the Commons”?

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Hardin (1968); “user pursues its own (short-term) benefits over

the (long-term) common benefit to maintain a healthy ecosystem”.

In these cases, literature advises to: improve communication and trust between the stakeholders, steer towards a “regulation-driven win-win situation”.

For the Manila Bay key for success is:

Regulatory and trustworthy government body for Manila Bay Buy-in from private sector Involvement NGOs

Let’s not wait for a Masterplan!


Thank you for your attention

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