POLICY BRIEFPolicy paths for addressing coastal erosion in the Philippines

 

Immediate actions needed to curb human activities leading to coastal land loss

Coastal erosion as a national issue

  Coastal erosion is prevalent in the Philippines (e.g., Fig. 1). As an archipelagic landmass, the loss of coastal lands poses a serious threat, not just to the 60% of the population occupying coastal regions, but this extends to the rest of the community as damaged infrastructure and industries, salty aquifers, uncultivable coastal lands, ultimately affect the fragile national economy. Beaches in many tourist sites are eroding and, if not properly managed, will continue to do so, eventually impacting revenue in the area.

Typically, long shorelines with narrow coastal plains border the Philippines from large open oceans that are exposed to typhoons. Rapid sea-level rise, more than the global average, and intensifying storms due to climate change heighten the susceptibility of Philippine coasts to erosion.

Human activities worsen coastal erosion Human activities speed up the rates of erosion beyond natural limits. These include unregulated foreshore development, extraction of beach materials, abuse of natural habitats, and even the mal-adaptive use of hard structures to manage coastal erosion.

Strictly enforce the current easement guideline but consider improving it 

Adopt technical guidelines for the design and placement of coastal structures (i.e. piers, seawalls, groins, etc.) 

Revise the current easement guideline to further buffer against coastal erosion and sea-level rise.

Recognize that accreted land is public domain and consider this in delineating the easement

Use the highest high tide as the seaward limit of the easementProhibit construction within the easement and the adjacent foreshore

What should be done about it?

Botolan, Zambales | 2006

© UP-MSI | Geo Oce Lab

Figure 1. Coastal erosion in Zambales. At the southernflank of Bucao River, as much as 40 m of shoreline eroded after a storm event in 2006.

Call to action. Coastal erosion must be recognized as a national issue. Urgent action from the national government is needed to mitigate man-made causes, and to manage and prepare for the worsening effects of climate change. Explicit policies to address this national problem should be put in place.

Sagip Baybay PH

What is the common response to coastal

erosion in the Philippines?

Oftentimes, the default response to erosional events especially after a typhoon is the placement of seawalls. However, seawalls can speed up erosion. Over time, the beach fronting the seawall narrows and eventually vanishes. Similarly, building of groins that trap sediments to widen the beach can lead to an undesired consequence elsewhere: by effectively trapping sediments on its updrift side, less sediments can pass through causing erosion downdrift (Fig. 3a). Solid-based piers also function like groins.

Hard structures on the foreshore can further hasten, rather than arrest, coastal erosion. What makes things worse is that these structures are built piecemeal, often without considering its impacts on adjacent coastlines. 

Figure 3a. A groin field alongthe coast from Agoo to Sto.Tomas in La Union. Rubblegroins (top) were constructed inthe mid-1980s to arrest erosionresulting in a highly irregularshoreline (right), andaccelerated erosion downdrift.

  Sto. Tomas, La Union | 2001

    © UP-NIGS | Marine Geo Lab

dow

ndrift

downdrift

updrift

longshore transport

up

drift

    Caba, La Union | 2001

    © UP-NIGS | Marine Geo Lab

Figure 2. Caba, La Union after the passage of Typhoon Feria in 2001. Numerous houses were destroyed by large waves during the onslaught of Typhoon Feria. Erosion persisted even after this typhoon. Stronger typhoons are expected with warming climates.

Unregulated foreshore development, extraction of beach materials, abuse of natural habitats, and even the management of coastal erosion using hard structures (seawalls, groins, solid-based piers, and ports) may worsen coastal erosion.

Fig. 3b. A solid-based pier in Sta. Fe, Bantayan Island inCebu function like a groin. It hinders the transport ofsediments leading to accretion updrift and erosion downdrift ofthe pier.

Bantayan Island | 2013

Evaluate through Environmental Impact Assessment (EIA) whether foreshore structures cause and/or worsen erosion.

Use geomorphological boundaries such as continuous coastline or embayment (instead of political boundaries) when conducting assessments and/or planning for coastal protection (Fig. 4).

Apply technical guidelines in designing and placing foreshore structures:

Build ports and piers on coastal segments where there will be minimal disruption on the longshore drift. Apply technical guidelines in designing and placing foreshore structures:

Avoid building ports and piers on coral reefs, a protection and barrier to beach erosion. The loss of coral reefs not just affect fisheries, but beach stability  as well.

If seawalls are necessary, consider that erosion tends to worsen at their front and along adjacent coasts (Fig. 6). Seawalls can also change the substrate and associated habitats. Further, they require high initial and maintenance costs .

    © Ma. Angelique Doctor

   Tolosa, Leyte |  2015

Baler, Aurora | 2015

    © UP-MSI | Geo Oce Lab

© UP-MSI | Geo Oce Lab

What should be done about coastal erosion?

  Addressing coastal erosion calls for minimizing human activities that speed up beach loss. Below are critical actions that should be considered urgently. 

1.  Improve the design and placement of coastal

structures. 

Use of solid-based piers and seawalls must be minimized for coasts to be more resilient. When resorting to such hard structures, consider the connectivity of coastal processes, which usually extends beyond municipal or political boundaries, demanding a concerted effort of neighboring municipalities in combating land loss.

Figure 5. Pier built on stilts. This type of pier allows sediment to pass through, preserving a continuous shoreline.

Figure 6. Seawall in Baler, Aurora. This seawall is no match to the strong waves. Itsrepair and maintenance is costly.

Figure 4. A geomorphological boundary may consist of an embayment, or a linear beach bounded by rivers or cliffs. Longshore currents continuously transport sediments within a coastal cell. Disturbance of sediment transport in one segment of the cell can cause erosion in another segment. For example, in Cell 3, a solid-based pier built in Municipality C will prevent riverine materials from reaching the coast of Municipality D that will cause shoreline erosion in the latter. The connectivity of processes (e.g., longshore currents, waves) within such boundary should encourage close coordination in the management of the coastlines of these contiguous municipalities.

If hard structures are necessary, where amenable, combine them with soft measures, such as using natural barriers like coral reefs and mangroves, which will require their conservation.

If groins are necessary, determine the net longshore drift because erosion worsens on the downdrift area and will exacerbate erosion in those municipalities.

EASEMENT AS DEFINED IN THE WATER CODE OF THE PHILIPPINES (PD 1067)

“Structures of any kind cannot be built on the banks of rivers and streams and the shores of the seas and lakes throughout their entire length within a zone of three (3) meters in urban areas, twenty (20) meters in agricultural areas and forty (40) meters in forest areas. These zones are subject to the easement of public use only for recreation, navigation, floatation, fishing and salvage.” (PD 1067 (Water Code), Art. 51) (Fig. 7) 

The easement is essentially a “no-build zone”. This guideline addresses the problem of “building too close to the waterline”, and can provide buffer against the effects of coastal erosion and sea-level rise. In many places, however, the easement is not observed as development is initiated too close to the waterline. The poor implementation of this guideline should be addressed promptly to arrest coastal erosion. 

Figure 7. The easement and foreshore as defined in the Water Code (PD 1067) and Fisheries Code (RA 8550) of the Philippines.

2. Improve the current easement guideline 

The easement guideline is unclear and unenforced. 

As a remedial measure, strictly enforce the current easement guideline as a minimum requirement. To implement this properly, the following should be addressed:

Clarify the seaward limit of the easement. 

LGUs should consider the building regulations for the foreshore sub-zone in the CLUP guidebook, which states that “no permanent buildings or structures are allowed, except for duly-approved protective structures” (HLURB, 2013; 2014). 

The prohibition for construction within the easement should extend to the immediate foreshore. The presence of structures on the foreshore would directly interfere with water and sediment movement.

The current guideline prescribes     simply “the high-tide line,” but this is variable with the moon phase. Consider instead the average of the highest high tide over a period of at least 18 years (1 nodal cycle), where available. 

NAMRIA can provide the data for the highest high tide and may also be involved in the survey and delineation of the seaward limit of the easement. 

Revise the current easement guideline to further buffer against coastal erosion and ongoing sea- level rise.  

Recognize that accreted land is public domain and this has to be considered in delineating easement

Consider the inclusion of the new easement guideline as a requirement for new coastal development.  

In the latest CLUP Guidebook (HLURB, 2013), the LGUs may declare an expanded easement for high-risk area to be determined from historical trends and projection of sea-level rise and coastal erosion (Fig. 8). 

Add the projected rates of erosion and SLR to the minimum easement requirement in PD 1067 and adopt whichever provides a wider easement. 

In lieu of  a fixed-distance easement, consider rolling easement, which moves with the high-water mark (e.g., highest high tide, vegetation line) (Fig. 9).

Recommend that coastal structures be built on stilts to allow the free flow of water as well as the landward migration of beach vegetation and mangroves with rising sea levels.

ARTICLE 4 OF THE SPANISH LAW OF WATERS

Lands added to the shores by accretion and alluvial deposits caused by the action of the sea form part of the public domain. When they are no longer washed by the waters of the sea and are not necessary for the purpose of public utility, or for the establishment of special industries, or for the coast guard service, the government shall declare them to be property of the owners of the estates adjacent to thereto and as increment thereof.

Fig. 8. Expanded easement recommended in the CLUP Guidebook (HLURB, 2013).

Figure 9. The concept of rolling easement. Dynamic public easements move with the vegetation line and prohibit hard structures within its limits. Structures perched on stilts allow the vegetation line and mangroves to move landward as sea level goes up. These structures can still be used until the migrating vegetation and rising seas reclaim it.

Works Cited:

 

Editorial Team

  Writers:      Fernando P. Siringan; Caroline Marie B.                          Jaraula;  Ma. Yvainne Y. Sta. Maria

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Sagip Baybay PH is part of an information dissemination project about coastal erosion under the Marine Science Institute of the University of the Philippines – Diliman and funded by the Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development (PCAARRD) of the Department of Science and Technology.

For additional information, read the accompanying book Coastal Erosion Management in the Philippines: A Guidebook Room 318, Marine Science Institute University of the Philippines, Diliman, Quezon City 1101

Housing and Land Use Regulatory Board. 2013. A   Guide to Comprehensive Land Use Plan Preparation: The Planning Process, pp. 246.

Housing and Land Use Regulatory Board. 2014. A Guide to Comprehensive Land Use Plan Preparation Volume 3: Model Zoning Ordinance, 86 pp.

Nicholls, R.J., P.P. Wong, V.R. Burkett, J.O. Codignotto, J.E. Hay, R.F. McLean, S. Ragoonaden and C.D. Woodroffe, 2007: Coastal systems andlow-lying areas. Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth AssessmentReport of the Intergovernmental Panel on Climate Change, M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson, Eds., Cambridge University Press, Cambridge, UK, 315-356.

PNAR. 2013. Coastal Erosion in the Philippines: A National Assessment Report. Submitted to the COBSEA YEOSU Project: Addressing the Challenge of Sea-Level Rise and Coastal Erosion in the East Asian Seas – Initial Implementation of the COBSEA Regional Programme on CoastalErosion.

Siringan, F.P., Sta. Maria, M.Y.Y., and Pang-ot, G. 2006. Coastal erosion in Northern La Union: Trends and possible mitigating measures (unpublished). A terminal report submitted to the Provincial Government of La Union, 102 pp.

Siringan, F.P. , Sta. Maria, M.Y.Y., and Jordan, J.C.J. 2015 (unpublished). Coastal erosion management in the Philippines: A Guidebook, 146 pp   National policies and programs Presidential Decree No. 1067 (31 December 1976): The Water Code of the Philippines  actions that should be considered urgently. 

Editors:        Fernando P. Siringan; Cherry L.. Ringor;                             Noreen Marie F. Galpo; Joanne R.                                              Constantino; Michelle T. Manglicmot

Layout  &:    Joanne R. Constantino, Michelle T.  Design           Manglicmot; Ma. Yvainne Y. Sta.. Maria

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