Structural Integrity and Flood Risk in Kasiglahan Village, Montalban, Rizal: A Report


September 3, 2015


Due to widespread poverty and landlessness in the countryside, Filipinos in the thousands continue to flock to urban centers in hopes of greener pastures there, only to face a myriad of new problems including, among others, the lack of proper housing. They then resort to settle on available lands and build makeshift homes there, establishing urban poor communities. To date, over 5 million Filipino people [1] live in such communities bearing the brunt of several social and economic problems of the Philippine society such as joblessness, poverty and lack of social services.

To worsen their situation, big “developing” firms, with the support and encouragement of local and national government institutions, systematically drive poor families from their community to make way for “development” projects such as condominiums, malls or business centers. According to Ibon, at least 70,000 families  have been forcibly removed from their communities in the Aquino administration alone as of April 2015 [2]. The affected families are usually relocated to areas very far from their place of work and schools. One such site is Kasiglahan Village in Montalban, Rizal.

During the Ramos administration, the Kasiglahan Village was conceptualized as a relocation site for informal settlers living along the Pasig River. Construction started during the Estrada administration. 

This report aims to present the condition of relocation homes in terms of disaster resiliency, particularly the integrity of structures to withstand earthquakes and the risks to the community associated with flooding incidents in case of typhoons and/or heavy rains. 

On structures

At the advent of natural disaster and calamities, Filipino engineers should be vigilant in the construction and maintenance of safe and reliable infrastructures. Importance should be given in ensuring that sound engineering principles coupled with the prescribed national codes are being implemented, most especially in residential government projects nationwide. In this regard, last July 5, 2015 (Sunday) an ocular inspection and field assessment was conducted by a technical team under AGHAM at a socialized low-cost housing facility at Kasiglahan Montalban, Rizal. On-site inspection was done on random sample houses to assess its structural integrity and flood susceptibility, most especially those built near river banks.

The technical team discovered that the houses built for the communities did not have the adequate structural elements, which are required by the National Structural Code of the Philippines (NSCP), such as concrete reinforced columns needed to keep houses sturdy against earthquake and wind loads. Ground settlement can be seen everywhere. Furthermore, the spacing of the rebar reinforcements of the concrete hollow blocks did not match those required of the NSCP. Moreover, the elevation of the row houses with respect to the nearby river is suspected to be inadequate for flood protection. Verification should be made whether the houses were designed, with consideration to the possible flood level under a 20-yr return period.

The technical team of AGHAM believes that the design and construction materials of the homes that shelter over a hundred impoverished Filipinos might not withstand strong storms and earthquakes (This can be verified if the occupants can provide a complete structural plans used in the project that can be shared to AGHAM technical team for evaluation). Therefore, the constructed houses has a high probability of jeopardizing the lives of the people living in Kasiglahan Montalban, Rizal in the event of a strong earthquake. Drastic engineering solutions should be done as soon as possible to correct and retrofit the inadequate structural and hydraulic concerns before all forms of natural disasters. 

Map showing location of Kasiglahan village vis-à-vis the west and east valley faults. Photo from Project Tremors:

On flooding

The relocation site in Kasiglahan Village,Rodriguez (Montalban), Rizal experienced flooding in the recent year. After the visit last July 5, 2015 (Sunday) points from the relocation site were plotted in the map of Santillan et al., 2013 [3]. Another map shows the points in higher resolution.

Based on the simulation of flood heights caused by Typhoon Ondoy in 2009, most of the relocation sites are in high danger of being flooded. Some areas were even situated in red zones, with > 5.0 m flood depth.

Conclusions and recommendations

This report highlights the dangers that urban poor relocates in Montalban, Rizal currently face.  By choosing and approving the area as a relocation site, authorities have put an unnecessary risk to the residents. This risk was increased by the disaster-prone design of the relocation homes.  

In this regard, relevant government offices must be held accountable for this situation. An in-depth investigation is needed in order to determine why relocations sites were positioned in such a high-risk area.

On a broader perspective, a moratorium on resettlement at least in Montalban area must be implemented pending this investigation. Similar investigations must be conducted on the safety and vulnerability of other relocations sites in the Philippines. Government agencies must ensure that relocation sites are safe and socially acceptable. 

Furthermore, community members and organizations must increase their capacity to cope and respond to disasters. Immediate interventions such as community-based disaster risk management must be instituted in the area.  Stricter implementation of structural regulations in housing must be realized to ensure the safety of relocates. 

Works cited:

[1] Marife M. Ballesteros. 2011. Why slum poverty matters. Policy Notes, Philippine Institute for Development Studies.

[2] Birdtalk Midyear 2015: Aquino’s final year – Legacy of elite economics and governance.

[3]Santilian and Ramos.2013. Development, calibration and validation of a flood model for Marikina River Basin, Philippines and its applications for flood forecasting, reconstruction, and hazard mapping

kasiglahan_village_report.pdf1.08 MB