Flood Early Warning System in Metro Manila, Philippines

Topics:
Disaster Risk Reduction and Management
Flood Prevention
Non-structural Disaster Planning

Location: Banaba, Metro Manila, Philippines

Organizers:
Center for Disaster Preparedness, University of Philippines
Community members
Christian Aid
UK Government

Project Implementation: November 2012

Background: Located on the bend of a river on a floodplain outside Manila, the community of Banaba is highly exposed to and frequently suffers from flooding during heavy rains. The slum neighborhood lacks flood prevention infrastructure. Furthermore, residents are economically vulnerable to disasters as they have limited options for relocation, improvement of their housing, or other insurance methods. Although the community had an evacuation plan in the event of heavy rains, the absence of reliable and timely flood prediction systems prevented the community from mobilizing quickly enough to avoid injuries and loss of valuable assets. Prior to the intervention, residents would rely on the alarmed cries of pigs to determine if river levels were high enough to warrant evacuation.

Banaba neighborhood. The strip of land between the sharp bends in the river is particularly flood-prone. Upstream communities in the highlands also report river data to University of the Philippines researchers

 

The pylons on this bridge have been painted to gauge river height. River measurements are typically taken twice a day. Abnormally large rises in height over time indicate flood risk.

Program: With funding and support from Christian Aid and UK Government, residents of Banaba teamed with researchers and hydrologists at the University of the Philippines to create an accurate flood prediction and early-warning system. University scientists trained residents to monitor and collect information related to flooding, particularly river height, speed of river rise, and meteorological information such as rainfall. In addition, residents communicate with upstream riparian communities that also monitor river metrics; the upstream communities can let Banaba residents know about weather events and river speed in their area. Data about river conditions are sent to the specialists at the University to be incorporated within river-system computer flood models. If the river conditions indicate imminent flooding according to the model, then an evacuation notice is sent out to the Banaba residents. The community follows its evacuation route to a community center. Regular monitoring of river conditions provides more data for researchers so that they may create earlier, more accurate evacuation predictions.

Transferability: The early-warning system is adapted to the Banaba context in two key ways. First, structural flood prevention – such as with levees or river bank armoring – would need to be extensive due to the site’s high vulnerability to flooding; such infrastructure is likely beyond the means of the low-income neighborhood. The simplicity of the monitoring tools and the partnership with the University reduces costs while maximizing life- and asset-saving measures. Secondly, the density of Metro Manila complicates relocation options for the community members; strict zoning would limit their access to economic opportunities. By working with residents to alert them to flood conditions, residents are able to make informed decisions about their residence.


Sources:
Photo Courtesy: BBC.