The Philippines experienced an average of 3.5 destructive typhoons per year (1990 to 2003) with damages costing up to P 96.566 B mostly incurred from flood-damaged properties, infrastructures and crops (CTI Engineering International Co., Ltd., 2004). For the Cagayan river, flooding has been a perennial problem. This longest river in the Philippines has a total length of 520 km within a drainage area of 27,493.49 km2 , It covers 2,459 barangays in 122 municipalities/cities in 12 provinces within three regions namely Region 3, CAR and Region 2 (DENR, 2017).
It has been projected that water surface level in the Cagayan river will rise up by 1-3 m versus the baseline conditions (DENR , 2017). Of the estimated 388,494 hectares (14% of the river basin) susceptible to flooding, about 60% of this has high to very high susceptibility. Areas near the river systems have high to very high susceptibility to flooding mostly parts of Isabela and Cagayan.
Recently, typhoon Ulysses (2020) brought essentially parts of Cagayan underwater, registering a 13.30 m flood height recorded at Buntun bridge at the lower Cagayan River surpassing the previous record at 12.70 m in 2010. This new record costs about 10B (CNN report, Nov 19, 2020) both in infrastructure and in agriculture, affecting 3.67k people, displaced 2.77k people, 73 deaths, and damaged 67k houses (UN-OCHA, 2020).
Despite the government’s efforts to mitigate the effects of floods either brought about by typhoons and/or monsoon rains, significant damages in agriculture and infrastructure still persist. Today, there is a need to address the following observations: (a) devastating effects of riverine and inland floods on the lives of the people and the economy; (b) lack of comprehensive decision support platform for flood information and effective flood risk management; (c) insufficiency of flood control infrastructures; (d) failure of flood control infrastructures to mitigate the damaging effects of flood waters; and (e) shortened service life of flood control infrastructures.
Studies show that the main culprit is climate change. The occurrence of El Niño and La Niña phenomena has not spared even the advanced societies. Goal 13 of the UN Sustainable Development Goals (SDGs) specifically urges all member states to combat climate change and its impacts. Along with SDG 9, resilient infrastructure must be built to promote inclusive and sustainable industrialization and foster innovation. This project was conceptualized to come up with resilient flood control infrastructures using science-based approach and modern tools tested and proven abroad. It will introduce new methods utilizing new softwares and integrating the river styles framework as proposed by Fryirs and Brierly (2005).
Specifically, hydrological modeling simulations will be done using updated flood data to assess the vulnerabilities and degree of exposure in the hot spot areas. Inventory of the existing flood control infrastructures to determine their functionalities and obtaining river geomorphologic data and sediment transport are significant inputs to coming up with prototypes of the structural solutions to be demonstrated, deployed, and adopted by DPWH. The conceptual designs will be depicted in a miniature model using a 3D printer. The designs will be specific for the two subwatersheds. The same designs will be funded by DPWH for deployment and demonstration to provide flood protection with high reliability. For example, Chen et al (2018) tested the key performance of Mobile Flood Protection System used in Germany, Austria, UK, and China using a comprehensive test site for mobile flood wall. They investigated the anchor plate installation, seepage characteristics, and stress behavior of mobile flood protection systems using a process test, a water impounding test, and a post loading/unloading test. Also, Kryžanowski et al (2014) made a review of the structures that were taken to cope with the floods in selected cities along the Danube river such as Vienna, Bratislava, and Belgrade. Based on these studies, these tested flood control infrastructures have been found effective in the sites mentioned.
This study will help attain the projected economic life of flood control infrastructures estimated at 50 years and ultimately benefit those living within the Cagayan river banks estimated at 6k population, decreased agriculture and infrastructure damages and alleviating at least 47 local government units (LGUs) against the impacts of flooding.
Generally, this study will utilize integrated assessment and analysis reports for flood control infrastructure using smart flood monitoring, remediation and mitigation within the Cagayan river basin.
Specifically, it aims to:
- To conduct inventory of all existing flood-related initiatives, programs/projects of different agencies;
- To develop science-driven decision support platform for flood information and risk management; and
- To design, improve and implement resilient flood control infrastructures.
- Cagayan River Basin Management Council
- Regional and Local Disaster Risk Reduction and Management Councils
- Local Government Units
- Relevant NGAs (DPWH, PAGASA)