The Philippines is exploring the potential of constructing dams across its 18 major river basins as a multifaceted solution to the country's persistent flooding issues, while simultaneously addressing water security, irrigation, and energy production challenges. National Irrigation Administration (NIA) Administrator Eddie Guillen has advocated for this approach, highlighting the possible integration of flood control, agricultural support, and hydropower generation within these projects.
Estimating costs at roughly 10 billion pesos (approximately $159 million) per dam, the total investment could reach about 180 billion pesos over five years. However, this figure serves as a preliminary benchmark rather than a definitive budget. For comparison, the Salaur River Multi-Purpose Project Stage II—comprising three dams along with irrigation and other infrastructure—has an estimated cost of 19.7 billion pesos.
The Philippines’ abundant natural water resources create favorable conditions for hydropower development, particularly pumped-storage hydroelectric systems, where the country is a regional pioneer. The Agus-Pulang Hydropower Complex in Mindanao exemplifies this potential. Commissioned in 1953, the facility consists of seven hydroelectric plants producing around 1,000 megawatts. It draws water from Lake Lanao, moving through the Agus River and Maria Cristina Falls, contributing to sustainable energy, flood mitigation, and agricultural productivity for generations. Similarly, the Caliraya-Botocan-Kalayaann pumped-storage plant holds the distinction of being Southeast Asia’s oldest facility of its kind.
Despite these advantages, proposed "mega-dams" often face significant opposition from environmental groups and affected communities. Criticism centers on ecological disruption, potential displacement, and threats to Indigenous rights. The ongoing debate surrounding the Kaliwa Dam project in the Sierra Madre highlights this tension, with coalitions arguing that the dam violates environmental statutes and fails to secure the free, prior, and informed consent of Indigenous peoples. They stress that it endangers critical rainforest areas and downstream communities’ safety during floods, advocating instead for watershed preservation and restoration.
Similar resistance has marked dam initiatives in the Cordillera region since the 1970s, evolving into broader Indigenous land rights movements. Experts caution that sudden alterations to river systems can worsen flash flood risks during typhoon seasons. The recently proposed 2,000-megawatt Maton Pumped-Storage project in Apayao has also met opposition due to concerns over habitat loss, impacts on freshwater species, and infringement upon ancestral domains of the Isnag people.
Environmental critiques often act as necessary checks, encouraging improved project designs, legal compliance, and risk management. Incorporating these perspectives may foster less harmful and more climate-resilient water and energy strategies.
Supporters of dam development emphasize that well-designed projects offer lasting benefits that can outweigh their risks. The Philippines, with 421 principal rivers and 18 major basins overseen by the National Water Resources Board, currently operates 21 large dams. Properly sited reservoirs can store excess water during heavy rains, attenuating downstream flooding, and release it during dry spells to support irrigation and potable water supply, in addition to generating electricity.
Nonetheless, challenges remain. Dams cannot entirely prevent floods, alteration of river dynamics is inevitable, and each dam project requires tailored planning to address local conditions. The envisaged 18 dams would not be uniform but adapted to the specific needs of each basin, considering inflow volumes, reservoir capacity, irrigation demands, flood mitigation prospects, environmental and social impacts, watershed health, operational management, and overall economic viability.
Experts advocate for a combined approach that integrates dam infrastructure with watershed rehabilitation, floodplain restoration, improved river management, enhanced drainage, land-use regulation, and real-time monitoring of rainfall and water levels. Such a strategy aims to maximize the impact of public investment, ensuring that each peso spent yields optimal returns across flood protection, food security, water availability, and renewable energy generation.
Ultimately, the question facing policymakers is not solely the number of dams to be constructed, but how to allocate resources most effectively across the country’s diverse landscapes and communities to build sustainable resilience against flooding and water scarcity challenges.