Creating synergy at the provincial scale: three nature-based approaches in Bulacan, the Philippines

The Partners for Water programme supports three nature-based approaches in Bulacan province in the Philippines. These approaches – coastal restoration, wetland restoration and river basin adaptation processes – aim to help communities adapt to flooding and land subsidence. During the ASEAN cross-learning event in Malolos in September 2026, Partners for Water programme coordinator Liliane Geerling visited the three project locations with consortium partners working on the various nature-based approaches. She shares how working with nature across a whole region can make it more climate-resilient.

The three locations are in the low-lying delta of the Pampanga River, where it flows into Manila Bay. During the rainy and monsoon seasons, they suffer from chronic severe flooding. In September 2026, parts of the region stood under water for more than six weeks. Homes, shops and schools flooded at ground level. Children missed weeks of school, shops stayed closed and vital services came to a halt.

The main cause lies underground. Groundwater is pumped up for drinking water, and the land sinks as a result, in some places by up to 20 centimetres a year. This makes the relative sea level rise much faster than climate change alone would. This sinking cannot be reversed. The only way to regain height is to let sediment build up the land again. The Philippine National Adaptation Plan (NAP) names Bulacan province as a major priority and focal point for climate adaptation.

Three ways of working with nature

All three projects supported by Partners for Water take a nature-based approach. They make use of the services that healthy ecosystems provide. Regulating services keep natural processes in balance, for example by managing stormwater, purifying water and cooling cities. Supporting services form the foundation for the rest, such as allowing suspended sediment to settle and build up land, and recharging groundwater. Provisioning services deliver products people use directly, like fish and natural materials. These natural systems can adapt over time. In a region where the land is sinking and the climate keeps changing, that flexibility is valuable.

“Once you’ve built a dike or dam, it’s not easy to adapt, especially in a densely built-up area. It becomes a fixed element in the landscape,” says Geerling. “A healthy mangrove forest or wetland can grow and change over the years. Once a mangrove forest starts trapping sediment, the land grows with it.” Vegetation also stores carbon, whereas producing concrete emits it. “So you create synergy between climate mitigation and adaptation.”

Coastal restoration on Pamarawan Island

Pamarawan Island is a barangay of the City of Malolos. A barangay is the smallest political and administrative unit in the Philippines. On the island, the city is building a nature-based coastal defence with its own municipal budget. The Partners for Water programme funds the design, technical assistance and monitoring. First came bamboo sediment traps, then a wave barrier of sediment covered with oyster shells packed in coconut mats. “The mats are sewn with the same technique fishers use for their nets,” explains Geerling. A green dike is next. “Right now, the water is too deep for mangroves to grow. So the first step is to raise the coastline by trapping sediment. Then the mangroves can come back.” The first results are already visible: sediment is building up, and less wave energy reaches the community.

Flood prevention in the Pampanga River Basin

Along the Pampanga River, the national government and the Asian Development Bank (ADB) are preparing flood protection measures. The first design was a single large concrete channel. Under a letter of intent on nature-based approaches between Partners for Water and the ADB, Partners for Water connected experts in Nature-based Solutions to the national team. Together with local farmers and a local wetland organisation, the experts developed hybrid alternatives, such as retention basins that hold water upstream and natural riverbanks. “The farmers are willing to collaborate,” says Geerling. “They see that something has to change.” The ADB and the national government are now evaluating the proposals.

Calumpit-Hagonoy wetland restoration

The Calumpit–Hagonoy Basin is a wetland system that lies between the two towns. “Restoring it could reduce groundwater extraction, store water for drinking, create new sources of income and eventually halt subsidence,” says Geerling. The idea came from former mayor Angel Boy Cruz and was first discussed with the Philippine delegation at the previous ASEAN cross-learning event in Kuala Lumpur in 2025. In the first half of 2026, residents in both villages were interviewed. They showed strong support for restoring the wetland, combined with better livelihoods. “A consortium of Dutch and local experts is now developing the next phase of the plan together with local stakeholders.”

Thinking at landscape scale

Each project tackles a different challenge in the delta. “It makes little sense to work on preventing coastal erosion if you do nothing upstream along the river, such as letting sediment and water flow into connected wetlands or retention basins again,” says Geerling. “We try to zoom out and look for the missing links in the wider landscape.” Along the Pampanga River, that means holding on to water and sediment, and preventing uncontrolled river flooding. “If everything flows straight to the sea through one concrete channel, the sediment is lost.” The wetland between Calumpit and Hagonoy targets the root cause of the sinking land: groundwater extraction. On Pamarawan Island, the focus is on stopping coastal erosion.

The projects reinforce each other. Sediment that stays in the landscape can help raise the sinking delta instead of being lost to the bay. Less groundwater extraction can slow subsidence over time, so the height gained with sediment is not lost as quickly. And a stronger coastline protects the communities and land behind it. On its own, each project can only do so much. Together, they can make the whole region more climate-resilient.

Working at this scale is complex. “These are all small communities, divided by municipal and provincial borders,” says Geerling. Most of the land is also privately owned, so change only works together with the people who live there. “We want to create some kind of glue between these projects, so the whole region becomes more climate-adaptive.” If each project works, it can be scaled up. “Then the areas in between can follow a similar approach.”

Building with communities

Local communities play a key role in all three projects. On Pamarawan Island, fishers are paid to build the sediment traps and the wave barrier. “They had to give up their fishponds close to the shore to get a safer coast,” says Geerling. The community will also maintain the defence, using local techniques and materials. Wageningen University & Research is training the local university to monitor it. Pride is growing. “People ask you: have you seen our Nature-based Solution?” says Geerling. “You need ambassadors like that to take this further.”

From pilot to impact

Partners for Water does not fund large-scale construction. “We don’t have tens of millions in our programme. We work with a few hundred thousand,” says Geerling. “With that, we can de-risk: show that it can be done differently, so financiers dare to invest.” That is why local mayors and international financial institutions like the ADB are involved from the start.

For Geerling, the projects carry a clear message for other countries: “Dare to experiment. Listen to local people. And as a national government, support local administrators.” The mayor of Malolos, Christian D. Natividad, shows what that can look like. “He dares to invest in a nature-based coastal solution instead of a grey dike. That’s where it has to start.”

What comes next

Work continues on all three fronts. Together, the projects are more than three separate pilots. They make the region a place where others can see how nature-based approaches work in practice, and what impact they have. Climates and landscapes across Southeast Asia are much alike, and the design on Pamarawan itself builds on methods from Indonesia. “What works here can be adopted far more easily in countries like Indonesia, Thailand or Vietnam than what we build in the Netherlands,” says Geerling.

The projects are small steps, but the ambition is large. “If this works and is scaled up, many more people will live in a climate-adaptive environment, with healthier nature and better livelihoods. And fewer areas will flood again and again, taking people’s homes and incomes with them.

Read more about Partners for Water’s work in ASEAN and beyond and the ASEAN cross-learning event in Malolos.