What happened
Floods and landslides struck Aceh, North Sumatera and West Sumatera from late November 2025, killing more than 1,100 people and displacing hundreds of thousands more.
The immediate cause was extreme rainfall. Bireuen Regency in Aceh recorded 411 mm in a single day, exceeding its normal monthly total; comparable totals fell across the three provinces within the same week. Rivers rose faster than any warning could travel, and in the steep upper catchments the water arrived as debris flow rather than flood.
The scale of the damage, however, was not set by rainfall alone. Decades of forest loss in the upper catchments, conversion of riparian land, and settlement on floodplains had reduced the landscape’s capacity to absorb, slow and store water. What fell as rain in the hills reached the towns within hours instead of days. Roads, bridges, irrigation systems, schools and clinics were destroyed alongside housing, and agricultural land was buried under sediment that will take seasons to recover.
Why recovery has to change the landscape
Reconstruction can rebuild what was there, or it can rebuild the catchment. Only the second reduces the loss the next time it rains that hard.
Rebuilt to the previous standard, the same settlements face the same hazard against a rainfall distribution that is shifting: intense events are becoming more frequent, and 2026 brought a super El Niño on top of it. Hard engineering — embankments, channels, retaining walls — is necessary in places but expensive to maintain and prone to shifting risk downstream when it fails.
Nature-based measures work on the part of the system that failed. Restored upper-catchment forest and riparian buffers slow runoff and hold soil. Reconnected floodplains and retention areas give water somewhere to go. Restored mangrove and coastal vegetation reduce surge and hold shorelines. Agroforestry on steep land keeps it productive without keeping it bare. Each has a measurable hydrological effect, and each also produces carbon, water and livelihood value that hard infrastructure does not.
The obstacle is not evidence but budget architecture. Recovery money is disbursed against assets — kilometres of road, units of housing — while catchment restoration sits in environmental programmes with no claim on reconstruction funds. This initiative exists to close that gap: to specify restoration as recovery infrastructure, cost it, and finance it from the same envelope.
What the initiative does
Three lines of work, running in the three provinces and coordinated with the agencies responsible for recovery.
First, assessment: mapping where in each catchment restoration delivers the largest reduction in flood and landslide risk, and quantifying that reduction so it can enter a cost-benefit case alongside engineered options. The rapid assessment published as Landscape 360 — Sumatera Floods Series #3, Warned by Nature, Recover with Nature, is the starting point.
Second, institutional design: bringing district and provincial government, community rights holders, plantation and concession operators and civil society into a standing multi-stakeholder arrangement per landscape, with responsibility assigned for planning, implementation and monitoring — the landscape approach applied to a recovery timetable.
Third, financing: structuring the money so restoration is funded for the years it takes to establish, blending recovery allocations, public budget, concessional finance and ecosystem-service revenue including carbon. Without that tenure, plantings are made and then abandoned, and the catchment is no more resilient than before.
Warned by Nature, Recover with Nature
A rapid assessment of increasing resilience through nature-based recovery in Aceh, North Sumatera, and West Sumatera — the starting point for this initiative.
Nature-Based and Ecosystem Services Program
The programme that carries this work, with its current, incubating and past projects.
The Landscape Approach
The method behind the institutional design: spatial, participatory, and carried through planning to evaluation.