Hamulauon River

A river in the central Philippines and the final entry in the global dataset's reviewed table of named outfalls. Global inventories place the Hamulauon among the world's highest-ranked plastic outfalls even though it is scarcely documented outside the dataset itself.[1]

Last reviewed: July 20, 2026 Reviewed by: Plastic Bank Research Team

Why This River Matters

The Hamulauon closes the global model's reviewed table: rank #50 of 31,819 modeled outfall points, with an estimated 2,170 metric tons per year. Below it, the dataset continues through thousands of unnamed points, so this river marks the boundary between the outfalls science has named and the far longer tail it has only located.[1]

Almost nothing about the Hamulauon circulates in international sources, and that obscurity is itself the finding. A model built from waste statistics, population, rainfall, and coastal distance surfaces rivers that no monitoring program tracks and no headline has covered, and it ranks this one above waterways draining entire countries.[1]

Its data profile matches the national pattern. The outfall coordinates sit in the central Philippines, where population concentrates near the coast, rainfall is heavy and seasonal, and typhoons cross regularly; the study attributes more high-ranked outfalls to the Philippines than to any other country. Plastic entering rivers in this setting typically has a short, well-watered path to the sea.[1]

For a river like this, the first intervention is knowledge: verifying the basin on the ground, confirming the name against local hydrographic records, and measuring what actually flows. UNEP pairs that data-building with the practical work of extending collection service in coastal municipalities, the measure its assessment ties most directly to reduced river inputs. This page will be updated as verified local information becomes available.[2]

Key Facts

What Drives Emissions Here

Coastal population pattern. Philippine settlement concentrates near the shore, placing waste generation close to river mouths throughout the archipelago.[1]

Heavy seasonal rainfall. Monsoon rain and typhoon events move accumulated litter from land to channel to sea in concentrated pulses.[1]

Archipelagic geography. Island geography keeps most Philippine basins comparatively close to the coast, shortening the typical path plastic travels to salt water.[1]

Thin monitoring coverage. Little documented local data exists for this basin, so mismanaged waste moves without measurement or interception.[2]

Municipal service gaps. Collection coverage outside major Philippine cities remains partial, leaving rivers as a default disposal pathway.[2]

Methodology Note

Figures cited are modeled estimates from global-scale studies; they are not direct measurements from continuous monitoring of plastic flux at the Hamulauon River mouth. Improving local waste data and field campaigns may refine these values. Use this profile to understand systemic drivers and regional context, not as a definitive audited mass balance.

Hamulauon River FAQ

How much modeled plastic emission is associated with the Hamulauon River?

This profile reports 2,170 metric tons per year for the Hamulauon River in the Meijer et al. (2021) global river plastic emissions framework. The value is a modeled annual estimate, not a continuous field measurement at the river mouth.

Is the Hamulauon River one of the most polluted rivers in the world?

For plastic specifically, the Hamulauon River ranks #50 of 31,819 modeled river outfall points worldwide in Meijer et al. (2021). "Most polluted" has no single definition, and this dataset models plastic transport to the ocean rather than overall water quality, so the ranking is best read as a plastic-specific indicator, not a general pollution verdict.

How does the Hamulauon River compare to other high-ranked rivers in the Philippines?

The Philippines has 19 rivers among the 50 named highest-emission outfalls in the dataset, and the Hamulauon River ranks nineteenth among them by modeled emission. Nearby entries from the same country include the Pasig River (#1) and the Tullahan River (#2).

Are the Hamulauon River figures direct measurements?

No. The figures on this page come from global-scale modeling that blends waste statistics, population layers, hydrology, precipitation, and distance-to-coast assumptions. They are best used for relative priority and context, not as literal tonnage measured by a permanent gauge.

Sources

  1. Meijer, L.J.J. et al. (2021). "More than 1000 rivers account for 80% of global riverine plastic emissions into the ocean." Science Advances, 7(18). DOI: 10.1126/sciadv.aaz5803
  2. UNEP (2021). "From Pollution to Solution: A Global Assessment of Marine Litter and Plastic Pollution." View report

How to Cite This Page

Plastic Bank. "Hamulauon River: Modeled Riverine Plastic Emissions." Rivers Carrying Plastic to the Ocean. https://rivers.plasticbank.com/rivers/hamulauon. Reviewed July 20, 2026.