THE TWIN PROBLEMS OF SILTED RIVERS AND RISING SEA LEVELS
THE TWIN PROBLEMS OF SILTED RIVERS AND RISING SEA LEVELS
While the Department of Public Works and Highways (DPWH) is busy building dikes, floodways, and other infrastructure to control flooding, one has to wonder: are we ignoring a more fundamental problem? The twin crises of silted rivers and rising sea levels are quietly conspiring to make flooding, saltwater intrusion, and water insecurity worse — and I don’t hear enough national alarm bells going off.
How Silt Closes Our Rivers
Rivers across the Philippines are becoming shallower due to silt build-up. DPWH itself has admitted that many major rivers are badly silted, but that desilting hasn’t been funded properly — year after year.
Take the Pampanga River: Governor Lilia Pineda recently urged desilting along a 34-kilometer stretch, citing reduced capacity and massive flood damage amounting to over ₱432 million in infrastructure losses.
And in Nueva Ecija, the Digmala River, a part of the Upper Pampanga River system, is being desilted — 4.4 kilometers are being cleared to restore its depth and reduce overflow.
Why does this matter? Because when rivers are choked by silt, their capacity to channel rainwater drops dramatically. During heavy downpours, the water has nowhere to go, and the result is more frequent and more devastating flooding. Added sediment also smothers aquatic habitats, reducing biodiversity and harming rivers’ self-cleaning capacity.
When the Sea Creeps In
At the same time, our coastal areas are under siege from rising sea levels. In Manila, sea level is reportedly increasing at a rate of 2.6 cm per year, according to a recent study. Part of the culprit? Land subsidence—our cities are sinking, in some cases, because we extract too much groundwater.
Rising seas aren’t just a distant worry — they are already pushing saltwater into rivers, estuaries, and aquifers, threatening both agriculture and drinking water supply. For example, nearly 28 percent of coastal municipalities in Luzon already report saltwater intrusion.
In a place like Dagupan, coastal and riverine flooding risks are compounded by the combined forces of sea-level rise, land subsidence, and saltwater intrusion — putting farms and homes at risk.
A Dangerous Interaction
Here’s the scary part: silted rivers and rising sea levels don’t act in isolation — they amplify each other. Saltwater pushed in by rising seas travels further upstream in silted, slow-moving rivers. That means inland flooding, salinized fields, and infrastructure strain. Older bridges, irrigation systems, and even water supply networks are not built for this double whammy.
What Can Be Done — And What’s Already Being Tried
1. Desilting & Sediment Management
Dredging: Targeted dredging of silted river channels to restore depth and flow. For instance, Ilocos Norte has begun clearing its Bislak River under a new DENR policy.
Watershed reforestation: Planting trees upstream to slow erosion and reduce incoming sediment.
Sediment traps, dams, and natural flow restoration: To catch silt before it blocks the river downstream.
2. Adapting to Rising Seas
Ecosystem restoration: Mangroves and wetlands can buffer waves and surges, while also filtering water.
Climate-smart urban planning: Raise key infrastructure, coordinate zoning to allow retreat zones in vulnerable areas, and update flood maps.
Better water use management: Limit groundwater extraction to reduce subsidence, and improve aquifer recharge.
Global cooperation: Push for stronger climate action that slows sea-level rise.
But Why Isn’t It Happening Fast Enough?
Broken water management: Our system is fragmented. DPWH, DENR, LGUs — too many agencies, too little coordination.
Budget gaps: DPWH has repeatedly asked for funds to desilt rivers, but often comes up empty.
Low visibility: Infrastructure projects get attention, but "invisible" work like riverbed restoration doesn’t have the same political appeal.
Short-term thinking: We often react to floods after they happen, not plan for long-term resilience.
My Two Cents
If we are serious about long-term resilience, we need to stop treating river desilting and sea-level rise as separate issues. They are deeply interconnected. Funds and political will should catch up with science.
Let’s form a National Water Resilience Task Force that unites DPWH, DENR, LGUs, scientists, and community stakeholders to plan desilting and adaptation.
Incentivize community-led monitoring: involve fisherfolk, farmers, and barangays in tracking silt levels and reporting saltwater intrusion.
Tie climate loans (like from ADB or other multilateral lenders) to projects that tackle both sediment and sea-level threats.
Finally, let’s build a public narrative: restoring our rivers is not just about preventing floods — it’s about protecting our land, our water, and our future.
The fires of climate change and environmental neglect are burning. We cannot afford to feed them with inaction. It’s time to act before our rivers are choked, and the sea takes back what once was ours.
RAMON IKE V. SENERES
www.facebook.com/ike.seneres iseneres@yahoo.com senseneres.blogspot.com 09088877282/07-05-2026
