PALMOILMAGAZINE, BANDUNG – The massive floods that swept across parts of Sumatra struck with little warning. Within just one to three days, rainfall equivalent to an entire month poured down at once. The sheer volume was staggering—roughly comparable to 2.24 times the capacity of the Jatiluhur Reservoir, which holds about 2.4 billion cubic meters of water. It is therefore unsurprising that the destruction was severe and the human toll devastating.
Casualty figures reflect the scale of the disaster: more than a thousand people were killed, hundreds remain missing, and nearly half a million were forced to flee their homes. While these numbers are far below the 2004 Aceh tsunami, which claimed around 169,000 lives, floods and tsunamis share a terrifying similarity—both occur when enormous volumes of water inundate land simultaneously. The difference lies in timing: tsunamis are triggered by massive earthquakes within seconds, while extreme floods are born from relentless rainfall over several days.
This episode of flooding in Sumatra was worsened by landscapes stripped of their natural buffers. Mining activities and logging that left land “bare of vegetation” allowed water to rush unimpeded downstream. Large logs—more than 50 centimeters in diameter and over four meters long—were swept away by the current, smashing into houses, bridges, and public facilities. Under normal conditions, moving timber weighing three to eight tons would require heavy machinery. During floods, however, the immense mass of water lifted and carried it with ease.
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Indonesia’s Meteorology, Climatology, and Geophysics Agency (BMKG) recorded extreme rainfall across several regions. In Aceh, for example, daily rainfall reached 411 millimeters, while average soil absorption capacity is only about 200 millimeters. Once the soil becomes saturated, infiltration stops. All subsequent rainfall turns into surface runoff, merging into powerful currents that sweep away everything in their path. Average water levels reached around 40 centimeters, with some areas inundated by one to two meters—enough to carry massive logs downstream.
To grasp the scale, imagine the Jatiluhur Reservoir collapsing. Greater Jakarta would be submerged, with almost unimaginable consequences. The floods in Aceh, North Sumatra, and West Sumatra were estimated to carry more than twice the reservoir’s volume. In Aceh Tamiang alone, floodwaters were estimated at around 2.2 billion cubic meters in a single day, excluding upstream inflows. In Tapanuli, North Sumatra, volumes reached an estimated 4.15 billion cubic meters. Fortunately, Lake Toba—with a capacity of around 250 billion cubic meters—served as a “giant buffer,” reducing downstream discharge.
As always, disaster rekindled a familiar debate: forests and palm oil plantations were quickly blamed as the primary culprits. Yet this explanation is overly simplistic. Cities such as Jakarta, Bekasi, and Semarang—areas with little forest cover and virtually no palm oil plantations—are routinely hit by floods. Meanwhile, Riau, home to Indonesia’s largest palm oil acreage, was relatively spared during this event. This suggests that the decisive factor remains extreme volumes of water falling simultaneously, driven by climate anomalies, rising temperatures, wind dynamics, and even lunar gravitational effects.
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This is where the issue broadens. Natural resource governance must indeed be evaluated and improved. But at the same time, Indonesia must avoid being trapped in narratives that ultimately benefit external interests. Many developed countries exhausted their forests long ago, yet Indonesia continues to be pressured to remain the world’s “lungs.” Critical scrutiny is necessary, but it must be grounded in national interests.
Ironically, much of the control over palm oil plantations, mining areas, and industrial forests lies with foreign interests or a narrow domestic elite. When disasters strike, their contributions are often negligible compared to the profits they have reaped. While the state may refuse foreign aid, it should firmly compel large corporations—especially those exploiting natural resources—to channel a portion of their gains into disaster response and recovery. Mobilizing hundreds of trillions of rupiah is not, in fact, impossible.
Amid the devastation, lessons must be learned. The social impact of flooding is far more enduring than physical damage. Trauma from losing family members, livelihoods, and a sense of security can last for years. Both local and central governments must therefore prioritize social recovery, not merely infrastructure reconstruction.
Looking ahead, this disaster should serve as a loud alarm for all stakeholders. Mitigation can no longer be piecemeal. The construction of dams, retention basins, infiltration pits, terracing, and river embankments must be accelerated. Reservoir water management must adapt to increasingly extreme seasons. Strict oversight of forestry, plantation, and mining sectors is non-negotiable, and environmental law enforcement must be consistent.
Indonesia lies in a disaster-prone region—vulnerable to earthquakes, climate change, and governance failures. As such, mitigation must be elevated to a national priority. The Sumatra floods are not merely natural disasters; they are reflections of policy choices that demand serious correction. Otherwise, the country will continue to count victims instead of preventing the next tragedy. (*)
By: Memet Hakim – Social and Hydrology Observer
Disclaimer: This article represents the author’s personal views and is entirely his responsibility.
