INDONESIA, ACEH | insetgalusnews.com | Mount Kappi, located within the core zone of Gunung Leuser National Park, is considered to play a vital role as Aceh’s primary hydrological buffer. The area is widely known as the “water tower” of Sumatra because it regulates water availability for millions of residents in downstream regions. Damage to forest functions in the area is believed to be contributing to the rising risk of flash floods affecting several districts in Aceh on Saturday (20/12/2025).
An environmental observer from Gayo Lues Regency, AML, explained that Mount Kappi is a montane forest ecosystem that functions like a giant sponge. The area absorbs extreme rainfall and releases it gradually, maintaining stable water discharge across several major river basins in Aceh.
“When forest cover is disturbed, that natural mechanism collapses. Rainwater flows uncontrollably, carrying mud and timber debris downstream,” AML said.
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According to AML, damage in the Mount Kappi area has a direct impact on three geographically distant sectors of Aceh. In the western sector, runoff forms the Tripe River, which flows through Dabun Gelang, Rikit Gaib, Tripe Jaya, and Terangun subdistricts in Gayo Lues Regency. The river then passes the border of Aceh Barat Daya and Nagan Raya Regency before emptying into the sea.
In the eastern sector, part of the runoff flows into the Lesten River in Pining Subdistrict and is reinforced by flows from the Goh Lemu mountains. The water passes through Pining, enters East Aceh Regency (the Lokop/Serbejadi area), then continues through Aceh Tamiang Regency before emptying into the Malacca Strait.
Meanwhile, in the southern sector, runoff flows into the Alas River, which traverses Kutacane, Subulussalam, and Aceh Singkil Regency before discharging into the Indian Ocean. The Alas River is also reinforced by the Agusen River, which originates from the Leuser Blang Beke core zone.
AML warned that if Mount Kappi’s natural “sponge” function continues to deteriorate, the threat of flash floods will become increasingly frequent. “Without upstream buffers, floods can strike downstream areas suddenly, carrying mud and forest debris, and damaging settlements and agricultural land in Gayo Lues, Aceh Tenggara, Aceh Tamiang, East Aceh, Nagan Raya, and Singkil,” he said.
Editorial Desk | insetgalusnews
