Antara, Jakarta – Indonesia's Environment Minister Hanif Faisol Nurofiq has identified several key activities contributing to the worsening floods in Sumatra, particularly in South Tapanuli Regency, North Sumatra.
"We have identified at least three main factors driving the floods," said Hanif, who also heads the Environmental Control Agency, as quoted by Antara on Saturday, December 6, 2025.
He said the greatest environmental pressures in the Batang Toru Watershed stem from plantation forestry operations, major hydropower development projects, and intensive gold mining.
"All of these activities significantly increase environmental stress," he said.
The disaster has raised fresh concerns over environmental governance in one of Indonesia's most ecologically sensitive regions.
Hanif said the assessment was based on aerial monitoring and on-site inspections at locations suspected of accelerating surface water runoff. These observations, he noted, highlight worsening conditions in the upper watershed due to land-use expansion.
He added that the upstream zone is also dominated by extensive farmland, both irrigated and dry, which reduces the soil's ability to absorb rainfall.
The Ministry is now conducting detailed field verification to ensure that the data leads to concrete corrective measures. Hanif stressed that environmental recovery efforts must examine the entire ecosystem rather than isolated points.
He also warned that the recent patterns of extreme rainfall should serve as a new baseline for spatial planning and land-use control.
"With rainfall intensities now exceeding 250 to even 300 millimeters, the Ministry and Environmental Control Agency will re-evaluate all environmental approvals in the Batang Toru Watershed," he said.
As part of this effort, the Ministry is tightening oversight in areas prone to floods and landslides. Two companies in Batang Toru were recently subject to sudden inspections, as authorities recheck environmental permits and spatial compliance for activities on steep slopes, upper catchment zones, and river channels. Legal action will follow if violations that heighten disaster risk are identified.
Hanif said field verifications will continue, including at other companies suspected of adding to environmental pressures that have worsened this year's flood disaster in Sumatra.