Soil science teaches that flooding is not merely a matter of how much\nwater falls from the sky, but also how well the landscape can absorb,\nstore, and channel it.<\/p>\n
Jakarta (ANTARA) \u2014 The city of Padang was struck by major flooding\nagain on 3 August 2026. Very high-intensity rain fell almost all day,\ncausing four main rivers \u2014 Batang Kuranji, Batang Arau, Batang Aie\nDingin, and Batang Guo \u2014 to overflow almost simultaneously.<\/p>\n
At least 15 locations across Padang were reported submerged,\nincluding health facilities, while the Regional Disaster Management\nAgency (BPBD) had to evacuate residents using rubber boats.<\/p>\n
Various media reports indicated accumulated rainfall of between\nroughly 250 mm and more than 380 mm at several observation points.\nDespite differences between rain stations, all the data showed that\nPadang experienced rainfall in the very extreme category.<\/p>\n
Using a conservative figure of 250 mm, and assuming the rain fell\nevenly across Padang\u2019s entire area of 694.96 square kilometres, the\nvolume of rainwater that fell amounted to about 173.7 million cubic\nmetres, or around 174 billion litres of water.<\/p>\n
With a higher rainfall figure, the volume of water entering Padang\u2019s\nhydrological system could even exceed 260 million cubic metres in only\nabout ten hours. Such a volume is enough to overwhelm the soil\u2019s\ninfiltration capacity, urban drainage, and the main rivers all at\nonce.<\/p>\n
The almost simultaneous overflow of Batang Kuranji, Batang Arau,\nBatang Aie Dingin, and Batang Guo shows that the flooding was not simply\nthe result of drainage channels unable to carry away the water. It was a\nhydrological response by several watersheds (DAS) to widespread extreme\nrainfall.<\/p>\n
Under such conditions, rainwater falling in the hills immediately\nbecomes surface runoff. Water flows through tributaries into the main\nrivers in a relatively short time, so discharge rises very rapidly. When\nriver capacity is exceeded, water spills onto the floodplain and enters\nresidential areas.<\/p>\n
This phenomenon shows that urban flooding cannot be separated from\nthe condition of the upstream watersheds.<\/p>\n
Satellite traces<\/p>\n
The major flood that struck Padang on 3 August 2026 did not occur in\nwatersheds that had recovered. Analysis of the latest Sentinel-2\nsatellite imagery, recorded on 31 July 2026, about three days before the\nflood, shows that the upper reaches of the Batang Kuranji watershed\nstill bore the scars of the flash floods of 26\u201327 November 2025.<\/p>\n
Vegetation cover had not returned to its pre-disaster condition,\nwhile parts of the slopes still showed open areas, former landslide\nscars, and river corridors that remained wider than normal. This\nindicates that the watershed\u2019s ecosystem recovery is still ongoing and\nhas not yet restored its hydrological function optimally.<\/p>\n
These findings complement earlier Sentinel-2 analysis comparing\nconditions on 4 October 2025, before the flash floods, with 1 February\n2026, after them. That analysis showed around 80 hectares of vegetation\nhad turned into bare ground or sediment deposits, while the river\ncorridor widened from about 37 hectares to roughly 153 hectares.<\/p>", "url": "https:\/\/jawawa.id\/newsitem\/when-extreme-rainfall-meets-an-unrecovered-watershed-the-anatomy-of-the-padang-flood-1785916503", "image": "" }, "sponsor": "Okusi Associates", "sponsor_url": "https:\/\/okusiassociates.com" }