Flood Disaster and Flood Management in Indonesia

Overview

Between 24 and 28 November 2025, Cyclone Senyar struck Northern Sumatra with 1000 mm of precipitation falling over 4 days, and with over 400mm of that rainfall on just one day. Such an event had not previously been recorded as the area had been outside the known cyclone belt.

The cyclone caused widespread damage with reports of over 1,200 deaths, 142 missing and over 7,000 injuries (Wikipedia). There was substantial loss of wildlife, damaged rice fields and other crops. Huge volumes of timber blocked river channels below bridges and were washed onto riverbanks. A lot of the forest damage was blamed on deforestation.

David will comment on why this was not entirely true as the Indonesian environment is particularly vulnerable to cyclones. He will also share his experience working on relevant projects in the area and describe the process of flood management studies he has undertaken with the ADB, with particular emphasis on the Padang river basin flood studies.