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Semarang Prepares: The Anatomy of a Flood Simulation

Semarang Flood Simulation

In 2010, a flash flood ravaged the Indonesian city of Semarang, situated on the island of Java—the destruction included six deaths and over 100 injuries in the surrounding area. A vulnerability assessment conducted by Mercy Corps in 2011 indicated that flooding in ensuing years would only intensify, and that public resources would not be sufficient in the short-term to widen the nearby river in order to improve drainage systems. The assessment also identified seven particularly vulnerable areas in the city going forward.

Taking its future safety into its own hands, the city undertook a project—supported by The Rockefeller Foundation’s Asian Cities Climate Resilience Network (ACCCRN)—to develop a flood early warning system in these seven communities, involving coordination between key stakeholders across governmental departments and sectors, including the planning, water resources, meteorological and disaster management agencies, Diponegoro University, the Indonesian Red Cross and Bintari Foundation.

As part of this effort, the Wonosari community—one of the seven communities in the project area—came together in December to simulate what would happen in the event of a flood. This is how it went:

The Siren Sounds

Semarang Flood SimulationAt 1:45pm, the first siren sounded from the loudspeakers as well as from kentongan drums. In their homes, community members got ready, fetching their evacuation packs containing vital supplies. Within minutes, the alert escalated, signaling that it was time to leave. By the next warning level, everyone was already heading to the flood shelter, following designated evacuation routes.


Semarang Flood SimulationThe community disaster team of volunteers simulated evacuating the sick, disabled and elderly to the shelter, which was located on high ground. Once there, a tally began to identify any missing community members. Community members simulated first aid procedures for the injured. The KSB, a local community disaster preparedness group comprised of volunteer leaders from each community, led the planning of the exercise. They refined the evacuation process with each activity allowing them to improve on the next.


IMG_0717The simulation was an apparent success. Once all members were at the shelter, the exercise ended with a community-wide debrief. Leaders each shared reflections, including issues they saw arise and any improvements needed in the procedure. This time, large rocks on the side of the hill were identified as obstructing a major path leading to the shelter, and they needed to be removed.

The wider project served to initiate a process for multi-stakeholder collaboration, building local capacity and deepening awareness of the climate change shocks and stresses. This latest simulation was planned and entirely funded by the Semarang city government, an encouraging sign that this kind of work—key to building urban resilience, not only in Semarang, but around the globe—will continue well into the future.

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