Bengawan Solo Mapping to Support Contingency Plan

  • oleh

Bengawan Solo river is the biggest, longest, and the oldest river in Java. With total length of 343,6 km, this river crosses 5 districts and 198 villages in East Java Province. Behind the unique phenomenon of its reversal flow due to tectonic activities two million years ago, nowadays Bengawan Solo become a nightmare for 300.000 people live along this river due to the flood every year. Last flood in January 2013 inundate about 26.229 hectares area and the lost estimated about 47 billion.


Respond to the fact that the flood will be happen every year, Regional Disaster Management Agency (BPBD) of East Java, in collaboration with United Nations Office for the Coordination of Humanitarian Affairs (UN – OCHA) and Australia – Indonesia Facility for Disaster Reduction (AIFDR) have agreed to update ”Bengawan Solo flood” contingency plan 2013 as one of disaster risk reduction effort. Contingency plan is a document that states what we should do if a contingency condition (such as disaster) is happening, what we must prepare and how much it is. Thus, detail and up to date data are needed to make a good contingency plan. That is why OSM join this project, as a tool to collect data –which is very easy to use and to be updated.

This project was initialized with a three days OSM training for enumerator. The training was purposed to train the scouts –our volunteer partner in this project, to collect data either graphic data (by digitizing imagery) or attribute data (by field survey and then input it through JOSM). About 40 scouts attend this training, then continued with 5 days field survey (April 29 – May 3, 2013) in 5 districts passed by Bengawan Solo river : Ngawi, Bojonegoro, Tuban, Lamongan, and Gresik.


To meet the need of contingency plan, we were collecting various of data, some of them very specific, consist of vulnerability data (such as is there any disable man, sick man, or pregnant woman in a house) and capacity data (such as how many vehicle they have; and is there any electricity, water supply, toilets, and communication facilities in a public building) with GPS and a bunch of fieldpapers.

At the end of the project, about 35.000’s building have been mapped in OSM.  Those data then employed as exposure layer along with AsiaPop data in InaSAFE simulation. InaSAFE simulation have run well and deliver result that about 20.000’s building might be flooded (the number might be more than this number since some area have not been mapped completely), with 242.000’s people might be affected and 2.000’s of them might need evacuation (1% evacuation threshold).


Thanks to everyone who had involve and contribute actively during this project. Hopefully, everyone especially scouts of East Java continue mapping, so we can improve the data and produce the better analysis.