Survey Report of Sediment Disaster in Kotmale, Sri Lanka, on September, 2015

On the afternoon of Friday September 25, 2015, a landslide occurred in Lilisland, part of the Wedamulla Estate of Kotmale, Nuwara Eliya District, Sri Lanka ; seven people were killed. Immediately after the disaster, the National Building Research Organization (NBRO) conducted a survey and produced the “Preliminary Land Survey Report on the Landslide Occurrence in Lilisland of Wedamulla Estate of Kotmale AGA Division, Nuwara Eliya District” (hereafter, the NBRO report). A Japan International Cooperation Agency (JICA) survey team performed a field survey after the landslide disaster in Koslanda, Badulla District, at the end of October 2014, and introduced a sediment disaster survey method that is now widely used in Japan and Sri Lanka. Also at this time, we (i. e., a JICA survey team) conducted a 2-day field survey on September 30 and October 1, 2015, for the purpose of elucidating the type of disaster and its underlying mechanism. In addition, we conducted an after-action review (AAR) on September 30 and October 1, 2015, and on December 19, 2016, and confirmed the situation at the time of the disaster. We compiled the results into a report for use in countermeasures against sediment disasters in Sri Lanka.