Lessons from a Flash Flood in Tehran Subway, Iran

Lessons from a Flash Flood in Tehran Subway, Iran Brief Incident Report 2 PLOS Currents Disasters 2 0 1 Department of Disaster Public Health, School of Public Health, Tehran University of Medical Sciences , Tehran , Iran , 2 Department of Disaster & Emergency Health, National Institute of Health Research, Tehran University of Medical Sciences , Tehran , Iran; Department of Disaster Public Health, School of Public Health, Tehran University of Medical Sciences , Tehran , Iran 1 , Seyedeh Vahideh Soleimani , Ali Ardalan 2 May 2, 2013 Brief Incident Report Abbas Ostad Taghizadeh On 15 April 2012 at around 13:00 local time, following a heavy rainfall in Tehran, a break in the channel wall of Kan River caused a flash flood in the Tehran metro tunnels. Consequently, line 4 of the metro went out of operation for about two weeks 1 . The flood was running for 30 hours in the metro system so that three stations were flooded causing damage to four trains and 28 wagons 2. It is estimated that approximately one million m3 of water and debris rushed in the metro tunnels through the break. Although this flash flood caused property damage of about $21 million (at the official exchange rate) to the metro especially its electrical system, fortunately no death and injury ensued 1,2,3,4 . Quick measures were taken to disconnect electricity and evacuate more than 1,500 passengers and staff from the adjacent stations while simultaneously the water was draining. For a few days, more than 10 thousands m3 of debris and precipitants were removed from the stations and trains. Finally, damaged stations were repaired and got back to the operation in 12 days 3 . It was claimed that 2,500 persons worked every day during the response to this disaster. Immediate disconnection of the electricity system prevented electrocutions. Timely emergency evacuation in this event saved hundreds of lives. All trains were stopped in adjacent stations and the passengers were instructed by the staff to safely evacuate the metro. In addition, dwellers near at risk stations were relocated to safe buildings. Here, we wish to address some challenges along with corresponding lessons learned that have a bearing on revisions to the emergency plan of Tehran in general and Tehrans metro in particular: 1. Experts believe that over excavation near the river channel was the main reason for this event1 . In fact, millions of dollar could have been saved if excavation code was respected. Rigorous supervision of construction activities in urban areas will prevent similar events in the future. 2. Tehrans early warning system (EWS) for flash floods must be improved. Citys inhabitants and the infrastructures including Tehrans metro, in particular, will benefit from this system. A timely and effective EWS prevents the loss of lives and unnecessary functional and economical damages. It however requires further collaboration among Tehrans Disaster Management Center, Meteorological Organization and Water and Sanitation Organization. 3. Risk transfer is a key component of disaster risk management. Tehrans metro system was insured up to $8 million (at the official exchange rate), but the damage caused by the flash flood far exceeded that amount2 . This challenge could be prevented through more detailed risk assessment. 5. While fortunately no death was reported in this event, but it is worth emphasizing continuous education of metros passengers in term of safety issues especially risks of electrocution during the flooding and stampede toward the exit doors. This will save lives and assist the metro operators for safer and quicker response. The authors received no fund for this study. The authors have declared that no competing interests exist. Corresponding Author 1. Nikzad A , Shakib H , Mehrabian AA. Presidential selected committees report regarding Tehran's metro flood . Tehran. 2012 . [Cited 11 June 2012]; Available from: http://www.dolat.ir/NSite/FullStory/News/? Serv=0&Id=216166 2. Shakib H. Line 4 subway accident report . Tehran. Islamic Council of Tehran. 2012 . [Cited 16 June 2012]; Available from: http://www.mehrnews. com/detail/News/1628155 3. Communication Management System of Tehran Municipality. Reopening western part of Metro line 4. Tehran 2012 [Cited 30 April 2012 ]; Available from: http://www.tehransama. ir/NewsDetail .aspx? NewsID=949172 4. Communication Management System of Tehran Municipality . Detailed description of the occurrence and control of Tehran's recent flood . Tehran 2012 [Cited 30 April 2012 ]; Available from: http://www.tehransama. ir/NewsDetail .aspx? NewsID=949116 (...truncated)