Environment and Security

Environment and Security / 47


37 Mudflows and floods are sometimes considered as the most destructive natural events in the Ferghana valley. The high density of the river network, steep slopes and degraded soil cover increase mudflow risk, especially in the piedmont parts of the Ferghana valley. Mudflows are formed due to interaction of hydro-meteoro- logical and geological factors: cloudbursts, rapid snow melting, steep slopes, easily washed grounds, etc. Almost all the piedmont territory of the Ferghana valley is vulnerable to mudflows, including radioactive waste sites. Over 1,000 river basins are estimated to hold from moderate to high mudflow risk. In spring 1998, in Tajiki- stan and Kyrgyzstan, torrential rains caused severe flooding with over 20,000 people affected and many buildings and elements of infrastructure destroyed. The years 2003 and 2004 also featured flooding events in many areas, including the Syr Darya delta. Winter ice and a failure to observe regional water use agreements trigged floods along the Syr Darya River in Kyzyl-Orda, Southern Kazakhstan in early 2004 official national data) 38 Kyrgyzstan and Tajikistan are parties to UNECE Aarhus Conven- tion on Access to Information, Public Participation in Decision- making and Access to Justice in Environmental Matters, but its full-scale implementation on the local level will require considerable resources and time

as landslide dam outburst floods (LDOFs). One example is the catastrophic flood in the Shohimardon valley (see the main text) that killed nearly 100 people and destroyed many households. In 1999, the Asht Valley of Northern Tajikistan was hit by an LDOF killing 19 people, and destroying or damaging several hundred houses and elements of infrastructure 36 The mountain areas of Central Asia, including the Ferghana valley, are seismically active. National Seismological Networks recorded over 500 earthquakes of magnitude M>5 during the period 1900- 2000 only in Kyrgyzstan, mostly in the Ferghana valley and its mountains. Destructive earthquakes took place in Namangan, Andi- jan, Ferghana, Jalal-Abad, Isfara areas. Maximum seismic activity has been observed in the Chatkal, Alai, and Ferghana mountains, where 8-9 M events are possible (official national data) Most territory of the Ferghana valley and adjacent mountains are vulnerable to earthquakes with many small and large settlements located in the epicentre zones of the potentially devastating earthquakes (Isfara, Jalal-Abad, Osh, Kara-balta, etc). Some 30 settlements are threatened by both strong earthquakes and re- sultant risks (mudslides, unstable ground нестабильные участки территории-поверхности, etc). The earthquakes (M>7) that struck the Ferghana valley and adjacent mountain territory from 1911 onwards caused several thousands casualties and millions of dollars in economic loss (official national data)

39 Though reliable statistical data are not available, a range of anecdotal information confirm this trend

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