Impacts of climate change and water induced disasters in high altitude on hydropower development in Nepal. Rijan Bhakta Kayastha, D. Sc.

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1 Impacts of climate change and water induced disasters in high altitude on hydropower development in Nepal Rijan Bhakta Kayastha, D. Sc. Associate Professor and Coordinator Himalayan Cryosphere, Climate and Disaster Research Center (HiCCDRC), Kathmandu University EGM on Water-Food-Energy Resilience (Security) under SDGs and Climate Change (Paris Agreement) in Mid-Latitude Region November 2016, Seoul, Republic of Korea

2 Climate Change Scenario of Nepal Global Temperature Change: 0.80 ᵒC ( ) based on analysis conducted by scientists at NASA s Goddard Institute for Space Studies (GISS) Nepal s Temperature Change ( ) Maximum temp. trend: o C/year Minimum temp. trend: o C/year Based on analysis conducted by scientists at the Dept. of Hydrology and Meteorology, Gov. of Nepal

3 Mean Maximum Temp. Trend: Annual ( )

4 Mean Minimum Temp. Trend: Annual ( )

5 Precipitation Trend: Annual ( )

6 Trend of annual precipitation and maximum and minimum air temps. ( )

7 Summary ( ) Maximum temperature is in increasing trend in large magnitude than the minimum temperature in almost all the seasons. Maximum temp. trend: o C/year Minimum temp. trend: o C/year Maximum temp. trend: higher in high altitude region Minimum temp. trend: higher in low altitude region

8 Variations of Climatic Parameter Historic maximum temperature variation in Kathmandu ( ) 27.0 Maximum temp. o ( C) World Data Centre for Paleoclimatology, Boulder, USA and DHM

9 Impacts of Climate Change on cryosphere Number of Glaciers in Nepal in 2010: 3808 Number of Glacial Lakes in Nepal: 1466 Glacier area: 3902 km 2 Glacier Volume: 312 km 3 During a period from 1977 to % of glacier area (38 km 2 /yr) decreased 29 % ice reserve decreased (From Bajracharya et al ICIMOD)

10 GEN and CREH 2006, updates Glaciers are retreating Glacier AX010 in Shorong Himal, east Nepal 2008

11 Yala Glacier in Langtang Valley

12 Yala Glacier in November 2014

13 Yala Glacier in May 2016

14 Rikha Samba Glacier in Hidden Valley

15 Dig Tsho GLOF (Eye opening GLOF in Nepal) Dig Tsho Glacial Lake burst on 4 August 1985 due to ice avalanche from Langmoche hanging glacier The GLOF destroyed nearly completed Namche Hydropower Plant, 14 bridges, cultivated land and caused many casualties

16 After the Dig Tsho GLOF Government of Nepal started to study glacial lakes * Tsho Rolpa Glacial Lake * Imja Glacial Lake * Thulagi Glacial Lake * Lower Barun Glacial Lake

17 Tsho Rolpa Glacial Lake (Dolakha)

18 Tsho Rolpa Glacial Lake Test siphon, early warning and mitigation Lake Development

19 Climate Change Adaptations Test Siphons Siphon option was not used for lake drawdown because of high maintenance requirement after winter freezing and lack of space to lay large number of pipes

20 The System: - 2 Sensing stations - Meteoburst and ELOS transmission - 19 warning stations (17 villages) - 2 Data Management Centers

21 Lake level lowering by open channel excavation US $ 3.1 m

22 GLOF PREVENTION Reinforced Spillway at Tsho Rolpa

23 Imja Glacial Lake in October 2010

24 Location map of Imja Glacial Lake in the Sagarmatha region (from Sakai et al. 2007)

25 Development of Imja Glacial Lake ( )

26 GLOF Prevention New outlet in Imja Glacial Lake (Oct. 2016) -3.4 m in October 2016 by Nepal Army Global Environment Fund (DHM, UNDP)

27 GLOF Prevention New outlet in Imja Glacial Lake

28 Imja, Tsho Rolpa and Thulagi Glacial Lakes were studied in detail in 2009 by ICIMOD and found that they all poses serious risk of outburst but not immediately. Imja There is an urgent need of a preventive measures to reduce risk of outburst. Lake level lowering with hydropower facility rather than only early warning system is demanded by the people of Dingboche. (ICIMOD, 2011)

29 GLOF Modeling study of Imja Lake

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31 Distance Imja Tsho Rolpa VDCs Population VDCs Population Within 50 km km km km Total (ICIMOD, 2011)

32 Existing and Potential Hydropower Projects 1500 MW 1863 MW (ICIMOD, 2011)

33 Properties Exposed: Land, Crops and Livestock Properties Imja Tsho Rolpa Land (ropani) Khet (Irrigated land) Bari (rain-fed land) Crops (Mt) Paddy Wheat Maize Millet Potato Other crops 0.6 Vegetables (1 ropani = ha) (ICIMOD, 2011)

34 Population downstream within 100 km that could be affected Description Imja Tsho Rolpa Population potentially directly affected due to loss of resources Population potentially indirectly affected Replacement costs in billion US $ 96, , , , (ICIMOD, 2011)

35 Thulagi Glacial Lake (Manaslu) Manaslu (8169 m) N

36 Thulagi Glacial Lake (1996)

37 Strategic location of Thulagi Glacial Lake UMHEP MMHEP LMHEP

38 Past GLOFs in Nepal No. Date River Basin Name of Lake years ago Seti Khola Machhapuchhare 2 August 1935 Sun Koshi Taraco, Tibet 3 Sept. 21, 1964 Arun Gelaipco, Tibet 4 Sun Koshi Zhangzangbo, Tibet Trishuli Longda, Tibet Arun Ayaco, Tibet Arun Ayaco, Tibet Source: WECS 1998; DHM; ICIMOD

39 Past GLOF in Nepal contd. No. Date Basin Lake Arun Ayaco, Tibet 9 Sep. 3, 1977 Dudh Koshi Nare Tibet 10 June 23, 1980 Tamur Nagma Pokhari, Nepal 11 July 11, 1981 Sun Koshi Zhangzangbo 12 August 27, 1982 Arun Jinco, Tibet 13 August 4, 1985 Dudh Koshi Dig Tsho 14 July 12, 1991 Tama Koshi Chubung 15 Sep. 3, 1998 Dudh Koshi Tam Pokhari Source: WECS 1998; DHM; ICIMOD

40 Major Flood Disasters in Nepal 1) 1993 Central Nepal Bagmati Flood 540 mm rainfall on 24 July ,029 people killed 400,000 another people affected 25,000 houses damaged 40,000 ha of agricultural land destroyed (Dhital et al., 1993)

41 2) 2002 Central Nepal Flood (Kath., Sarlahi, Makawanpur districts) Heavy down pour from 21 to 23 July 2002 more than 200 mm rainfall on 23 July 2002 (Sarlahi) 445 people killed 12,800 houses damaged

42 3) 2008 Koshi River Flood (Nepal and India) The embankment (old) was breached on 18 August 2008 due to heavy downpour in the upstream 50,000 family of Nepal 2.3 million people in Bihar, India

43 4) Flash flood of Seti River, Pokhara The flash flood of 5 May 2012 in Seti River in Pokhara, Western Nepal Due to debris-mixed snow avalanche and then damming of the flow in the high Himalayas 31 people dead 40 people missing

44 5) 2013 Mahakali Flood in Nepal Rainfall at Dipayal 16 June: 80.4 mm of rain 17 June: mm 77 buildings swept away Few people were dead 2000 households affected

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46 Vulnerability Assessment of NEPAL The recent country wide vulnerability assessment showed that 9 districts most vulnerable to flood, 29 most vulnerable to landslide, 12 vulnerable to GLOF and 22 vulnerable to drought

47 Summary Impacts of climate change in Nepal has already started Increasing trend in air temp. but no clear trend in ppt. Decreasing glacier area and ice volume Increase in glacial lake area and volume of stored water in lakes Increase in flood events Due to these various phenomena The hydropower development in Nepal is becoming more challenging

48 Way Forward Go for generating more and more hydropower with reservoir type power plants Install flood early warning system in major rivers Go for adaptation and mitigation options to reduce negative impacts of climate change

49 THANK YOU! Tsho Rolpa Glacial Lake, 2009