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 28-29 November 2016, Seoul, Republic of Korea
Climate Change Scenario of Nepal Global Temperature Change: 0.80 ᵒC (1880-2015) based on analysis conducted by scientists at NASA s Goddard Institute for Space Studies (GISS) Nepal s Temperature Change (1971-2012) Maximum temp. trend: 0.037 o C/year Minimum temp. trend: 0.012 o C/year Based on analysis conducted by scientists at the Dept. of Hydrology and Meteorology, Gov. of Nepal
Mean Maximum Temp. Trend: Annual (1971-2012)
Mean Minimum Temp. Trend: Annual (1971-2012)
Precipitation Trend: Annual (1971-2012)
Trend of annual precipitation and maximum and minimum air temps. (1971-2012)
Summary (1971-2012) Maximum temperature is in increasing trend in large magnitude than the minimum temperature in almost all the seasons. Maximum temp. trend: 0.037 o C/year Minimum temp. trend: 0.012 o C/year Maximum temp. trend: higher in high altitude region Minimum temp. trend: higher in low altitude region
Variations of Climatic Parameter Historic maximum temperature variation in Kathmandu (1897-1977) 27.0 Maximum temp. o ( C) 26.0 25.0 24.0 23.0 1890 1910 1930 1950 1970 1990 World Data Centre for Paleoclimatology, Boulder, USA and DHM
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 2010 24 % of glacier area (38 km 2 /yr) decreased 29 % ice reserve decreased (From Bajracharya et al. 2014-ICIMOD)
GEN and CREH 2006, updates Glaciers are retreating Glacier AX010 in Shorong Himal, east Nepal 2008
Yala Glacier in Langtang Valley
Yala Glacier in November 2014
Yala Glacier in May 2016
Rikha Samba Glacier in Hidden Valley
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
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
Tsho Rolpa Glacial Lake (Dolakha)
Tsho Rolpa Glacial Lake Test siphon, early warning and mitigation Lake Development
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
The System: - 2 Sensing stations - Meteoburst and ELOS transmission - 19 warning stations (17 villages) - 2 Data Management Centers
Lake level lowering by open channel excavation US $ 3.1 m
GLOF PREVENTION Reinforced Spillway at Tsho Rolpa
Imja Glacial Lake in October 2010
Location map of Imja Glacial Lake in the Sagarmatha region (from Sakai et al. 2007)
Development of Imja Glacial Lake (1963-2009)
GLOF Prevention New outlet in Imja Glacial Lake (Oct. 2016) -3.4 m in October 2016 by Nepal Army Global Environment Fund (DHM, UNDP)
GLOF Prevention New outlet in Imja Glacial Lake
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)
GLOF Modeling study of Imja Lake
Distance Imja Tsho Rolpa VDCs Population VDCs Population Within 50 km 5 12184 11 32499 50-75 km 9 31862 14 67659 75-100 km 14 34585 9 41753 100-120 km 7 18136 Total 35 96767 34 141911 (ICIMOD, 2011)
Existing and Potential Hydropower Projects 1500 MW 1863 MW (ICIMOD, 2011)
Properties Exposed: Land, Crops and Livestock Properties Imja Tsho Rolpa Land (ropani) 7422 2541 Khet (Irrigated land) 5420 2227 Bari (rain-fed land) 2002 314 Crops (Mt) 1801.3 666.9 Paddy 696.3 247.5 Wheat 252.4 52.1 Maize 478.5 179 Millet 82.6 119.8 Potato 277.9 54.8 Other crops 0.6 Vegetables 13.6 13.2 (1 ropani = 0.0509 ha) (ICIMOD, 2011)
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 $ 96,767 141,911 501,773 524,323 8.98 2.4 (ICIMOD, 2011)
Thulagi Glacial Lake (Manaslu) Manaslu (8169 m) N
Thulagi Glacial Lake (1996)
Strategic location of Thulagi Glacial Lake UMHEP MMHEP LMHEP
Past GLOFs in Nepal No. Date River Basin Name of Lake 1 450 years ago Seti Khola Machhapuchhare 2 August 1935 Sun Koshi Taraco, Tibet 3 Sept. 21, 1964 Arun Gelaipco, Tibet 4 Sun Koshi Zhangzangbo, Tibet 5 1964 Trishuli Longda, Tibet 6 1968 Arun Ayaco, Tibet 7 1969 Arun Ayaco, Tibet Source: WECS 1998; DHM; ICIMOD
Past GLOF in Nepal contd. No. Date Basin Lake 8 1970 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
Major Flood Disasters in Nepal 1) 1993 Central Nepal Bagmati Flood 540 mm rainfall on 24 July 1993 1,029 people killed 400,000 another people affected 25,000 houses damaged 40,000 ha of agricultural land destroyed (Dhital et al., 1993)
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
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
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
5) 2013 Mahakali Flood in Nepal Rainfall at Dipayal 16 June: 80.4 mm of rain 17 June: 221.8 mm 77 buildings swept away Few people were dead 2000 households affected
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
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
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
THANK YOU! Tsho Rolpa Glacial Lake, 2009