Reviving drying springs in the Himalayas:

Transcription

1 Reviving drying springs in the Himalayas: Mitigation measures for Hydropower International Centre for Integrated Mountain Development Kathmandu, Nepal

2 TOTAL CAPACITY (MW) NUMBER OF HYDROPOWER PROJECTS Nepal s hydropower boom Total capacity (MW) Number of hydropower projects Beyond 2020 NA YEAR WHEN THE PROJECT WILL START COMMERCIAL OPERATION

3 Drying springs Springs are groundwater discharge points Springs are the main source for drinking, domestic and sometimes, irrigation water Anecdotal evidence that springs in mid hills are drying up Drying of springs has led to acute drinking and domestic water problems Yet, scientific knowledge is very sparse

4 Abandoned Lholing village, Bhutan Empty houses Empty houses Abandoned land Lone occupant About 50 households left their land and houses and settled along Pachhu river. Only one household still staying in the village. By: Kaka WMD, Bhutan

5 Understanding mutual benefits- what can hydropower companies gain through spring revival? Purpose of this presentation: Building Bridges with Businesses Awareness building what causes drying of springs? Knowledge sharing how can we revive drying springs and how can hydropower companies help?

6 Himalayan springs are sources of water for communities IMPACTS Wellbeing (Social) Livelihood (Economic) Climate (Environmental) Springs are drying SOLUTION Climate change Increased extraction CAUSES Infrastructure including hydro Other factors Partnership in Reviving Drying Springs in Himalayas

7 People often perceive that hydropower tunnels leads to disturbance and disappearance of springs THE LOCATIONS OF THE JORETHANG LOOP HYDROPOWER DAM, TUNNEL AND POWER HOUSE INCLUDING SEVERAL SPRING LOCATIONS (GOOGLE EARTH, 2011) From: Bram Droppers, 2014

8 Why and how hydropower tunnels affect springs? CASE-1: A tunnel passing through the aquifer that feeds springs can disrupt the flow The tunnel drilled across disturbs the aquifer feeding springs. The tunnel will affect the natural groundwater flow in the aquifer thereby affecting the spring discharge.

9 Impacts of digging tunnels on its environment CASE-2: A tunnel creates fractures through which aquifer can drain out The tunneling process will induce fractures across multiple lithounits causing leakage from the aquifer into adjoining units leading to loss in total storage in the aquifer.

10 Case 3: In karst spring, construction of tunnels can lead to collapse of the entire underground system and tunnels

11 Case 4: Tunnel blasting creates tremors very similar to earthquakes causing landslides, which can disturb or remove a spring aquifer GEOLOGICAL CROSS SECTION OF THE FIRST PART OF THE JORETHANG LOOP TUNNEL From: Bram Droppers, 2014

12 Birta Ko Dhara Spring, Sindhupalchok: An example of spring dried up due to landslide after earthquake

13 Protocol for Springs Revival and Springshed Management Six steps approach Integrating physical science/social science & research and implementation

14 Study Sites

15 Comprehensive Mapping of Springs Paduka VDC, Dailekh

16 Setting up of Data Monitoring System Dailekh Raingauge ID: RG Dullu District: Dailekh Municipality/ VDC Dullu, former Paduka VDC Village: Dullu Latitude: 28 51' 46.7" Longitude: 81 36' 17.7" Elevation: 1432 masl Data Collector: Sita Nepali/ Bhakta Nepali Mobile no: ,

17 Hydrogeological Mapping Methodology of fieldwork + Google Earth for mapping hydrogeology at local scales Plotting all the geological observations using Google Earth Preparing Geological map based on the observations plotted

18 Developing hydrogeological conceptual layouts and identifying recharge areas Identifying potential recharge area for the spring based on hydrogeological setting

19 Recharge area demarcation using Google Earth

20 RECHARGE STRUCTURES There are hundreds of options and have been practiced in the watershed management programmes since long. What is new? They are applied in the recharge zone not everywhere in the springshed. Choice of structures depend on land use, land ownership and land use right of recharge zone. Structures are barriers that reduce/stop speed of water to increase infiltration.

21 RECHARGE STRUCTURES 1.Structural 3. Agronomic 2.Vegetative 4. Management 5. Combination

22 Structural measures Shallow pond, trench, pit and bund Recharge Zone: uncultivated land Shallow Pond: Depth < 1 m Staggered trench Continuous trench L: variable ( 5-10 m) W: 0.6 m D: 0.5 m Triangular pit Stone bund

23 Vegetative measures Hedgerow, Palisade Recharge zone: cultivated and uncultivated land Hedgerow Palisade

24 Agronomic measures Mulch Recharge zone: cultivated land (Mulch) Minimum tillage and Mulch Mulch

25 Management measures Recharge zone: Grazing land rotational grazing/ controlled grazing

26 Combined measures (Structural + vegetative) Recharge zone: cultivated land Bench terraces Inward sloping terrace Sloping land Recharge zone: uncultivated land

27 Interventions- Maikarol Spring, Dailekh Within the recharge zone, 278 square kilometres of plantation fencing was performed, along with the construction of 11 staggered contour trenches, 45 staggered eyebrow trenches and gully plugging.

28 Step 6. Impacts monitoring Maikarol spring hydrograph Improvements: post-intervention This translates to ~ additional 61,700 litres over 4 months, and provide minimum water security to ~ 1550 people (@ 40lpcd) 2.51 lpm 2.86 lpm Indication of increased base flow after one years of intervention.

29 Linking benefit sharing in hydropower with spring revival Investments in vegetative measures in recharge areas Afforestation programs Royalty payment to government Hydropower shares to locals Investments in recharge measures in recharge areas Electricity, irrigation & infrastructure Trainings and employment Trainings to locals to become parahydrologists Source: Benefit sharing study by ICIMOD

30 Why be Engaged in Reviving of Springs now? Supporting UN Sustainable Development Goals Taking climate action & responsible business practices Increasing water efficiency brings Win-Win benefits

31 Role of ICIMOD Provide technical assistance and expertise to hydropower companies to implement spring revival activities in selected sites Help in capacity building of project staff who may be interested in undertaking spring revival activities Ensure access to safe & secure water supply for drinking, domestic and agricultural purposes to marginalised mountain communities by reviving springs using tested scientific and community engagement.

32 Role of Hydropower Companies Enhance understanding of factors influencing drying on springs & utilise existing knowledge to ensure sustainable business practices Incorporate new knowledge for sustainable water management practices to benefit communities and hydropower companies Take the lead to ensure that present & future water sustainable management practices protect environment by adopting ways operating them more effectively

33 Thank you