The theme for World Water Day this year is Nature for Water. Every year, on 22 March, the world focuses its attention on the importance of water through this event. This year’s theme begs us to examine how we can explore nature or use nature-based solutions to overcome the water challenges of our time.
For the mountains, this year’s theme is an apt one. Mountains are the source of all mighty rivers, and their fragile environment demands that our water solutions be as nature-based as possible. In the Hindu Kush Himalayan (HKH) region, an area that extends 3,500 kilometres across all or part of Afghanistan, Bangladesh, Bhutan, China, India, Myanmar, Nepal, and Pakistan, the drying of natural springs is an issue for which there are nature-based solutions available.
Springs, which are groundwater discharge points where the water-bearing layer in the mountains and hills intersect with the ground surface, are unique to the mountain landscapes. In our HKH region, even by a conservative estimate, there are close to five million springs. These springs are the lifeline of water security in the region and provide water for drinking, and domestic and irrigation purposes. Most mountain towns also depend on these springs for urban water supply. Springs perform very important ecological functions by providing base flows to rivers and sustaining rich biota. Springs are also important from cultural and religious points of view and are often worshipped by the local communities.
There is anecdotal evidence from all across the HKH that these natural springs are drying. There are multiple causes for drying of springs – changing rainfall and temperature patterns due to climate change; changes in land use and land cover, including infrastructure projects such as road construction and hydropower; and increased demand for spring water due to demographic changes and changing lifestyles. Drying of springs causes multiple hardships for local mountain people for whom springs are the only accessible and safe source of water. Most settlements in the mid-hills and mountains of the HKH region are on the ridge top while glacier-fed perennial rivers flow at the valley bottoms and the glaciers themselves are too far away to access. These hardships are compounded for the marginalized –women, dalits (the so-called “lower” caste among Hindus), and the ethnic minorities – who often withstand the worst of this water scarcity.
So how can we use nature-based solutions to preserve our natural springs? Given that springs are groundwater discharge points, there has to be a recharge area somewhere above. Very simply put, imagine the recharge areas are the water tanks on our roofs, and the springs are taps in our bathrooms and kitchen– unless the tank on the roof is full, the taps will not yield water. Spring discharge can be increased in most cases by enhancing recharge in the recharge zone. This begs the question – how do we identify the recharge zone?
The answer to this question brings us to the realm of hydrogeology – the science of understanding groundwater, based on the knowledge of underground geology or rock structure. Put simply, the Himalaya are one of the most complex geological structures in the world. The presence or absence of groundwater is dictated by the kinds of rock (some rocks have inherently more water bearing capacity than others); the natural dip and strike (that is inclination) of these rocks; and by the numerous faults and fractures in these rocks – faults and fractures can hold water even if the rock itself is impermeable.
Using simple field-level geology that most villagers can understand after some training, we can go about demarcating recharge areas. Over the course of working on spring recharge with villagers, we have observed that local communities often have good intuition guiding them to probable recharge areas. Historically, these recharge areas had ponds dug in them, but over the years, many such ponds have become neglected and dried as a result. However, local communities still carry anecdotal stories about the role these ridge top ponds play in recharging springs in their villages. Community members are able to see the connection between recharge and discharge quite easily.
Once such recharge areas are identified using field geology and local knowledge, nature-based solutions and simple watershed interventions can be deployed to revive springs. Nature-based solutions include the use of vegetative measures such as hedgerows and palisades (small natural dams with local vegetation) to enhance recharge in identified recharge areas. Nature-based solutions would also include planting of suitable species for water conservations. In the humid and sub-humid mid-hills of the Himalaya, for example, broad-leafed deciduous trees are generally better at water retention and recharge than coniferous trees like pines, although this might differ with altitudinal and climatic conditions.
Nature-based approaches to spring recharge have been implemented successfully in the Indian Himalaya, particularly in the states of Sikkim and Uttarakhand. There is a national policy for spring recharge in place in all 11 Indian mountain states. In Nepal, these approaches have been successfully implemented in the far western district of Dailekh. As a result, the amount of spring discharge in the dry season (November–March) has increased considerably, even doubling in some cases to substantially increase local water security.
This approach of using simple geology to demarcate recharge areas and then to carry out recharge interventions in those areas has been well tested and tried. A policy push is now required. Local governments in the new federal Nepal need to be empowered to train their human resources in the nature-based identification of recharge areas and recharge of springs, and then invest their resources in such recharge activities. Other countries in the HKH can also learn from successful spring revival work done on a pilot basis in India and Nepal, and put policies in place that use nature-based solutions to preserve one of our purest sources of natural water – the mountain springs.
Mukherji is a human geographer by training and heads the Water and Air theme at the International Centre for Integrated Mountain Development (ICIMOD).