The Himalayas, an important part of the geography of India, extend along the entire Northern and North-Eastern boundary of the country. It spans six Indian States namely, Jammu and Kashmir, Himachal Pradesh, Uttaranchal, West Bengal, Sikkim and a major part of Arunachal Pradesh from west to east.
The Himalayan mountain system has a profound effect on the climate of the Indian subcontinent. It shields South Asia from the dry Arctic winds and keeps the region warm. More importantly, the Himalayas play a very vital role in bringing precipitation to the subcontinent by acting as a barrier to the monsoon winds and preventing their northward escape.
Springs and groundwater recharge
The report titled 'Groundwater scenario of Himalayan region, India' published by the Central Ground Water Board, Ministry of Water Resources, Government of India gives an overview about the complex structure and morphology that control the hydrogeology of the region. The chief source of groundwater recharge in most of the Himalayan region is through glaciers. In the foothills, although rainfall is quite high and contributes to groundwater recharge, a vast quantity of water just flows out as surface runoff. This results in a decreased amount of water seeping into the ground.
Groundwater comes out as seepage through springs under favourable situations and this forms the major source of water supply to rural and urban settlements. Springs also contribute additional water to the surface drainage network of the area. In the north-eastern part of India, groundwater occurs in consolidated crystallines and meta-sedimentaries which is usually extracted through dug wells and borewells of limited yield.
Issues with groundwater quality
Although groundwater in the region is considered good and used for drinking and agricultural use, the concentration of chemicals in hot springs in the region is quite high and above permissible limits. For example, high iron content has been found in some parts of Jammu & Kashmir and Sikkim. Nitrate levels beyond acceptable limits have been found in shallow aquifers in valley areas of Jammu & Kashmir, Himachal Pradesh and Uttarakhand.
Fluoride concentration above permissible limits has been observed in spring waters in Jammu & Ladakh Regions of J & K State and in Simla, Mandi and Lahaul & Spiti districts in Himachal Pradesh. In Ladakh regions, tube well water is also found to have a marginally higher concentration of nitrate.
The groundwater in the North Eastern States has been found to have higher concentrations of iron, fluoride and arsenic. Iron concentration exceeds permissible limits in most of the districts of Assam, Meghalaya, Manipur and Tripura. Fluoride content in groundwater in parts of Karbi Anglong, Nagaon and Kamrup districts of Assam also exceeds the permissible limits while arsenic contamination has also been found in shallow aquifers in parts of Dhemaji district and Majuli area of Jorhat district. Arsenic concentration has also been reported in shallow ground waters from Thoubal and Bishnupur districts of Manipur valley as well.
Groundwater development and sustainability: Concerns
Earlier, the population in the Himalaya’s hilly areas remained totally dependent on streams and spring water for drinking as well as for other domestic uses. However, urbanisation and increase in population have put pressure on these water resources, which are now increasingly becoming scarce. Industrial growth and tourism in the plains also contributes to the adverse effect on the region’s groundwater sources.
For example, there have been instances of contamination of shallow aquifers in Uttarakhand and Himachal Pradesh as many industries have been found to discharge their untreated effluents directly to nearby water bodies. This greatly affects the quality of water available for potable purposes in the area.
Harsh climatic conditions, erratic rainfall, snow, freezing of water in pipes and the lack of irrigation facilities leads to disruption of water supply in various seasons. High iron and fluoride content in some parts have rendered the water in the area unfit for drinking.
Strategies to deal with the Himalayan groundwater concern
Finding groundwater resources located at greater depths in addition to restoring the health of the streams in the area is one alternative. Encouraging rain water harvesting along with the locating deeper sources and restoring the health of springs is being contemplated as solutions to ensure sustainable supply of water.
The report suggests some strategies to deal with the groundwater issues in the Himalayan region to ensure sustainable use of water resources in the area. Efforts need to be made to arrest optimum surface run-off and harvest maximum rainwater through:
- Suitable conservation techniques that include hill and catchment area treatment.
- Grass plantation, forestry development and stopping the grazing activities to reduce soil erosion as also to enhance the groundwater recharge.
- Identifying cavernous limestone areas in Himalayas that can be used for groundwater storage.
- Exploring the option of procuring groundwater through tube wells, dugwells or borewells depending on the topography of the region as an alternative to springs and streams in times of water scarcity for consumption as well as irrigation.
- Encouraging the development and revival of springs and protect the existing perennial springs.
- Conserving rainwater by adopting suitable methods according to topography that include roof top rainwater harvesting and encouraging rainwater harvesting measures like construction of ponds, percolation tanks, check dams and contour bunds on gentle slopes or foothills, slope terracing in high slopes and bench terracing and cultivation on steep landscapes
The report can be downloaded below.