‘Research based on GIS and remote sensing helps in identifying reliable and sustainable drinking water sources’

Nearly half of Kinnaur district in Himachal Pradesh has moderate to very high potential for groundwater recharge, according to a new study that uses advanced geospatial tools to map water sustainability in the fragile Himalayan terrain.

Kanwarpreet Singh, associate professor in the department of civil engineering at Chandigarh University and lead author of the recently published article in the journal Nature, speaks to Susmita Sengupta for Down To Earth about the use of advanced tools in mapping groundwater recharge zones for the sustainability of groundwater sources.

Susmita Sengupta (SS): In your recent study, you have used Geographic Information System (GIS) and remote sensing (RS)  along with other advanced techniques to map groundwater recharge zones in complex Himalayan terrain. How do you think such tools are advantageous?

Kanwarpreet Singh (KS): This study delineates groundwater recharge potential zones in the complex Himalayan terrain of Kinnaur district (Himachal Pradesh), showing that 45 per cent of the study area falls under medium to very high recharge potential. It highlights the dominant role of rainfall, land use, and terrain factors like slope, Topographic Wetness Index (TWI), curvature in controlling recharge. 

The spatial distribution of high and very high groundwater potential zones in Kinnaur district indicates a clear pattern, mainly influenced by terrain, hydrological and geological characteristics. These zones are mostly found in the south and south-western regions of the district, especially in and around Nichar, Sangla Valley (Baspa Valley), the Kalpa region and other lower areas of the Sutlej river basin.

One of the main advantages of this research is the use of geoinformatics, particularly GIS and RS, which allowed the incorporation of several hydrogeological parameters into a single analytical framework. Remote sensing data were used to derive high-resolution Digital Elevation Models (DEM), which in turn enabled the extraction of vital terrain parameters including slope, curvature, drainage density and TWI. 

Satellite-based data, such as Landsat imagery, played a crucial role in producing precise land use/land cover maps, while rainfall data from international archives made it possible to incorporate spatial and temporal climatic variability.

These various datasets were systematically weighted and integrated using GIS-based multi-criteria decision analysis (MCDA) and the analytic hierarchy process (AHP). This method offered a scientifically sound and spatially explicit picture of groundwater recharge potential, which is otherwise difficult to obtain in mountainous landscapes with limited data.

These areas are highly conducive to the construction of artificial recharge systems, including percolation tanks, check dams, recharge trenches and infiltration galleries. They may also be crucial for the management of springsheds, where safeguarding and improving recharge zones upstream can significantly increase spring discharge downstream. 

The study emphasises that groundwater recharge in Kinnaur is both localised and terrain-specific, with the southern valleys acting as recharge hotspots. GIS and RS technologies have proved highly effective in capturing this spatial heterogeneity and offer practical solutions for the sustainable management of water resources.

SS: How effective can such studies be for different government programmes and state action plans to develop a water security plan?

KS: The current work provides a scientifically proven and spatially explicit model that can be effectively integrated into State Action Plans on Climate Change and water resource management plans, particularly in Himalayan regions such as Himachal Pradesh.

Through an AHP-based GIS multi-criteria technique, the study identifies groundwater recharge potential areas based on nine key hydrogeological and terrain parameters, while also accounting for variability in rainfall over time—an important factor under changing climatic conditions. Priority areas can thus be targeted for specific recharge interventions, while low-potential areas may require alternative water management approaches.

State agencies can directly use the generated groundwater potential maps to:

• select appropriate sites for artificial recharge systems (check dams, percolation tanks, recharge pits)

• assist in the planning and regulation of groundwater extraction

• design water security-oriented climate adaptation strategies

The inclusion of time-varying rainfall data adds further value in the context of climate change, where rainfall patterns are becoming increasingly unpredictable. It enables planners to move beyond conventional assessments and consider dynamic recharge processes, thereby enhancing the resilience of water management plans.

Further, the outputs can be effectively integrated with other government programmes such as watershed development, spring rejuvenation and rural water supply schemes, improving their overall performance. The spatial prioritisation offered by this research ensures more efficient allocation of financial and technical resources, avoiding trial-and-error approaches and focusing efforts on high-impact zones.

This targeted strategy enhances infiltration and contributes to the recovery of declining spring discharge, which is vital for local communities. In a tourism-dependent region like Kinnaur—where areas such as Sangla Valley, Kalpa and Chitkul rely heavily on natural water sources—the restoration of springs would help ensure water availability for tourism, hospitality and livelihoods. The research thus also supports eco-tourism and the long-term environmental sustainability of the region.

SS: Jal Jeevan Mission is in its last lap and is focusing on the sustainability of drinking water sources in the country. How do you think your study can add value to the sustainability plan? 

KS: The research provides a scientific basis for improving source sustainability under the Jal Jeevan Mission. It helps in identifying reliable and sustainable drinking water sources, especially in areas such as Nichar, Sangla and Kalpa, by mapping zones with medium to very high groundwater recharge potential (around 45 per cent of the area).

It supports the scientific selection of sites for borewells and recharge structures based on integrated parameters such as slope, drainage, lineaments and TWI, thereby reducing failure rates. The outputs can directly strengthen source sustainability plans by identifying recharge zones and guiding targeted interventions.

Additionally, by incorporating terrain and rainfall variability, the study helps reduce the risk of source depletion due to climate change and excessive groundwater extraction, making rural water supply systems more robust and sustainable.