Vulnerability of Himalayan springs to climate change and anthropogenic impact: a review

The climate change and unsustainable anthropogenic modification can intensify the vulnerability of the Himalayas. Natural springs are the principal source of potable water security for the Himalayan population. The changes in the trend of precipitation, temperature and glacier melt are expected to impact the quantity and quality of spring water significantly. This review presents an insight to unravel the effects of climate change and land use land cover changes on the spring resources and outline the essential elements of spring hydrology in the Himalayas. The sensitive response of spring flow to the climate has been observed to follows an annual periodic pattern strongly dependent on snowmelt, rainfall, and evapotranspiration. Among all types, Karst aquifers were found to be highly vulnerable. The changes in the forest and urban landscapes are affecting the recharging sites in the headwater region. In the Central Himalayan region (Kosi River basin, Kumaun), the number of perennial springs is decreasing at a rate of three springs year(-1), and non-perennial springs are increasing at the rate of one spring year(-1). The high concentration of NO3-, Cl-1, SO42-, and coliform counts reported from the spring water evidence a high susceptibility of shallow aquifers to the non-point source of pollution. Future projections indicate high surface-runoff and occurrence of extreme events such as floods, glacial lake outbursts, and landslides can affect the flow and water quality of springs. As the impact of climate change and anthropogenic activities are expected to increase with time remarkably, there is an urgent need to promote regional scientific studies on springs targeting hydrogeochemical evolution, vulnerability assessment, recharge area dynamics, and development of springshed management program.