Impact of climate change on surface water resource availability of Sainj Basin in lesser Himalayan region

Abstract

115-119Water is a very important natural resource without which our survival is impossible. As per IPCC report the mean annual temperature of Earth's surface has increased by 0.74±0.18 ºC over the last century and it is expected that by 2100 the increase in temperature could be 1.4°C to 5.8°C. This increasing temperature will exert a tremendous impact on glaciers and resultant water resources of the Himalayan region. Keeping this fact in reckoning, the present study has been undertaken in Sainj basin of Lesser Himalayan region in Kullu district of Himachal Pradesh to evaluate the impact of climate change on surface water resources of the basin. The Sainj basin area extends about 55 km in length and covers an area of about 741km2. The elevation of the basin varies from 900 m to 6100 m above mean sea level. A marked spatial variation in precipitation amount, snow cover and glaciated area has been observed in the basin with the altitude. The hydrometeorological data pertaining to this study has been collected from Bhakra Beas Management Board, Pandoh for the period 1981-2004. The analysis of rainfall data revealed that no marked changes were observed in the amount of rainfall during 1981-2004 in the basin. However, river discharge demonstrated a declining trend during the study period and this decrease in the river discharge was found to be statistically significant during the months of December, January and April. The significant declining trend in river discharge during these months may be attributed to lesser snow cover in the lower, middle and higher reaches, thinning of small glaciers and ice patches over the period of time in the basin. The decline of discharge will be a challenging task for the upcoming and already established hydro-power projects in the Sainj basin. Therefore, in future planners and policy makers need to debate before the establishment of hydro-power and irrigation projects in the region. The outcome of this research will also prove a boon to agricultural scientists, water resource policy makers and especially to the dam engineers in making the effective future decisions on water resources of the region. Moreover, this study will strengthen activities pertaining to the sustainable development of irrigation and hydropower projects