Snow and glacier melt in the Satluj River at Bhakra Dam in the western Himalayan region

Abstract

Streamflow in the Himalayan rivers is generated from rainfall, snow and ice. The distribution of runoff produced from these sources is such that the streamflow may be observed in these rivers throughout the year, i.e. they are perennial in nature. Snow and glacier melt runoff contributes substantially to the annual flows of these rivers and its estimation is required for the planning, development and management of the water resources of this region. The average contribution of snow and glacier melt runoff in the annual flows of the Satluj River at Bhakra Dam has been determined. Keeping in view the availability of data for the study basin, a water balance approach was used and a water budget period of 10 years (October 1986-September 1996 was considered for the analysis. The rainfall input to the study basin over the water budget period was computed from isohyets using rainfall data of 10 stations located at different elevations in the basin. The total volume of flow for the same period was computed using observed flow data of the Satluj River at Bhakra Dam. A relationship between temperature and evaporation was developed and used to estimate the évapotranspiration losses. The snow-covered area, and its depletion with time, was determined using satellite data. It was found that the average contribution of snow and glacier runoff in the annual flow of the Satluj River at Bhakra Dam is about 59%, the remaining 41% being from rain. Key words Himalayan mountain system; snow-covered area; hydropower potential; water budget; precipitation distribution; remote sensing; snow and glacier melt; isohyetal method La fonte nivale et glaciaire à l'écoulement de la Rivière Satluj au niveau du Barrage Bhakra, à l'ouest de la région Himalayenne Résumé L'écoulement dans les rivières himalayennes est dû à la pluie, la neige et la glace. La distribution de ces différentes origines est telle que l'écoulement peut être observé dans ces rivières tout au long de l'année, c'est-à-dire qu'elles sont naturellement pérennes. La fonte nivale et glaciaire contribue de manière substantielle à l'écoulement annuel de ces rivières et son estimation est requise pour l'aménagement, le développement et la gestion des ressources en eau de cette région. La contribution moyenne de la fonte nivale et glaciaire dans l'écoulement annuel de la Rivière Satluj a été estimée au niveau du Barrage Bhakra. Compte tenu des données disponibles pour ce bassin versant, le bilan hydrologique a été analysé sur la période de 10 ans allant d'octobre 1986 à septembre 1996. L'afflux pluviométrique sur le bassin, pour la période considérée, a été calculé à partir des isohyètes construites grâce à 10 stations de mesure implantées à différentes altitudes. Le volume total écoulé pendant la même période a été calculé à partir des données de la station de jaugeage de la Rivière Satluj au niveau du Barrage Bhakra. La relation entre la température et l'évaporation a été estimée et utilisée pour estimer les pertes par évapotranspiration. La zone enneigée, et son évolutio...

Analysis of Temperature Trends in Sutluj River Basin, India

“…Over 90% of the catchment lies above 1525 meters above mean sea level (masl) whereas the permanent snowline is at an elevation of 5400 m. The snow line descends to an elevation of about 2000 m by the end of winter with snow covering about 65% of the basin. It crosses 5000 m altitude by the end of the summer season with about 20% of the total drainage area remaining under perpetual snow and glaciers [33]. There is a large spatial variation in precipitation amount with many parts of the basin receiving heavy precipitation, whereas the Tibetan Plateau has a cold desert type climate with very little precipitation.…”

“…The contribution of snow and glacier melt to streamflow at Bhakra, the major reservoir in the Satluj basin, is around 59% [33]. There have been increases in temperatures worldwide, and several climate models suggest that this trend will continue under climate change.…”

Modelling and estimation of different components of streamflow for Gangotri Glacier basin, Himalayas / Modélisation et estimation des différentes composantes de l'écoulement fluviatile du bassin du Glacier Gangotri, Himalaya

“…Himalayan rivers receive substantial contributions from snow and glacier melt runoff to annual streamflows (Singh & Jain, 2002). The water yield from a high Himalayan basin is about double that of an equivalent basin located in the south of the plains region (peninsular part) of India.…”

“…Several other field studies have determined the temperature lapse rates for mountainous regions of the world in the range of 0.5-0.7ºC/100 m (Pielke & Mehring, 1977;Barry, 1992;de Scally, 1997;Singh & Singh, 2001;Singh & Jain, 2002;Singh & Jain, 2003;Thayyen, 2003). For the Himalayan basins, temperatures were lapsed at 0.60ºC/100 m to the mean hypsometric elevation of different elevation zones for melt computation (Singh & Jain, 2002) and such a lapse rate was used in the present study.…”

Climate Change in the Himalayas: Current State of Knowledge

“…Studies from the Indian Himalaya mostly give an account of lumped meltwater (combined snow and glacier melt) contribution to streamflow (Hasnain, 2002;Kumar et al, 2007;Singh and Jain, 2002;. Other recent studies (Immerzeel et al, 2010;Kaser et al, 2010) have also lumped snow and glacier melt together.…”