Water Resources

Snow Cover Mapping and Monitoring

Snow in the Himalayas is a vital water resource to India and the snowmelt runoff occurring mostly during summer months constitute a substantial part of water resources of the river systems like Indus, Ganga and Brahmaputra. Snow cover mapping is done using remote sensing data regularly. Snow cover, with relatively high albedo, appears very bright on standard False Colour Composite (FCC) images and is easily differentiated with other land cover features.

The prior information on availability of quantity of snowmelt during critical summer months is essential in planning the reservoir operations. Development of snow melt runoff models, both seasonal (3 months) and short term (16 days), for forecasting during summer months (Apr-May-Jun) in 5 basins (Chenab, Beas, Sutlej, Yamuna and Ganga) is done using remote sensing inputs. During the years 2012 to 2016 seasonal forecast was provided for April to June months by 1st April. Six short term forecasts were provided on time for each 16-day period during April, May and June months of each year.

The satellite derived inputs such as snow cover, snow albedo, snow surface temperature and snow emissivity along with field data was used in computing net radiation. The net radiation forms the basis in estimating snow melt runoff using energy balance method in spatially distributed approach. The basin wise models and necessary data were transferred to CWC along with training support for internalization and usage at their end.