ISLAMABAD: A mapping study carried out by the Space and Upper Atmosphere Research Commission for the period between 2008 and 2013 has shown that snow cover over the Indus River basin during the winter of last year was greater.

If meteorological conditions remain average, it is expected that rivers this year will have greater flows when compared to previous years, says the study.

The snow cover has been calculated for the entire Indus river basin, including its eastern and western tributaries.

Results show large variations in snow cover from year to year, with a rising trend from 2008 to 2013. Snow cover in 2013 was higher as compared to the rest of the years (2008-2012), the study shows. February 2013 saw greater snow cover over Indus Basin as compared to the other years.

The snow and glacier melt stream flow is especially valuable because it occurs between April and June before monsoon rains.

In May 2013, snow cover over Kabul river basin above Nowshera was calculated at 29.037km which was higher than the rest of the years between 2012 and 2008. Similarly in June 2013 the snow-covered area was measured at 18,510km which is also higher than the rest of the years.

The major sources of river flow in Pakistan are Hindu Kush Karakoram-Himalaya mountains, which are mostly covered with snow throughout the year.

Monthly averages of snow covered areas from 2008 to 2013 have been calculated to assess the runoff situation in the Indus.

According to an analysis of the data, monthly average snow-covered area over the entire Indus basin in Jan and Feb 2013 was 232,775km and 344,981km, respectively. In March it was 298,850km and in April, May and June 236,270km, 176,608km and 116,587km, respectively.

Similarly, monthly average snow-covered area from Jan to June 2013 at upstream Tarbela was 132,026km, 191,813km, 172,949km, 146,415km, 98,940km and 76,196km, respectively.

The study concludes that as runoff depends not only on snow cover but also on thermal conditions and if the temperatures remain the same as that of previous years then there will be higher runoff contribution due to snowmelt as compared to the previous years (2008-2012).