March 7, 2017

Basodino Glacier, Switzerland Mass Balance Loss & Hydropower

Posted by Mauri Pelto

Basodino Glacier in August and September of 2016 illustrating the upward shift of the snowline in the 15 days between the Landsat (left) and Sentinel (right) image. purple dots mark snowline. 

Basodino Glacier is a small northeast facing slope glacier in the southern Swiss Alps.  The glacier is in the Ticino River watershed and supplies the Robiei Hydropower system. The glacier is in the same basin as Cavagnoli Glacier, which is fading away. The main branch presently covers an area of 1.8 km2 and extends from 2562 to 3186 m.  In 1973 the glacier had an area of 2.3 km2 .  Detailed mass balance investigations have been carried out since 1990.  During this period the glacier has lost more than 11 m w.e. thickness.  In seven years from 1980-2014 the glacier has had an AAR below 10 (Bauder, 2016).  This is indicative of minimal retained accumulation and not a consistent accumulation zone (Pelto, 2010) .  Huss (2012) noted that mean glacier mass balance in the European Alps was −0.31  m w.e./ year from 1900–2011, and −1 m w.e. /year over the last decade.  For Basodino Glacier the loss during this enite period averaged ~-0.2 m w.e./year (Huss, 2012).  The glacier advanced 95 m from 1967-1986 and has retreated 260 m since, front observations are completed and submitted by Claudio Vallegia of Ticino, Sezione Forestale (Swiss-ETHZ, 2016).

Water from glacier melt  is channelled to the Robiei-Zött reservoirs and hydro plants, generating enough electricity for a city. The Cavagnoli and Naret reservoirs at 2310 m feed the Robiei power station, situated 400 m below. The Robiei power station is also capable of pumping the water from the Robiei-Zött up to the higher Cavagnoli-Naret reservoirs.

Basodino Glacier in late August of 2016 had 5-60% of the glacier still in the accumulation zone. two weeks later on Sept. 9, 2016 the glacier had 35% of the glacier in the accumulation zone.  This is the accumulation area ratio, which needs to be above 55% for equilibrium.  For Basodino Galcier 2016 will be another year of mass balance loss and retreat.  The detailed monitoring will provide specific values for each reporting to the Swiss Glacier Monitoring Network system and the WGMS.