Sandvatn is a rather large lake in the highlands of Iceland, close to the glacier Langjökull and Kjalvegur mountain road.
There used to be large mud–flats around Sandvatn and in dry periods these caused much sand erosion down in the farming country. To prevent this the water level of Sandvatn was raised in 1994 by closing the two outlets, Sandá and Ásbrandsá. This created a new outlet in the Sandá river flowing east into Hvítá. Ásbrandsá is now a clear river and along with small streams from Haukadalsheiði moor forms Tungufljót, which has become good for salmon–raising after the salmon–ladder was made in the Faxi (or Tungufoss) waterfall.
If you are planning to drive to the Icelandic highlands please keep in mind that they are only open during summer time. You can see the conditions of roads in the highlands on www.road.is