Draining lava flow field

Hundreds of waterfalls in Hraunfossar seem to be fed from a lava flow field in northwest Iceland. Rainwater and a branch of a glacial river seep away in the porous lava of 1000 year old Hallmundarhraun. A few meters deeper an impermeable basaltic layer conducts this sediment-poor water and leads to the formation of hundreds of small waterfalls further downstream where sediment-loaded Hvita River, that has carved its bed into the lava.