The Kerauga cave and Lækjarbotnaveita in South Iceland ‒ groundwater safety and hydrogeology

• Published in: Journal of Water Security
• Main Authors: Ketilsson, Jónas, Óskarsdóttir, Sigríður Magnea, Claesson, Andrea, Collet, Nathalie Jonasson
• Format: Other/Unknown Material
• Language: English
• Published: 2017
• Subjects: Aquifer; Groundwater system; Kerauga; Poultry farm; Water safety; Þjórsá; Rangá; Ytri-Rangá; Iceland
• Online Access: https://doi.org/10.15544/jws.2017.001; https://hdl.handle.net/20.500.12259/104283

This research looks at water protection of Lækjarbotnar and Kerauga springs in South Iceland. Discharge measurements show that Minnivalla- and Tjarnalækur streams lose 350 and 1350 l/s respectively into the ground. The equivalent amount springs to surface along the edge of the Þjórsá Lava and Búði Glacial Moraine in a few springs. Tracer tests indicate that lost surface water of Minnivallalækur transits partly along a fracture to Kerauga in 65 days and to Lækjarbotnar in 125 days through the Þjórsá Lava over a similar distance of about 5 km. Hence the lost surface water of Tjarnalækur in the east is unlikely to travel past this drainage divide west of the fracture to Lækjarbotnar but more likely to drain into Ytri-Rangá. Thus a proposed poultry farm in that area proposes minimum direct risk to water safety of Lækjarbotnar. As a result of this connection Kerauga is not a safe source of drinking water. The aquifer is considered unconfined, heterogeneous and anisotropic. It is recommended to define inner and outer protection zones for Lækjarbotnar further north and to springs of Minnivallalækur respectively. It is hypothesized that Kerauga cave is manmade.