Saline groundwater extraction from the fjord delta aquifer, Sunndalsøra, Møre og Romsdal, Norway

Abstract

The fjord delta at Sunndalsøra has been investigated by geophysical measurements, drilling and pumping in order to examine the possibilities of saline groundwater for use in fish farming. A geological model of the delta's lithostratigraphy is presented. The hydraulic conductivity shows a cyclicity with the highest values on the landward side in each cycle. In the outer part of the delta the saline groundwater is located at shall- ower depths than along the river and on the landward side. The freshwater layer in the fjord and in the aquifer, the hydraulic gradient and the distribution of hydraulic conductivity in the delta all contribute to a reduction in salinity during pumping the groundwater. It is estimated that lateral, freshwater-induced recharge from the river to the wells along coarse-grained layers contributes about 18% of the total yield. By means of two-level pumping in the outher area of the aquifer, the salinity of the abstracted water may be increased to at least 20 per mille.