ABSTRACT
Well construction, and especially leakage at the base of the casing, has been investigated by video camera in 213 Norwegian wells in crystalline bedrock. In addition, fractures, type of well head protection and land use has been recorded. Both wells supplying private households and waterworks were filmed. Leakage, via the base of the casing, was observed in 60 out of 150 wells. Cavities and fractures in the borehole wall from directly below the casing and down to about 10 m below surface, were observed in 126 out of 213 wells. Biofilm and mineral precipitation were common in the wells. In Norway both well drillers and well owners have been aware of groundwater vulnerability and the importance of proper well construction due to increased focus on the topic since 1995. Photos and videos from the wells illustrating the problems, have contributed to this.
