On behalf of the Norwegian Public Roads Administration Region East (SVV) and the National Rail Administration Development Bane NOR, carried out monitoring in connection with the development of the Minnesund-Espa section for the E6 and the Dovre Railway Line along lake Mjøsa. NGI has assisted in documenting environmental status prior to commencement of the construction work, during the operational phase and after the construction work was completed.

Challenge

The challenge with such construction work, which includes drilling and blasting of tunnels and rock cuts, is that the chemical quality and quantity of groundwater can be affected. This could potentially adversely affect the groundwater wells for dwellings in the area. NGI has therefore instrumented several groundwater wells, as well as conducted sampling and chemical and bacteriological analyses for the control of drinking water.

The construction work could also result in discharges to nearby recipients, in this case lake Mjøsa, through local supply streams. In collaboration with NIVA, NGI conducted surveys of these recipients on a regular basis throughout the construction period.

Method

Construction of roads and railways can lead to a lower groundwater level as a result of changes in rock crack patterns or infiltration of surface water. One method of monitoring this has been vegetation mapping with GIS attached fixed photography points as well as survey and field registration.