Work gets underway later this week drilling boreholes in Christchurch's Port Hills.
The work will initially involve drilling at five sites - Clifton Terrace/Kinsey Terrace, Lucas Lane, Deans Head, Richmond Hill and Moa Bone Cave area.
City council city environment general manager Jane Parfitt said the work was expected to take three months to complete.
"It is part of the council's wider programme of geotechnical investigations in the Port Hills.
"The drilling will enable the council to better understand the nature of the soil, bedrock and groundwater conditions, as well as help inform decisions on planning and development in the Port Hills," she said.
"This work will also help with decisions on engineering lifeline routes, particularly at Moa Bone Cave, Clifton Terrace and Deans Head."
Mrs Parfitt said the boreholes would be drilled as deep as 90 metres to complete core sampling and to put in place monitoring equipment for any slope movement and groundwater levels.
"Residents are advised that in some areas the road will be narrowed to single-lane traffic and there could be traffic delays. Water run-off from the drilling rig could also affect pedestrian access along some footpaths and roads."
The drilling rig will operate from 7am to 7pm Monday to Saturday and 10am to 7pm on Sundays.