Gas Pipeline Routing and Surveying

Project Description
High demand from the northeastern United States has provided a market for the rich natural gas deposits of the Sable field, located off the Atlantic coast of Nova Scotia. Global Positioning Systems (GPS) and navigation was used to enhance the route selection process for the pipeline. A 30 inch pipeline was constructed in 1999 from Goldboro, Nova Scotia to Calais, Maine. Lateral lines were constructed to the metropolitan areas of Halifax, Nova Scotia and Saint John, New Brunswick.

Services Provided
Terrain Group, as a major player in Terratech Consultants Inc., a consortium of Maritime Canadian surveying firms, has provided surveying and mapping services in support of this $800 million project. GPS technology and methods have been used to efficiently complete a wide-range of technical tasks including project control, legal surveys, reconnaissance surveys, feature mapping, and construction stakeout. One of the more successful GPS applications has been real-time navigation and mapping for final pipeline route selection. Identification of the environmental and construction-related constraints enables "fine tuning" of the preliminary alignment. This requires a detailed inspection of the alignment on the ground. Traditional "line of sight" field survey methods are expensive and time-consuming at this stage. GPS technology provides a cost-effective alternative for on-site navigation and medium accuracy mapping.

We walked and inspected over 200 kilometres of pipeline route, through all types of terrain. The alignment was flagged during the inspection to aid landowners and other consultants in locating the proposed route. We also mapped physical features and obstructions as required for realignment. This provided the design engineers with a complete picture of the pipeline route. It also helped to minimize time-consuming and costly realignments. Survey support was also supplied during the construction phase.