Fieldwork for the Trans Mountain Expansion Project (TMEP) is gearing up. Surveying for the Project right-of-way is underway in some areas. One of the remarkable aspects of the Project is the technology available to support construction compared with equipment available to surveyors for the original Trans Mountain Pipeline in the early 1950s. We connected with one of our original surveying contractors, McElhanney, which is now doing survey work on TMEP, to learn more.

McElhanney is the oldest, employee-owned engineering and geomatics firm in Canada. Tell us about your company’s history.

McElhanney was founded in Vancouver in 1910 by William Gordon McElhanney. In the early- to mid-1950s, the firm was busy with booming development in the city of Vancouver, construction of the Kemano Project for the aluminum smelter in Kitimat, a new highway up the west part of BC to the Yukon and supporting crews in the gas fields being discovered in the Fort St. John area. McElhanney company partner Bill Papove, a professional surveyor and professional engineer, led our crews working on the Trans Mountain Pipeline for Canadian Bechtel Ltd.  

What equipment and methods were available in the early 1950s to survey a linear route such as a pipeline or road?

We would have used air photos, a staff compass and a hand-held clinometer with a chain or cloth tape for doing initial reconnaissance for the pipeline and access roads. Survey control would have started from the government’s Primary Triangulation Network and would have been densified along the route using a Wild T1 theodolite with a steel chain. (A theodolite is a survey instrument that includes a telescope and is used to measure vertical and horizontal angles). The T1 was a very accurate instrument. A level with a wooden rod was used for transferring elevations along the route except in some of the steeper regions where they may have used the T1 theodolite and measured vertical angles to calculate the elevations using trigonometry.

One of the big advances for measuring distances in that era was the invention of the electronic tellurometer (which measures distance using microwaves). But it wasn’t available for sale until 1957. McElhanney beat out the provincial government to be first in BC to get their hands on the $10,000 MRA-1 tellurometer and we used it for controlling aerial mapping projects in the late 1950s.

Are all of those pieces of equipment still in use today?

Most manual instruments have been replaced by electronic instruments with built-in distance measuring equipment. However, on some projects we still use a precise manual theodolite with a precise level and invar rods. (Invar rods provide extremely accurate measurements because they don’t contract or expand with changes in temperature). Once in a while we’ll still use a compass, hand-held clinometer (for measuring the angle of slopes) and tape for route reconnaissance or flagging a corridor, but most of this work has been replaced with hand-held GPS (global positioning satellite) instruments.

What are the most significant technological changes in surveying in recent years?

Between the mid-1950s and the late 1970s, changes were led by the invention of computers and electronic distance-measuring equipment. Then from the late 1970s to today, it was GPS. LiDAR (laser-based) mapping has reduced the amount of topographic survey effort required in the field and machine control survey systems have reduced the survey effort required for road and grade construction as well as ditch excavation.

In the 1950s, aerial photogrammetric mapping would have been used to select an initial pipeline route.  Today, we’re using $1.5-million, airborne LiDAR systems with million-dollar, large-format digital cameras to create accurate, three-dimensional terrain models for initial route selection, design of roads, pipelines and infrastructure sites.

Modern survey equipment includes using terrestrial LiDAR scanners for measuring details of existing facilities, robotic total stations equipped with reflectorless distance measuring equipment and GPS/GNSS (global navigating satellite system) equipment using dozens of satellites to accurately position our survey work. Drones are being employed to accurately map and monitor construction progress.

What are some of the benefits from these changes?

On a project such as TMEP, GPS equipment has saved thousands of hours of cutting out lines and conventionally traversing through the forests. Not only has accuracy improved because of GPS equipment and new methodologies, but also the route information can be collected using safer methods. LiDAR mapping at a million points per second allows us to create a detailed topographic map of the corridor. The accuracy of aerial mapping has increased significantly over the past 20 years. Engineers can take this detail and fine-tune the alignment of the pipeline saving millions in construction costs. This in turn saves thousands of hours of boots on the ground surveying. Of course, we still need to get into the field and confirm data such as thickness of overburden, high-water marks of creeks or rivers, as well as property boundary determination and demarcation.

What’s the single biggest physical challenge for a surveyor?

Some of the challenges we have today are no different than what we had back in the 1950s. Severe floods, avalanches and forest fires are some of the hazards still affecting field work along the corridor. But I would say the biggest challenge back then and now is working in extremely steep terrain. There are segments along the TMEP line that will be challenging even for the most experience hikers on the crew.