2017 | Coquitlam, BC
The Coquitlam Intake Tower, owned and operated by the Greater Vancouver Water District (GVWD), forms a critical piece of infrastructure for Metro Vancouver’s water supply system, supplying up to 40% of the region’s drinking water during peak demand. Located in the Coquitlam Watershed at the southeast corner of Coquitlam Lake, the tower was constructed in 1913 and has been designated a heritage landmark structure by the American Water Works Association. It stands 27m tall with a constant diameter of 5.5m, and is made of unreinforced concrete. A 20m long bridge connects the hillside to the tower providing access to the control room, as about half of the tower is submerged in the Coquitlam Lake.
Because the intake tower is such a crucial piece of infrastructure in the area’s water supply system and it is now over 100 years old, a seismic upgrade was deemed necessary by GVWD to stabilize the structure and continue to provide safe and high-quality drinking water in the event of seismic activity. Metro Vancouver chose Mott MacDonald as the structural consultant, and they retained McElhanney to provide survey services to support their design.
The survey work for the intake tower included GPS, 3D laser scanning, UAV, and multi-beam bathymetry. The team used GPS to establish primary control from which to base the survey, and then extended that control network around the site with a conventional total station. There were portions of the tower exterior that could not be captured with the scanner by land so our team used their UAV to infill those areas that were hidden from view of the scanner. Multi-beam bathymetry was used to collect underwater topography around the tower exterior and within the tower structure.
Each data capture instrument outputs its own point cloud. McElhanney’s team stitched together the data to output a unified point cloud of the entire site that could be used to provide Mott with a detailed 3D model of the of the structure and accurate topography of the surrounding area both above and below the water. A terrain model was created in Civil 3D and this was linked into the Revit model of the tower structure that included all architectural, structural, and mechanical, electrical, and piping elements.
This is an ongoing project that we are working very closely with the engineers on collaborative workflows that incorporate the latest methodologies of virtual design and construction as well as building information modelling.