Husky Energy- Raw Water Intake Project
When we were first invited to a site visit in the fall of 2017, the shear magnitude of this project created continuous excitement. As with any new development, when we arrive on site the terrain is completely untouched other than a few survey stakes. From that point forward, it was very clear that the project had been in the planning and engineering stages for many years. The fact that we were not only going to be working alongside the North Saskatchewan River but eventually in the river itself, only added to the environmental complexity of this huge undertaking.
The general scope of work for Husky Energy was to construct a new raw water intake to provide the necessary water for their many SAGD facilities in the surrounding area on both sides of the river. The scope was further defined as constructing the low lift, mid lift and high lift pads, as well as the retention ponds at the top of the valley 3.5 km away. These scopes were relatively straight forward with the major challenge being the construction of the intake structure in the river itself. Considering the enormous undertaking of this entire project, Husky Energy hired Graham Construction to oversee all scopes as a general contractor and we were graciously recommended to Graham as a preferred contractor for the civil earthwork scope.
The North Saskatchewan River is a federally regulated waterway, so environment protection was of the utmost concern along with the overall safety of working in and around the water. Our equipment working close to the water had to have the oils replaced with environmentally friendly bio fluids to avoid any potential spills and everything had to be completely washed and disinfected prior to arriving on site. A highly trained swift water rescue team was on-site 24 hours a day with a rescue boat to provide constant support in the event of an unlikely incident. Our crews were all orientated specifically for risks of around the clock shifts and working around the water.
The concrete intake structure was engineered to be placed in the thalweg of the river, which is the deepest channel at a given location. To accomplish this, a coffer damn had to be built to allow for the construction of the structure. Due to the fast-flowing river, a diversion spur had to be built first to direct the flowing water away from the coffer dam or it would quickly erode from the river. The diversion spur was constructed of a 3-inch washed rock structure. The material was hauled from a stockpile at the top of the valley with rock trucks and placed in the river with a GPS guided equipment. The deflection spur was approximately 10 meters wide at the base and roughly 200 meters long.
Once the diversion was completed this allowed for the construction of the coffer dam. Clay material was then loaded and hauled from the top of the valley with rock trucks, similar to the process with the deflection spur. In order to place and compact the material as quickly as possible, the coffer damn was built with trucks hauling 24 hours a day to ensure that everything was in place before the river froze in the fall of 2018.
Once the coffer dam was complete, the outside of it was rock armoured to provide additional erosion control. At this point, the fish trapped inside the coffer dam had to be safely salvaged and removed so that the water could be pumped out to provide the work area for the intake structure construction. The next step of protection for the work inside the coffer dam was the installation of sheet piles to ensure the area would be protected from the elements of flowing water and future ice flows while the construction was under way.
Retention Ponds and River Reclamation
Now that the coffer damn was complete, our scope shifted to other areas of the project over the next year while Graham’s crews began construction of the intake and various pumping facilities at the bottom of the valley. We worked to construct the high lift pad and complete the 1200 mm clay liner on various retention ponds at the top of valley as well as other civil infrastructure. We also provided mechanical support for Graham’s equipment to reduce any delays associated with equipment down time.
In the summer of 2019 as Graham worked towards completing the intake structure, planning began to remove the coffer dam and return the river to its original state. With the bathymetric survey of the river bottom completed earlier in the engineering phases, we were able to load this information into our equipment grade control software to provide an accurate reclamation of the river.
Graham completed the intake structure in the fall of 2019 and we followed up with assisting the sheet pile removal and the task of removing the coffer dam and deflection spur. With freezing temperatures approaching quickly and strict environmental timelines, our crews worked around the clock to excavate, load and haul the coffer damn and spur material to a stockpile at the top of the valley. This was another unique process with environment and safety being the utmost importance. With close collaboration of all stakeholders in the project the task was completed with great success.
With the coffer dam removed and winter starting to set in, we finalized most of the earthwork with the plan to return in the spring of 2020 to complete final grading of the site so it could be transferred to Husky Operations.
It goes without question that the Husky River Intake was one of the most extensive projects Precision Contractors has been involved in. We are proud to have the opportunity to showcase our experience, resources, and ability to adapt to the challenges of a constantly changing environment. We worked closely with a dedicated team of professions and we appreciate being apart of the success of this high-profile project.