EPCOR Drainage Service
Ph: (780) 509-8080
On October 8, 2020, during an inspection of a sewer trunk line that runs 23 metres below 61 Ave, a 2.5 metre long opening was discovered along the top of the sewer trunk line. Upon further investigation, materials surrounding the trunk line were found to be eroded, creating an underground void in the earth above the trunk line at the intersection of 61 Ave and 109 St. On October 12, a hole formed in the surface of the road in the intersection.
The intersection of 61 Ave and 109 St has been closed since the hole in the trunk line was discovered on October 8.
There is no structural risk to homes and businesses in the area. Based on assessments, it appears the void area is limited to a section under 61 Ave. We continue to monitor the roadway and surrounding infrastructure for any changes.
The sewer trunk line that runs under 61 Ave is 1650mm in diameter and carries both storm and sanitary flows.
What's happening now
EPCOR has finalized plans to repair the sewer trunk line and the void above the trunk line and anticipates the intersection to be reopened in May 2021.
Two shafts and four 30mm holes have been drilled down 23 metres to the trunk line under 61 Ave. These will be used to safely access the trunk line for repair work as well as support bypass activities. A bypass takes flows from the below ground drainage system, brings them above ground in a pipe to discharge the flow into the four 30mm holes away from the work area. We are currently using the shafts to remove debris that accumulated in the trunk line. A new bypass has also been installed using the new shafts. The previous bypass from 111 St to 106 St has been removed, with the exception of the portion of the bypass immediately south of the work site.
Due to the oval shape of the trunk line we are required to custom order a pipe. Measurements will be taken to procure a specially fabricated fiberglass pipe from Dubai that will be inserted into the trunk line to rehabilitate it. It will take approximately 8 weeks for the fiberglass pipe to be manufactured and delivered to Edmonton.
While we await the arrival of the fiberglass pipe we will work to fill the void and stabilize the area. The opening in the trunk line will be plugged using a balloon-like device and then the void above filled. Once filled, a soil stabilization study around the void area will be undertaken to ensure the road is safe. Once the trunk rehabilitation work is completed, there may be a period of reduced construction activity while we await the arrival of the fiberglass pipe from Dubai. However, there will still be ongoing monitoring and inspection work at the site. Once the new fiberglass pipe is delivered to site, it will be installed in the trunk line in segments and grouted into place.
The two shafts will then be converted to new manholes, and the four 30mm holes and old manhole near the void will be backfilled. The road will then be restored and the intersection reopened.