Engineers this week planned to conduct geotechnical testing of a section of the Brackendale dike where a sinkhole was discovered last week as part of the process of determining the next course of action, a municipal official said.
The two-foot-wide sinkhole, which was reported by alert residents who spotted it on April 16 while walking in the area, was being monitored twice a day for any changes to the current situation, Christina Moore, District of Squamish (DOS) spokesperson, wrote in an email to The Chief on Tuesday (April 23).
While the sinkhole is not currently a threat to public safety or property, officials are conducting investigations to determine the extent of deterioration of the dike and the most prudent course of action to ensure the dike's long-term stability, Moore said.
The Chief's request for an interview with one or more of the engineers working on the problem was denied. The engineers would prefer to wait for a few more tests and data to be collected prior to providing a meaningful update, Moore wrote.
As for the work that is being done, she wrote, A detailed survey of the area north and south of the sinkhole has been completed to determine elevations and the dike footprint. Some nondestructive testing has occurred, with more planned.
Geotechnical drilling will take place later this week, and information gathered from this will plot our path forward. At this stage, the testing and research part of our activities to determine what caused the sinkhole remain most critical.
The sinkhole, which is just off the public pathway north of the eagle viewing dike, has been covered and the area around it has been marked with cones. Signs have been placed at the trailhead advising pathway users, Trail unsafe. Use at your own risk.
After the sinkhole was discovered, it was brought to the attention of the provincial inspector of dikes and has been discussed with Squamish Nation officials, DOS officials said.
Any situation that involves the structure of our dikes is treated as a top priority, Acting Mayor Bryan Raiser said in a statement issued last Wednesday (April 17). We are taking all measures to understand the situation and will update the public as we have new information to share.
The section of dike that includes the sinkhole is among those identified in a 2011 report by engineering consultants Kerr Wood Leidal (KWL) as having excessive seepage and that is in need of work on a high-priority basis, the report said.
The DOS's five-year capital plan identifies flood protection work as a high priority and includes funding for such projects, officials said. The DOS has either just completed or planned flood-protection work worth more than $6 million, officials said.
