- What are sinkholes?
- What to do if you see a sinkhole?
- How are sinkholes repaired?
- Which business unit is responsible for repairing sinkholes?
1. What are sinkholes?
A sinkhole is a sudden hole that appears in the road surface when soil is removed by water or other forces.
New sinkholes are typically caused by:
- Water main breaks
- Intensive rain and flooding
- Ground-water pumping
- Construction and development practices
Sinkholes can also form when natural water-drainage patterns are changed and new water-diversion systems are developed. Sinkholes are difficult to detect and repair before they appear.
2. What to do if you see a sinkhole?
Residents should report a sinkhole calling by 311. The size of sinkhole is difficult to assess simply by looking at the opening on the surface. Sometimes, there is only a small opening on the surface but the water has caused several metres of the soil beneath the opening to erode.
For your safety, stay far back from the edge of the sinkhole. It is important you do not drive or enter a sinkhole area until the City contractor has removed all the equipment, barriers, and signs.
3. How are sinkholes repaired?
The reported sinkhole locations are immediately investigated and secured by The City of Calgary staff if they are within City's property.
- Some sinkhole locations may require a detailed geotechnical investigation to determine what caused deep or large voids underneath of the roadway surface. Based on the results of the investigation proper repairs are completed.
- Depending on the causes of a sinkhole, the root problem has to be dealt with, such as fixing the leaking pipe or intercepting a groundwater source.
- The sinkhole is excavated to remove loose or wet materials and is backfilled with good material.
- Once the sinkhole is repaired to City standards, surface improvements (roadway, sidewalk, etc.) are completed.
4. Which business unit is responsible for repairing sinkholes?
The City of Calgary business unit responsible for repairs is determined by the cause of the sinkhole.
- Water Services repairs sinkholes caused by water main breaks.
- Development & Building Approvals looks after sinkholes within a road right of way when they are caused by abandoned construction sites or private development, as well as sinkholes located on private property. For more information see the Safety Response Unit.
- Parks is responsible for sinkholes in natural areas, environmental reserves and all other public parks spaces.
- Roads is responsible for investigating and repairing all other sinkholes within the road right of way, within City of Calgary limits.
Repairs are usually performed by business unit city forces or can also be publicly tendered and awarded to pre-qualified contractors. Typically, contract work is awarded to increase The City’s capacity to maximize construction season production.
Sinkhole Quick Facts