Dome Substation LID Stormwater Storage

Dome Substation LID (Low Impact Development) Stormwater Storage

As part of EPCOR’s Stormwater Integrated Resource Plan (SIRP), underground stormwater storage was constructed at the Dome Substation in south Edmonton to reduce peak runoff and slow stormwater release to the existing municipal system. The project supports EPCOR’s “SLOW” stormwater management strategy by capturing and temporarily storing runoff within the substation site before controlled discharge to the downstream storm network along Parsons Road.

The work involved the construction of an underground stormwater storage system consisting of a large-diameter reinforced concrete pipe, new precast storm manholes, overflow piping, and associated control infrastructure. The system was integrated into existing storm assets through new connections and selective abandonment of legacy storm sewer and catch basin infrastructure, all executed within a constrained substation environment governed by strict safety and access requirements.

Construction activities were completed within an active high-voltage power substation, requiring close coordination with EPCOR’s EDTI and Substation teams. The scope included temporary fencing and grounding modifications, low-impact construction techniques to minimize disturbance, engineered excavation and shoring, flow isolation and bypass measures, and full site restoration, including gravel yard reinstatement, fencing, and access road construction. All work was delivered in accordance with EPCOR safety standards, City of Edmonton requirements, and IFC design documentation.

Dome Substation LID Stormwater Storage project demonstrates the team’s ability to deliver technically complex underground infrastructure in highly controlled operational environments, while balancing stormwater performance objectives, constructability, and safety within critical utility facilities.

Dome Substation LID Stormwater Storage – Key Quantities

Stormwater Storage Volume:

• ~100 m³ underground storage capacity

Primary Storage Pipe:

• ~88 m of 1,200 mm diameter reinforced concrete pipe

Storm Manholes:

• Two new 2,100 mm diameter precast concrete storm manholes
• Catch basin manhole and downstream control manhole

Storm Piping:

• ~20 m of 525 mm diameter PVC storm sewer
• 525 mm diameter overflow pipe to existing system

Flow Control:

• Mounted slide gate with orifice plate to regulate discharge rates

Existing Infrastructure Modifications:

• ~100 m of existing storm sewer abandoned
• Multiple existing catch basins and leads abandoned

Surface Works:

• New swale to direct yard runoff into storage system
• New asphalt access road and commercial crossing to Parsons Road