Rehabilitating the Kildonan-Redwood Feeder Main River Crossing with a Flexible Fabric Reinforced Pipe (FFRP) Liner

The Kildonan-Redwood Feeder Main is a 600 mm (24 in.) diameter steel pressure pipe crossing of the Red River, adjacent to the Harry Lazarenko Bridge in Winnipeg, Manitoba, Canada. The feeder main was inspected in March 2019 as part of the city’s High Risk River Crossings (HRRC) program. The inspection consisted of an electromagnetic (EM) assessment using remote field testing (RFT) technology and multiple leakage tests. The EM inspections revealed that the steel crossing pipe was in relatively good condition structurally (e.g., it had full hoop strength); however, the leakage tests confirmed that its hydrostatic integrity was compromised, and the feeder main was removed from service to preclude direct discharge of chlorinated water to the river. The crossing was originally constructed in 1955, is 238 m (780 ft) long, and was constructed using a complex balance of tunneling on its west side, through a 16 m (52 ft) deep vertical shaft through a 90 degree to a horizontal tunnel section and then transitioning to shallow open-cut construction across the river and up its east side, using coffer dams to facilitate installation through the channel. Replacement of the crossing using new installation trenchless techniques was also deemed to be prohibitively expensive ($7−10 million). In 2019/2020, an AWWA Class III lining solution was designed and tendered using a reinforced CIPP for potable pressure service. However, the configuration was deemed to have excessive installation risk, and no bids were received. In 2020/2021, the use of FFRP, which was discarded in the initial predesign, was further investigated. It was found to have acceptable hydraulic impacts in review of the overall system, and its installation and long-term operational risk was deemed to be acceptable as well. In 2022, the project was tendered and successfully constructed for a cost of approximately $1.2 million or about 15% of the capital cost of a new installation with a comparable anticipated design life. This paper provides an overview of the long journey of the Kildonan-Redwood Feeder Main through its complex beginnings, modern assessment, and eventual rehabilitation to achieve a new design life.