Add six more cracks to Sarnia’s failing shoreline.
Storms last week battered revetments in Bright’s Grove, prompting another closure of Old Lakeshore Road and the need for more temporary repairs.
“Its condition has worsened over winter due to lack of ice cover,” said city construction manager Rob Williams. “We’re rallying this week to come up with solutions.”
Old Lakeshore was closed April 10 between Pine Avenue and Huron Lane where a revetment failed. The shoreline structure built in 1992 was fenced off last fall because of erosion, Williams said.
Work crews poured tonnes of stone fill called “rip-rap” there and at another section west of Marion Avenue. It’s a Band-Aid until the city can resume $4.7 million in long-term shoreline reconstruction this summer, he said.
“The rip-rap really just buys us time.”
Williams said the shoreline work, which is suspended during fish-spawning season, is expected to resume despite the COVID-19 pandemic.
“Contractors would need to implement social distancing,” he said, adding, “However COVID-19 is also affecting suppliers too. It’s kind of multiple impacts.”
Water levels in the lake are 18 inches higher than they were last year, and the U.S. Army Corps of Engineers predicts Lake Huron levels will reach an all-time high in 2020.
“They’re as high as they’ve ever been,” Williams said. “It’s difficult to predict. Most people are concerned that the water will continue to go up.”
Construction began in February on sloped stone revetments to immediately secure some banks in Bright’s Grove. Groynes, which extend into the lake from shore and allow new beach to build up, require federal permits that won’t likely be approved until late 2020, the city has said.
A combination of revetments and steel or stone groynes spaced to support beach development is the approach recommended by the St. Clair Conservation Authority and coastal engineers.
If Sarnia does nothing, it risks losing public lakefront land, recreational trails, watermains, sewers and other infrastructure, the report states.
More than $1 million was spent last year on temporary, emergency shoreline repairs, mostly in Bright’s Grove. Williams said the cost of the new emergency repairs, which also included several spots between the Cull Drain and Mike Weir Park, are not yet known.