The Hamilton Spectator
High lake water levels helping destructive carp get into Cootes Paradise
Call it the invasion of an invasive species.
Huge numbers of non-native common carp — which scientists have been trying to confine to Hamilton Harbour for decades because they are destructive to adjoining marsh lands — have been escaping in record high water levels. They’re pushing their way into Grindstone Creek, Cootes Paradise and even through city’s sewer system.
Officials with the City of Hamilton say for the first time ever, carp and other fish were found in intakes to the city’s wastewater treatment plant on Woodward Avenue this week. It’s believed the fish travelled several kilometres through the city’s underground infrastructure after gaining access through flooded overflow tanks near the shoreline.
At the other end of the bay, the Royal Botanical Gardens Fishway is under 12 inches of water. That’s never happened before with the $2.3 million structure that is designed to keep large carp out of Cootes Paradise while letting desirable species of fish through. RBG staff have been frantically “working like beavers” to expand and fortify the structure against the onslaught of carp looking for spawning grounds. They believe the effort has been generally successful so far with few carp getting through.
But Grindstone Creek is another story. A makeshift carp barrier fashioned from old Christmas trees across the waterway in February has been swept over, letting the carp freely swim over top with little that RBG workers can do. The carp not only have free reign of the creek but flooding waters have turned surrounding meadows into shallow waters where the carp can be seen thrashing about.
All these problems, and many more, are explained by Lake Ontario water levels, which are at the highest level since records began being kept in 1918. Levels are currently listed at 75.84 metres and the Hamilton Conservation Authority says more heavy rain or high easterly winds over the coming days and weeks could cause severe flooding in shoreline areas.
“Additional rain isn’t going to help the situation.” says Scott Peck, the authority’s director of watershed planning and engineering.
Easterly winds will churn up waves and push the high waters against shorelines of Stoney Creek, Confederation Park and the Beach Strip in Hamilton, he said. Luckily, the prevailing wind is westward.
“It’s hard to speculate about how much higher the waters will get. May will probably not see much in the way of decreases. All we can hope for is that we get into more of a traditional summer where the rain will decrease and the levels will slowly go back,” said Peck.
Tys Theysmeyer, head of natural lands for the RBG, says he’s hopeful the waters have peaked.
“We’re definitely under stress. The carp barrier is basically being held together by rocks and wire fence because the original barrier is under water.”
Twentieth anniversary celebrations of the fishway, originally scheduled for later this month, have been put on hold until late August. Not only is the barrier washed out, but so are the access pathways for people to walk to it.
Dan McKinnon, the city’s head of public works, said the lake levels are so high they’ve engulfed the emergency overflow outlets of underground sewage-catching tanks near Eastwood Park and Bayfront Park.
That means harbour water is flowing into the sewage-holding tanks, rather than the other way around.
It also means fish — mostly carp — are swimming into the tanks, through the sewer system and all the way to the Woodward treatment plant to be discovered by dumbfounded city workers.
“Once they get in the tank, they can swim into the sewer, then the flow of the sewer would carry them down to Woodward,” said McKinnon. “It’s extraordinary. We’ve never seen fish in there before.”
Meanwhile, the City of Burlington has closed the beach at Burlington Beach Regional Waterfront Park, the Beachway, until further notice because of high water levels. The playground, concessions, washrooms, parking and trail remain open.