City outlines plan to find rogue sewer leaks

Hamilton is pitching new sewer sampling, electronic pipe-monitoring experiments and maybe even sewage-seeking drones in response to a provincial spill prevention order.

Ontario ordered the city late last year to come up with a plan to find and prevent hidden sewage leaks after workers discovered a botched repair under Burlington Street that had sent flushed sewage straight into the harbour since 1996.

Another quarter-century spill from 11 homes on Rutherford Avenue was found earlier this year.

The city has now submitted part of the ordered plan to the Ministry of Environment, Conservation and Parks via a consulting report that recommends “dry-weather sampling” of storm sewers and outfalls in the older parts of the city.

In a nutshell, that’s a hunt for “flow that shouldn’t be there” in storm sewers on an otherwise dry day, said Shane McCauley, the city’s director of wastewater operations.

“The main gist of the proposed plan is to do an inspection starting at each outfall and working back (up the storm sewer) to sample any flow,” he said.

If the inspections find dry-weather flow in those storm sewers, the city will test for bacteria — but also reliably human indicators like caffeine — to determine whether a rogue pipe connection is spilling flushed sewage into the wrong pipes.

Sampling at up to 53 different pipe outlets around the bay, Red Hill and Chedoke Creeks — and working “upstream” to test at maintenance holes along those pipes — will probably require two or three years to complete.

The city’s consultant also suggested experimenting with high-tech alternatives.

Think battery-operated flow monitors underground, or even high-flying drones that use thermal imaging to watch for high-temperature sewage spills — visible as a “coloured plume” on infrared thermal technology — at pipe outfalls around the harbour.

McCauley said the city will try to do some of the work with “existing resources,” but the consulting report suggests additional staff could be needed. A report on costs for all of the new monitoring efforts will come this summer.

In the meantime, the city has until May to fulfil the next part of the provincial order: a study on just how detailed an inspection is needed of the kilometres of old pipes under the lower city.

Running cameras through all of those old sewers could cost $10 million and require four or more years.