337 million litres of sewage spilled into Hamilton Harbour for 26 years: city

The city estimates 337 million litres of sewage from east Hamilton properties flushed undetected into the harbour for 26 years.

That calculation is based on water meter usage from about 50 properties connected to a combined sewer pipe that had a hole in it, creating a direct conduit to the lake.

The faulty connection - which city workers discovered last week in a sewer near Burlington and Wentworth streets - was corrected Wednesday night.

Hamilton Water staff completed repairs as urgently as possible, repairing the sewer within 31 hours of discovery," the water division says in an update.

The city says it shared the estimated volume of the nearly quarter-century leak with the Ministry of the Environment, Conservation and Parks on Monday morning.

The city speculates a contractor made the hole in error based on incorrect drawings in 1996. Staff were viewing a video made in 2013 of the pipe for an unrelated project when something appeared amiss.

A water division staffer recognized, based on their experience, that something did not look right' and arranged for a field investigation," notes an update to be presented to city council Monday afternoon.

The investigation confirmed an improper connection" between the combined sewer and the storm sewer that drained into Hamilton Harbour.

In their review, city water staff examined contract documents relating to a reconstruction and widening of Burlington Street East in 1996.

They revealed the road work involved upgrades to underground pipes and a change to an incorrectly labelled" combined sewage pipe that resulted in an improper connection" to the storm pipe.

Moreover, staff have located" two videos - made for camera inspections in 2009 and 2013 - that show the maintenance access hole where the problematic connection was made.

The footage clearly shows sewage discharging into a hole' in the bottom of the pipe, but this type of connection between sewers isn't uncommon in older cities like Hamilton," the staff report notes.

Because the videos didn't suggest immediate maintenance needs and the structures were in good condition, they would not have been flagged by the contractor for further review."

Consequently, staff do not believe that any city staff member reviewed either of these videos" until last Tuesday.

In addition, the contractor would not have had detailed enough knowledge of the city's sewer system to identify the improperly connected sewer pipes."

In 2015, the water division awarded a third contract for camera inspections, but the contractor wasn't able to complete all of them within the budget, so the wonky connection wasn't probed, the staff update notes.

Following this contract, Hamilton Water decided not to issue another tender for this work."

That was because, in part, the division had completed two rounds of inspections through a yearly sewer-flushing program that addressed many" maintenance issues. Moreover, maintenance access holes showed very little change in their structural integrity" during inspection cycles.

So far, the cost to contain the leak and correct the sewer configuration is roughly $30,000, the city says.

This included deploying vacuum trucks to the site to stop the sewage from flowing into the storm sewer before the pipes could be reconfigured.

The repair job involved installing a new 4.5-metre section of pipe to connect to the Woodward Avenue treatment plant and capping both ends of the old pipe.

City staff, meanwhile, are in the process of completing a hydraulic analysis of the reconfigured sewers to validate that the repairs made are the most appropriate long-term solution."

Last week, in the wake of the discovery, Environment Minister David Piccini said he'd order the city to audit its entire sewer system and potentially a remediation plan."

On Monday, the city said it hadn't yet received a formal order. A ministry spokesperson wasn't immediately able to respond to The Spectator's request for information.

But, ministerial order or not, the city says Hamilton Water is developing plans to investigate the sewer system so that all stakeholders, can be assured that similar improper sewer connections do not exist elsewhere."

The cost of a network-wide audit is undetermined. The existing city practice involves proactive inspections of less than two per cent of underground sewers every year - there are more than 1,268 kilometres of sanitary sewer and 573 kilometres of combined sewer pipes.

Last week, Mayor Andrea Horwath expressed hope the province would help plan and fund the audit. I think we need to be partners on this."

In its report, water staff say through consultations with public health, it is very unlikely that any member of the public would have come into direct contact with the contaminated water."

The division's environmental monitoring and enforcement unit has collected samples of the discharge entering the storm sewer and downstream from that location.

The provisional analytical results are indicative of normal residential sewage entering the storm sewer, and there is evidence that the sewage had been diluted by the time that it reached the downstream sample location."

Teviah Moro is a reporter at The Spectator. tmoro@thespec.com