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Water Today Title May 18, 2022

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2022/4/1


brought to you in part by

Café William



PRINCE RUPERT DRINKING WATER

OVERVIEW

  1. Can you describe the drinking water system in Prince Rupert, (distribution watermains, treatment plant, users, etc.) and the main challenges it faces?

Today, the Prince Rupert water system feeds approximately 6 million cubic metres of potable water per year to residents, businesses, and industry, utilizing over 50 kilometres of distribution line and close to 6000 individual service connections. The Community Water System supplies the Port of Prince Rupert and related industries, as well as BC Ferries. The system is also capable of meeting the peak seasonal demand of a number of industrial fish processors, an industry that has declined in recent years with the closure of local canneries, but when active can generate over twice the average daily consumption.

Our water system currently has a single barrier of treatment – chlorination. The treatment station is located across the harbour adjacent to Shawatlan Lake (our secondary water supply). Following a successful application for funding in 2019, the City is currently in the engineering phase to build a new water treatment plant on Kaien Island, where the City proper is located. This new plant will implement multiple barriers of treatment, vastly increase ease of access to our treatment system for maintenance and repair, balance pH of the raw water, and fully address high sediment and turbidity – which have been noted issues for the Health Authority over the past few years. Advisories specifically related to turbidity have also been due in part to the fact that we are drawing from our secondary source at Shawatlan Lake during the construction of a new dam, which is lower elevation and more prone to runoff during storm/major rain events.

  1. What is the source of drinking water?

The City draws its water from two lakes across the harbour from Prince Rupert – Woodworth and Shawatlan Lakes. As noted above, for the past few years we have been drawing from our secondary source at Shawatlan Lake while we replace the 100-year-old dam at Woodworth Lake, our primary water supply. These lakes are remotely located across the harbour from Prince Rupert in a Provincial Conservancy. Water is conveyed via two submarine waterlines beneath the harbour to Prince Rupert.

  1. Do the plants have any treatment for emerging contaminants such as PFAS, and endocrine disrupters?

The existing plant does not, but these are considerations being addressed in the engineering phase of our new treatment system, currently underway.

  1. With the increase in extreme weather events and flooding, what measures is Prince Rupert taking to protect its plants?

Although a coastal community, Prince Rupert is the rainiest city in all of Canada, and so infrastructure has and will always take significant weather impacts into consideration. In addition, the majority of the community is built at significant elevation, with a low risk of flooding except in a few areas surrounding local creeks/waterways. The site proposed for the new water treatment station is located at a significant elevation away from potential flooding hazards, and the existing treatment station is also located at an elevation set back from Shawatlan Lake.

  1. Combined sewage overflows are a common problem in cities across Canada. What is the situation in Prince Rupert?

The current sewerage system within the City of Prince Rupert dates back to the early 1900s and is divided into nine sewerage areas, each with a piped discharge into Prince Rupert Harbour. Of these nine areas, five are combined sewers and four are separated sanitary and storm sewers. The majority of the wastewater is currently discharged without any treatment.

What was the amount of CSO in recent years?

As per the previous question, more than half of the City’s sewerage system is combined.

  1. Lead connections are also a common problem, how many lead connections do you estimate there are in Prince Rupert? What is the city doing about it?

The City’s water supply is tested regularly for a number of potential contaminants, including lead, at sampling stations throughout the community, and the water supply falls well below the Maximum Allowable Concentration (legal limit) for lead. However, once the water reaches local homes or businesses it is possible that it makes contact with lead plumbing components. Like many coastal communities, our water has a slightly lower pH, which means that it has corrosive properties. Water with lower pH sitting idle in plumbing with lead over an extended period of time (more than a few hours) is more likely to contain lead.

Due to this risk factor, the City, in coordination with Northern Health, has run a local sampling program to determine lead exposure rates as well as if the City’s infrastructure could be contributing. Based on the results obtained from the sampling program, although there were a few outlier properties that did contain lead at or above the MAC, there did not appear to be any defined areas within the city that are more at risk of increased concentrations of lead or copper due to contributions from installed infrastructure. The lack of any clear problem areas means that targeted interventions such as localized treatment or replacement of installed infrastructure are not available to the City to reduce the risk of lead leaching in homes due to corrosion. Rather, the City’s work to install a new treatment system will address the corrosivity of supplied water. In the meantime, we have conducted significant community outreach to warn about the risks of lead leaching from home-based sources (Prince Rupert’s housing stock is fairly old), with flushing recommended to draw a fresh source of water from beyond the home.

This testing corroborates existing records, which indicate that due to the time period in which most infrastructure was installed, the City does not have lead service lines within the municipal infrastructure. The City is not responsible for water service infrastructure on private property but also has not observed lead service lines when private water services have been encountered.

  1. Are there other emerging issues you are looking into?

The City is working with Northern Health to monitor and reduce disinfection by-products within our existing system, with the elimination of them being a major consideration of the engineering of the new treatment system.