Water Supply and Treatment

Nanaimo's water supply and treatment system is well-developed and carefully managed to ensure a sustainable and clean water source for the community. Our mandate is to provide and sustain an adequate supply of good clean water, now and into the future. This is made possible through the development and use of programs that include long-range planning, system operation, system maintenance and capital works.   The mains goals of the City’s water resource are to:

  • Plan for continued population growth,
  • Help protect the environment,
  • Manage aging infrastructure and,
  • Build resilience to climate change and emergencies. 
Jump Lake Reservoir

Most of us seldom consider where our water comes from or how, but the reality is, as our population grows, so does our demand for water. We therefore need to carefully manage and wisely use our water.

Our Water Source:

Jump Lake Earth Dam

The City’s water comes from the South Nanaimo River Watershed, covering over 200 square kilometers of catchment.  The City of Nanaimo owns and operates two water supply dams that store water to ensure consistency of supply throughout the year and release water to maintain the environmental health of the river.  The highest dam, Jump Lake, impounds approximately seventeen million cubic meters of water and provides active storage, meaning that the level fluctuates over the course of the year.  The lower dam, South Fork, impounds approximately two million cubic meters of water.  The City’s water intake is at the South Fork Dam and the water level at the dam is maintained to provide a consistent level and supply pressure to the South Fork Water Treatment Plant.

Watershed Protection:

Strict access limitations and a partnership with Mosaic Forest Management helps protect the watershed from human contamination and other pollutants.

South Fork Lake Reservoir

Transportation and Treatment:

Water is transported to Nanaimo, Snuneymuxw First Nation, The District of Lantzville and the Community of Extension through a complex network including dams, supply pipelines, the South Fork Water Treatment Plant, balancing reservoirs, pumping stations, and distribution mains.

South Fork Dam and Fisheries Release

Self Sustaining Operation:

Nanaimo's water system is operated on a self-sustaining basis, with current water rates and development charges covering usage, maintenance, new capital projects, and administration.  Water rates are set at an expanding block rate to encourage water conservation.

Historical Water Management:

Nanaimo’s first public water system began just five years after the City was incorporated when, in 1879, the Vancouver Coal Company built the first wooden pipes to deliver water to the public from a spring on Wesley Street.  Significant progress was made when the City acquired water licenses for the Nanaimo River and built the South Fork Dam in 1930, setting a new benchmark for the public water utility. The concrete arch dam, which measures 50 meters across, stands 30 meters high and retains nearly 2 million cubic meters of water in South Fork Lake.

Treatment Plant Pipeline

From the South Fork Dam, the water supply travels through parallel pipelines. The smaller of the two (a 750 mm diameter steel pipe) was constructed in 1954 and supplies up to 50,000 cubic meters of water per day. As demand increased, a second larger pipeline (a 1,200 mm diameter steel pipe) was constructed in sections, on an as-needed basis. Completed in 1993, this pipeline increased the volume capacity to 240,000 cubic meters per day. Keeping pace with Nanaimo’s growth and increased requirements for water, the Jump Creek Dam was constructed above the South Fork in the early 1970’s. Floodgates were added to the dam’s spillway, which increased storage by 50%, to a total of 17 million cubic meters.

Jump Lake Flood Gates

Nine balancing reservoirs are located throughout the city to meet peak domestic demand and emergency fire flows. Emergency fire flows can exceed supply system capacity and draw reservoirs down for several hours. To serve the growing north end of the city, the first balancing reservoir was constructed at Lost Lake in 1969, followed by reservoirs at College Park and Rutherford Road. Additional reservoirs and pipelines were built at Duke Point Industrial Park, Langara Drive, and Tanya Drive to meet heavy growth in the 1980’s.

Continued growth of the City’s population resulted in the construction of another new reservoir in the Village of Extension in 2010. More recently in 2014, the City replaced the open reservoir on Nanaimo Lakes Road with a new reservoir and energy recovery facility. The City generates revenue daily by selling electricity back to BC Hydro as the reservoir fills up with potable water.

In April 2016, the City officially opened the South Fork Water Treatment Plant.

In addition, snow-pack and rainfall information is monitored by two automated measuring systems located in the watershed. This information is used to forecast stream flows and regulate the floodgates for summer storage. Overall, Nanaimo's water management system reflects a proactive approach to ensure a sustainable, clean water supply for both current and future needs.

Jan. 2011 Weather Station 030
watershed weather stn

Last updated: February 6, 2024

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