Integrated Stormwater Management Plan

The City developed a Citywide Integrated Stormwater Management Plan (ISMP) to help manage our rainfall, address water quality and quantity issues from stormwater runoff, and enhance our watersheds.

New Westminster’s Citywide Integrated Stormwater Management Plan (ISMP) was adopted by City Council in May 2017. The ISMP is a strategy to help manage rainfall, address water quality and quantity issues from stormwater runoff, and enhance our watershed. The ISMP is a requirement under Metro Vancouver’s Regional Integrated Liquid Waste Management Plan.

The ISMP includes a Best Management Practice Toolkit, which highlights Green Infrastructure tools and design guidelines for implementation throughout the City. Green infrastructure is a term used for more naturalized designs to manage stormwater in urban settings. It typically includes both engineered and natural components that mimic natural water flow and promote rainwater infiltration. Green Infrastructure (e.g., rain gardens) improves water quality to protect the environment, supports recreational water use, and meets current and emerging regulatory requirements.

NEW WESTMINSTER ISMP

Integrated Stormwater Management Plan Volume 1

Integrated Stormwater Management Plan Volume 2

RAIN GARDENS

The City has successfully incorporated rain gardens into recent designs for parking lots and roadways. They are designed with the objective of retaining water, allowing water to infiltrate naturally for a period of time before overflowing to the sewer systems. This supports the reduction of water in our sewers, improves water quality before entering the Fraser River, and benefits wildlife/pollinators, allowing for a greater diversity of plant species to survive.

Benefits of Rain Gardens
- Improve Water Quality
  Rainwater can be a source of pollutants as rain runs across urban landscapes picking up and carrying pollutants to downstream waterbodies.
  
  In a natural environment, rainwater is absorbed and filtered by soils and plants. Over half (53%) of New Westminster is made up of surfaces that cannot collect, absorb, or clean our rainwater.
  
  Conveying rainwater into rain gardens or other green infrastructure facilities provides a natural way to capture and clean our rain water before returning it to our atmosphere and surrounding rivers. This helps protect water quality, fish and wildlife habitat, and overall watershed health.
- Reduce Water Volume and Flooding
  Rain gardens promote sustainable urban rainwater management by slowing down and holding on to rainwater and runoff from impermeable surfaces such as streets and parking areas, allowing it to soak into the ground. This helps reduce the volume of water entering our sewer system and prevents flooding.
- Provide Resilience to Climate Change
  Green infrastructure uses rainwater as a resource for our communities and wildlife. It is key to our city’s resiliency and will help keep New Westminster healthy and safe as instances of drought, high temperatures, and intense rainstorms become increasingly frequent with climate change.
  
  More greenspace, such as rain gardens, increases the amount of rainwater that can be absorbed back into our atmosphere and helps cool our city during extreme heat events. It is important for us to support the growth of sustainable urban rainwater management practices now to ensure the longevity and health of our city.
- Enhance Biodiversity
  One of the critical and limiting factors restricting species survival in urbanized environments is access to water. All life on earth requires water at some point in their life cycle. Providing opportunities to access water in the City greatly enhances biodiversity.
  
  The City’s Biodiversity and Natural Areas Strategy recommends the use of rain gardens as a way to provide access to water sources and enhance biodiversity. For example, rain gardens are a great way attract pollinators like bees, butterflies, and birds.
- Reduce Infrastructure Costs
  Green infrastructure reduces the volume of water entering our sewer system by returning water to the natural water cycle. This increases the lifespan of our sewers and helps save on costly infrastructure maintenance and upgrades.