Low impact development

Helping manage rainwater in your neighbourhood

Low impact development (LID) is a way of designing outdoor spaces to manage rainwater where it falls. LID uses plants, special soils and natural landscaping to slow down, absorb and clean rainwater before it moves into the collection system to reduce runoff, improve drainage and enhance water quality.

Why is it called low impact development? The name comes from its purpose: to reduce the environmental effects of development. It works by mimicking natural processes, such as infiltration, to manage stormwater runoff locally and efficiently.

EPCOR's Stormwater Integrated Resource Plan (SIRP)—a 20-year, $1.6-billion investment—is our long-term plan to address flooding risks in Edmonton, which includes LID.

Benefits of LID design

Manages stormwater and prevents flooding: LID features are designed to naturally absorb rainwater and melted snow through vegetation, soil and landscape elements. In heavier rain events, LID slows down the water, helping reduce the volume entering the collection system and preventing water pooling and surface flooding.
Improves water and air quality: In some areas, stormwater flows directly into the North Saskatchewan River after running off streets and sidewalks and into the collection system. LID helps clean stormwater by filtering it through plants and soil before it flows to the river. LID vegetation also helps clean the air and provide shade.
Increases green space: LID features add natural beauty to streets, yards and public spaces and are also inviting for birds, pollinators and other wildlife.
Enhances resilience to climate change: As we experience more extreme weather events, LID helps reduce the risk of flooding during heavy rain events. LID also adds more green spaces to our communities, which help absorb carbon and cool the environment when temperatures are high.
Helps reduce infrastructure costs: Because LID helps manage stormwater, it reduces the need for major system upgrades and larger-scale construction, which in turn saves money and minimizes disruptions.

LID features and examples

Low impact development features blend into the landscape while helping manage rainwater. Here's what they could look like in your neighbourhood:

Bioretention gardens

These shallow garden beds have specially blended soils and are designed to soak up and filter rainwater. No pipes are needed.

A landscaped bioretention garden made up of various plants located beside a building, designed to absorb runoff and enhance urban green space.

A roadside bioretention basin with native vegetation, designed to manage stormwater and enhance urban green space.

Bioretention basins

Bioretention basins are like gardens but incorporate rocks and pipes into the loose soil, encouraging plant root growth and holding water during and after rainfall. Stormwater not absorbed by the plants is filtered by the soil before going to the collection system.

Box planters

These containers, which can sometimes be raised, are filled with plants and specially blended soils and are designed to hold and clean rainwater.

A concrete box planter with greenery designed to absorb and filter stormwater along a residential sidewalk.

Permeable pavement

This is a type of surface that lets water pass through it instead of running off like it does on regular concrete or asphalt.

Soil cells

Soil cells are plastic milk crate-like structures filled with loose, specially blended soils, designed to be installed beneath hardscape surfaces like sidewalks. They help encourage plant root growth and manage water underground.

Absorbent landscaping

This landscaping looks like regular grassed areas and may include plants or trees. It has a shallow dip with thicker layers of topsoil that temporarily hold stormwater and let it soak in. For larger rain events, excess water flows into the collection system.

Frequently asked questions about LID

LID handles light rain by soaking it up. Dry ponds hold large amounts of water during big storms. Both help slow the entry of stormwater into the collection system but work in different ways.

LID helps protect our rivers and watersheds by filtering out pollutants from rainwater and melting snow. They also reduce runoff and help plants grow. Trees and greenery create shade to cool down streets and make neighbourhoods more climate friendly.

No. Mosquitoes need water to sit for at least five days, and an LID is designed to drain within 48-72 hours.

We use plants that can handle both dry and wet conditions. Native plants are often chosen because they’re strong and suited to our weather.

If any plants don’t survive early on as they are establishing, they’ll be replaced as needed to ensure the LID continues to function and look its best. After plants are established it’s normal for some plants to thrive while others may not as with any ecosystem, as long as the vegetation overall is happy, established and covering the soil, this natural process will be allowed to progress.

Many factors guide where an LID is placed to ensure it will be the most effective, such as:

Natural water flow patterns
Existing drainage challenges
Road design
Proximity to catch basins and available greenspace

Infrastructure plans such as roadway changes are also taken into account to ensure the LID continues to work effectively with surrounding infrastructure over time.

Yes, some LID features include signage to inform and educate the public. You may see caution signs that highlight underground infrastructure, or educational signs sharing the benefits of the facility. These are most commonly placed near walking paths such as sidewalks and shared-use paths.

After typical rain or in continuous/back-to-back rain events, water should drain within 48 hours. During heavy rain or spring thaw, water may sit longer—this is normal. LID works year-round but is most efficient when the ground isn’t frozen.

LID installation is a shared responsibility

EPCOR installs LIDs as part of our projects but also invests in LIDs on public lands for City of Edmonton neighbourhood renewal and road renewal projects. Industrial and commercial customers are incentivized to install LIDs on their property for more effective stormwater management.

Help manage stormwater

All residents have a role to play in protecting their homes from flooding. Use these resources for more information on how you can incorporate effective stormwater management and improve drainage on your property.

EPCOR also welcomes opportunities to partner with industrial and commercial property owners to install LID on their properties. To explore partnership opportunities or learn more, please contact lidoutreach@epcor.com.

Rebates for LID installations on your property

EPCOR is offering Edmonton residents rebates on LID installations like rain gardens, box planters, soil cells, and absorbent landscaping on private property.

Check out the RainWise Rebate Program to learn more.

LID maintenance and how you can help

To keep LID's working well, both regular maintenance and community care are important.

What to expect for maintenance of an LID

EPCOR maintains LID features on public property with the exception of trees, which are taken care of by the City of Edmonton. LID in boulevards follow the same boulevard care responsibilities outlined here.

Our crews visit LID's throughout the year to check plants, remove weeds and test soil. We primarily focus on preserving infiltration capacity and ensuring the health of vegetation. Both of these are significantly affected by physical disturbances such as walking, biking, or driving through the facility. Minimizing these impacts is essential to maintaining the long-term functionality and ecological performance of LID systems.

Did you know?

LID areas may look different depending on the season. They can be bare in winter and full of greenery in summer.

How you can support LID features

Your help makes a big difference in keeping these areas healthy and working well. Here’s how you can contribute:

Stick to paths: Walking, biking or driving only on designated paths helps protect plants and keeps the soil loose so water can soak in.
Be mindful about play: Keeping children out of planted areas helps the vegetation thrive.
Keep it clean: Yard waste, chemicals and litter can harm LID features. Please use proper disposal methods.
Give plants time: New plantings need time to grow strong. Letting them establish helps the features work better.
Speak up: If you notice damage or drainage issues, let us know so we can take care of it.

Need help with an LID on public property?

If you notice any issues with an LID installation that may affect local drainage or water flow, please call EPCOR 24/7 at 780-412-4500 if you see:

Catch basins overflowing
Puddles near inlets
Water flowing past inlets
Water that isn’t decreasing within four days after a rainfall