LID Case Studies

Click the image above to access STEP's most recent report on the performance assessment of multiple LID features located at IMAX's corporate offices in Mississauga, ON.

Overview

This page is a repository of recent case studies that the Sustainable Technologies Evaluation Program (STEP) have conducted over the past two decades or so. Keep your eye on this page as current projects wrap up and new technical briefs or reports are developed, they will be added to this page.

Each of the documents are separated by the LID BMP feature that was studied / monitored or built, a number of these documents will appear several times throughout this page as many have information on multiple LIDs' and their design, performance and associated inspection requirements.

Feel free to review the documents and redirect back to the main LID practice's BMP page at the end of each section to learn more.

Bioretention

This report by TRCA found several stormwater management benefits by incorporating several LID principles Bioretention, Infiltration trenches/Infiltration chambers, and Enhanced grass swales into sustainable functional design in an underutilized space, now named the 'Bentway' under Toronto's Gardiner Expressway. This allowed for dual functioning of a public recreational area and suitable stormwater management. Read more by clicking the button above.

This report by TRCA discusses the recent 'Markham Municipal Green Road Pilot Project' that was established between 2015 - 2018 and which is located on Vanni Avenue, south east of the intersection of 14th Avenue and Middlefield Rd. in a a mixed use residential and commercial property area. The specially designed road includes multiple low impact development (LID) technologies, including Permeable pavement boulevards, Bioretention and Infiltration trenches/galleries underlain beneath the bioretention features to manage stormwater at the source. To learn more about this "Green Street" read the project brief by clicking the button above.

This report by CVC highlights the benefits of a multi-LID retrofit on a mixed-use street with residential homes and an education centre on Elm Drive in Mississauga. The retrofit included, a Permeable pavement sidewalk and parking layby along with six Bioretention cells connected with an Underdrain. The site now provides stormwater treatment by improving the quality of stormwater discharged (thermal mitigation, reduction in runoff volume to storm sewers, etc.) to Cooksville Creek. Read more by clicking the button above.

This report, released by CVC this year (2022) provides a thorough overview of the monitoring work done at the Imax Corporate Headquarters, located in Mississauga, ON. The parking lot was expanded and retrofitted with a combination of traditional asphalt and Permeable pavement. The asphalt runoff drains to one of three vegetated Bioretention units on site. The The parking lot runoff is collected, absorbed and filtered by these LID practices before entering a Wetland adjacent to the parking lot. Read more about these features performance over this multi-year study by clicking the button above.

This study evaluates a proprietary bioretention filtration system (Filterra®) that treats stormwater runoff from impervious surface areas over 100 times larger than the footprint of the facility. The space efficient unit is designed to be installed as part of a traditional curb and gutter road right of way design and is well suited to retrofit applications. Read more about this new proprietary filtration system and see how it performed at the Kortright Centre in Vaughan, ON., by clicking above.

This study compares the performance of nine different Bioretention facilities monitored by Toronto and Region Conservation Authority (TRCA) and Credit Valley Conservation (CVC) in the Greater Toronto Area. The monitored facilities of varying shape, size and design were constructed to manage runoff from parking lots, public roads and residential areas. Key performance variables assessed included peak flows, runoff volume, water quality, water temperature and functional characteristics. To learn more about the results and differences amongst the 9 facilities when it comes to volume and load reductions and water quality and quantity control, click the button above.

This report by TRCA highlights the first pilot project by Toronto Green Streets completed as a partnership between City Planning and Toronto Water. The site was first identified as a priority location for improving traffic flow and pedestrian safety in 2014, and the City took the opportunity to retrofit it as a green infrastructure demonstration site. For the project, the right turn lane from Fairford Avenue eastbound to Coxwell Avenue was eliminated and the space was used to build a landscaped Bioretention area and public seating. Read more about how this project was spurred by community request for pedestrian improvements to the area and showcased the aesthetic and instrumental value of the new parquetted designed with a bioretention cell on site, by clicking the button above.

This report by TRCA discusses the various Low Impact Development (LID) technologies used in key areas of interest throughout UOIT's campus (located in Oshawa, ON.), to both mitigate the impacts of the development and to green the campus. The processes are transparent to the campus community providing valuable visible lessons for students and faculty. The LID technologies used include Bioretention, linear Wetlands, Green roofs and Rainwater harvesting, all designed to reduce runoff volumes and pollutant loads to the adjacent ravine. Read more about the campus' design by clicking the button above.

This report by TRCA highlights the use of the Treatment Train Approach at Bill Crothers Secondary built back in 2008. The site used to a golf course and was located partially in the Rouge Watershed's floodplain. During the planning process for the school several low impact developments were identified to be used on site that included, Bioretention areas, Enhanced swales, Constructed Wetlands and Rainwater harvesting. To learn more about the design process for the school click the button above.

This study examined the effectiveness of reactive media amendments as a means of enhancing phosphorus retention in a bioretention cell draining a large parking lot in the City of Vaughan, ON. For testing purposes, the bioretention was divided into three hydrologically distinct cells: one with a high sand, low phosphorus media mix (control); one with a proprietary reactive media (Sorbitve™) mixed into the sandy filter media, and one with a 170 cm layer of iron rich sand (aka red sand) below the sandy filter media. Outflow quantity and quality from each cell was measured directly, while inflows and runoff quality were estimated based on monitoring of an adjacent asphalt reference site over the same time period. Click the button above to find out which of these cells performed the best when it comes to water quality and quantity levels.

This report by TRCA highlights the multiple LID installations located at Edwards Gardens, a botanical garden located at 777 Lawrence Avenue East in Toronto, Ontario and owned by the city. The retrofit of the Edwards Gardens parking lot introduces several new technologies to add to the existing Low Impact Development (LID) practices onsite – an extensive Green roof and a Rainwater harvesting system, along with Bioretention, Permeable pavement, Infiltration trenches, Exfiltration trenches, and Swales. The stormwater management benefits of the LID practices implemented onsite help to improve the quality and reduce the volume of runoff discharging to Wilket Creek, nearby. To read more about the various LID practices at Edwards Gardens and their performance, click the button above.

Creekside Crossing is a communal centre in a heavily urbanized area of Mississauga. Due to extensive development in the area, several Low Impact Development (LID) practices were constructed on site. All combined, the LIDs were able to fulfill the requirement of the TTRCA's water balance objective of retaining runoff from a 10 mm rain event onsite (usually set at 5 mm, but due to the rehabilitation work was completed in a floodplain this objective was increased twofold. The LIDs, which include Bioretention areas, Soakaways/Infiltration galleries, Vegetated filter strips and Permeable pavement, achieve the water balance objective through attenuation/infiltration and evapotranspiration. To read more about this site and the performance of the LIDs mentioned, click on the button above.

The University of Toronto (Scarborough Campus) - UTSC, has been growing steadily over the past decades from 2011 - 2015 alone, campus growth has resulted in nearly 60,000 m2 of new buildings. To minimize the impact on the environment and managing increased stormwater runoff were important considerations that the university wanted to address. As a result, the East Arrival Court (EAC) retrofit, which captures stormwater in the Bioretention area of the parking lot and in the nearby Dry pond, which provides temporary storage, and greater opportunities for infiltration and evapotranspiration were installed to help to improve the quality and reduce the volume of runoff discharging to the nearby Rouge River. To read more about this project click the button above.

The Lakeview district is a residential neighbourhood within the City of Mississauga. CVC led the retrofit of this neighbourhood by removing existing ditch and culvert systems and replacing them with boulevard Bioretention and Permeable pavement practices within the municipal road right of way (ROW). Permeable pavement was incorporated at the end of resident’s driveways and bioretention units were situated along frontages in the boulevard. To read more about the Lakeview project being a fully functional LID demonstration showcase site that can be used as a model for future ROW retrofit projects, click the button above.

The PORTICO Community Church site, located in Mississauga, ON. was one of the first site to develop an LID parking lot in the province, in accordance with LID Stormwater Guidelines. The 2 hectare parking lot at Portico Community Church features Permeable pavement, Bioretention and two Bioswales. These LID features help to treat and reduce runoff flowing into the Credit River. Read more about this site and how the church , CVC and volunteers worked together to set up an ongoing maintenance schedule for the LID installations mentioned by clicking the button above.

O’Connor Park is located on Bala Drive in the west end of Mississauga, ON. in the Sawmill Creek subwatershed, that later flows into the Credit River and Lake Ontario. The primary LID installation completed in the park were Bioretention, Bioswales, Permeable pavement, and Infiltration trenches, running along the soccer fields on site that later drains into the pre-existing small natural Wetlands and nearby pond. The O’Connor Park Development Project Team received the Brenda Sakauye Environment Award in recognition of the park’s advancement of the City of Mississauga’s Living Green Master Plan, as well as the 2012 Mississauga Urban Design Award of Merit for Community Scale, Living Green, Innovation and Execution. Learn more about the award-winning design that went into O'Connor Park by clicking the button above.

The South End divisions, located in Guelph, ON. (Clairfields, Westminster Woods and Pine Ridge subdivisions) were a new development site that also includes a number of green demonstration homes, including Canada’s first LEED Platinum home and a water efficient Blue Built Home, built with Infiltration trenches in the backyards of the homes. Throughout much of the subdivisions, stormwater runoff is collected from the roadways using typical catchbasins and piping. However, rather than discharging to a stormwater management pond, the runoff is directed to large-scale Bioretention facilities, known as “greenways. Learn more about the use of "greenways" by clicking the button above.

The Unitarian Congregation in Mississauga (UCM) is located on South Service Road within the Cooksville Creek Watershed. that drains into Lake Ontario. The site sits on sandy soils, which are ideal conditions for low impact development practices that infiltrate stormwater. A large Bioretention cell was constructed in the center of the parking lot. The bioretention cell filters and absorbs rainwater running off the parking lot. The bioretention cell is also landscaped with many native plants that create habitat for the numerous bird and insect species on the site. Filter strips, were added a year after construction of the site, which successfully stabilized the edge and eliminated most of the erosion issues occurring around the edge of the bioretention facility.

An Ontario Ministry of Transportation (MTO) carpool parking lot was constructed in 2010 in the community of Beamsville. The site included, four Bioretention cells to manage stormwater runoff. The site also incorporates a test strip of special Permeable pavement containing recycled material, referred to as “rubber modified asphalt”. The bioretention cells were installed to add aesthetic value while offering an enhanced level of stormwater management compared to a conventional parking lot. The project received the 2011 Recognition Award from the Environmental Commissioner of Ontario. To learn more about the performance of the bioretention cells and the permeable concrete paver strip click the button above.

Read more about Bioretention here.

Permeable Pavement

This report, released by CVC this year (2022) provides a thorough overview of the monitoring work done at the Imax Corporate Headquarters, located in Mississauga, ON. The parking lot was expanded and retrofitted with a combination of traditional asphalt and Permeable pavement. The asphalt runoff drains to one of three vegetated Bioretention units on site. The The parking lot runoff is collected, absorbed and filtered by these LID practices before entering a Wetland adjacent to the parking lot. Read more about these features performance over this multi-year study by clicking the button above.

This report by CVC highlights the benefits of a multi-LID retrofit on a mixed-use street with residential homes and an education centre on Elm Drive in Mississauga. The retrofit included, a Permeable pavement sidewalk and parking layby along with six Bioretention cells connected with an Underdrain. The site now provides stormwater treatment by improving the quality of stormwater discharged (thermal mitigation, reduction in runoff volume to storm sewers, etc.) to Cooksville Creek. Read more by clicking the button above.

This study by TRCA evaluates the capacity of two surface cleaning techniques applied before traditional vacuum sweeping to improve the effectiveness of Permeable pavement maintenance. The research, conducted in collaboration with University of Toronto researchers, builds on previous studies at the Kortright Centre's permeable pavements research facility on the effectiveness of conventional vacuum sweeping of permeable pavements. The post maintenance surface infiltration rates were much lower for some types of permeable pavers when compared to their initial capacity shortly after installation, others remained clogged or did not show any change following maintenance. To see which types of permeable pavement performed better after maintenance click the button above.

This study, conducted by CVC was focused on work completed at the Ontario Ministry of Transportation's (MTO) carpool parking lot in Campbellville adjacent to Guelph Line and Highway 401 in the fall of 2007. The site was selected by the MTO as an ideal location to test the use of pervious concrete mix (Permeable pavement) as a substitute for conventional asphalt or (impervious) concrete for the parking surface. Permeability monitoring was conducted for 22 months following construction. At this site sand use did not significantly reduce permeability of the concrete; however, the amount of traffic did. High use traffic lanes decreased permeability over time compared to parking spaces. It is presumed that the additional loading compacts debris into pore spaces. Maintenance techniques (annual sweeping) improved permeability, but did not restore the permeability to just after initial installation levels. It is important to note that even after 22 months of monitoring, permeability was still higher than 299 mm/hr (the maximum rainfall rate expected at the site). So even with some loss in permeability, the site would still have performed well during intense rainfall events. Learn more about this study sight by clicking the button above.

This report by CVC highlights how the CA (per its mandate) and its member municipalities approached the construction of an addition to the CVC head office as an opportunity to showcase a green building that effectively manages water resources on the site in keeping with the Credit River Water Management Strategy. The report goes over how CVC created the new construction as a demonstration site that showcased LID practices within a typical commercial office setting. It also allowed the CA the opportunity to ‘learn by doing’ and closely monitor the performance and maintenance of LID practices and communicated the ways to improve the design, installation and management of LID features. Monitoring found that all LID practices (Permeable pavements, grass swales, and a Rainwater harvesting system) at CVC's Head Office reduces the runoff volume of rain events by 63%. This is an improvement from typical parking lots where the majority of runoff travels directly into the storm sewers and into our streams and Lake Ontario. The site also removes 81% of total suspended solids. Learn mroe about this work by clickign the button above.

This report by TRCA discusses the recent 'Markham Municipal Green Road Pilot Project' that was established between 2015 - 2018 and which is located on Vanni Avenue, south east of the intersection of 14th Avenue and Middlefield Rd. in a a mixed use residential and commercial property area. The specially designed road includes multiple low impact development (LID) technologies, including Permeable pavement boulevards, Bioretention and Infiltration trenches/galleries underlain beneath the bioretention features to manage stormwater at the source. To learn more about this "Green Street" read the project brief by clicking the button above.

This report by TRCA highlights the multiple LID installations located at Edwards Gardens, a botanical garden located at 777 Lawrence Avenue East in Toronto, Ontario and owned by the city. The retrofit of the Edwards Gardens parking lot introduces several new technologies to add to the existing Low Impact Development (LID) practices onsite – an extensive Green roof and a Rainwater harvesting system, along with Bioretention, Permeable pavement, Infiltration trenches, Exfiltration trenches, and Swales. The stormwater management benefits of the LID practices implemented onsite help to improve the quality and reduce the volume of runoff discharging to Wilket Creek, nearby. To read more about the various LID practices at Edwards Gardens and their performance, click the button above.

Creekside Crossing is a communal centre in a heavily urbanized area of Mississauga. Due to extensive development in the area, several Low Impact Development (LID) practices were constructed on site. All combined, the LIDs were able to fulfill the requirement of the TTRCA's water balance objective of retaining runoff from a 10 mm rain event onsite (usually set at 5 mm, but due to the rehabilitation work was completed in a floodplain this objective was increased twofold. The LIDs, which include Bioretention areas, Soakaways/Infiltration galleries, Vegetated filter strips and Permeable pavement, achieve the water balance objective through attenuation/infiltration and evapotranspiration. To read more about this site and the performance of the LIDs mentioned, click on the button above.

The Lakeview district is a residential neighbourhood within the City of Mississauga. CVC led the retrofit of this neighbourhood by removing existing ditch and culvert systems and replacing them with boulevard Bioretention and Permeable pavement practices within the municipal road right of way (ROW). Permeable pavement was incorporated at the end of resident’s driveways and bioretention units were situated along frontages in the boulevard. To read more about the Lakeview project being a fully functional LID demonstration showcase site that can be used as a model for future ROW retrofit projects, click the button above.

The PORTICO Community Church site, located in Mississauga, ON. was one of the first site to develop an LID parking lot in the province, in accordance with LID Stormwater Guidelines. The 2 hectare parking lot at Portico Community Church features Permeable pavement, Bioretention and two Bioswales. These LID features help to treat and reduce runoff flowing into the Credit River. Read more about this site and how the church , CVC and volunteers worked together to set up an ongoing maintenance schedule for the LID installations mentioned by clicking the button above.

O’Connor Park is located on Bala Drive in the west end of Mississauga, ON. in the Sawmill Creek subwatershed, that later flows into the Credit River and Lake Ontario. The primary LID installation completed in the park were Bioretention, Bioswales, Permeable pavement, and Infiltration trenches, running along the soccer fields on site that later drains into the pre-existing small natural Wetlands and nearby pond. The O’Connor Park Development Project Team received the Brenda Sakauye Environment Award in recognition of the park’s advancement of the City of Mississauga’s Living Green Master Plan, as well as the 2012 Mississauga Urban Design Award of Merit for Community Scale, Living Green, Innovation and Execution. Learn more about the award-winning design that went into O'Connor Park by clicking the button above.

An Ontario Ministry of Transportation (MTO) carpool parking lot was constructed in 2010 in the community of Beamsville. The site included, four Bioretention cells to manage stormwater runoff. The site also incorporates a test strip of special Permeable pavement containing recycled material, referred to as “rubber modified asphalt”. The bioretention cells were installed to add aesthetic value while offering an enhanced level of stormwater management compared to a conventional parking lot. The project received the 2011 Recognition Award from the Environmental Commissioner of Ontario. To learn more about the performance of the bioretention cells and the permeable concrete paver strip click the button above.

Read more about Permeable pavement here.

Stormwater Tree Trenches

This study, conducted by TRCA and City of Toronto, assesses the health of street trees planted in ‘soil cells’ and conventional tree trenches. Three sets of the same two tree species planted in 2009 on Queensway Boulevard in Toronto were compared. The first two sets of trees were planted in supported soil cell systems (silva cell™). The others planted further west in tree trenches according to standard City of Toronto tree planting specifications were used as controls. One set of soil cell trees received stormwater runoff since the trees were planted. The other adjacent set of trees had the stormwater inlet pipe intentionally plugged by Toronto staff after 2 years to facilitate assessment of the effects of stormwater runoff on tree health. To look at the results of this comparative study and see if trees in Stormwater Tree Trenches receiving street runoff outcompeted those that didn't, make sure to click the button above.

The Sustainable Sidewalk project was initiated as a solution to address the disturbance of street tree roots associated with the removal of sidewalks for utility cuts. A working group with participants from various City of Toronto Divisions was formed and the group decided to use Soil cells for a Stormwater Tree Trenches (Bioretention) and in the fall of 2008 constructed The 'Queensway Sustainable Sidewalk Pilot Project'. Monitoring results from the study found that the soils were able to reduce TSS (>80%) and heavy metal concentrations in the road run off that entered the system. Also the outlet flow meter did not show any flow release after a rainfall of 3 mm that was preceded by a period of no rain, showcasing the systems ability to mitigate excess stormwater runoff in the heavily urbanized location.

The Central Parkway low impact development (LID) road retrofit is located on Central Parkway East, just south of Burnhamthorpe Road in Mississauga, Ontario. Read the brief authored by CVC about the performance of the Stormwater Tree Trenches LID feature is able to reduce the majority of stormwater runoff leaving the site during most rainfall events. The Central Parkway project was the first green road retrofit to take place in Mississauga where the Silva Cell system Soil cells were specifically used for stormwater treatment in addition to encouraging tree growth and aesthetic design.

Read more about Stormwater Tree Trenches here.

Wetlands

The purpose of this document authored by TRCA and CVC is to inform the need for, and the design of, mitigation measures to ensure a minimal difference between the post-development and pre-development water balance of a wetland. This Modelling Document provides an overview of wetland hydrology modelling, the strengths and weaknesses of various hydrological models, and the information that needs to be included in a wetland feature-based water analysis report. Read more about the importance of choosing the correct hydrological model and inclusion of the pertinent information required for a proper water analysis report by clicking the button above.

This report by TRCA discusses the various Low Impact Development (LID) technologies used in key areas of interest throughout UOIT's campus (located in Oshawa, ON.), to both mitigate the impacts of the development and to green the campus. The processes are transparent to the campus community providing valuable visible lessons for students and faculty. The LID technologies used include Bioretention, linear Wetlands, Green roofs and Rainwater harvesting, all designed to reduce runoff volumes and pollutant loads to the adjacent ravine. Read more about the campus' design by clicking the button above.

The following document from TRCA helps user better determine the appropriate model to simulate wetland hydrology, wetland storage dynamics, and the representation of stormwater management and low impact development (LID) facilities, etc. This document is an appendix to the previously mentioned, Wetland Water Balance Modelling Guidance Document and is intended to be a resource for modelers to help them make more informed decisions in modelling wetland water balance scenarios. Read more about this valuable resource for modelers to consult for applications requiring a wetland water balance, by clicking the button above.

This report, released by CVC this year (2022) provides a thorough overview of the monitoring work done at the Imax Corporate Headquarters, located in Mississauga, ON. The parking lot was expanded and retrofitted with a combination of traditional asphalt and Permeable pavement. The asphalt runoff drains to one of three vegetated Bioretention units on site. The The parking lot runoff is collected, absorbed and filtered by these LID practices before entering a Wetland adjacent to the parking lot. Read more about these features performance over this multi-year study by clicking the button above.

This report by TRCA discusses the various Low Impact Development (LID) technologies used in key areas of interest throughout UOIT's campus (located in Oshawa, ON.), to both mitigate the impacts of the development and to green the campus. The processes are transparent to the campus community providing valuable visible lessons for students and faculty. The LID technologies used include Bioretention, linear Wetlands, Green roofs and Rainwater harvesting, all designed to reduce runoff volumes and pollutant loads to the adjacent ravine. Read more about the campus' design by clicking the button above.

O’Connor Park is located on Bala Drive in the west end of Mississauga, ON. in the Sawmill Creek subwatershed, that later flows into the Credit River and Lake Ontario. The primary LID installation completed in the park were Bioretention, Bioswales, Permeable pavement, and Infiltration trenches, running along the soccer fields on site that later drains into the pre-existing small natural Wetlands and nearby pond. The O’Connor Park Development Project Team received the Brenda Sakauye Environment Award in recognition of the park’s advancement of the City of Mississauga’s Living Green Master Plan, as well as the 2012 Mississauga Urban Design Award of Merit for Community Scale, Living Green, Innovation and Execution. Learn more about the award-winning design that went into O'Connor Park by clicking the button above.

Read more about Wetlands here.

Rain Garden

The Kleinburg Starbucks Fusion Garden is the first one York Region has established as part of their Fusion Gardening® pilot project. The case study discusses the benefits of a Rain garden, which allows for a beautiful tailored aesthetic for the owner, while also serving as a more absorbent landscape that reduces stormwater runoff and conserves water on site. The garden also uses an Infiltration trench for irrigating the planting bed and Permeable pavement on the pedestrian paths and seating area. Read more about this design concept by clicking the button above.

Glendale Public School (P.S.) is located in the City of Brampton, within the Fletchers Creek SNAP (Sustainable Neighbourhood Action Plan). The site has experienced increased urbanization and had a lack of stormwater controls, which was impacting the health of Fletchers Creek’s aquatic organisms, particularly Redside Dace, which is an endangered fish species. In addition to this problem, Glendale P.S. had existing draining issues on their property that needed to be addressed. As a result, the CVC team developed a large-scale Rain garden, that would address the drainage issues on site and water quality issues in nearby Fletchers Creek , A “treatment train” approach was adopted and included three Swales (one overflow and two conveyance into the rain garden), conveyance pipes, an Underdrain system, a flow control valve for water to either infiltrate naturally into the system or flow through the underdrain to the storm sewer in heavier rain events. The project was successful in:

• Managing the runoff from a 27mm storm, covering up to the 90th percentile of the annual rain events in the area.
• Improving stormwater runoff water quality by reducing total suspended solids (TSS) by 80% before entering Fletcher’s Creek,
• Providing heat mitigation by cooling runoff before discharging it to the receiving waterbody; and,
• Increased floodplain storage by a total of 800m3 reducing flooding potential during large storm events.

Read more about the successes of this project by clicking the button above.

Green Glade Sr. Public School is a senior elementary school located in south Mississauga, adjacent to Rattray Marsh, a provincially significant Wetland. In 2011, Green Glade and Peel District School Board (PDSB) staff worked with Credit Valley Conservation (CVC) to retrofit the school property to incorporate a Rain garden low impact development (LID) feature. The rain garden accepts runoff from a portion of the school’s roof as well as runoff from a section of the parking lot. Learn about how the site was used as one of seven Bioretention practices that were studied in an effort to develop ‘certification protocols’ for LID practices. These protocols are a process that municipalities and property managers can use to ensure that LID practices function as intended. To learn more click the button above.

Terra Cotta Conservation Area (TCCA) is a 250 hectare naturalized area in the village of Terra Cotta. Located in the Niagara Escarpment, it is home to several different species of plants, birds, and wildlife. In the summer of 2011, a Rain garden was constructed next to the Visitors Welcome Centre at TCCA. This rain garden was similar to what would typically be constructed on a residential property. By collecting water level data and recording maintenance requirements, CVC staff have been able to determine how well the rain garden functions. The rain garden is successful at treating stormwater runoff from the roof of the Visitors Center, although there have been few instances of the rain garden overflowing. Nearly all runoff from the roof was either infiltrated through the rain garden or lost through evapotranspiration. To learn more click the button above.

In the fall of 2014, the Town of Ajax completed the construction of three bioretention areas that blend function with aesthetics. Located within a well-established community adjacent to lakefront access and trail systems, the Rain gardens were constructed in the Town’s road allowance and the parking area south of Lake Driveway West and follows the recommendations of the Town of Ajax Stormwater Management Retrofit Master Plan which aims to improve water quality for South Ajax. To learn more about how the rain garden installation aligned with Ajax's SWM Master plan, click the button above.

Read more about Rain gardens here.

Bioswales

This report by TRCA's STEP group highlights how in July of 2014, the City of Brampton constructed two Bioswales featuring impermeable liners within the road right-of-way of County Court Boulevard, a medium traffic collector road that services residential, institutional and parkland areas in the neighbourhood. In November 2014, simulated storm event tests were completed to verify that each swale was functioning as intended and examine runoff reduction performance during a medium-sized rain event (i.e. approx. 12 mm, 40 minute rain storm). Results show that East and West Swales retained 32% and 10% of the water, respectively. This suggests that substantial runoff volume reduction benefits can be provided by swales designed with impermeable liners. To learn more about these swale configurations, and their performance click the button above.

The PORTICO Community Church site, located in Mississauga, ON. was one of the first site to develop an LID parking lot in the province, in accordance with LID Stormwater Guidelines. The 2 hectare parking lot at Portico Community Church features Permeable pavement, Bioretention and two Bioswales. These LID features help to treat and reduce runoff flowing into the Credit River. Read more about this site and how the church , CVC and volunteers worked together to set up an ongoing maintenance schedule for the LID installations mentioned by clicking the button above.

O’Connor Park is located on Bala Drive in the west end of Mississauga, ON. in the Sawmill Creek subwatershed, that later flows into the Credit River and Lake Ontario. The primary LID installation completed in the park were Bioretention, Bioswales, Permeable pavement, and Infiltration trenches, running along the soccer fields on site that later drains into the pre-existing small natural Wetlands and nearby pond. The O’Connor Park Development Project Team received the Brenda Sakauye Environment Award in recognition of the park’s advancement of the City of Mississauga’s Living Green Master Plan, as well as the 2012 Mississauga Urban Design Award of Merit for Community Scale, Living Green, Innovation and Execution. Learn more about the award-winning design that went into O'Connor Park by clicking the button above.

This study by TRCA evaluates the effectiveness of two lined, filtration-only Bioswales (i.e., biofilter swales) retrofitted into a portion of the right-of-way of County Court Boulevard, a medium-traffic collector road in the City of Brampton. Scheduling of road maintenance work by the Public Works and Transportation department in 2014 provided the opportunity to retrofit biofilter swales for stormwater treatment within the road right-of-way. Effectiveness of the biofilter swales retrofit project was examined with respect to the following: • Runoff volume and pollutant load reduction; • Effects on effluent temperature; • Effects of winter operation on treatment performance and maintenance needs, and; • Life cycle cost of total suspended solids removal over a 50 year life cycle. Click the button above to read the results of the bioswales' stormwater treatment performance and further details on BMP design for these features.

Read more about Bioswales here.

Infiltration Trenches / Soakaways

This report by TRCA found several stormwater management benefits by incorporating several LID principles Bioretention, Infiltration trenches/Infiltration chambers, and Enhanced grass swales into sustainable functional design in an underutilized space, now named the 'Bentway' under Toronto's Gardiner Expressway. This allowed for dual functioning of a public recreational area and suitable stormwater management. Read more by clicking the button above.

This report by TRCA discusses the recent 'Markham Municipal Green Road Pilot Project' that was established between 2015 - 2018 and which is located on Vanni Avenue, south east of the intersection of 14th Avenue and Middlefield Rd. in a a mixed use residential and commercial property area. The specially designed road includes multiple low impact development (LID) technologies, including Permeable pavement boulevards, Bioretention and Infiltration trenches/galleries underlain beneath the bioretention features to manage stormwater at the source. To learn more about this "Green Street" read the project brief by clicking the button above.

This report by TRCA highlights the multiple LID installations located at Edwards Gardens, a botanical garden located at 777 Lawrence Avenue East in Toronto, Ontario and owned by the city. The retrofit of the Edwards Gardens parking lot introduces several new technologies to add to the existing Low Impact Development (LID) practices onsite – an extensive Green roof and a Rainwater harvesting system, along with Bioretention, Permeable pavement, Infiltration trenches, Exfiltration trenches, and Swales. The stormwater management benefits of the LID practices implemented onsite help to improve the quality and reduce the volume of runoff discharging to Wilket Creek, nearby. To read more about the various LID practices at Edwards Gardens and their performance, click the button above.

Creekside Crossing is a communal centre in a heavily urbanized area of Mississauga. Due to extensive development in the area, several Low Impact Development (LID) practices were constructed on site. All combined, the LIDs were able to fulfill the requirement of the TTRCA's water balance objective of retaining runoff from a 10 mm rain event onsite (usually set at 5 mm, but due to the rehabilitation work was completed in a floodplain this objective was increased twofold. The LIDs, which include Bioretention areas, Soakaways/Infiltration galleries, Vegetated filter strips and Permeable pavement, achieve the water balance objective through attenuation/infiltration and evapotranspiration. To read more about this site and the performance of the LIDs mentioned, click on the button above.

O’Connor Park is located on Bala Drive in the west end of Mississauga, ON. in the Sawmill Creek subwatershed, that later flows into the Credit River and Lake Ontario. The primary LID installation completed in the park were Bioretention, Bioswales, Permeable pavement, and Infiltration trenches, running along the soccer fields on site that later drains into the pre-existing small natural Wetlands and nearby pond. The O’Connor Park Development Project Team received the Brenda Sakauye Environment Award in recognition of the park’s advancement of the City of Mississauga’s Living Green Master Plan, as well as the 2012 Mississauga Urban Design Award of Merit for Community Scale, Living Green, Innovation and Execution. Learn more about the award-winning design that went into O'Connor Park by clicking the button above.

The South End divisions, located in Guelph, ON. (Clairfields, Westminster Woods and Pine Ridge subdivisions) were a new development site that also includes a number of green demonstration homes, including Canada’s first LEED Platinum home and a water efficient Blue Built Home, built with Infiltration trenches in the backyards of the homes. Throughout much of the subdivisions, stormwater runoff is collected from the roadways using typical catch basins and piping. However, rather than discharging to a stormwater management pond, the runoff is directed to large-scale Bioretention facilities, known as “greenways. Learn more about the use of "greenways" by clicking the button above.

Read more about Infiltration trenches & Soakaways here.

Exfiltration Trenches

This report by TRCA highlights the multiple LID installations located at Edwards Gardens, a botanical garden located at 777 Lawrence Avenue East in Toronto, Ontario and owned by the city. The retrofit of the Edwards Gardens parking lot introduces several new technologies to add to the existing Low Impact Development (LID) practices onsite – an extensive Green roof and a Rainwater harvesting system, along with Bioretention, Permeable pavement, Infiltration trenches, Exfiltration trenches, and Swales. The stormwater management benefits of the LID practices implemented onsite help to improve the quality and reduce the volume of runoff discharging to Wilket Creek, nearby. To read more about the various LID practices at Edwards Gardens and their performance, click the button above.

Read more about Exfiltration trenches here.

Infiltration Chambers

This report by TRCA found several stormwater management benefits by incorporating several LID principles Bioretention, Infiltration trenches/Infiltration chambers, and Enhanced grass swales into sustainable functional design in an underutilized space, now named the 'Bentway' under Toronto's Gardiner Expressway. This allowed for dual functioning of a public recreational area and suitable stormwater management. Read more by clicking the button above.

Read more about Infiltration chambers here.

Swales / Enhanced Wales / Grass Swales

This report by TRCA found several stormwater management benefits by incorporating several LID principles Bioretention, Infiltration trenches/Infiltration chambers, and Enhanced grass swales into sustainable functional design in an underutilized space, now named the 'Bentway' under Toronto's Gardiner Expressway. This allowed for dual functioning of a public recreational area and suitable stormwater management. Read more by clicking the button above.

This report by CVC highlights how the CA (per its mandate) and its member municipalities approached the construction of an addition to the CVC head office as an opportunity to showcase a green building that effectively manages water resources on the site in keeping with the Credit River Water Management Strategy. The report goes over how CVC created the new construction as a demonstration site that showcased LID practices within a typical commercial office setting. It also allowed the CA the opportunity to ‘learn by doing’ and closely monitor the performance and maintenance of LID practices and communicated the ways to improve the design, installation and management of LID features. Monitoring found that all LID practices (Permeable pavements, Grass swales, and a Rainwater harvesting system) at CVC's Head Office reduces the runoff volume of rain events by 63%. This is an improvement from typical parking lots where the majority of runoff travels directly into the storm sewers and into our streams and Lake Ontario. The site also removes 81% of total suspended solids. Learn mroe about this work by clickign the button above.

This report by TRCA highlights the use of the Treatment Train Approach at Bill Crothers Secondary built back in 2008. The site used to a golf course and was located partially in the Rouge Watershed's floodplain. During the planning process for the school several low impact developments were identified to be used on site that included, Bioretention areas, Enhanced swales, Constructed Wetlands and Rainwater harvesting. To learn more about the design process for the school click the button above.

This report by TRCA highlights the multiple LID installations located at Edwards Gardens, a botanical garden located at 777 Lawrence Avenue East in Toronto, Ontario and owned by the city. The retrofit of the Edwards Gardens parking lot introduces several new technologies to add to the existing Low Impact Development (LID) practices onsite – an extensive Green roof and a Rainwater harvesting system, along with Bioretention, Permeable pavement, Infiltration trenches, Exfiltration trenches, and Swales. The stormwater management benefits of the LID practices implemented onsite help to improve the quality and reduce the volume of runoff discharging to Wilket Creek, nearby. To read more about the various LID practices at Edwards Gardens and their performance, click the button above.

Read more about Swales, Enhanced swales, Enhanced grass swales here.

Green Roofs / Blue Roofs

This report by TRCA discusses the various Low Impact Development (LID) technologies used in key areas of interest throughout UOIT's campus (located in Oshawa, ON.), to both mitigate the impacts of the development and to green the campus. The processes are transparent to the campus community providing valuable visible lessons for students and faculty. The LID technologies used include Bioretention, linear Wetlands, Green roofs and Rainwater harvesting, all designed to reduce runoff volumes and pollutant loads to the adjacent ravine. Read more about the campus' design by clicking the button above.

This report by TRCA highlights the multiple LID installations located at Edwards Gardens, a botanical garden located at 777 Lawrence Avenue East in Toronto, Ontario and owned by the city. The retrofit of the Edwards Gardens parking lot introduces several new technologies to add to the existing Low Impact Development (LID) practices onsite – an extensive Green roof and a Rainwater harvesting system, along with Bioretention, Permeable pavement, Infiltration trenches, Exfiltration trenches, and Swales. The stormwater management benefits of the LID practices implemented onsite help to improve the quality and reduce the volume of runoff discharging to Wilket Creek, nearby. To read more about the various LID practices at Edwards Gardens and their performance, click the button above.

This brief by CVC talks about the benefits of Blue roofs and how they are emerging as a recognized as an innovative rooftop stormwater management solution that provides flood protection and drought resistance. Instead of quickly conveying stormwater away from a property, blue roof systems temporarily capture rainwater until it either evaporates from the rooftop, is sent to rainwater harvesting storage tanks. The CVC head office Building A is typical of most flat roof buildings across North America. In July 2020, Intact awarded the CVC a Climate Action Grant to pilot a Smart Blue Roof system on-site to evaluate real world performance and scalability in a Canadian context. Piloting and monitoring a smart blue roof system at the CVC office begins the summer of 2022.

This three-year study, initiated in 2003, evaluated the hydrologic, water quality and biodiversity benefits of a green roof located on a multi-story building at York University in Toronto, Ontario. The performance of the green roof was compared to a conventional (control) roof through water quantity and quality analysis and hydrologic modelling. A biodiversity assessment conducted investigated flora, birds and bees on the green roof. Continuous precipitation and runoff data collected over 18 months (excluding winter) indicated that the green roof discharged 63% less runoff than the adjacent control roof. Flora monitoring showed that despite the fact that the original green roof seed mix was primarily non-native, its low-nutrient, low-competition environment would be conducive to the establishment of conservative or rare native plants of concern. To learn more about the overall performance and biodiversity benefits of this installation over this multi-year study, click the button above.

Read more about Green roofs & Blue roofs here.

Rainwater Harvesting

This report by TRCA discusses the various Low Impact Development (LID) technologies used in key areas of interest throughout UOIT's campus (located in Oshawa, ON.), to both mitigate the impacts of the development and to green the campus. The processes are transparent to the campus community providing valuable visible lessons for students and faculty. The LID technologies used include Bioretention, linear Wetlands, Green roofs and Rainwater harvesting, all designed to reduce runoff volumes and pollutant loads to the adjacent ravine. Read more about the campus' design by clicking the button above.

This report by CVC highlights how the CA (per its mandate) and its member municipalities approached the construction of an addition to the CVC head office as an opportunity to showcase a green building that effectively manages water resources on the site in keeping with the Credit River Water Management Strategy. The report goes over how CVC created the new construction as a demonstration site that showcased LID practices within a typical commercial office setting. It also allowed the CA the opportunity to ‘learn by doing’ and closely monitor the performance and maintenance of LID practices and communicated the ways to improve the design, installation and management of LID features. Monitoring found that all LID practices (Permeable pavements, Grass swales, and a Rainwater harvesting system) at CVC's Head Office reduces the runoff volume of rain events by 63%. This is an improvement from typical parking lots where the majority of runoff travels directly into the storm sewers and into our streams and Lake Ontario. The site also removes 81% of total suspended solids. Learn mroe about this work by clickign the button above.

This report by TRCA highlights the use of the Treatment Train Approach at Bill Crothers Secondary built back in 2008. The site used to a golf course and was located partially in the Rouge Watershed's floodplain. During the planning process for the school several low impact developments were identified to be used on site that included, Bioretention areas, Enhanced swales, Constructed Wetlands and Rainwater harvesting. To learn more about the design process for the school click the button above.

This report by TRCA highlights the multiple LID installations located at Edwards Gardens, a botanical garden located at 777 Lawrence Avenue East in Toronto, Ontario and owned by the city. The retrofit of the Edwards Gardens parking lot introduces several new technologies to add to the existing Low Impact Development (LID) practices onsite – an extensive Green roof and a Rainwater harvesting system, along with Bioretention, Permeable pavement, Infiltration trenches, Exfiltration trenches, and Swales. The stormwater management benefits of the LID practices implemented onsite help to improve the quality and reduce the volume of runoff discharging to Wilket Creek, nearby. To read more about the various LID practices at Edwards Gardens and their performance, click the button above.

This report by TRCA evaluates the effectiveness of a rainwater treatment system that is not only capable of:

• removing chemical and microbiological contaminants,
• providing safe, treated water at all points of use in the system, and
• providing enough water to meet household demands immediately when it is needed

But, that apply the use of an ozone-based water treatment and disinfection system to render rainwater potable when collected through domestic rainwater harvesting systems. Click the button above for the technical brief to see the comparisons of using ozone, UV radiation and chlorine as effective disinfectant and see which one is best.

This report by TRCA evaluates the performance of stormwater source control practices retrofitted into an industrial-commercial lot located in a densely-developed portion of Toronto that drains to the Malvern Branch of Highland Creek. The rainwater cistern and landscape irrigation system, Infiltration trench and three soakaway ponds. Performance parameters examined were runoff volume reduction, rainwater use/municipal water conservation, pond drainage rate and frequency and cause of overflows. Results show that the rainwater cistern/irrigation system and soakaway ponds/infiltration trench systems reduced runoff volume from their roof drainage areas by 64% and 89% respectively over the summer to fall 2015 evaluation period. Read more about these results and the subsequent recommendations for future designs and further research are provided in the report by clicking the button above.

Read more about Rainwater harvesting here.

Vegetated Filter Strips

Creekside Crossing is a communal centre in a heavily urbanized area of Mississauga. Due to extensive development in the area, several Low Impact Development (LID) practices were constructed on site. All combined, the LIDs were able to fulfill the requirement of the TTRCA's water balance objective of retaining runoff from a 10 mm rain event onsite (usually set at 5 mm, but due to the rehabilitation work was completed in a floodplain this objective was increased twofold. The LIDs, which include Bioretention areas, Soakaways/Infiltration galleries, Vegetated filter strips and Permeable pavement, achieve the water balance objective through attenuation/infiltration and evapotranspiration. To read more about this site and the performance of the LIDs mentioned, click on the button above.

The Unitarian Congregation in Mississauga (UCM) is located on South Service Road within the Cooksville Creek Watershed. that drains into Lake Ontario. The site sits on sandy soils, which are ideal conditions for low impact development practices that infiltrate stormwater. A large Bioretention cell was constructed in the center of the parking lot. The bioretention cell filters and absorbs rainwater running off the parking lot. The bioretention cell is also landscaped with many native plants that create habitat for the numerous bird and insect species on the site. Filter strips, were added a year after construction of the site, which successfully stabilized the edge and eliminated most of the erosion issues occurring around the edge of the bioretention facility.

Read more about Vegetated filter strips here.

Dry Ponds

The University of Toronto (Scarborough Campus) - UTSC, has been growing steadily over the past decades from 2011 - 2015 alone, campus growth has resulted in nearly 60,000 m2 of new buildings. To minimize the impact on the environment and managing increased stormwater runoff were important considerations that the university wanted to address. As a result, the East Arrival Court (EAC) retrofit, which captures stormwater in the Bioretention area of the parking lot and in the nearby Dry pond, which provides temporary storage, and greater opportunities for infiltration and evapotranspiration were installed to help to improve the quality and reduce the volume of runoff discharging to the nearby Rouge River. To read more about this project click the button above.

Read more about Dry ponds here.

Salt Management

STEP released a technical brief on the alternatives to municipalities across Canada using salt as their primary deicer agent in winter, which has significant impacts (corrosion of infrastructure and other metal structures such as railings and doorways; damage to vehicles; contamination of surface and groundwater; impacts to roadside vegetation; increased wildlife collision rates; and large amounts of product waste due to blowing or bouncing off roadways). Numerous alternatives were tested to see what could feasibly replace the overreliance on rock salt which at a high-level include: chloride deicers, acetate deicers, and agricultural by-products (organics). To read more about the benefits, drawbacks, cost estimates and lowest working temperature for a given deicing agent, click the button above.

LSRCA staff highlight in this brief about some BMPs have been developed specifically for winter maintenance in parking lots. Along with recommendations around the proper use and calibration of equipment, many of these practices relate to plowing the lot and walkways before applying salt, and applying the recommended amount of salt for the conditions. Several studies have been conducted, by industry and academia, to determine what the “right” amount is, and, while “proper” application can vary depending on temperature and conditions. This report talks about main considerations contractors face in maintaining parking lots in winter:

• what application rate should be used?
• what is the level of service expected by the client, for which the bare pavement return time is a common measure?

In order to better understand these questions; in 2017 the LSRCA obtained a friction tester, with a goal of quantifying the effectiveness of various practices and salt application rates. LSRCA’s friction testing showed that bare pavement is safest, as it has the highest friction value, and that the over-application of salt does not translate to safer conditions. Read more about this study by clicking the button above.

STEP released a best practices document for winter maintenance contracts for private businesses to help reduce over-salting and ensuring that salt is applied responsibly on parking lots and walkways. The document highlights how an easy way to do this is by ensuring that businesses' snow and ice maintenance contract includes provisions requesting that industry best practices be employed and operators are adequately trained. Furthermore contracts should request evidence of knowledgeable contractor and property management staff, requiring training and certification through the Ontario Smart about Salt Program. Read more about how these BMPs can help protect the local environment and businesses' money and prevent damage to building infrastructure, by clicking above.

CVC developed a technical brief exploring the efficacy of the use of sand for winter maintenance, its associated environmental issues, and where its use is most appropriate. Sand although a known and regularly used alternative in some jurisdictions, tends to have additional costs and limited effectiveness when compared to rock salt. To read about these costs, effectiveness concerns and additional environmental impacts click the button above.

Read more about Salt management here.

Construction Considerations

CVC, back in 2014 developed a document aimed at contractors, whose clients (municipalities) are facing many stormwater challenges, including aging and deficient infrastructure, frequent extreme weather, flash flooding, and degrading water quality. Municipalities are relying on stormwater management ponds for flood control and water quality treatment, but they are consistently looking at Low Impact Development (LID) as a way to shore up their stormwater management strategy. This document and CVC’s, LID Construction Guide are a great way for contractors to understand what Municipalities are looking for who want to implement well designed and well-performing LID installations. Click the button above to learn more.

CVC, back in 2014 developed another document aimed at designers, consulting engineers, municipalities, landowners and inspectors. This document and CVC’s, LID Construction Guide will allow you to be able to:

• Minimize challenges/issues during the plan review and permitting process
• Minimize additional site visits to review and correct deficiencies
• Minimize costly and time consuming repairs
• Minimize unnecessary maintenance over the long term
• Minimize complaints from the public

When this case study document is used with the above Contractors document, the Wiki and former SWM guidance documents, you can gain a comprehensive understanding of how to ensure an LID project is successful through design, tender, construction, and commissioning. Click the button above to learn more.

Technical brief by STEP discussing the current problem with urban stormwater management and how "A Made in Ontario Solution" utilizing the Drainage Act. This solution is being tested by CVC, with funding support from the Federation of Canadian Municipalities (FCM), by implementing at source, low impact development (LID) stormwater infrastructure on private lands using property aggregation and a communal design, build and maintenance approach. read more by clicking the button above.

Read more about Construction Considerations here.

Sustainable Technologies Evaluation Program

Low Impact Development. A stormwater management strategy that seeks to mitigate the impacts of increased urban runoff and stormwater pollution by managing it as close to its source as possible. It comprises a set of site design approaches and small scale stormwater management practices that promote the use of natural systems for infiltration and evapotranspiration, and rainwater harvesting.

Best management practice. State of the art methods or techniques used to manage the quantity and improve the quality of wet weather flow. BMPs include: source, conveyance and end-of-pipe controls.

A shallow excavated surface depression containing prepared filter media, mulch, and planted with selected vegetation.

Toronto and Region Conservation Authority

A stormwater management strategy that seeks to mitigate the impacts of increased urban runoff and stormwater pollution by managing it as close to its source as possible. It comprises a set of site design approaches and small scale stormwater management practices that promote the use of natural systems for infiltration and evapotranspiration, and rainwater harvesting.

A shallow excavated surface depression containing prepared filter media, mulch, and planted with selected vegetation.

Credit Valley Conservation

The portion of water precipitated onto a catchment area, which then flows as surface discharge from the catchment area past a specified point.

Water from rain, snow melt, or irrigation that flows over the land surface.

A mixture of mineral aggregates bound with bituminous materials, used in the construction and maintenance of paved surfaces.

The technique of removing pollutants from runoff as it infiltrates through the soil.

A hard surface area (e.g., road, parking area or rooftop) that prevents or retards the infiltration of water into the soil.

Natural vegetation and vegetative technologies in urban settings such as: urban forests; green roofs; green walls; green spaces; rain gardens; bioswales; community gardens; natural and engineered wetlands and stormwater management ponds; and porous pavement systems. These systems are designed to provide multiple benefits, such as moderate temperatures, clean air and water, and improve aesthetics.

Low impact development is a stormwater management and land development strategy applied at the parcel and subdivision scale that emphasizes conservation and use of on-site natural features integrated with engineered, small scale hydrologic controls to more closely mimic pre-development hydrologic functions.

A stormwater management strategy that seeks to mitigate the impacts of increased urban runoff and stormwater pollution by managing it as close to its source as possible. It comprises a set of site design approaches and small scale stormwater management practices that promote the use of natural systems for infiltration and evapotranspiration, and rainwater harvesting.

The drainage area of a river.

An area of land that drains into a river or a lake. The boundary of a watershed is based on the elevation (natural contours) of a landscape.

The area adjacent to a stream that is, on average, inundated once a century

Mineral particles which are smaller than 2 mm, and which are free of appreciable quantities of clay and silt. Coarse sand usually designates sand grains with particle size between 0.2 and 0.02 mm.

The engineered soil component of bioretention cell or dry swale designs, typically with a high rate of infiltration and designed to retain contaminants through filtration and adsorption to particles.

The accounting of inflow and outflow of water in a system according to the components of the hydrologic cycle.

Reduction of peak flow and increase of the duration of the flow event.

The quantity of water transpired (given off). Retained in plant tissues, and evaporated from plant tissues and surrounding soil surfaces. Quantitatively it is usually expressed in terms of depth of water per unit area during a specified period. e.g. mm/day

The combined loss of water to the atmosphere from land and water surfaces by evaporation and from plants by transpiration.

Refers to the conditions in which an organism lives and survives or the conditions in which an organism resides. These conditions can be described as aspects of a “physical”, “social” or an “economic” environment, depending on the perspective perceived by the observer.

A long narrow trench or furrow dug in the ground, as for irrigation, drainage, or a boundary line.

An alternative practice to traditional impervious pavement, prevents the generation of runoff by allowing precipitation falling on the surface to infiltrate through the surface course into an underlying stone reservoir and, where suitable conditions exist, into the native soil.

The drainage area of one or more contributing watercourses to a river.

A body of water smaller than a lake, often artificially formed.

Refers to the conditions in which an organism lives and survives or the conditions in which an organism resides. These conditions can be described as aspects of a “physical”, “social” or an “economic” environment, depending on the perspective perceived by the observer.

Surface runoff from at-grade surfaces, resulting from rain or snowmelt events.

Defined as those plants (including grasses, herbaceous species, shrubs, vines and trees) that have historically existed within a particular area. Native plants have co-evolved with the local ecosystems and natural processes.

An alternative practice to traditional impervious pavement, prevents the generation of runoff by allowing precipitation falling on the surface to infiltrate through the surface course into an underlying stone reservoir and, where suitable conditions exist, into the native soil.

The total mass of a pollutant entering a waterbody over a defined time period.

The net amount of something (e.g. chemical, such as phosphorus), calculated as the product of concentration and volume in a given time. Some BMPs significantly reduce loading of pollutants to the environment by reducing volume more so than concentration.

Total suspended solids

refers to the characteristics and functions of a system prior to urban development.

A vegetated area such as a bog, fen, marsh, or swamp, where the soil or root zone is saturated for part of the year.

Relating to the properties, distribution and effects of water on and below the earth’s surface, and in the atmosphere.

The changing of land cover and land uses from rural to urban; the growth of urban settlements.

Stormwater management following the hierarchical approach: Source Control measures, Conveyance Control measure and End of Pipe treatment to achieve the water quality and water balance target for lot level development of the preferred strategy.

A combination of lot level, conveyance, and end-of-pipe stormwater management practices.

A lot level bioretention cell designed to receive and detain, infiltrate and filter runoff, typically used for discharge from downspouts.

A perforated pipe used to assist the draining of soils.

Stormwater Management

Linear bioretention cell designed to convey, treat and attenuate stormwater runoff. The engineered filter media soil mixture and vegetation slows the runoff water to allow sedimentation, filtration through the root zone, evapotranspiration, and infiltration into the underlying native soil.

A road on which traffic movement and access to property have similar importance.

A shallow constructed channel, often grass-lined, which is used as an alternative to curb and channel, or as a pretreatment to other measures. Swales are generally characterized by a broad top width to depth ratio and gentle grades.

A shallow constructed channel, often grass-lined, which is used as an alternative to curb and channel, or as a pretreatment to other measures. Swales are generally characterized by a broad top width to depth ratio and gentle grades.

A shallow constructed channel, often grass-lined, which is used as an alternative to curb and channel, or as a pretreatment to other measures. Swales are generally characterized by a broad top width to depth ratio and gentle grades.

A bioretention BMP featuring an impermeable liner and underdrain that prevents infiltration of runoff into the underlying native soil; provides sedimentation and filtration of urban runoff as it passes through the mulch layer, engineered filter media and vegetation root zone.

A bioretention cell that features an impermeable liner that collects and treats stormwater through sedimentation and filtration only (i.e., no infiltration).

The portion of water precipitated onto a catchment area, which then flows as surface discharge from the catchment area past a specified point.

Water from rain, snow melt, or irrigation that flows over the land surface.

The total mass of a pollutant entering a waterbody over a defined time period.

Linear bioretention cell designed to convey, treat and attenuate stormwater runoff. The engineered filter media soil mixture and vegetation slows the runoff water to allow sedimentation, filtration through the root zone, evapotranspiration, and infiltration into the underlying native soil.

Ground depression acting as a flow control and water treatment structure, that is normally dry.

The downward movement of water through the soil, the downward flow of runoff from the bottom of an infiltration BMP into the soil.

Loss of water from a drainage system as a result of percolation or absorption into the surrounding medium (e.g., the infiltration of water into the native soil through a perforated pipe wall as it is conveyed).

The practice of intercepting, conveying and storing rainwater for future use. Captured rainwater is typically used for outdoor non-potable water uses such as irrigation, or in the building to flush toilets.

A thin layer of vegetation and growing medium installed on top of a conventional flat or sloped roof, also referred to as living roofs or rooftop gardens.

Any form of rain or snow.

A practice or structural measure that is usually implemented at the beginning of a drainage system or at the lot level, to reduce the volume of runoff and minimize the concentration of pollution in overland flow from private property and prevent pollutants from entering Stormwater runoff or other environmental media, as described by the Ministry of Environment.

Tank used to store rainwater (typically roof runoff) for later use.

Human application of water to agricultural or recreational land for watering purposes. City of Toronto Wet Weather Flow Management November 2006 47

An underground water storage reservoir into which stormwater is directed and allowed to percolate into the underlying native subsoil.

An excavated area lined with geotextile filter cloth and filled with clean granular stone or other void forming material, that receives runoff and allow it to infiltrate into the native soil; can also be referred to as infiltration galleries, French drains, dry wells or soakaway pits.

Reduction in applied water due to more efficient water use such as implementation of Urban Best Management Practices or Agricultural Efficient Water Management Practices. The extent to which these actions actually create a savings in water supply depends on how they affect net water use and depletion.

The water below the surface, and typically below the groundwater table.

Lake Simcoe Region Conservation Authority

Mineral particles which are smaller than 2 mm, and which are free of appreciable quantities of clay and silt. Coarse sand usually designates sand grains with particle size between 0.2 and 0.02 mm.