LID Case Studies

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 new projects wrap up and 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, several of these documents will appear several times throughout this page as many have information on multiple LIDs' performance.

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 paver 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 by CVC 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 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 i nthe 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 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 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.

Stormwater Tree Trenches

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 trench system (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.

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.

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.

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.

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.

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.

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

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

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.

Total suspended solids

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

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