Innisfil Drain Winding Through Fields
Innisfil Drain Winding Through Fields

South Innisfil Creek Drain

Drainage Engineering Services

Designing an ecological municipal drainage system that is a Drain Done Differently.



Town of Innisfil


Innisfil, Ontario

Key Team Members

Chris Pfohl, C.E.T., EP, CAN-CISEC

Innisfil Drain Winding Through Fields

Project Story

The South Innisfil Creek Drain (SICD) is a Municipal Drain established by the Town of Innisfil (Town) through the authority of a by-law created under the Drainage Act (Act). This project presented several challenges that Burnside saw as opportunities to design an ecological drainage system that can be considered a Drain Done Differently.

Please refer to our Municipal Drainage Services page and the Ontario Government’s Municipal Drains page for more details on Municipal Drains, the Drainage Act, and how they relate to this project.

The SICD was first established in 1903. In the 1950s, several branches were added to the system and improvements were also made to the main drain. The SICD is currently being improved through a Municipal by-law adopting a Report authored by Burnside, a copy of which can be found here.

The SICD (see map) has a contributing watershed of over 80 square kilometres that features about 900 properties and serves lands and roads in the southwest portion of the Town, as well as in the northern portion of Bradford West Gwillimbury. The outlet for the 10 km SICD Main Drain is a natural watercourse known as Innisfil Creek – a 44 km tributary of the Nottawasaga River – which enters the Nottawasaga River near Alliston about 80 km from its final outlet into Nottawasaga Bay at Wasaga Beach. Innisfil Creek is the outlet for almost 150 km of Municipal Drains and has a catchment area of approximately 480 square kilometres.

Important challenges and opportunities for the SICD project included:

  • Flooding: Past flooding events caused almost $1M in damages to properties and resulted in legal challenges. One of the outcomes of the legal challenges was an order for the Town to make improvements to the SICD that would address the flooding concerns of the property owners in the affected area.
  • Regulatory Approvals: The proposed improvements had the potential to impact various environmental and social resources. Therefore, before physical changes to the SICD could be made, approvals were required from Fisheries and Oceans Canada (DFO), the Nottawasaga Valley Conservation Authority (NVCA), the Ministry of Transportation (MTO), the Ministry of Natural Resources and Forestry (MNRF), and the Ministry of the Environment, Conservation and Parks (MECP).
  • Highway 400: The existing crossing was too small and too high where the SICD passes under Highway 400, limiting flow capacity and acting as a barrier to fish passage. A major component of the project was to coordinate improvements (i.e., lowering and enlarging) to this crossing under Highway 400.
  • Appeals: The Act process provides property owners with various rights of appeal. There were 25 appeals on assessments filed to the municipal Court of Revision and a further seven appeals filed with the Agriculture, Food and Rural Affairs Appeal Tribunal.

The SICD is considered to be a “Drain Done Differently” for the following important reasons:

  • Public Liaison Committee (PLC): A relatively unique aspect of this project was the establishment of a PLC, comprised of representatives of the Town, the Agencies, Burnside, and property owners affected by the SICD. The purpose of the PLC was to identify and address issues as quickly as possible.
  • Public Information Centre (PIC): Prior to filing the Engineer’s Report, all potentially affected landowners and Utility Companies within the watershed were invited to attend a PIC. The Open House format of the PIC allowed all stakeholders to receive an update on the project status and offered them an opportunity to ask questions and provide input.
  • Ecological Enhancements and Improvements: A significant component of the SICD project is the design and implementation of extensive ecological enhancements and improvements, as summarized in the following bulletins:
  • Baseline eDNA: Precision Biomonitoring Inc. (now part of NatureMetrics & SQI Diagnostics) was engaged to conduct and establish complete baseline eDNA testing at strategic locations along the 10 km Main Drain, believed to be the first time this technology was used as part of a Municipal Drain project. This technique identifies the species found in the surrounding environment from the DNA in the cellular material shed by organisms and allows for testing to be realized without having to attempt to visually observe each species present and/or sample the actual organism/species itself. It is hoped that this testing will provide better quality data to support the five-year monitoring program required by DFO.
  • Monitoring and Reporting: In addition to requirements from DFO, there will also be ongoing monitoring and reporting in regard to various aquatic and terrestrial species.
  • Hydrology and Hydraulics Reports: The NVCA was actively engaged in the project, including reviewing and providing feedback on the Hydrology and Hydraulics Reports. They also reviewed the SICD design, specifically the geometry of the two-stage design and proposed Main Drain cross-section.

OSPE Land Drainage Committee



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On behalf of R.J. Burnside & Associates Limited and with the generous funding of the Ontario Ministry of Agriculture, Food, and Rural Affairs – OMAFRA – we bring you this story about a “Drain Done Differently,” an innovative drainage project in the Town of Innisfil that is intended to reduce future flooding events and improve drain water quality for its residents and stakeholders.

Ontario has countless municipal drains – constructed under the Drainage Act since the early 1800s – which, simply put, are systems that help improve the drainage of primarily agricultural properties.

The South Innisfil Creek Drain – or SICD – is a municipal drain that has existed since 1903, spanning a length of 10 kilometres and a watershed area of over 80 square kilometres. In all, the SICD helps to collect and convey runoff from about 900 properties, so it is critical that it performs as intended.

In addition, the SICD is a part of the headwaters of the Nottawasaga River, which ultimately flows into Georgian Bay at Wasaga Beach, the longest freshwater beach in the world and a location with Blue Flag ecological status from the Foundation for Environmental Education.

Like any built infrastructure, the SICD’s performance had declined over time, and it was considered one of the most degraded portions of the Nottawasaga River, according to Nottawasaga Valley Conservation Authority (NVCA) staff. As such, it was critical for the SICD to be improved to address not only the quality of water discharged through it, but also the quantity of water that it could handle.

In 2016, Burnside was retained by the Town to complete an Engineer’s Report for a series of improvements to the SICD.  Key recommendations from the report included:

Extend the SICD downstream, approximately 500 metres south of Highway 89.

Improve approximately 10 km of the Main Drain for free flow conveyance of a two-year storm event plus freeboard.

Improve the crossings under Hwy. 400 & Reive Blvd.

Improve approximately 4.5 km of four Branch Drains.

Following adoption of this report by Town Council in 2019, Burnside was then retained to tender and complete the construction of the report’s recommendations.”

“The project team understood the unique challenges that the SICD presented, and the team wanted to address these challenges with correspondingly unique and innovative solutions. In short, the SICD would become a Drain Done Differently.The first unique innovation was the construction of a two-stage drain, rather than the usual trapezoidal design common to most municipal drains. The two-stage solution was chosen for its ability to better mimic the structure of a natural channel, as well as its ability to produce faster flow velocities in the low flow portion which improves water quality via reduced sediment deposition and provides better aquatic habitat. Furthermore, a cleaner drain allows for more volume to flow through, requires less drain maintenance for stakeholders and saves costs.

Additionally, a two-stage drain is more stable, thanks to its ability to distribute larger flow events such as spring runoff, storm events and overland flooding over its wider vegetated floodplain bench which acts as a natural filter strip. This bench slows down the flow velocity, allows for sediment deposition out of the low flow portion, and provides nutrients for vegetation growth, shade cover and habitat.

Approximately 20 locations along the SICD benefited from the development of Woody Material Structures, which helped to improve flow conditions, stabilize drain banks, reduce sediment deposition, and provide species habitat.

The structures were built by taking existing woody material that had created flow blockages in the drain, supplementing it with woody material cut and salvaged on-site, adding additional material such as rip rap and sod mats to provide ballast and vegetation coverage, and securing the structures to the drain bank with sharpened wood pieces to act as stakes or pins installed by an excavator. The result is a natural looking bank that is stable, permits undisturbed flow, and is a prime habitat for local species.

One unique innovation was dubbed the “leaky berm,” a perforated organic barrier built to permit water to flow through it to support a backwater habitat refuge.

Organic debris and sediment had built up in a 90-degree bend in the drain, clogging and disrupting the low flow portion. As a result, this blockage had created a backwater area that had become a habitat for several species in the area.

The desire to protect this habitat while restoring proper flow in the SICD gave rise to the ‘leaky berm,’ built with woody materials and sod mats, and anchored in place using long cedar pins placed with an excavator. This solution was innovative in that nothing was sacrificed – species habitat was maintained, and the low flow portion was reinstated to match the pre-improvement condition.

Two other unique drain improvement features were the creation of an offset wetland in an existing oxbow off the main drain, and the stabilization of a severely eroded drain bank while protecting and retaining a bank swallow nesting habitat.

The entire Burnside team would like to thank OMAFRA for funding the promotion of the success of the SICD, as well as the NVCA for their support and collaboration throughout the project.

Special thanks also go out Town Staff and Council, the watershed community stakeholders, and notably R&D Excavating LTD, who did outstanding work in constructing the designed improvements to the drain.

Please visit for more details on this important green infrastructure project, one that is truly a Drain Done Differently.

Innisfil Drain Winding Through Fields
Chris Pfohl Headshot

Chris Pfohl, C.E.T., EP, CAN-CISEC

Senior Aquatic Ecologist

Project Contact

We encourage you to contact us if you have any questions or require assistance.