Rural Stormwater

Managing stormwater better to protect water quality

Slow down the water. Hold back the water. Soak it in.

When storms happen in rural areas, water runs off of land, and management practices and projects are needed to slow that water down, filter it, and store it. 

Improved management measures help to preserve topsoil and nutrients and keep them on the land where they're needed, to limit erosion, and to reduce impacts on creeks, rivers, groundwater, and Lake Huron.

A new computer model helps to better understand and manage this stormwater runoff. 

New computer modelling tool created to find projects and practices that work best, in the right places, at the right scale to protect water quality; improved long-term monitoring; project implementation and evaluation 

The work of the Healthy Lake Huron: Clean Water, Clean Beaches Partnership has created the Rural Stormwater Management Model (RSWMM),  innovative new modelling software technology for a largely rural area, which stretches from Sarnia to Tobermory.

This Healthy Lake Huron project increased long-term monitoring and introduced five new or expanded monitoring stations (for water quality, water quantity, and weather) in five priority areas or sentinel sub-watersheds along Lake Huron’s southeast shores.

These key areas are beacons. They are places for long-term monitoring and research, community watershed planning, and project implementation and evaluation - with lessons learned that can be applied along the rest of Lake Huron's southeast shore.

Rural Stormwater Management Model (RSWMM)

The improved Rural Stormwater Management modeling software builds upon PCSWMM, which is a spatial decision support system for SWMM5, one of the most widely-used models developed and maintained by the United States Environmental Protection Agency (EPA).

Where can I get the model?

How is this new rural model different from other models?

Stormwater models are common in urban areas but some models have been limited when they tried to represent the movement of water runoff in rural areas. The new Rural Stormwater Management Model (RSWMM) technology is designed to work in rural areas while still maintaining the means to model urban areas as well.

How is the new RSWMM model different from current, largely urban modelling of stormwater?

 Before RSWMM, no current model package had urban modelling features, plus:

  • Tracking of key pollutants (sediment, phosphorus, and nitrogen);
  • Best management practices including agricultural BMPs, plus:
  • Seasonality in parameterization (for example, changes in crop cover), plus:
  • Modelling of roads, ditches, and small hydraulics (for example, under-the-road culverts), plus:
  • In-stream treatment processes (such as erosion, deposition – is there an open channel? Pipe? What is slope? Is terrain rough?), plus:
  • Dynamic-wave equation (capturing a range, from low to high – such as the ups and downs, highs and lows, rises and flows, of water travelling through a channel), plus:
  • Ongoing technical support

An urban model might look at an area with roads and houses that may not change very much. A rural property may have many different things going on at one site. The way stormwater runoff acts may differ depending on the season or even with a season.

The new model combines urban modeling features with rural features such as agricultural best management practices; understanding of changes from season to season or even within a season (such as changes in crop cover); modeling of roads, ditches, and culverts; slope and terrain types; dynamic travel of water running over land; tracking of key pollutants (sediment, phosphorus and nitrogen); and other features. 

Comparison of Features of Different Stormwater Management Models 


SOURCE: Adapted from presentation slide – EOR Water, Ecology, Community – Model Comparisons 

Computer modelling applications are common in urban areas, and some existing models have some rural features, but no current model has all the features needed for rural areas.

The Rural Stormwater Management Model (RSWMM) may be a useful addition to the suite of tools your staff use.

The technology was designed for use along Lake Huron’s southeast shoreline in Ontario but has the potential to be adopted and used in other locations of Canada and the United States.

What are the successes of this project to date?

Healthy Lake Huron’s rural stormwater management project has:

  • Created five new or upgraded monitoring stations to improve long-term monitoring of water quality, water quantity and weather in five sentinel watersheds, identified as priority areas along Lake Huron’s southeast shore.
  • Created a powerful new tool for strategic decision-making by landowners and community groups working with watershed resource managers and drainage engineers.
  • Increased public awareness of the need for, and ways to, better manage water running off of land during storm events.

Stewardship funding is limited. It needs to be invested strategically with the best and most detailed information possible. We need to identify the projects that work best, put them in the locations where they can do the most good, and construct them at the scale that will be most effective.

This new rural model, with funding support from the Province of Ontario’s Showcasing Water Innovation Program, helps to find ways to undertake projects where they will have the greatest benefit to conserve soil and protect water.

The project has also led to increased environmental expertise and capacity in rural Ontario.

Who created the model?

Healthy Lake Huron: Clean Water, Clean Beaches is a partnership that includes all levels of government, local public health and conservation, and landowners and community groups. The partnership works to keep this Great Lake great by protecting and improving water quality along Lake Huron’s southeast shoreline in an area stretching from Sarnia to Tobermory.

Ausable Bayfield Conservation Authority (ABCA) led the Rural Stormwater Management Model project (2011-2014) in partnership with Maitland Valley, St. Clair Region, Saugeen Valley, and Grey Sauble conservation authorities and other partners including the Healthy Lake Huron: Clean Water, Clean Beaches (Lake Huron Southeast Shores) initiative, an inter-agency partnership. Project partners include provincial and federal ministries, county departments, health units, environmental agencies, and landowners. The partners completed the new rural model project between 2012 and 2014.

Ausable Bayfield Conservation and Healthy Lake Huron worked on the RSWMM development with Emmons & Olivier Resources, Inc., an engineering and environmental consulting firm that specializes in water resources, watershed planning, and modeling; and Computational Hydraulics International (CHI), consultant in stormwater management, wastewater and watershed modeling software.

The project shows a collaborative integrated watershed management model in action through the pooling of resources and the sharing of information.

The Ontario Ministry of the Environment (now the Ontario Ministry of the Environment and Climate Change) announced, on December 20, 2011, a Showcasing Water Innovation Program grant of $700,000 towards this new, and truly rural, water-quality initiative. Additional support and in-kind contributions of more than $200,000 has come from other partners.

Local government and government departments and ministries, and local public health and conservation agencies, are working together with landowners and community groups to protect the vital resource of southeastern Lake Huron, and the overall health of the watersheds draining to the lake.

 In 2010, the Lake Huron Southeast Shores Executive Steering Committee (LHSSESC), now known as Healthy Lake Huron: Clean Water, Clean Beaches, was formed by a partnership of five conservation authorities, three counties, four health units, two federal agencies, and four provincial agencies.  

Reducing the amount of nutrients (such as phosphorus and nitrogen) entering Southeast Lake Huron can help to diminish algae growth, while also potentially decreasing the levels of related pollutants such as Escherichia coli (E. coli). This could lessen risks to human health by protecting and improving water quality in Lake Huron, which is the source of raw water for drinking water for hundreds of thousands of people and is also used for fishing and recreational activities including swimming and boating.

How was the model created?

The Rural Stormwater Management Model project was funded by a $700,000 grant from the Ontario Ministry of the Environment and Climate Change’s Showcasing Water Innovation (SWI) Program and in-kind contributions from other partners. Investment has totalled more than $900,000. That investment benefits the economy, rural knowledge and capacity, and human health.

Who is using the model?

Some staff of the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) and conservation authorities in the five priority areas are testing and starting to use the model. Some consulting engineers in the drainage industry have also expressed interest in using the model.

Staff are continuing to test and use the model as funding permits. Conservation staff members are currently working with participating rural landowners to continue monitoring in priority watershed areas and to refine and test the capabilities of this RSWMM tool, integrated into PCSWMM.

Landowners are undertaking stewardship projects that reduce the chances of runoff affecting water bodies. Their support and participation is an important part of this project and their continued good work benefits water quality.

Where is the model being used?

Since completion of the rural stormwater management project, the Healthy Lake Huron: Clean Water, Clean Beaches Partnership has received funding through the Canada-Ontario Agreement (COA) on Great Lakes Water Quality and Ecosystem Health to continue to monitor in the five priority areas of Lake Huron’s southeast shore.

Those five sentinel watersheds are:

This data helps in model updates and calibration to ensure the most accurate and consistent results possible.

How is the new model being used?

Management of water running off of land during storm events can help to reduce bacteria and pathogens; sediment; and chemicals from reaching storm sewers, creeks, rivers, and drinking water sources such as Lake Huron.

Healthy Lake Huron partners have worked for the past few years to develop and use a new tool to reduce the impacts of water running off of land during storm events.

Improved monitoring and advanced modelling combine to inform the design and placement of stewardship projects and best management practices that protect and improve water quality locally.

Case Study

Download the case study, in English or French, for the Rural Stormwater Management Model RSWMM Project:  (pdf files)

Subscribe to Rural Stormwater Management Model Project Newsletter at this link:

Project Final Report – Rural Stormwater Management Model (RSWMM) Project

The project team has created a Final Report for the Rural Stormwater Management Model Project. Download this technical report now (large 6 MB PDF file) at this link:

Rural Stormwater Management Model project featured across Ontario

A Lake Huron project spearheaded by the Healthy Lake Huron partnership was one of the projects highlighted in a provincial report.

The Province of Ontario has released a final report about Ontario communities that have developed new water management tools with support of Ontario’s Showcasing Water Innovation (SWI) program. This project by Ausable Bayfield Conservation and the Healthy Lake Huron: Clean Water, Clean Beaches partnership is included in the document.

The provincial report highlights features of the stormwater management project including upgraded long-term monitoring of weather, stormwater, and water quality and quantity monitoring in five sentinel watersheds.

The new modeling software incorporates field-scale treatment and best management practices for stormwater and erosion and sediment control and compares the impacts of potential projects on water quantity and quality.

The model makes it possible for rural extension staff, working with landowners, to better evaluate, prioritize, design and implement soil and water conservation projects to protect Lake Huron.

“We are very pleased to have this new technology featured across the Province,” said Ausable Bayfield Conservation’s Water and Planning Manager Alec Scott, the project manager for Healthy Lake Huron's Rural Stormwater Management Model Project. “The model can be used to evaluate potential projects so landowners can have the best information possible when choosing which erosion and runoff control projects will work best on their properties.”

Download Showcasing Water Innovation Program Final Report now. This provincial report is now available online at:

The report shows how Ontario communities are being water technology pioneers by adding new, innovative, and cost-effective tools to protect water resources, conserve water, lower energy use, and reduce capital investment costs.

The model is not only helping with projects to benefit water quality along Lake Huron’s southeast shores. It also helps to create a rural focus for stormwater management that can be applied across the Province of Ontario and beyond.

A one-page summary of the Healthy Lake Huron rural stormwater management project is featured on page 31 of the Province of Ontario’s Showcasing Water Innovation (SWI) Program final report:

The project also appears on page 22 and on the Ontario map on page 11.

Photos from the project are included on the Table of Contents page and page 31.

The Province of Ontario noted that the development of this model was possible thanks to landowners who took part in the monitoring improvements, to the Province of Ontario’s Showcasing Water Innovation (SWI) Program, and to the public health, local conservation agencies, and governmental and community partners along Lake Huron’s southeast shoreline.

Ausable Bayfield Conservation Authority (ABCA) was lead on this water-quality project in partnership with Maitland Valley, St. Clair Region, Saugeen Valley, and Grey Sauble conservation authorities and other partners of the Healthy Lake Huron: Clean Water, Clean Beaches initiative. Project partners include provincial ministries and federal departments in Canada, counties and municipalities, conservation and public health agencies, and participating landowners and community groups.

“ABCA created a Rural Stormwater Management Model that can predict the impact of stormwater draining from rural settings, and help determine best-value actions to improve water quality,” according to the report. “Partners are using and working on improving this powerful new model as an important decision-making tool.”

Showcasing Water Innovation (SWI) is an Ontario program to demonstrate leading-edge, innovative, and cost-effective solutions for managing drinking water, stormwater and wastewater systems in Ontario communities. The program has supported 32 Ontario communities, formed 263 partnerships, undertaken 44 pilot texts and 32 new technologies, and supported seven First Nations partners and 16 university and college partners.

Due to the introduction of new capabilities, as well as to the unique and intuitive nature of the PCSWMM software, the RSWMM is a promising tool, currently being used and refined, with broad applicability in rural watersheds. The RSWMM allows watershed managers to better evaluate, prioritize, design and implement soil and water conservation projects to protect Lake Huron.

This project was undertaken with the financial support of the Ontario Ministry of the Environment and Climate Change’s Showcasing Water Innovation program and the partners of Healthy Lake Huron: Clean Water, Clean Beaches. Additional thanks are given to all private landowners for their cooperation and support of this project, especially by participating landowners for allowing property access to gather monitoring data.

Recommended next steps

Several areas for improvement were identified throughout the first phase of the Rural Stormwater Management Model project:

  • Firstly, monitoring programs should continue to collect data that can be used to improve the calibrations of the models. Of particular importance is the collection of winter precipitation data, which will aid in the crucial task of accurately calibrating to spring snowmelt runoff events.
  • Secondly, the individual models should be updated to include more detailed hydrologic and hydraulic information, where possible, and to incorporate new BMP developments on the landscape.
  • Thirdly, the process of model development should be streamlined through careful coordination among conservation authorities involved prior to future model construction. The improvements would ensure efficient data transfer between the field, the laboratory, and the modelling staff.
  • Finally, further improvements to the PCSWMM software and the RSWMM enhancements should be continually pursued. While great strides have been made toward meeting the project objectives, more robust and efficient methods related to model construction, generating and processing pollutants, and implementing BMPs should all be considered in future phases of the RSWMM project.

Why was this project needed?

The valuable new Rural Stormwater Management Model tool was needed for local rural areas to better manage stormwater runoff, to slow down water running off of land, to store that water, and to filter that runoff to improve water quality.

Changes in land use, and intensification of land use, have contributed to the loss of historical wetlands and woodlands throughout the watersheds draining to Southeast Lake Huron.

Occurrences of nuisance algae and beach closures or postings have occurred over the past decades.  These occurrences are in part caused by excessive nutrients and bacteria in the water draining to Lake Huron from private septic systems, municipal wastewater and runoff, runoff over agricultural, rural, and urban lands, among other known and unknown sources, including natural sources.

Because of the potential significant impact of urban, rural, and agricultural drainage on the health of the lake, Healthy Lake Huron identified the following five priority areas for immediate action in developing and supporting implementation of watershed management plans.

Visit the priority areas page to find out about the five sentinel or beacon watersheds:

At the time that these priority areas were identified, there was no stormwater management model for rural Ontario that fully met a set of specific criteria that had been identified for the Rural Stormwater Management Model project.

Stormwater models are frequently used in urban areas but have limitations in representing the hydrology, hydraulics, and hydrogeology in rural areas.

The Rural Stormwater Management Model (RSWMM) was developed in an effort to begin to address these limitations and maintain the capabilities of modelling urban areas.  

The RSWMM project was set out, in part, to “Develop a physically-based computer model which will help practitioners choose the location for agricultural best management practices (BMPs) or other stewardship projects in a watershed which will have the most water quantity and water quality benefits at the watershed outlet.”

Components of the project included:

  • Development of specific software for a rural stormwater management model
  • Integration into the model of more precise information such as precipitation, drainage patterns and systems, flow paths, forest cover, land uses, etc.
  • Increased monitoring through five stations in priority watersheds along the southeast shores of Lake Huron
  • Communication with landowners, public, governments, and agencies
  • Sharing model when finished for the benefit of others

Using the five priority areas as sentinel (or priority) watersheds for model development, five models were constructed in an upgraded version of PCSWMM that, in addition to the standard storm runoff flow rates and volumes, now includes the ability to simulate:

  1. The impacts of a suite of agricultural best management practices (BMPs) on both water quantity and quality
  2. Landscape loading of nitrogen, phosphorus, and sediment
  3. Nitrogen and phosphorus depletion along streams and creeks
  4. The impact on runoff from the different crop stages throughout the farming season

Groundwater hydrology and drain-tile hydraulics

Significant steps have been taken toward the following objectives for the use of the RSWMM model:

1.a) The ability to identify priority management areas within a watershed;

2.b) The ability to incorporate both field-scale and treatment BMPs; and

3.c) The ability to assess the impact of different management alternatives on water quantity and quality at any location within the modeled area.

This is a new and truly rural initiative to better understand how stormwater systems work in rural Ontario.

This leading-edge work had not previously taken place, and filled a gap in understanding the nearshore water quality of Lake Huron.

Better information will make it possible to implement improved strategic actions that protect water quality.

A fuller understanding of how stormwater moves and is managed in our rural area is valuable for farmers and other landowners, with the support of stewardship practitioners.

New information gained from this project guides landowners in managing drainage efforts to keep soil on the land. It also improves the strategic implementation of on-the-ground projects that limit runoff and the effects of water movement during a storm.

Alec Scott is Ausable Bayfield Conservation Authority (ABCA) Water and Planning Manager. He was Project Manager for the RSWMM project. The model is an exciting new tool, according to Alec.

“When combined with continued support for strategic on-the-ground water-quality projects and long-term monitoring, the model has the potential to be a valuable tool to support the work being done to protect and improve water quality in Lake Huron.”

Detailed modelling of stormwater impacts already exists for urban environments. This model is creating more understanding about how drainage works in a rural context. This increased understanding helps to effectively reduce and manage runoff by strategically investing limited stewardship dollars on the right projects in the right places. It helps stewardship practitioners, in partnership with landowners, to implement effective runoff and erosion control projects and other best management practices. The model helps people to know which projects work best to protect water quality, the best places to locate the projects, and the ideal size the projects should be.

How do I find out more?

For more information on managing water running off of land during storm events or the new model technology, visit healthylakehuron.ca and abca.on.ca or phone 519-235-2610 or toll-free 1-888-286-2610.

Rural Stormwater Management Model Project
 c/o Ausable Bayfield Conservation,
 71108 Morrison Line, RR 3 Exeter, ON • N0M 1S5
 519–235–2610 • 1–888–286–2610
 abca.on.cainfo@abca.on.ca
 Attention:  Alec Scott, Project Manager