Ausable Bayfield Conservation Authority

Rural Stormwater Management Model

Help to manage stormwater well to protect water quality
Help to manage stormwater well to protect water quality

The Rural Stormwater Management Model (RSWMM) is a new tool to reduce stormwater runoff impacts. This valuable tool was needed for rural areas to better manage stormwater, to slow runoff down, store it, and filter it to improve water quality.

Case Study

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

Case study for Rural Stormwater Management Model Project (English)

L’étude de cas - En français - Modèle Informatique pour la Gestion des Eaux Pluviales en Milieu Nouvel outil pour réduire l’impact de l’écoulement des eaux pluviales

Subscribe to Rural Stormwater Management Model Project Newsletter:

Project Final Report

Download the Final Report and Technical Report for the Rural Stormwater Management Model Project.

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

Final Report - Development of a Rural Stormwater Management Model.

Showcasing Water Innovation Program Final Report 

Project featured provincewide

Lake Huron project spearheaded by Healthy Lake Huron partnership one of projects highlighted in provincial report

Ausable Bayfield Conservation Authority (ABCA), Healthy Lake Huron: Clean Water, Clean Beaches developed new rural stormwater management modeling technology; Project featured in new Showcasing Water Innovation Final Report released by Province of Ontario

Download Showcasing Water Innovation Program Final Report now.

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

This provincial report is now available online 

MonitoringThe 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.

Ausable Bayfield Conservation Authority (ABCA) led the Healthy Lake Huron multi-partner project to develop a new Rural Stormwater Management Model (RSWMM). 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.

A one-page summary of the Healthy Lake Huron rural stormwater management project is featured on page 31 of the provincial 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. “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.”

Healthy Lake Huron is a partnership of all levels of government, public health, local conservation agencies, and landowners and community groups. The partnership works to protect and improve water quality along Lake Huron's southeast shoreline in an area stretching from Sarnia to Tobermory. The Healthy Lake Huron 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 watersheds of Lake Huron’s southeast shore. Those five sentinel watersheds are Pine River; Garvey Creek and Glenn Drain; Lambton Shores; Bayfield North; and Main Bayfield. This data is to help in model updates and calibration over the next couple of years to ensure the most accurate and consistent results possible.

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.

Alec Scott was Project Manager for the RSWMM model. “We are very pleased to have this new technology featured across the province,” he said. “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.”

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, agency, governmental, and community partners along Lake Huron’s southeast shoreline, Scott said.

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.

“The model is an exciting new tool,” Scott said. “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.” The new modeling software builds upon PCSWMM, which is described as 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). For information on PCSWMM visit

Stormwater models are common in urban areas but some models were limited when they tried to represent the movement of water runoff in rural areas. The new technology is designed to work in rural areas while still maintaining the means to model urban areas as well. Staff will continue to test and use the model as funding permits.

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. 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.

For more information on rural stormwater management or the new model technology, visit Healthy Lake Huron ( and and or phone 519-235-2610 or toll-free 1-888-286-2610.

About the Rural Stormwater Management Model (RSWMM)

When storms happen in rural areas, water runs off land, and management practices and practices are needed to slow that water down, filter it, and store it. This management can help to preserve topsoil, limit erosion, and reduce impacts on creeks, rivers, and Lake Huron.

Ausable Bayfield Conservation was lead on a 2012-2014 project by the Healthy Lake Huron: Clean Water, Clean Beaches Partnership to create a new computer model to better understand and manage this stormwater runoff. The project has created this innovative new technology in a largely rural area, stretching from Sarnia to Tobermory along Lake Huron's southeast shoreline.

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, usable tool with broad applicability in rural watersheds. Although a work in progress, the RSWMM will allow watershed managers to better evaluate, prioritize, design and implement soil and water conservation projects to protect Lake Huron.

The 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 to better manage water running off of land during storm events.

This project was undertaken with the financial support of the Ontario Ministry of the Environment and Climate Change Showcasing Water Innovation program and the partners of Healthy Lake Huron: Clean Water, Clean Beaches. Such support does not indicate endorsement by the Government of Ontario of the contents of this material.

Additional thanks are given to all private landowners for their cooperation and support of this project, especially by allowing property access to gather monitoring data.

Land use alterations have caused the loss of historical wetlands and woodlands throughout the watersheds draining to Southeast Lake Huron.  Occurrences of nuisance algae and beach closures and postings have become more frequent over the past 20 years.  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 lands, among other known and unknown sources, including natural sources.  Reducing the amount of nutrients (such as phosphorus and nitrogen) entering Southeast Lake Huron will diminish algae growth, while also potentially decreasing the levels of related pollutants such as 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.

Government ministries and local public health and conservation agencies are working together to protect property, 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 referred to 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.  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 shown in Figure 1 for immediate action in developing and supporting implementation of watershed management plans:

  • Pine River
  • Garvey-Glenn
  • Bayfield North
  • Main Bayfield
  • Lambton Shores

At the time these priority areas were identified, there was no stormwater management model for rural Ontario that fully met a set of specific criteria that have 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) has been developed in an effort to begin to address these limitations and maintain the capabilities of modelling urban areas.  The RSWMM builds upon PCSWMM, which is a spatial decision support system for US EPA SWMM5, one of the most widely-used models developed and maintained by the United States Environmental Protection Agency (EPA). 

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.” Using the five priority areas as sentinel watersheds for model development, five models have been 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 BMPs on both water quantity and quality

2.      Landscape loading of nitrogen, phosphorus, and sediment coming from farm fields

3.      Nitrogen and phosphorus depletion along streams and creeks

4.      The impact on runoff from the different crop stages throughout the farming season 

5.      Groundwater hydrology and drain-tile hydraulics

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

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

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

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

Several areas for improvement were identified throughout this first phase of the RSWMM 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. A detailed summary of recommendations for each model is included in this report. Thirdly, the process of model development should be streamlined through careful coordination among CAs involved prior to future model construction. The improvements summarized in this report will 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.

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 will help to effectively reduce and manage run-off by strategically investing limited stewardship dollars on the right projects in the right places. It will help stewardship practitioners, in partnership with landowners, to implement effective runoff and erosion control projects and other best management practices. The model will help 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.

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 and federal ministries in Canada, county departments, environmental and public health agencies, and participating landowners.

Ausable Bayfield Conservation worked 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 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 Program and in-kind contributions from other partners. Investment has totalled more than $900,000. That investment will benefit the economy, rural knowledge and capacity, and human health. The Rural Stormwater Management Model will benefit water quality along Lake Huron's southeast shores and help create a rural focus for stormwater management that can be applied across the province and beyond.

For information on the Rural Stormwater Management Model Project visit:

Ausable Bayfield Conservation

The groundbreaking new model offers more detailed and precise information on how to manage any stormwater impact during springtime and heavy rainfall events. This increased understanding will guide new stewardship projects designed to effectively reduce and manage run-off.

The project has increased long-term monitoring and introduced five new water monitoring stations in five priority watersheds along Lake Huron's southeast shores. For more information on the five priority watershed areas visit:

The creation of this model helps water quality improvement projects in the priority areas, and benefits all of rural Ontario.

The Government of the Province of Ontario has recognized that understanding how the environment functions in rural Ontario cannot take place through an urban model. It requires a new focus that will result in better information, more strategic stewardship investments and actions to protect water in a rural context.

This is a new and truly rural initiative to better understand how stormwater systems work in rural Ontario. This leading-edge work has not previously taken place, and fills a gap in understanding the nearshore water quality of Lake Huron.  Better information makes 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 helps to guide 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.

Projected benefits of a more precise rural stormwater management model include:

  • Reduction in stormwater
  • Reduced impacts on lakes and rivers
  • Reduction in risks to health
  • Limiting erosion
  • Reducing flooding

Components of the project include:

  • 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

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 will benefit water quality.

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

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