Stay connected with LSRCA

RSS FeedSubscribe to our YouTube ChannelLike us on FacebookFollow us on Twitter

Reports & Studies

The LSRCA undertakes or is involved in studies of both the region's subwatershed and the entire watershed as a whole. Studies may involve assembling data, creating computer simulations of the impacts of land use on water quality, documenting the state of the subwatersheds, and recommending courses of action.

Ontario Agri-Environmental Archive

This is a link to an external site that houses an archive of agri-environmental programs in Ontario.

See the archive.

Annual Report

An archive of our annual reports from 2004 to the present.

View our annual reports

Aquatic Macrophyte Survey of Cook's Bay (2006)

An inventory of the aquatic plants of Cook's Bay was conducted in August of 2006, to contrast data collected in 1984 and 1987 and to provide a baseline against future change. Macrophyte growths are dense enough to have had significant effects on water quality, and management options are limited to manual harvesting, nutrient reduction, biological control, and chemical treatment. Although manual harvesting along the eastern shoreline is ongoing, the bay is too large to implement a large-scale harvesting operation, and nutrient inputs have and will continue to be minimized. Biological and chemical control options are not feasible on such a large scale.

View report (PDF)

Aquatic Plants in Lake Simcoe: Distribution, Environmental Controls and Utility as Ecological Indicators (2011)

In 2008, LSRCA investigated the aquatic plants in Lake Simcoe with respect to species diversity, distribution, biomass, and utility as indicators of lake trophic status. While previous studies (1984, 1987, 2006) focused on Cook's Bay, this study covered the entire lake area and identified four environmental variables controlling plant biomass: depth, substrate type, nutrient loading, and subwatershed area.

In comparison with previous studies in Cook's Bay, the plant community has been altered (since 1984) by invasive species (i.e. Eurasian Watermilfoil), has a greater maximum depth of colonization (10.5 m in 2008, 6.0 m in 1984), and has almost tripled in biomass (1.2 kg/m2 in 1984, 3.1 kg/m2 in 2008).

View report (PDF)

Assimilative Capacity Study

Assimilative capacity is the relationship between water quality and quantity, land use, and the capability of the watercourse or lake, to resist the effects of landscape disturbance without impairment of water quality. An assimilative capacity study was done of the Lake Simcoe watershed in 2006.

Find out more about assimilative capacity in the Lake Simcoe watershed

Aurora Engineered Wetland Performance Monitoring Report 2013

The Aurora Engineered Wetland represents a new kind of stormwater management facility. Upon completion in 2011, Lake Simcoe Region Conservation Authority undertook performance monitoring of the facility through to October 2012. This report details the findings of that study. Overall the pond has achieved high reductions in total and dissolved phosphorus and total suspended solids and therefore appears to be functioning very well.

Aurora Engineered Wetland Performance Monitoring Report 2013 (PDF)

Barrie Creeks, Lovers Creek, and Hewitt's Creek Subwatershed Plan

This subwatershed plan looks at the Barrie Creeks, Lovers Creek, and Hewitt's Creek subwatersheds, located in the west-central portion of the Lake Simcoe watershed around the tip of Kempenfelt Bay. These subwatersheds fall mainly within the City of Barrie and Town of Innisfil, with very small portions found in the Townships of Oro-Medonte and Springwater. The Barrie Creeks subwatershed is roughly 37.5 km2 in size, with 75% of its area occupied by urban land uses, and the remaining land mainly occupied by natural features and agriculture. The Lovers Creek subwatershed, which is close to 60 km2, falls just to the east of Barrie Creeks. Natural features and agriculture each occupy close to 35%, with developed land uses accounting for 21% of its area. Finally, the Hewitt's Creek subwatershed has a surface area of only 17.5 km2, over half of which is occupied by agriculture, with natural and urban features both occupying close to 20%.

Barrie Creeks, Lovers Creek, and Hewitt's Creek Subwatershed Plan, 2012 (PDF) | Executive Summary only (PDF) | Implementation Plan (PDF)

Beaver River

The Beaver River is the Lake Simcoe watershed’s easternmost subwatershed. The subwatershed is 327.3 km2 in area, with 85.1% of its area within Durham Region and the remaining 14.9% within the City of Kawartha Lakes. The subwatershed includes the Townships of Brock, Scugog, and Uxbridge and the communities of Beaverton, Cannington, Sunderland, Blackwater, Lorneville, Woodville, and Derryville.

Wetland Conservation Area Management Plan 2010 (PDF)

Beaver River Subwatershed Plan 2012 (PDF) | View the 2012 Executive Summary only (PDF)

Black River Subwatershed

The Black River subwatershed occupies 375 square kilometres of land south of the eastern portion of Lake Simcoe. With the headwaters originating on the Oak Ridges Moraine, the Black's watercourses flow mainly through natural features and agricultural areas throughout much of the system before reaching the community of Sutton and the outlet into Lake Simcoe.

Subwatershed Plan 2010 (PDF) | View the Executive Summary only (PDF) | York Region Subwatershed Implementation Plan (PDF)

East Holland River Subwatershed

The Holland River is located in the southwest corner of the Lake Simcoe watershed. It is composed of two major tributaries, the East Holland and the Holland/Schomberg. The East Holland River is the smaller of the two, draining approximately 243 square kilometres, or 41 percent, of the total subwatershed.

Subwatershed Plan 2010 (PDF) | View the Executive Summary only (PDF) | York Region Subwatershed Implementation Plan (PDF)

State of the Watershed Report 2000 (PDF)

Management Plan 2001 (PDF)

Ecological Flows Guidance Document

The objective of this report is to offer guidance towards the assessment of ecological flows and water levels in a holistic way. By placing ecological flows and water levels in the context of the natural flow regime, we have recognized that flow variability is essential in maintaining ecological function. It is also acknowledged that non-flow related processes play an important role. Therefore it is critical to integrate the development of an ecological flows and water levels process into the broader watershed management efforts within the Lake Simcoe watershed.

Read the Report (PDF)

Engineered Wetlands

A large engineered wetland was constructed to treat stormwater runoff in the Town of Aurora. These reports summarize the effectiveness of this engineered wetland.

Read the Report (PDF)
Raw Data and Appendices (PDF)

Environmental Monitoring Report (2013)

This report provides an overview of factors that influence the health of the Lake Simcoe watershed. LSRCA's extensive monitoring program studies the lake's nearshore ecosystem, water quality and quantity in both the tributaries and groundwater, and biological parameters in the lake's rivers, streams, and creeks. This collection of monitoring data (2007 to 2011) summarizes the watershed's most current conditions and examines long-term and short-term biological and environmental trends.

Read the Report (PDF)

Innisfil Creeks Subwatershed Plan

This subwatershed plan looks at the tributaries that make up the area known as the Innisfil Creeks subwatershed, which drain into the western side of Lake Simcoe, including Cook's and Kempenfelt Bays. Almost all of the subwatershed area falls within the Town of Innisfil, with 3% falling within the City of Barrie and 1% in the Town of Bradford West Gwillimbury. The subwatershed is 107 km2 in area, and consists of 17 named streams, most of which have their headwaters in agricultural areas, and then flow downstream, some through urban areas, before entering the lake.

Innisfil Creeks Subwatershed Plan 2012 (PDF) | Executive Summary only (PDF) | Implementation Plan (PDF)

Integrated Watershed Management Plan

The Lake Simcoe Integrated Watershed Management Plan is intended to be a road-map to provide future direction for the protection and rehabilitation of the watershed ecosystem.

Download the Report (PDF)

Lake Simcoe Basin Stormwater Management and Retrofit Opportunities (2007)

Stormwater runoff represents a major source of pollution to Lake Simcoe and its tributaries. The lake, which is already showing signs of impairment due to anthropogenic activities, is under increasing stress due to urban growth. The purpose of this study is to create a complete, consistent and contemporary data set of all urban catchments, outlets, and existing and potential locations of Stormwater Management Facilities, as well as to calculate the phosphorus load associated with urban stormwater runoff.

Find out more about Stormwater Management (PDF)

Lake Simcoe Protection Plan

The Ontario Ministry of Environment's Lake Simcoe Protection Plan came into effect on June 2, 2009. This watershed-based plan provides a roadmap to help restore and protect the health of Lake Simcoe.

Find out more about the Plan from the Ontario Ministry of the Environment
View the Lake Simcoe Protection Plan
Read our comments on the draft Plan (PDF)

Lake Simcoe Environmental Management Strategy (LSEMS)

LSEMS studies were initiated in 1981 in response to a declining coldwater fishery in Lake Simcoe. Scientists reported that increasing urban development and agricultural activities in Lake Simcoe's drainage basin were filling the lake with excess nutrients. The resulting increase in plant life reduced the oxygen supply in the water, and was identified as a contributing factor in the collapse of the coldwater fishery.

In 1985, the "Final Report and Recommendations of the Steering Committee" recommended that phosphorus inputs from rural and urban sources be reduced. Thanks to a generous financial contribution from the Ontario Ministry of the Environment, the Lake Simcoe Environmental Management Strategy launched a website in 2003, featuring on-line LSEMS charts, reports, maps and data providing visitors with unique insight on the state of Lake Simcoe, and efforts to restore this $200 million annual resource to its former glory.

Find out more about LSEMS

Lake Simcoe Science Newsletters

A series of newsletters written by LSRCA science and monitoring staff. Each volume focusses on the various factors that impact the health of Lake Simcoe and its watershed based on the monitoring data we collect and analyize.

Read the newsletter series: Lake Simcoe Science

Maskinonge River Subwatershed

The Maskinonge River subwatershed is located in the south-central portion of the larger Lake Simcoe watershed. It has a drainage area of approximately 60 square kilometres, a little more than two percent of the entire Lake Simcoe watershed. Since the mid-1980s, the Maskinonge River has been plagued by the excessive growth of algae and aquatic plants, most noticeably duckweed.

Subwatershed Plan 2010 (PDF) | View the Executive Summary only (PDF) | York Region Subwatershed Implementation Plan (PDF)

Remedial Strategy Final Report 1998 (PDF)

More information about the Maskinonge Remedial Project

Musselman's Lake Watershed

The purpose of the Musselman's Lake Subwatershed Assessment and Stewardship Opportunities Report (Stewardship Opportunities Report) is to describe the environmental issues facing Musselman's Lake and its subwatershed and put forward recommendations to remedy or control these environmental issues.The final draft of the Musselman's Lake Subwatershed Assessment and Stewardship Opportunities Report was presented to the Town of Whitchurch-Stouffville Council on April 7th, 2009.

View report (PDF)

Natural Heritage System for the Lake Simcoe Watershed

This report attempts to identify the components of the Natural Heritage System (NHS): significant habitats for endangered and threatened species, wetlands, woodlands, valleylands, wildlife and fish habitats, areas of natural and scientific interest, and linkages. The report also attempts to provide the criteria and mapping to the planning authority. The NHS is based on land use mapping for the entire watershed.

View report (PDF)

View NHS map (PDF)

Natural Heritage System, Land Securement Project (2006-2010)

The conservation lands division of the LSRCA has set a goal to secure 4,000 hectares of ecologically sensitive land through purchase, easement and donation by 2010. This Natural Heritage System land securement project furthers the LSRCA's mission and goals by securing interests in land both through purchase and holding rights to property, thereby removing sensitive ecological areas from potential future development. Where possible, the rehabilitation and restoration of land that has or is experiencing degradation will be implemented by the LSRCA and other partners.

View report (PDF)

Oak Ridges Moraine and Adjacent Greenbelt Lands Environmental Health Report Card (2015)

This report card was prepared by the Conservation Authorities Moraine Coalition (CAMC) to provide science-based information to inform the 2015 review of the Greenbelt Plan and the Oak Ridges Moraine Conservation Plan. Key funding support generously provided by the Friends of the Greenbelt Foundation.

Grades for subwatersheds in the Lake Simcoe watershed

Grades for subwatersheds across the whole Oak Ridges Moraine (PDF)

Oro & Hawkestone Creeks Subwatershed Plan

This subwatershed plan looks at three separate, but fairly similar, subwatersheds lying in the northwest portion of the Lake Simcoe watershed, with their headwaters originating on the Oro Moraine: Oro Creeks North (75 km2 within the Township of Oro-Medonte, with just over 20% falling within the City of Orillia), Hawkestone Creek (48 km2 entirely within the Township of Oro-Medonte), and Oro Creeks South (57 km2 also fully within the Township of Oro-Medonte). This subwatershed plan was prepared under the direction of the Lake Simcoe Protection Plan (LSPP)

Oro & Hawkestone Creeks Subwatershed Plan (PDF) | Executive Summary only (PDF) | Implementation Plan (PDF)

Oro Moraine Report Card, 2010

The report card provides a summary of environmental health on the Oro Moraine. It is the first report card based on a physiographic feature in Ontario and represents an innovative approach to feature-based reporting.

View the Oro Moraine Report Card (PDF)

Pefferlaw River

The Pefferlaw River subwatershed is approximately 425 km2 in area, located on the eastern side of the Lake Simcoe watershed. It lies almost entirely within the Regional Municipality of Durham, with a small portion in York Region. It includes the Townships of Brock, Scugog, Uxbridge, and Georgina, and the communities of Pefferlaw, Udora, Sandford, and Siloam.

Pefferlaw River Subwatershed Plan 2012 (PDF) | View the Executive Summary only (PDF)

Report on Phosphorus Loads to Lake Simcoe

Phosphorus was identified as a problem for the health of the lake in the 1970s. We have been monitoring it to help us understand its sources and impacts. The purpose of the report is to share with our watershed partners the most current data about the amount of phosphorus entering the lake.

The following report presents our findings for the period 2007-2009:
Report on Phosphorus Loads to Lake Simcoe, 2007-2009 (PDF)  |  Phosphorus Loads Report FAQs (PDF)

The following report presents our findings for the period 2004-2007:
Report on Phosphorus Loads to Lake Simcoe, 2004-2007 (PDF)

Annual Water Balances, Total Phosphorus Budgets and Total Nitrogen and Chloride Loads to Lake Simcoe

This report is meant to complement the corresponding "Report on Phosphorus Loads to Lake Simcoe" above and provides technical details including the methodology used for all components of the phosphorus load calculations.

View the 2007–2009 report (PDF)
View the 2004-2007 report (PDF)

Estimation of Phosphorus Loadings to Lake Simcoe, September 2010

This report estimates phosphorus loadings to Lake Simcoe under various scenarios: The Base Case (existing conditions), Growth, and selected BMP scenarios. An understanding of the amount and sources of phosphorus delivered to the lake, the amount that could result from future projected watershed development, and the amount after implementation of Best Management Practices (BMPs) is necessary to successfully develop a nutrient strategy necessary to meet the dissolved oxygen target for Lake Simcoe. The tools used to achieve the objective are the modeling programs Canadian Nutrient and Watershed Evaluation Tool (CANWET™) (version 3.0) and the Pollution Reduction Impact Comparison Tool (PRedICT)...

View the Estimation of Phosphorus Loadings to Lake Simcoe Report (PDF)


In partnership with the Ontario Ministry of the Environment, the Lake Simcoe Region Conservation Authority tested a phosphorus reduction product called Phoslock in 2008. The project investigated the effectiveness of Phoslock in both lab and field tests within the Lake Simcoe watershed. The field trials were conducted in the Scanlon Pond Reservoir and the Cane Parkway (aquatic ecosystems in the Lake Simcoe watershed). A series of toxicity tests with sediment and water column dwelling organisms were performed to assess the toxicity of Phoslock granules. Phoslock is a modified bentonite clay product developed, produced by Australia's CSIRO (Commonwealth Scientific and Industrial Research Organization), to permanently bind phosphorous in systems where phosphorous levels lead to problematic algal bloom formation.

Phoslock Report (PDF)

Phoslock Toxicity Report (PDF)

Retrofitting of Urban Stormwater Management Facilities Using Innovative Technologies: Comparison of Three Innovative Solutions

Through the Ontario Ministry of Environment's Showcasing Water Innovation program, Lake Simcoe Region Conservation Authority (LSRCA) worked with our community, municipal and other government partners to implement stormwater management retrofits. Three facilities recognized in our watershed management plans were identified for retrofit: George Richardson (Newmarket), Colony Trail (East Gwillimbury), and Lincoln Pond (Uxbridge). In this case study we compare the efficiency of three innovative technology approaches to retrofitting stormwater management ponds, each designed to decrease the level of phosphorous and other pollutants discharged to the receiving water body. This project has received funding support from the Government of Ontario.

View the report - English (PDF)

View the report - French (PDF)

Showcasing Water Innovation: Stormwater Performance Monitoring Report 2013 (PDF)

Appendix to above (PDF)

Rogers Reservoir Conservation Area Management Plan

After several years of public consultation, Lake Simcoe Region Conservation Authority is pleased to announce the release of the Rogers Reservoir Conservation Area Management Plan.

View the management plan (PDF)

Scanlon Creek Conservation Area Management Plan

After several years of public consultation, Lake Simcoe Region Conservation Authority is pleased to announce the release of the Scanlon Creek Conservation Area Management Plan and Stewardship Plan.

View the management plan (PDF)

View the stewardship plan (PDF)

Scanlon Creek Class Environmental Assessment - Notice of Approval

In March 2011, the Lake Simcoe Region Conservation Authority completed the planning and design process approved under the Environmental Assessment Act in the "Class Environmental Assessment for Remedial Flood and Erosion Control Projects" for undertaking a project to naturalize the area in and around the reservoir at Scanlon Creek Conservation Area.

This study examined ways of naturalizing the area in and around the existing reservoir in order to improve aquatic habitat values, while maintaining or enhancing recreational and educational values in the conservation area. The preferred methods of improving aquatic habitat values in the creek, as identified by this Class Environmental Assessment include assisting landowners in the Scanlon Creek subwatershed to implement riparian best management practices on their land, and to decommission the dam in Scanlon Creek Reservoir, and restore the creek to its pre-dam condition.

Download the Environmental Assessment (PDF)

Sheppard's Bush Management Plan

After months of public consultation, we are pleased to announce the release of the Sheppard’s Bush Conservation Area Management Plan.

Sheppard's Bush Management Plan - 2009 (PDF)

Sheppard's Bush Conservation Area Conceptual Plan Map (PDF)

Species at Risk

The Lake Simcoe watershed is home to at least 32 "Species at Risk." They live in wetlands, in forests, on farmland, in streams and even in Lake Simcoe itself.

Find out more about Species at Risk

Stormwater Management Master Plan Guidelines

This document provides direction to municipalities on how to prepare and implement comprehensive stormwater management master plans for settlement areas located in the Lake Simcoe watershed, in accordance with the intent of Policy 4.5-SA of the Lake Simcoe Protection Plan.

View the document

Stormwater Pond Maintenance and Anoxic Conditions Report

Urban stormwater runoff is widely recognized as a significant source of pollutants to Lake Simcoe and accounts for an estimated 14 percent of annual phosphorus (P) loading. Therefore, interception and treatment of these waters is crucial to maintain the ecological health of receiving streams and lakes. This is most commonly achieved through the use of stormwater ponds of which there are 135 quality facilities in the Lake Simcoe watershed. In 2010, a survey of 98 ponds was conducted to evaluate the efficiency of these ponds as compared with their original design efficiency and investigate the prevalence of low oxygen conditions in stormwater ponds. Both these factors influence the ability of the pond to effectively trap and retain sediments and nutrients. The study found that the majority of ponds are experiencing low oxygen conditions and require some degree of clean out maintenance and are therefore not achieving the nutrient reductions previously assumed.

View report (PDF)

Strategic Plan, 2011 - 2014

Our strategic goals for the protection and restoration of Lake Simcoe and its surrounding watershed are framed by our four pillars of Integrated Watershed Management. Simply stated, Integrated Watershed Management (IWM) is the evolving process of managing human activities and natural resources. The principles of Integrated Watershed Management allow us to concurrently tackle competing interests, address a variety of issues and make sound plans for the future. When harmonized with our conservation vision, our mission, goals, strategies and outcomes will continue to support superb water and resource management and help us to realize our vision of A Watershed For Life.

View report (PDF)

Subwatershed Plans Implementation Report

To meet the recommendations of the Lake Simcoe Protection Plan (LSPP), the Lake Simcoe Region Conservation Authority (LSRCA) and its partners have been developing subwatershed plans to focus protection and restoration efforts in Lake Simcoe's subwatersheds. After the plans are completed, LSRCA continues to work with municipal and provincial partners to implement the plans' recommendations.

This report summarizes progress made in 2013 on achieving subwatershed plan recommendations.

View report (PDF)

Upper York Sewage Solutions (UYSS)

Full and transparent decision-making is important to the Lake Simcoe Region Conservation Authority and our partners. Since 2010, our staff have been involved in the consultation process with York Region on the development of the Upper York Sewage Solutions (UYSS). We will continue to be involved and engaged in all stages of the Environmental Assessment (EA) as the project moves forward.

Visit the Upper York Sewage Solutions section of this website for more information.

Uxbridge Brook Watershed Plan (1997)

The watershed planning process uses drainage boundaries and embraces an ecosystem approach, which recognizes that "everything is connected to everything else." In recognition of the need for carefully managed growth to protect the area's natural resources, the Uxbridge Brook Watershed Plan identifies resources, management issues, and recommends development constraints and best management practices for the watershed.

View report (PDF)

Uxbridge Country Preserve Management Plan

The Uxbridge Countryside Preserve, located in the heart of Uxbridge, was opened for public use in 2005.  The preserve covers approximately 40 hectares of rolling landscape on the Oak Ridges Moraine.  With its central location, extensive network of trails and space for activities year-round, the Uxbridge Countryside Preserve is a favourite destination for outdoor enthusiasts.

View report (PDF)

Water Reuse

This study was conducted to look at the technical feasibility of water reuse, and explore available supply, demand and the cost benefit for various reuse options. We also provide a summary of findings from a scan of local stakeholder and public attitudes towards the concept of reclaiming treated wastewater.

Read the Water Reuse Report (PDF)
Read the Summary of Findings on Public Attitudes Toward Water Reuse (PDF)

Watershed Report Card

Monitoring and protecting the watershed is a very important part of our overall effort to preserve the health of the environment upon which we all depend. We work with our partners year-round to provide the best scientific investigation of the health of the watershed and to establish programs for its protection and restoration. This includes continually monitoring, evaluating and communicating the results. One way to inform our community about the health of our watershed is through our Watershed Report Card.

Read LSRCA's Watershed Report Cards

West Holland River Subwatershed

The West Holland River subwatershed occupies 354 square kilometres of land immediately to the southwest of the tip of Lake Simcoe's Cook's Bay. Originating on the Oak Ridges Moraine, the headwaters of the subwatershed flow through mainly forested and agricultural areas before entering the Holland Marsh. The system then flows past the Town of Bradford, and then past forested and agricultural areas before discharging into Lake Simcoe.

Subwatershed Plan 2010 (PDF) | View the Executive Summary only (PDF) | York Region Subwatershed Implementation Plan (PDF)