Hillman Marsh Restoration Plan
The Hillman Marsh Conservation Area, located in Leamington, Ontario, is a barrier-protected coastal wetland and is classified as an Environmentally Significant Area, Provincially Significant Wetland, and an Area of Natural and Scientific Interest. As a part of Carolinian Canada, Hillman Marsh helps to preserve hundreds of rare and endangered species that are seldom seen in Ontario, including the American Lotus, Blanding’s Turtle, King Rail, Large Yellow Pond-lily, Least Bittern, Midland Painted Turtle, Northern Map Turtle, Piping Plover, Prothonotary Warbler, Snapping Turtle, Spiny Softshell, and the Swamp Rose-mallow. In 1989, two dykes were constructed creating two controlled wetland cells that allow for water level control carried out by a pumping station. Drawdowns are completed every 10-15 years, removing most of the water from the cell, exposing the mudflats and allowing for seeds to germinate. In the past, this has resulted in a 30-48% increase in vegetation cover. Since breaching, the open marsh is no longer protected from Lake Erie, resulting in impaired water quality and harsh wave conditions. Subsequently, most submerged aquatic vegetation, tree cover, and woody vegetation has been lost or dislodged, making these controlled wetland cells more crucial than ever.
Goals and Objectives
This plan will propose recommended actions to reduce climate change risks and enhance coastal wetland resilience for long-term health, function, and the provision of wetland goods and services. This plan consists of three main goals, and phased objectives to achieve these goals:
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Employ a transformational adaptation approach to restore and enhance the Hillman Marsh barrier beach feature to withstand climate change extremes, protect the wetland ecosystem, and safeguard homes and businesses.
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Restore the wetland plant community within the approximate 115 hectares of open water behind the barrier feature to enhance wetland structure, function, diversity, and resilience to climate change impacts using historical records and expert opinion.
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Make the restored and enhanced Hillman Marsh ecosystem accessible to all of society and future generations to enjoy.
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1. Beginning in Spring 2024, utilize available resources and expertise to conduct numerical modelling of natural conditions (waves, sediment transport, and hydrodynamics) and physical modelling of design components (alignment and elevation of the barrier, offshore rock shoals, artificial reefs, and outlet geometry) with a collective aim to minimize wave agitation, ensure infrastructure and vegetation survival, and determine optimal dimensions and materials of critical design components.
2. In Fall 2024, implement upgrades to the south headland at East Beach Road and construct a 40 m test section of the proposed artificial barrier to mitigate ongoing erosion and anchor the future phases of work.
3. By early 2025 and into 2026, and with permits and approvals secured, integrate the results of numerical and physical modelling to complete the final detailed design and cost estimate of project elements and begin construction to stabilize the north headland.
4. By Spring 2026 and into 2027, develop both an adaptive management plan and a comprehensive set of construction ready drawings and specifications, including tender packages that will be utilized to secure quotations for the various phases of construction. Following this, commence construction of the artificial barrier beach and permanent outlet.
5. By Spring 2027 and into 2028, begin construction of hydraulic training structures and extensive wetland restoration, and implement an adaptive management plan involving continuous monitoring, risk identification and mitigation, and stakeholder engagement, allowing for future adjustments in response to changing conditions and unforeseen challenges.
6. Throughout all years of the project, effectively communicate with stakeholders, rightsholders, and the local community to inform, garner support, and seek feedback and approval through quarterly meetings, consultation events, and consistent updates to the project website.
Climate Change Threats
This plan will propose recommended actions to reduce climate change risks and enhance coastal wetland resilience for long-term health, function, and the provision of wetland goods and services. This plan consists of three main goals, and phased objectives to achieve these goals:
Lake levels are projected to increase in variability, resulting in more extreme highs and lows. Water level regimes define wetland processes, soil moisture conditions, vegetation dominance, and shoreline conditions. Water level changes need to be gradual to optimize wetland function and structure, therefore both extreme scenarios will alter species found within a wetland, and result in a decline in biodiversity and ecosystem services.
Climate change will also result in an increase in both the frequency and intensity of storm events. These extreme storm events produce intense waves that can cause coastal structures to breach. The barrier beach was the first line of defense against wave action, but without this protection, structures that were not built to withstand Lake Erie are compromising the controlled wetland cells, and surrounding homes and businesses.
The increased frequency and intensity of storm events can lead to increased sediment and nutrient runoff, which will result in water quality impairments such as high turbidity, eutrophication, and algal blooms. Excess sediments will lead to the burial of plant communities, a decrease in light penetration and photosynthesis, and a lack of oxygen.
Warming air and water temperatures will reduce winter ice cover, which is imperative in protecting shorelines from extreme storm surges as the ice prevents sediment loss from wave action. The absence of ice will also leave shoreline properties vulnerable to flooding. In the past this has resulted in the construction of shoreline protection structures, which in turn disrupt longshore drift, cuts off sediment supply, and disrupts normal processes of wind, wave, and current movement.
Project Partners
The Essex Region Conservation Authority (ERCA) is receiving financial support from the Canada Water Agency (CWA) to coordinate and conduct research for this project. Preliminary construction and improvements to the south headland is made possible by funding from the Ministry of the Environment, Conservation and Parks (MECP). This project will engage various rights holders and stakeholders in the co-development of a restoration and adaptation strategy for the Hillman Marsh Conservation Area. The Steering Committee includes representatives from:
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Caldwell First Nation
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Canada Water Agency
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Ducks Unlimited
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Fisheries and Oceans Canada
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Leamington Shoreline Association
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Ministry of Natural Resources
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Ministry of the Environment, Conservation and Parks
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Municipality of Leamington
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Parks Canada
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SJL Engineering
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University of Waterloo
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University of Windsor
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Zuzek Inc.
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Final Recommendation
Based on the opinion of experts on our Core Team and Steering Committee, and the opinion of the majority of the general public, ERCA recommends this project moves forward with Concept A as the preferred approach. The high crested barrier protects the marsh and provides the greatest opportunities for habitat restoration and vegetation re-establishment both on the barrier and behind it. Concept A is more robust and therefore more resilient against wave action, storm events, erosional forces, and future climate change extremes. Through in-depth discussions with various experts, ERCA recognizes that a low crested barrier presents a more dynamic system that will be better suited for wildlife and provides the fundamental services and structure for a healthy wetland. However, concerns remain that Hillman Marsh may not be able to handle this dynamic system, without failing, given its current state. Moving forward, numerical and physical modelling will be conducted by engineers to test the possibility of a structure that has variable crest elevations. If areas of both high and low crested barrier beach can be accommodated without compromising the wetland, then it will provide for a more biologically diverse outcome and will be pursued.
Caldwell First Nation has been part of the steering committee since its inception, but as the only other landowners in the marsh, staff would prefer to not commit to any preferred option, but instead to continue ongoing consultation with their leadership and community regarding their opinions. Administration has committed to continuing to work and communicate with and seek feedback from Caldwell First Nation if funding for this project is approved and it can move forward.
Final Restoration Strategy
The Hillman Marsh Restoration Plan began in 2022, with the goal of restoring the barrier beach and the coastal wetland it once protected. Years of extensive research, monitoring, and consultation have improved our understanding of historical and baseline conditions, the factors that led to the collapse of the barrier beach, and the conditions needed to support a successful and resilient restoration. This work confirmed that the historical barrier beach configuration would not be sustainable under current environmental conditions and future climate scenarios.
In partnership with SJL Engineering, DHI Water & Environment, Resolution Studio, and Zuzek Inc., five restoration concepts were developed and evaluated using advanced numerical modelling to assess wave conditions, currents, sediment transport, and water exchange between the marsh and Lake Erie. Concept E was selected as the preferred approach because its set-back configuration allows wave energy to dissipate further offshore and reduces flow into the marsh, improves water circulation, and supports smoother sediment transport to help maintain a stable barrier while minimizing impacts on neighbouring shorelines.
To further validate the design, physical modelling was completed in partnership with the National Research Council's Ocean, Coastal, and River Engineering Research Centre. A 1:40 scale model of Hillman Marsh’s existing bathymetric conditions and proposed rock structures was constructed in a wave basin and subjected to nearly 100 tests representing a wide range of conditions, from typical summer waves to 100-year storm events at 100-year water levels.
Testing confirmed that the proposed rock structures and barrier beach design perform well under both daily and extreme conditions. Offshore reefs reduce wave energy during storms, protecting the wetland and maintaining barrier beach stability. The modelling also validated the long-term stability of beach nourishment material, informed refinements to reduce sediment accumulation in the outlet, and reduced estimated construction costs by approximately $3 million without compromising performance.
After one year of detailed modelling, the final design has been completed. Construction of the hybrid barrier beach is scheduled to begin in summer 2026, supported through funding from the Canada Water Agency. Construction will occur in phases due to available funding, with Phase 1A beginning in 2026. Rock structures will be constructed first, and sand placement will follow after an 8- to 12- month settlement period to allow the structures to stabilize.
Wetland restoration planting efforts have been ongoing and will continue in Summer 2026, with more extensive plantings and aquatic habitat enhancements taking place in 2027.
Project Updates
June 28, 2023: On-site meeting with Steering Committee and Caldwell First Nation.
July 6, 2023: Letter of Advice obtained from Fisheries and Oceans Canada for Phase 1 works (south headland upgrade, E Beach Rd).
July 7, 2023: Turbidity sensor deployed in Hillman Marsh, collecting continuous measurements of temperature and turbidity at 15-minute intervals.
August 2023: Launch of project website and online feedback form.
August 8, 2023: Project brought forward to Leamington Council.
September 2023: Tender documents for Phase 1 works prepared.
October 3, 2023: First public consultation meeting held in Leamington.
October 10, 2023: Second public consultation meeting held in Leamington.
October 27, 2023: Turbidity sensor retrieved for the winter with a total of 111 full days and 2 partial days of data.
November 2023: Water quality data analysis.
December 2023: Environmental risk assessment completed for project construction.
January 2024: Hillman Marsh Restoration Plan report completed.
January 24, 2024: Steering Committee meeting to decide on final recommendations.
February 15, 2024: Restoration Plan report brought forward to ERCA's Board of Directors, where 19 board members, consisting of mayors, deputy mayors, and councillors of the Windsor-Essex region, supported the plan unanimously.
February 16, 2024: Funding application submitted.
June 11, 2024: Turbidity sensor re-deployed, collecting continuous measurements of temperature and turbidity.
September 2024: Environment and Climate Change Canada awards the Essex Region Conservation Authority with $4.2 million over 3.5 years to implement the engineering needed to initiate construction. Engineering work includes numerical and physical modeling as well as detailed design development.
September 10, 2024: Offshore wave buoy and four wave gauges deployed in Hillman Marsh by SJL Engineering and DHI.
October 2024: Phase 1 work completed, including updates to the South Headland at the end of East Beach Road, a pilot section of the barrier beach rock core, and wetland vegetation planting.
October 21, 2024: Water level logger deployed in Hillman Marsh.
November 7, 2024: Turbidity sensor retrieved for the winter with a total of 148 full days and 2 partial days of data.
December 2024: Numerical modelling in progress for flow, waves, hydrodynamics, and sediment transport by DHI (to be calibrated with processed field data).
December 16, 2024: Geotechnical field work completed by BGC Engineering.
May 5, 2025: Turbidity sensor re-deployed, collecting continuous measurements of temperature and turbidity.
June 2025: Continued numerical modelling of concepts, selection of preferred concept for detailed design, preparation for physical model study, and geotechnical analyses of structural components.
June 26, 2025: Physical modelling commences at the National Research Council research facility in Ottawa. Constructed at a 1:40 scale, the proposed restoration concept is tested against various water level scenarios and storms, including 100-year storm waves at 100-year water levels.
September 23, 2025: Over 600 pieces of plant material planted in Hillman Marsh along East Beach Road as a part of greater wetland restoration efforts.
November 6, 2025: Turbidity sensor retrieved for the winter with a total of 184 full days and 2 partial days of data.
May 6, 2026: Turbidity sensor re-deployed off East Beach Rd, collecting continuous measurements of temperature and turbidity.
May 22, 2026: Second turbidity sensor re-deployed at the mouth of Lebo Creek, collecting continuous measurements of temperature and turbidity.
Resource Library
The Cedar Creek basin is probably the most significant, most extensive, and most beautiful natural area in the Place for Life. Experience the Carolinian woodlands, rolling landscapes, creeks, tributaries and abundant wildlife. Cedar Creek is a pristine natural area offering excellent bird watching opportunities.
Be inspired by the sight of eagles soaring, herons and egrets wading, and turtles sun worshiping on logs. View the provincially rare American Lotus, Swamp Rose Mallow and other superb flora and fauna. Canoeing or kayaking can be a great way to explore this Conservation Area. Launch from the dock and head upstream for a magical journey meandering through the trees and Carolinian foliage, or head downstream to enjoy the widening expanse of water as you approach Cedar Beach Conservation Area.