DHI has partnered with SJL Engineering Inc. and the Essex Region Conservation Authority to restore the critically endangered Hillman Marsh ecosystem on Lake Erie, leveraging MIKE Powered by DHI technology to design nature-based solutions. This initiative is supported by grant funding from Environment and Climate Change Canada (ECCC) under the Great Lakes Freshwater Ecosystem Initiative (GLFEI).

Covering nearly 1,000 acres, Hillman Marsh is a designated Provincially Significant Wetland. Historically, the marsh was a thriving ecological system providing critical habitat to aquatic endangered species and numerous migratory bird populations, while providing ecosystem services such as water quality benefits. However, cumulative stresses from human development and climate change, particularly rising lake levels, have severely threatened its ecological value.

In addition to the significant loss of habitat and ecosystem services once offered by the Hillman Marsh, the propagation of lake waves through the newly breached barrier system and into the marsh presents a significant risk to the residents and agricultural lands within the interior of the Pelee Peninsula on Lake Erie, in Ontario Canada. The marsh is surrounded by a perimeter of dykes, which were constructed from native local materials including clay and peat. The interior lands are low-lying, with much of the Pelee Peninsula featuring elevations well below the 100-year flood level. There is potential for widespread flooding of more than 2,000 hectares and direct economic damages on the order $50,000,000 should the dyke suffer a breach based on the historical 100-year flood level.  

Reinstating 1,000 acres of wetland providing ecological, habitat, carbon sequestration and water quality services

The overall objective of the Hillman Marsh and Barrier Beach Restoration Project is to create a restored marsh environment with protection from lake waves and storm surge achieved through the design and implementation of a nature-based, dynamically stable, engineered artificial barrier feature. The restored marsh will serve to reinstate approximately 1,000 acres of wetland providing ecological, habitat, carbon sequestration and water quality services. The restored barrier system will ensure that these services are maintained in the future with increased resilience to the sheltered marsh and surrounding region against climate-related impacts on coastal processes.

To achieve this, the barrier is to be designed in a hybrid manner, combining several approaches to reduce wetland exposure, increase resilience and provide shoreline stability including traditional engineering techniques (e.g. breakwaters, headlands, reinforced dykes) with nature-based or green infrastructure (e.g. artificial reefs, sediment bypassing, beach nourishment, boulder clusters, dune restoration, barrier re-vegetation, etc.).

MIKE models key in designing nature-based solutions for effective restoration

In early September, DHI’s team in Canada commenced this multi-year project with a comprehensive field campaign, deploying wave monitoring, streamflow and water level monitoring instrumentation within the marsh. 

‘Our team will use the MIKE 21 FM Spectral Waves, Hydrodynamics, MIKE 3 Mud Transport and MIKE 3 Wave FM models to assess the marsh baseline and to develop nature-based hybrid design solutions to protect and restore the marsh habitat’, says Danker Kolijn, Project Director Americas-Pacific, DHI. 

He adds, ‘Our numerical models will integrate vegetation dynamics and morphological processes to understand the response of the system to future climate stressors and the proposed solutions. The final concept will be tested and refined in the physical model basin at the Federal Ocean, Coastal and River Engineering Research Centre in Ottawa, Canada. Once the design has been refined, plans will be prepared for the implementation, construction, monitoring and long-term adaptive management of the project.’

Watch this video to know more about the Hillman Marsh restoration project and contact Danker Kolijn for more information.