Toronto and Region Conservation Authority (TRCA) works toward enhancing our region’s natural environment while protecting our land, water and communities from the impacts of flooding, erosion and increasingly extreme weather. One key component in this process is the design and implementation of remedial erosion control/protection and slope stabilization works to protect human life and property. TRCA’s Erosion Risk Management Program (ERMP) monitors the condition of all TRCA-owned waterfront erosion protection structures on an annual basis, allowing for priority ranking. This helps determine whether detailed study, maintenance or remedial works, or further monitoring are recommended. Various factors that may be vulnerable to climate change implications, such as depth and crest height of a structure, known wave climate in the area, etc., are considered.
Several structures in Bluffer’s Park, monitored since 2006, were identified through the ERMP as failing following high lake level events in 2017 and 2019, and a severe wind storm weather event in 2018. These structures protect Bluffer’s Park, which is an artificial landform built in the 1970s at the base of the Scarborough Bluffs, located within the City of Toronto on the north shore of Lake Ontario. The park is owned by TRCA and managed by the City, with TRCA maintaining these structures that protect the park and nearby bluffs.
The extreme weather and lake events prompted initiation of the planning process to develop designs, acquire permits and approvals, and complete major maintenance. Climate change and opportunities for aquatic habitat enhancement were key components of the design. TRCA’s objective was to restore and enhance the original erosion protection capability of these structures, thereby protecting Bluffer’s Park from wave energy and continued erosion. Improvements, to increase resiliency and address climate change impacts, included increasing the structure crest height, using larger material, incorporating splash pads behind structures to account for wave overtopping during extreme events, as well as moving trails and public viewing areas to safe distances. Major Maintenance on four (4) structures within the Park was completed between 2018 and 2022. Construction is currently ongoing on a headland structure, scheduled to be complete in 2024, with planning and design underway for another adjacent series of structures. TRCA has undertaken this work to improve resiliency and address climate change factors, and will continue to plan and implement similar projects along the Toronto waterfront within the same framework.
n the southern shore of Lake Ontario, the sediment transport processes are complex due to a highly dynamic environment, complex shoreline configuration, and large range of sediment fractions which includes silt/clay to cobbles and boulders. Generally, the nearshore environment is supplied by sediments released through the natural erosion and retreat of the bluffs which are found in long stretches along the shoreline ranging from several hundred meters to kilometers in length. The retreat of these shoreline bluffs can result from a variety of processes that operate at different rates and that respond to different triggering mechanisms. For example, wave erosion at the toe of the bluff is a primary cause of bluff retreat, and brief, intense storms that generate large waves can trigger large amounts of bluff retreat in a matter of a few hours or days. Longer term basin-wide or eustatic increases in lake water level can also increase long-term rates of bluff erosion and recession by exposing bluffs more directly to wave action. Surface erosion at the bluff crest from overland runoff can also contribute to bluff recession. Once eroded from the bluffs the material is naturally sorted by the waves and nearshore hydrodynamics and subsequently these materials are transported both in an alongshore and cross-shore direction. Eroded materials are distributed throughout littoral cells and sub-cells or alternatively permanently lost from the system in offshore environment. Depending on the sediment fraction, the response in the nearshore environment differs.
To improve the understanding of coastal processes on the southern shore of Lake Ontario, the New York State Department of Environmental Conservation (DEC) initiated a Project titled: Engineering & Analysis for Coastal Resilience & Ecosystem Restoration Projects. The Project’s primary focus is to study the coastal processes to better inform coastal planning to reduce the risk from flooding and erosion while protecting the coastal ecosystem.
To support the Project, a detailed understanding of hydrodynamics, waves and sediment transport is required. As such, the Project involves a range of activities such as research and data analysis; field services to investigate physical processes, material properties, and shoreline features; desktop assessments; geographic information system analysis (GIS); and a comprehensive numerical modelling program of coastal processes. The key outcomes from the study include wave, hydrodynamic and sediment transport models as well as a detailed sediment budget from Great Sodus Bay to Oswego, which considers fine sediment (silt and clay), sand, and the coarse sediment fractions (pebbles and cobbles) which has not been done in the past due to the lack of data relating to the coarse sediment fractions.
This presentation will describe the overall Project and the latest results with a focus on the numerical modelling including waves, hydrodynamics, and sediment transport. In particular, the presentation will discuss the various sediment sources and sinks, the estimated rate of sediment bypassing at the long jetty structures at Sodus Bay and Little Sodus Bay, and how this information feeds into the sediment budget for the reach of shoreline from Great Sodus Bay to Oswego.
Since the City of Buffalo’s inception, it has been impacted by Lake Erie storm surges, including the infamous 1844 event that topped a 14-foot seawall and caused extensive loss of life and property along the City’s waterfront. These surges are caused by powerful winter storms blowing along the long axis of Lake Erie and providing a low atmospheric pressure environment, which together drive water towards the east end of Lake Erie and the City of Buffalo waterfront. Climate change may increase the City of Buffalo’s exposure to storm surges by reducing ice coverage, which would otherwise suppress storm surges, and by increasing Lake Erie water levels, which reduces the freeboard available to accommodate surges when they occur.
The City of Buffalo Coastal Resiliency Study (BCRS) is a comprehensive effort to evaluate flood risks and to identify solutions to protect public and private assets. It grew out of the Imagine LaSalle initiative, a community-driven program to develop a resilient design for LaSalle Park (now called Ralph Wilson Park), which often takes the brunt of Lake Erie storm surges. The success of that program; major Lake Erie storm surges in 2019, 2020, 2021 and 2022; as well as concern for climate change underscored the need to broaden that community-driven framework to the City of Buffalo waterfront.
The BCRS is supported by a lake-wide hydrodynamic model which informs a high-resolution (4 m) over- bank flood model as well as a sewer backup model. This approach enables evaluation of climate change scenarios on Lake Erie surges while also enabling detailed understanding of flooding outcomes at the neighborhood scale. The BCRS models complement ongoing modeling and coastal assessments by filling a gap in the types and scale of information needed.
The modeling is supported by extensive review of historical data and literature, including Lake Erie water levels, meteorological data, the latest climate change research and projections of lake conditions, Buffalo River and Scajaquada Creek discharge data, regional and local bathymetric and topographic surveys, land-use data, infrastructure databases, proposed land development plans, and evidence of historical flooding. Ten simulation scenarios evaluated past and projected flood risk. Extreme water levels were selected based on a joint-probability analysis of measured surge and static lake levels for return periods ranging from 1- to 500-years. Four of the scenarios include climate change considerations for the 2050- and 2080-time horizons.
Information gained from modeling will be used to support an asset risk assessment, enabling stakeholder-driven selection of project priority areas and development of shoreline resiliency projects. The BCRS is supported by a GIS-based online presence, creative use of time-lapse imagery, and virtual reality tools to help stakeholders understand Lake Erie storm surges and their impacts.
Lake Erie Eastern Basin is already experiencing the effects of climate change—trending warmer weather, less ice cover, more erratic weather events, and more frequent and bigger storm events. These conditions lead to increased stormwater runoff, which results in erosion, flooding, damaged infrastructure and more sewage overflow into our lakes and rivers. Toxic algae blooms are on the rise, due in part to excessive run-off of nutrient-rich stormwater, and ecosystems and habitats may be permanently altered. New York State is responding to the Climate Crisis with a series of legislative actions such as the Climate Leadership and Community Protection Act and the Environmental Bond Act to name a few.
Buffalo Niagara Waterkeeper is working with local government and community partners to build resiliency to the impacts of climate change, like flooding and erosion, within the WNY and Great Lakes regions. As guardians of New York’s freshwater coast, Buffalo Niagara Waterkeeper works to identify opportunities to enhance community and ecosystem resilience through policy, partnerships, and nature-based solutions.
Buffalo Niagara Waterkeeper is working to enhance understanding and public awareness of Western New York’s Lake Erie coastline and nearshore environments and foster stewardship in WNY’s Lake Erie watershed through our project titled, “Ecosystem Assessment towards the Prioritization of Coastal Resiliency Projects in Lake Erie’s Eastern Basin Communities”. Data gathered through this project is contributing to a greater understanding of the state of WNY’s recreational waters to protect human health, inform pollution prevention, and identify potential priority areas for coastal and climate resiliency investments.
Through this project, Buffalo Niagara Waterkeeper undertook a detailed literature review of data and research focused on the Eastern Basin of Lake Erie water quality. The literature review has informed opportunities to expand and develop a more robust water quality and ecosystem monitoring program through additional water quality sampling sites, including offshore water sampling via boat. Coupled with this additional water quality data, Buffalo Niagara Waterkeeper implemented a shoreline visual assessment tool (using the NYS Department of State Coastal Visual Assessment Tool as a model) to identify opportunities for increased coastal resilience efforts. Data gathered through our water quality monitoring program and visual shoreline assessments will guide our municipal engagement. Collaboratively, with municipal officials, we will identify potential priority areas for shoreline and coastal resiliency projects based on municipal priorities and identified opportunities to increase resiliency, mitigate flooding, improve water quality and create valuable habitat.
Under the Remedial Action Plans for the Great Lakes, the Toronto and Region AOC lists the Beneficial Use Impairment (BUI) of Loss of Fish and Wildlife Habitat and Degradation of Fish and Wildlife Populations as impaired. A Prioritization Tool is needed to guide aquatic habitat restoration along the waterfront to achieve delisting targets for Beneficial Use Impairment (BUI) 14 Loss of Fish and Wildlife Habitat and BUI 3 Degradation of Fish and Wildlife Populations and support ongoing restoration efforts post-delisting. Ecosystem restoration planning requires an integrated approach considering many components of the natural system when prioritizing where and what to restore. Toronto and Region Conservation Authority (TRCA) and partners are developing a strategic approach to restoration planning, using the concept of applied science to inform meaningful implementation decisions focusing on priority areas rather than opportunism. TRCA has amassed a wealth of knowledge and data on terrestrial biodiversity, aquatic ecosystems, lake processes and hydrology. Consolidating these data sets to compare discrete areas based on different parameters and thresholds has helped direct future restoration initiatives. The Waterfront Integrated Restoration Prioritization (WIRP) framework uses existing data to reflect different restoration goals, ensuring important habitats and corridor linkages are protected, enhanced or rehabilitated. This is achieved by identifying where impairments to ecological function are located and prioritizing restoration opportunities that could contribute most to improving the existing habitat along the Toronto waterfront. This approach has been used in watershed planning and has proven successful for garnering support and new partnerships which has resulted in measurable improvements to the natural system. This presentation will outline WIRP methodology and demonstrate how it can be used as a tool to successfully achieve different natural resource planning objectives.
Great Lakes coastal wetlands are diverse and dynamic ecosystems that have developed to function under disturbances from both terrestrial and aquatic systems. Climate change is projected to alter these disturbances outside their historical ranges, subjecting coastal wetlands to warmer temperatures, more extreme precipitation events, greater variability in lake levels, and increased wind and wave action. These anticipated changes pose as an uncertain risk to coastal wetland habitats and are therefore challenging for natural resource managers, who must contend with limited resources for wetland management, preservation, and adaptation efforts. Using Lake Superior as a pilot, we are developing a framework to quantify the relative sensitivity of Great Lakes coastal wetland habitats to the anticipated effects of climate change. Data from the Coastal Wetlands Monitoring Program (CWMP) and state databases are used in conjunction with published literature, the Wisconsin Initiative on Climate Change Impacts (WICCI), and expert opinion of regional and state-wide wetland professionals to assign sensitivity scores to each wetland. Here, we present the frameworks developed and share initial sensitivity rankings for vegetation, fish, and bird habitats of coastal wetlands within the Lake Superior basin of Wisconsin. By combining sensitivity and adaptive capacity scores, estimates of wetland resiliency will assist in the prioritization of coastal wetland management efforts and inform site-specific adaptation strategies, which can then be replicated on other Great Lakes systems.
Often when we talk about coastal resilience, we are diving right into solutions that enhance or otherwise protect shorelines from the natural process. On low- and sometimes medium-energy shorelines, nature-based solutions lend themselves to positive environmental enhancements. However, on high-energy shorelines typical of Great Lake’s coastline, erosion and wave protection requires greyer infrastructure. Interrupting the natural process with rock or steel isn’t always the best solution and can be costly. We also know that climate change is resulting in periods of higher intensity storms and more extreme high and low water levels which puts valuable coastal property and infrastructure at risk.
Considering relocation for existing infrastructure and planning for higher water levels in the future are a necessary step in the planning process. It is a difficult shift to make for many communities and homeowners but can result in significant cost savings by being proactive and developing comprehensive alternatives analyses. Adapting the way projects are approached and considering all options takes a mindset shift. We will look at the planning process and execution of a Michigan State Park project where a hybrid solution was developed to save a historic building and protect prime public access to the Lake Michigan shoreline. Successful resilience requires not only innovative design, but a willingness to adapt the human emotional response as well.
