Monday
Introducing the Watershed and Ecosystems Living Lab (WELL): Building a multidisciplinary outdoor lab to support river restoration teaching and research
Elli Papangelakis1
1McMaster University, Hamilton, Canada
The Watershed and Ecosystems Living Lab (WELL) is an outdoor teaching and research facility on McMaster University’s campus that supports experiential learning in the environmental sciences and engineering. Designed by multidisciplinary team of geomorphologists, engineers, hydrologists, climatologists, and biologists, WELL integrates a wide array of real-time sensors, data loggers, and autonomous sampling systems to monitor the natural spaces on McMaster’s West Campus. The site supports undergraduate and graduate courses, student-led research, and training workshops across the University. Its educational value is enhanced by ongoing and planned renaturalization initiatives, including a restored riparian buffer, constructed wetlands and vernal pools, extensive tree planting, and a forthcoming river restoration project. This presentation introduces WELL and reflects on the opportunities and challenges of multidisciplinary collaboration in teaching and research.
Natural Awe Restoration: Revitalizing Eudora, AR Through Community-Led Design
David Bidelspach1,
Lee Forbes2,
Mike Geenen3,
Tomeka Butler4,
Mike Sullivan5
15 Smooth Stones Restoration, United States
25 Smooth Stones Restoration, Southeast, United States
3Green Watershed Restoration, Michigan, United States
4Eudora, Arkansas, United States
5Sullivan and Associates, United States
Rural communities like Eudora Arkansas are often left behind when it comes to ecological restoration and flood mitigation. This session explores a bold, community-led approach that integrates stream and wetland restoration, nature-based flood control, and restorative agriculture to reconnect residents with the land and each other. The guiding principle, Natural Awe Restoration, reframes restoration as not only ecological, but emotional and economical.
Attendees will explore how restoration projects can deliver direct community benefits by integrating social and economic goals into the planning, design, and implementation phases. Presenters will share innovative tools and models, including Stream Management Corridors that double as blue-greenway trails, frameworks for community-owned green infrastructure enterprises, and strategies for aligning funding with holistic outcomes.
Ecological Restoration should have the ability to Awe humans. Are you still able to experience a combination of dread, veneration, and wonderment that inspires you to be overwhelmed by greatness, and diverse complexities? Awe Restoration is term used to encourage the “child-like” wonder of our youth. During design, instead of focusing on optimizing ecological restoration based on ecological goals and objectives, this presentation will propose a backward way. Instead of Ecological Restoration being the end point, ecological restoration is the starting point or building block towards Economic and Ekklesia Restoration.
Naturalization of North Strasburg Creek – A Case Study in Multi-Disciplinary Approaches to the Restoration of Industrial Creek Corridors
Jacob Ursulak, MASc., P.Eng.1,
1Aquafor Beech Limited, Toronto, Canada
Channel restoration within urban creek corridors inherently invites the intersection of a complex web of multi-disciplinary objectives, constraints and stakeholder interests. The careful and effective management of competing interests and opportunities presents a challenge to practitioners, but also an opportunity to achieve immense added value when compared to following a strictly single-objective design approach. The recently completed restoration of the North Strasburg Creek corridor in the City of Kitchener represents an effective case study in the development of a multi-disciplinary design to restore urban channel systems in an industrialized area.
This presentation will outline the design techniques used to successfully implement a complex multi-disciplinary design intended to naturalize four reaches of North Strasburg Creek, including over 500 m of concrete lined channel. This in turn allowed for the achievement of interdisciplinary design objectives related to: flood mitigation, erosion control, infrastructure protection, ecological enhancement, and active transportation. Project management and engagement strategies will also be discussed, including the benefits and challenges associated with actively collaborating with groups at the federal, municipal, regulatory and community levels.
Lessons learned from all stages of the project life cycle, from design through construction, will be reviewed. This will illustrate how through effective interdisciplinary communication and a commitment to a multi-disciplinary design philosophy the project was able to achieve the following: naturalization of over 500 m of concrete lined channel, improve floodplain storage capacity, mitigate erosion risks to municipal infrastructure & private property, establish ecological linkages through a fragmented industrial corridor, and integrate active transportation infrastructure into the broader creek corridor system. Ultimately through the realization of this multi-disciplinary design, the project team was able to breathe new life into the anthropogenically modified North Strasburg Creek corridor and potentially recreate lost habitat for Brook Trout and other aquatic species that were displaced by historic development practices within the watershed.
Designing Large-Scale Fish Habitat Offsets for a Major Mine Development: A Multi-Disciplinary Approach
Heather Amirault1,
Cody Jackson2,
Mathieu Boucher3
1Stantec Consulting Ltd., Waterloo, Canada
2Stantec Consulting Ltd, Winnipeg, Canada
3Canada Nickel Company Inc., Toronto, Canada
Large-scale mine developments can pose a variety of challenges for natural channel systems, particularly where extensive harmful alteration, disruption or destruction (HADD) of fish habitat is unavoidable. The Crawford Nickel Project, located north of Timmins, Ontario, is one of Canada’s most prominent proposed mining projects, having been referred to the federal Major Projects Office and included in Ontario’s “One Project, One Process” framework. Canada Nickel is committed to meeting regulatory requirements and protecting the natural environment during the execution of this project.
The proposed mine project (approximately 11,800 ha) is predicted to overprint approximately 115 ha of fish habitat, requiring extensive fish habitat creation to offset losses due to overprinting. A multi-disciplinary offsetting strategy has been developed to address regulatory requirements while supporting long-term ecological function. A relative habitat value (RHV) approach was applied to compare habitat losses and offset gains across diverse waterbody types, including lakes, ponds, and multiple stream orders.
The offsetting approach is a large-scale, time-sensitive, collaborative effort that is pushing the boundaries of the natural channel design field. A central focus of this offsetting approach is the design and implementation of channel diversions as offsetting features. The design of these features highlights the importance of early collaboration with multiple disciplines, including understanding geotechnical and hydrogeological constraints, hydrology and hydraulics, and functional fish habitat requirements. Lessons learned from historical projects, including technical failures and long-term performance challenges, informed a design philosophy emphasizing durability, adaptive capacity, and regulatory confidence.
The project integrates opportunities beyond fisheries, including navigation needs, habitat for species at risk such as Blanding’s turtle, and Indigenous Knowledge-based monitoring. This presentation will discuss the challenges and lessons learned to date throughout the offsetting design process.
How Deep Do Streams Scour? Insights from Small Meandering Channels
Bryce Molder1,
Paul Villard1.
1GEO Morphix Ltd., Campbellville, Canada
Scour is the erosion of materials resulting in the lowering of the local or overall stream bed elevation. An understanding of scour is important for evaluating the hazard to underground infrastructure crossings of streams and in the design of bank protection treatments to prevent undercutting. Various types of scour are documented, including local scour, general scour, and natural scour. Scour types are assessed semi-independently and the limits summed to determine the scour hazard limit. Many different empirical and rational procedures are available to practitioners for estimating scour types and/or the scour hazard limit. A wide range of scour limits is often found when applying or comparing procedures, which can confound the selection of practical “safe design” elevations by practitioners. In this presentation we will review the various types of scour with reference to numerous Ontario case studies. We will compare observed degrees of local scour, general scour, and natural scour for small meandering streams and in-stream features (e.g., bridges, weirs, woody debris, etc.) and review the relative degree of bed lowering (scour-to-depth ratios). We will also explore challenges associated with conventional scour estimation procedures and possible means of addressing them.
Understanding sediment transport processes in the Credit River Watershed.
Amy Nicoll1,
Sally-Beth Betts1,
Victoria Barlow1
1Credit Valley Conservation, Mississauga, Canada
Understanding of sediment transport processes was identified as a gap through the Credit Valley Conservation Watershed Plan. This leads to uncertainty in watershed management decisions which is compounded with climate and land use change. To address this gap CVC is taking both a top-down and bottom-up approach. At the watershed scale we are using specific stream power and excess stream power as a screening tool to characterize sediment transport patterns for existing conditions and future land use and climate change scenarios. In addition to the watershed scale assessment, CVC is conducting two detailed sediment budgets.
The sediment budget studies are being conducted within a rural catchment on the West Credit River near Erin, and a heavily urbanized catchment on Sheridan Creek at Rattray Marsh in Mississauga. The West Credit study is being completed with funding from the Ministry of Environment, Conservation and Parks (MECP). Two field sites have been established on each watercourse. Samples are collected during moderate and high flow events using ISCOs samplers for suspended sediment and using Helley-Smith samplers and bedload traps for mobilized bedload material. The data is being used to develop initial rating curves for bedload and suspended sediment transport for each site. CVC will continue to develop these rating curves in future years. The results may be used to inform watershed management, such as restoration of aggrading sites, and managing hazards at sites prone to erosion.
Investigating Changes to Bed Shear Stress in a Semi-Alluvial Channel Through a Mild Winter
Christopher Giovino1,
Jaclyn Cockburn2,
Paul Villard1.
1GEO Morphix Ltd., Campbellville, Canada
2University of Guelph, Guelph, Canada
Semi-alluvial channels are complex and understudied fluvial systems that contain diverse hydrodynamic and morphological processes. This study investigated velocity and bed shear stress magnitudes and variability along a 100-metre reach of Sixteen Mile Creek, a semi-alluvial channel characterized by a heterogeneous bed in southern Ontario. Using velocity data collected with an Acoustic Doppler Velocimeter (ADV), velocity profiles and bed shear stress estimates were analyzed along six cross-sections under varying discharge conditions during winter and spring 2024. Velocity patterns showed higher maximum and average velocities during high-discharge periods, with the highest velocities aligning with the thalweg in gravel-dominated channel sections. Throughout the study reach, gravel beds exhibited the highest variability and magnitude in bed shear stress, particularly during high flow events such as a rain-on-snow (ROS) event in January, which caused rapid increases in discharge and water levels. In contrast, bedrock surfaces exhibited lower bed shear stress variability and remained relatively stable across-flow conditions. Changes in bed morphology further influenced hydraulic response, with finer-sized gravels (e.g., pebbles and granules) infilling during the falling limb of a significant runoff event resulting in a less rough bed and reduced bed shear stress. The results provide critical insights for managing and restoring semi-alluvial streams, emphasizing the need for strategies that account for the interactions between flow conditions and bed morphology to mitigate erosion and enhance channel stability
Protecting Water from Water: Assessing Braided System Bank Erosion Threatening Water Supply in a Mediterranean Climate
Joshua Moraal1
Jeff Doucette1
Seth Stevens2
1GHD Limited, Mississauga, Canada
2GHD Limited, San Luis Obispo, United States
As climate change continues to make extreme weather events more common, it is more important than ever to be able to identify banks of watercourses that are the most at-risk of failing and compromising infrastructure. During the winter of 2023, the Salinas River Valley in Southern California saw its highest recorded rainfall in 25 years, leading to massive flooding in January of that year and the third-highest peak flow ever recorded for Salinas River at Paso Robles, California. During these high flows, approximately 50 m of lateral bank erosion occurred along the right bank of Salinas River in Atascadero, California, causing catastrophic damage to the Nacimiento Water Project (NWP), a buried water pipeline servicing communities between Lake Nacimiento and San Luis Obispo, California.
Unlike the meandering channels of Southern Ontario, bank erosion along Salinas River is not comprised of consistent, year-over-year outer-bank migration, but rather periods of bank stability interrupted by large flow events that can cause massive bank failure. These bank failure events were identified and measured by analyzing aerial photographs of the study area from between 1981 and 2024. 131 bank failure events were identified and quantified. The distribution of magnitudes of these bank failures was used to rate the risk posed to the NWP at 56 at-risk sites identified during an initial screening of the pipeline. Risk was also rated based on other factors, such as density of riparian vegetation, surficial geology, and watercourse gradient. The consequence of pipeline failure at each site was then rated based on factors such as ease of access and distance along the pipeline. Sites were then given final priority ratings, ranging from “Very Low” to “Very High”. These priority ratings, in tandem with field site visits, were used to identify key sites to be prioritized for bank stabilization
Finding Stable Gound and Passive Flow Management
Kent Rundle1
1MLC Ecosystem Restoration Inc
Building natural channels and wetlands rarely goes exactly as planned. These projects take place in challenging environments with unique, unexpected and changing conditions. Despite robust studies and designs, there are often discoveries when the shovels break ground that require collaborative, and sometimes innovative, approaches to find constructible solutions. Using recent real word examples, I will explore some of the equipment and strategies we have used to address unstable soils while limiting budgetary impacts to clients.
As the industry becomes more competitive, we’ve been trying creative approaches to passive flow bypasses that not only improve efficiency but also reduce our carbon footprint. This presentation highlights project examples to illustrate these approaches in practice.
Woody Material – There’s a lot at “stake”
Christopher Pfohl1, C.E.T., EP, CAN-CISEC
1R.J. Burnside & Associates Limited, Guelph, Ontario, Canada
Woody Material use in Natural Channel Design has been increasing due to the need for aquatic habitat diversity within primarily stone lined channels. The use of woody material can also support hydraulic diversity, provide a means of thalweg creation and maintenance. Woody material has been used in many stewardship projects to protect banks from erosion and still ensuring that habitat is provided for aquatic life. RJ Burnside has just completed 10km of channel improvements along the South Innisfil Creek Municipal Drain that included 5 Phases and numerous woody material prescriptions that incorporated specific orientation of wooden stakes to ensure stability of the features. Not typical for municipal drainage projects although very practical considering the steeper sandy banks and available woody material. This presentation will highlight a number of projects that Woody Material has been used, types of features constructed (i.e. woody material matrix for bank protection, “leaky berm” that supports high flow storage, keystone/cedar mix, pinning and staking and tree root wad placement). Additional projects that required Natural Channel construction field fit (working with contractors and equipment), successful monitoring of as-built conditions and cold-water species use (trout refuge and spawning). A conceptual design for specific orientation of woody material to promote channel morphology, sediment transport to deposition locations and thalweg maintenance will be presented and discussed. Additional opportunities to review drone footage of a large woody material maintenance project to promote sediment migration from years of deposition in a Brook trout stream. Based on the limited use of Woody Material in S. Ontario, it is a great opportunity to discuss options with the audience including designers and practitioners.
Knowing What is Below Your Feet: The Importance of Geotechnical Data in Stream Projects
Chase Konecny1,
Peter De Carvalho1
1Stantec Consulting, Waterloo, Canada
Stream designs are multidisciplinary. Among these disciplines, geotechnical analysis plays a crucial role as soil properties directly influence the design and construction of watercourses using natural channel principles. Successful stream design and construction requires characterizing the soil properties of the project site – knowledge that must be understood and shared by designers and contractors to meet project objectives.
This presentation will highlight important geotechnical properties of soil that inform design and construction decisions. Components of design and construction that are influenced by these properties will also be discussed. In some cases, adapting designs to challenging soil conditions requires innovative, site-specific solutions. Drawing on project experience, we show how early recognition of soil and geological factors can be critical in identifying project challenges and support project success and efficiency. Case studies of recent channel designs will be used to illustrate how soil properties have necessitated design components that are case-specific and crucial for stream health and stability. We will also explore challenges that contractors face and how knowledge of soil properties and sub-surface conditions can help inform construction planning.
Audience participation and discussion will be encouraged to share perspectives and ideas from both designers and contractors. The goal of the presentation is to spark a constructive dialogue on how understanding soil properties can effectively inform stream design and construction, ultimately supporting watercourse health.
Return of the Salmon – Working in the Wet to Restore Fish Passage
Lucas Warner1,
David Bidelspach2,
Brad Fairley3
15 Smooth Stones Restoration Inc., Rocky View County, Canada
25 Smooth Stones Restoration PLLC, Fort Collins, United States of America
35 Smooth Stones Restoration Inc., Kitchener, Canada
Canadian National (CN) Railway is Canada’s largest railway, stretching from the Atlantic to the Pacific oceans, with approximately 21,900 km of track. This vast network crosses thousands of streams, many of which provide spawning grounds for Salmon which are important for commercial and sport fishing, as well as subsistence fishing for First Nations communities. As part of CN’s sustainability program, stream crossings are assessed for fish passage and repairs are made to maintain connectivity to important upstream habitats. Where the CN line crosses Stone Creek, south of Prince George, British Columbia, the bridge across the valley required several piers. To protect the piers, CN created a concrete flume through which Stone Creek was directed. After many years, the creek created a large scour hole which was undermining the downstream end of the flume. This also created a large drop that was affecting fish passage, including chinook and sockeye salmon trying to reach spawning grounds upstream. 5 Smooth Stones Restoration Inc. (5SSR) worked with CN Environment, Bridges & Structures and Geotechnical engineers to remove the concrete flume and re-naturalize the channel. However, the crossing is in a narrow valley with limited access, making it difficult to meet DFO’s standard for in-water site isolation. High summer flows meant work could not be completed during the least-risk timing window. 5SSR’s design team worked with Commotion Creek contractors to develop a construction plan that could be completed in just 3 days, limiting instream work and disruptions to native fish populations. The work would be completed in late-fall when water levels are at their lowest to limit sediment mobilization. DFO approved the plan, acknowledging the benefits of working in the wet. The cost savings from the short construction schedule allows CN to investigate other crossing improvements. Because the crossing was located near the bottom of Stone Creek, native fish species, including chinook and sockeye salmon, now have improved access to over 350 km and approximately 87 hectares of upstream habitat.
Assessing Floodplain Topographic Complexity in Large-Scale Corridor Restorations Using Particle Image Velocimetry
Lindsay Davis1,
Paul Villard1,
Tye Rusnak1,
Karine Smith1
1GEO Morphix Ltd., Campbellville, Canada
Large-scale corridor restorations across southern Ontario have traditionally employed relatively flat floodplain designs incorporating low-flow channels and wetland pockets. While effective for flow conveyance, these approaches often lack topographic complexity and hydraulic diversity within the floodplain. To address this limitation, we have implemented restoration designs incorporating pit-and-mound features to enhance floodplain heterogeneity and hydrologic function. A recently constructed corridor in Milton, Ontario, incorporated pit-and-mound features into its design. A series of six mounds was constructed, ranging in height from 0.25m to 0.50 m. The mound elements are vegetated to increase surface roughness, thereby attenuating overbank flows, while adjacent pit features are intended to retain water and promote infiltration. During the spring freshet and large-flow events, surface water velocities around these features were captured using unmanned aerial vehicles (UAVs), enabling high-resolution spatial data collection over a broader area than conventional field methods. Acoustic Doppler Velocimeter (ADV) measurements were also collected to calibrate and validate UAV-derived velocities. Velocity vector distributions were processed using particle image velocimetry (PIV) in PIVLab, generating spatially distributed flow patterns and scatterplots for the assessment. These analyses allow us to evaluate flow attenuation, recirculation zones, and water retention associated with the pit-and-mound features.
Response of a Restored Wandering Channel to Ice Dam Formation and Failure on the Mad River
Paul Villard1,
Laura Wensink2,
Ben Miller1,
Tye Rusnak1
1GEO Morphix Ltd., Campbellville, Canada
2Nottawasaga Valley Conservation Authority, Utopia, Canada
Restoration projects are rarely tested under conditions that push flow beyond the channel and into the floodplain. This presentation examines the response of a recently restored section of the Mad River (Ontario) to an ice jam event that forced flow out of the channel and across the floodplain before returning upstream of an installed bank treatment.
Between 2023 and 2025, restoration focused on re-establishing channel complexity and stability in a historically straightened system. Measures included a vegetated rock buttress bank treatment, reactivation of secondary channels to support a wandering stream pattern, and the installation of in-channel boulder clusters to increase roughness and improve habitat.
During the 2026 freshet, an ice jam formed approximately 1.5 km upstream of the project site. Backwater conditions forced high energy flow into the floodplain and across agricultural fields, forested areas, and parkland. The overtopping event created defined flow pathways, initiated early-stage channel formation, and deposited significant amounts of sand, gravel, and cobble within the floodplain. The new flow path resulted in rapid headcutting through the project site, contributing to two defined bank erosion features and two bed scour features along this pathway. The temporary flow path re-entered the Mad River behind the installed bank treatment. Despite the upstream impacts, approximately 70 m of vegetated rock-buttress bank treatment remained intact and performed well given these reverse-flow conditions. Areas with reactivated secondary channels showed less erosion, indicating that distributed flow paths reduced energy and limited damage.
This case highlights several lessons learned. Bank treatments remain vulnerable when flow approaches from behind. Secondary channels can reduce erosion under high-energy conditions. Restoration performance must be evaluated at the corridor scale, not just the treatment footprint. There is also value in identifying potential overflow pathways where floodplain activation is likely.
City-wide Creek Erosion Inventories: Methodologies of Risk Assessment and Prioritization for Municipal Management Programs
Julia Howett, M.Sc.1,
Roger Phillips, Ph.D., P.Geo., FGC2
1Onterris, Guelph ON, Canada
2Onterris, Oakville ON, Canada
Municipal erosion inventory studies are typically initiated to document erosion concerns and to enable identification of priority sites for erosion hazard mitigation to ultimately inform Capital planning.
Asset management trends vary in complexity from simple mapping and database development representing absence/presence of erosion and bed/bank protection condition documentation, to a comprehensive tool that includes natural assets of habitat and watercourse/drainage features for priority ranking and long-term planning.
Standard erosion risk assessments evaluate hazards as the product of probability and severity. Erosion risk probability is evaluated through assessment of the likelihood of asset exposure to erosion hazards; and severity is evaluated as the relative consequence of erosion to impacted property, people, and/or infrastructure. Scoring criteria must apply to a large range of watercourse conditions (e.g., rural to urban, headwaters to major rivers) and various mechanisms of erosion. Assessment methodologies are also tailored to reflect responsibilities of municipalities in terms of risk to public safety and private land. Methods must be practical and easy to implement as a combined field and desktop assessment, balancing technical detail with efficiency. Professional judgement, supported by field experience and training, remains a key component of consistent application.
The success of a stream erosion inventory database is rooted in the collection and management of inventoried data. Building a framework for data collection must clearly identify the objectives of the database and planning needs. Consideration of relevant spatial and temporal scales is necessary, including how inventories are updated over time to reflect channel change and asset condition. Identification of parameters to inventory should allow for both static (i.e., data collected every iteration) and dynamic (forms to allow for flexibility of various inventory items) data. The platform in which the data is collected should be carefully selected with these considerations in mind, as a key element to long-term program sustainability is using tools that can be easily adopted by field staff and allow for reproducible results. Advantages and disadvantages are apparent with the digital world of data collection and should be reviewed while preparing for inventory data collection. Once the database has been developed, it becomes a powerful tool to enable scoring of sites and support transparent and adaptable prioritization of erosion risks over time.
Reflection on Natural Channel Design over the Past 20 Years in the Credit Valley Watershed
Rizwan Haq1
Jon Nodwell1
Sally Betts1
1Credit Valley Conservation
Over the past twenty years, natural channel design has been widely applied across the Credit River Watershed to address erosion, flood risk, habitat degradation, and channel instability within an increasingly urbanized landscape. During this period, dozens of projects have been implemented across a range of geomorphic settings and development contexts, creating a valuable opportunity to reflect on both successful outcomes and unintended challenges.
This presentation synthesizes lessons learned from two decades of natural channel design practice, drawing on case studies, post-construction monitoring, adaptive management, and long-term practitioner experience. The Huttonville Creek case study highlights the importance of anticipating beaver activity when designing naturalized corridors. Over time, beavers transformed the engineered corridor into an online wetland, fundamentally altering channel form, hydrology, vegetation, and ecosystem function.
The Springbrook Creek case study demonstrates that densely planted fast-growing plant species such as willows along channel banks may unintentionally drive geomorphic change. In this system, vigorous willow growth has modified channel hydraulics and sediment dynamics, shifting the intended low‑flow meandering planform into a braided morphology and, in some locations, into wetland conditions.
As practitioners, we must continue sharing lessons learned and adapting our approaches to natural channel design beyond traditional design expectations. We hope that this presentation will facilitate some discussion about what we can do better in the future.
Practitioner Perspectives and Lessons Learned from Over 20 Years of Fluvial Geomorphic Monitoring at Toronto Pearson International Airport
Matthew Iannetta1,
Jeff Hirvonen1
1GeoProcess Research Associates Inc., Dundas, Canada
It is well understood that urbanization contributes to changes in the hydrologic characteristics of the landscape, influencing the quantity, quality, and timing of surface runoff routed to stream networks. These modifications are linked to a variety of common symptoms observed in urban watercourses, commonly referred to as the “urban stream syndrome”, which include degraded water quality, reduced biotic richness, and altered channel stability and morphology. Etobicoke Creek and Spring Creek are two watercourses located in the Greater Toronto Area that exemplify the urban stream syndrome, situated within a predominantly urbanized catchment characterized by limited legacy stormwater management controls. As these watercourses traverse lands managed by the Greater Toronto Airport Authority at Toronto Pearson International Airport, they present potential erosion risks to critical adjacent property and infrastructure.
The Etobicoke Creek and Spring Creek erosion monitoring program, first commissioned by the Greater Toronto Airport Authority in the early 2000’s, is a long-term study that tracks rates of erosion, identifies at-risk infrastructure, and recommends mitigation following a risk-based framework. The program adopts an adaptive management philosophy, responding to the evolving needs of the river system within the unique operational constraints of the airport. The associated study area encompasses six distinct river reaches that are surveyed for physical indicators of channel instability, primarily focused on erosion, with repeated survey records dating back to 2009. Recent observations include a significant storm event that occurred in July 2024, offering insights into system response and resiliency to infrequent, high-magnitude floods. Monitoring program findings have contributed quantitative insights that have informed the implementation of stream restoration work throughout the history of the program.
In this session, we present perspectives and lessons learned from decades of stream restoration interventions implemented within the study area. By examining a spectrum of restoration outcomes, from well-established successes to notable failures, we can better understand how the stream system evolves and adapts, at times deviating from original design expectations. The findings derived from the program highlight the importance of long-term monitoring in guiding informed stream restoration outcomes within a dynamic urban landscape.
Since 1976 – A Creek Contractor’s Perspective on the Industry
Jared Reinders1
1R&M Construction
For nearly five decades, creek and waterway restoration has evolved from simple erosion control measures to complex, multidisciplinary projects that balance environmental stewardship, regulatory requirements, and constructability. Drawing on the lived experience of a contractor rooted in the industry since 1976, this presentation offers a practical, boots-on-the-ground perspective on how the field has changed—and where it is heading.
The session will highlight lessons learned from decades of field execution, including what works, what doesn’t, and how collaboration between designers, regulators, and contractors can lead to more successful outcomes.
Attendees will gain a deeper appreciation for the contractor’s role in delivering resilient, naturalized waterway solutions, and leave with practical insights that can improve project planning, design, and execution.
When Does a Process Become a Hazard? Managing a System of Complex River Crossings
Amber Garrett1
1Enbridge, Calgary, Canada
Linear infrastructure networks face the unique challenge of intersecting many different fluvial systems. For pipeline operators, this can involve managing tens of thousands of water crossings across multiple provinces, states, and countries, ranging from steep, confined mountain streams to unconfined alluvial systems in agricultural settings. Many of these crossings were constructed before fluvial geomorphology was routinely incorporated into engineering design, therefore, these crossings rarely accounted for scour, bank erosion, meander belt width, or avulsion potential. Over time, these processes can lead to exposures or unsupported spans that may exceed allowable stress or strain tolerances.
The nature of linear infrastructure requires management processes that accommodate both site-specific and regional variability within a common framework that is communicable to industry, regulatory bodies, and communities. Therefore, a water crossing management program must take an asset lifecycle approach, focusing on site identification, assessment, monitoring, and mitigation in a world characterized by uncertainty. Such a program must address key questions, such as: How do operators assess and prioritize risk? How do they decide when and how to monitor a crossing? When does a crossing require mitigation?
Rather than treating all channel change as inherently problematic, decisions within a water crossing management program are guided by the interaction between river processes and infrastructure tolerances. These decisions balance risk, uncertainty, constructability, permitting constraints, stakeholder considerations, and cost. This presentation will demonstrate a management approach that emphasizes managing river processes rather than attempting to eliminate them, within a framework that is scalable, defensible, and communicable to regulators and communities.
Don River Restoration and Sanitary Sewer Overflow DWST-2
Don McBrayne1, P.Eng.,
1Associated Engineering (Ont.) Ltd., Kitchener, Canada
As part of the City of Toronto’s Basement Flooding Protection Program, Associated was awarded the detailed design and construction for a trunk sanitary surcharge Dry Weather Storage Tank located in Villaways Park, northeast of Sheppard Ave. E and Leslie Street, on the East Don River. This presentation will focus on the first phase, the river crossing and restoration, now complete.
The presentation will begin with briefly describing the Natural Channel Design restoration elements – Pool and Riffles, Armourstone Ribs with bedding, Vegetated Boulder Revetment (VBR) slopes and a weir removal. The main focus will be addressing the challenges of construction phasing and implementation, resulting from attempting to limit construction disturbance of natural area with the inherent construction risks of doing so, including narrowing the open-channel flow path, and relying on the existing 2-year storm elevation as the basis for coffer dam height, and an unpredictable urban watershed.
After work-zone flooding, we realized the hydraulic model of the 2-year flood and recorded events did not align, as such the diversion plan would have benefited from more freeboard. Additionally, instead of dividing the channel in half for construction flow diversion, temporary widening/relocation of the river should have been a part of the flow diversion plan. The trees intending to be saved, did not survive construction, and yet resulted in a constricted flow path contributing to coffer dam overtopping. This speaks to a dichotomy between trying to meet the competing interests of both preserving natural treed area, whilst also attempting to satisfy the technical requirements of a construction bypass plan. Lots of Before, During and After photos will be included for interest.
Balancing erosion risk and habitat quality in a process-based restoration at a lake outlet
Megan Iun1,3,
David West2,
Bruce MacVicar3, etc.
1GHD Ltd, Waterloo, Canada
2Trinity Consultants, Vancouver, Canada
3University of Waterloo, Waterloo, Canada
This work is an update on preliminary results previously presented at the 2023 Natural Channels Conference. In partnership with the Nootka Sound Watershed Society and Mowachaht/Muchalaht First Nation, we designed a spawning habitat restoration for a threatened population of Chinook salmon on Vancouver Island (BC). The project site is in a heavily logged watershed, where hydrologic effects of reduced forest cover and climate change impacts have degraded fish habitat. Gravel augmentation is a process-based restoration technique that entails placement of clean, washed gravel in sediment-deficient streams to improve geomorphic and ecologic functions such as a healthy sediment balance and fish spawning productivity. However, gravel augmentation carries inherent risks related to clogging, scouring, or poor habitat quality if incorrectly designed. Lake outlets are perceived to be ideal locations for restoring Chinook spawning habitat as (1) the upstream lake traps fine sediment and attenuates peak flows and (2) Chinook prefer to spawn downstream of lakes. Lake outlets are characterized by non-uniform flow, adverse bed slope and minimal bedload supply, which differ from typical fluvial environments. Thus, existing guidelines and analysis methods need to be tested and adapted for these environments.
We developed a TELEMAC-2D hydrodynamic model of the site at Muchalat Lake outlet to characterize hydraulic conditions and assess three risk indicators: gravel mobility, hydraulic habitat quality and fine sediment deposition. Calibration was completed with velocity transects collected by Acoustic Doppler Current Profiler. Preliminary model calibrations were impeded by insufficient bathymetry and led to difficulties in setting appropriate boundary conditions. Model updates using high resolution bathymetry collected by drone eliminated calibration uncertainties. Shear stress maps generated from the model were used to predict spawning gravel mobility using Wilcock & Crowe (2003). Mobility zones were validated using a 3-year tracer stone monitoring program.
Model validation was limited by low peak flows during the monitoring period but suggested that the model was able to predict mobility on average. Results showed that high mobility zones corresponded closely to high-quality habitat, indicating a trade-off between mitigating erosion risk to maximize design longevity and supporting ecological preferences of the target species. These findings highlight the importance of risk and adaptive management for process-based restoration approaches. The gravel placement was constructed in September 2025 with preliminary monitoring showing high use by spawning salmon. Ongoing monitoring will be crucial to evaluate resilience of the gravel to peak flows and continued use of by returning salmon populations.
Regulation of Shorewalls on the Nottawasaga River: Can Conservation Authorities Manage Conflicting Interests of Ecology, Engineering and Aesthetics?
Nicole Vankooten1,
1Nottawasaga Valley Conservation Authority, Utopia, ON
The Nottawasaga Valley watershed is characterized by its Georgian Bay shoreline communities, though, pressures to urbanize and trivialize essential watershed functions present challenges to maintain balance between human settlement and natural hazards. Many lakeside and riverside properties rely on the construction and maintenance of shorewalls to protect their homes from erosion and flooding hazards.
Shorewalls, are considered to be “protection works” according to the MNR Technical Guidelines-Great Lakes-St. Lawrence River Shorelines-Part 7, consisting of “engineered non-structural or structural development and site alteration located within the hazard.” Ainley & Associates Limited identified five appropriate methods of structural and non-structural shoreline erosion protection for the Nottawasaga River on behalf of the Town of Wasaga Beach in their 2014 study Nottawasaga River Shorewall Standards. These standards intend to “promote stable riverbanks with regard for a more aesthetically pleasing shoreline” highlighting the important intersections between engineering and aesthetics. Furthermore, these standards bring awareness to the potential for shorewalls to maintain and promote, rather than destroy, critical riparian and aquatic habitat. The standard emphasizes the need to consider structural protection works only when naturalization and bioengineering techniques are not reasonable.
Despite the findings of this study twelve years ago, shoreline communities in the watershed continue to rely on structural works when constructing or maintaining shorewalls on riverside properties susceptible to erosion. Conservation authorities have a legislative duty to review proposed development, including shorewalls, within regulated areas to manage risk associated with natural hazards under the Conservation Authorities Act. This provides Conservations Authorities the opportunity to collaborate with municipalities, landowners and contractors to assess the viability of naturalization or bioengineering shoreline protection before permitting proposed structural works. The Shorewall Standards further provide inspiration for harmonious solutions that encompass multiple approaches, such as repurposing existing cedar post walls by cutting them down to the low water level with a layer of stone for scour protection at the toe of the slope and planting of native vegetation on the slope (see Figure). Promotion of these bio-engineered solutions in the permit review process with Conservation Authorities can effectively manage conflicting interests of ecology, engineering and aesthetics
Bridging Fish Passage and Infrastructure Needs: Lessons from Cross-Jurisdictional Watercourse Crossing Design Guidelines
Nikan Momenbeitollahi1,
Heather Amirault1
1Stantec Consulting Ltd., Waterloo, Canada
Historically, infrastructure design at watercourse crossings has prioritized structural stability, often at the expense of ecological connectivity. As expectations for fish passage, riparian function, and natural channel processes have evolved, practitioners are increasingly challenged to integrate these objectives into design of watercourse crossings where erosion hazards, infrastructure protection, costs, and constructability can pose critical constraints.
In Canada, legislation such as the Fisheries Act provides broad protections for fish and fish habitat but offers limited direction on how to balance ecological outcomes with stabilization and infrastructure requirements. As a result, designers rely on a wide range of fish passage design guidelines at watercourse crossings developed across various jurisdictions in Canada and the United States. While these guidelines share common ecological principles, they differ in technical recommendations and assumptions, which can significantly influence design outcomes.
This presentation explores how fish passage guidance at crossings is applied in practice when infrastructure objectives compete with ecological goals. Drawing on examples from different jurisdictions, we examine various design recommendations, where conflicts commonly arise, and what design compromises are often required. Using a sample watercourse crossing scenario, the presentation compares conceptual designs developed under different jurisdictional guidelines to highlight differences, best practices, with the goal of providing practitioners with a clearer understanding of how guideline selection and interpretation influence real-world crossing designs, and how to identify opportunities for balanced and ecologically functional solutions.
Lessons Learned on Water Quality Treatment Wetlands for Phosphorus Reduction in an Urban Setting
Paul Biscaia1,
Jennifer Dougherty1,
Kata Bavrlic1,
Benham Doulatyari1,
Sally-Beth Betts1,
1Credit Valley Conservation, Mississauga, Canada
The Good:
In 2020, Credit Valley Conservation (CVC) completed the Black Creek Subwatershed Study with Halton Region and other stakeholders. The study examined the subwatershed’s natural features and water resources, outlining goals and strategies for their long-term management. Improving water quality by deceasing nutrient inputs was a central recommendation of the study.
Based on a prioritization exercise completed by CVC and through discussions with Halton Region and Town of Halton Hills, a proposal to conduct a Feasibility Study to determine if constructed wetlands along Black Creek could address total phosphorus (TP) reduction in Fairy Lake in Acton, Ontario was developed.
The Bad:
Fairy Lake is a 26 hectare Provincially Significant Wetland with high phosphorus concentrations, elevated levels of E.coli and increasing frequency of cyanobacteria blooms, caused by mixed urban, agricultural runoff, septic systems and geese overpopulation.
The Ugly:
Background studies indicated that constructed wetlands could provide TP removal benefits up to 25% (US EPA 1995). Additional literature review indicated that there are important design considerations that influence nutrient removal efficiency such as: length of flow path, pretreatment, sufficient hydraulic head for gravity flow, controlled storm flow rates and catchment area to wetland area ratio.
Applying University of Guelph MIKESHEE model catchment data to two inlets into Fairy Lake, it was determined that neither site could accommodate wetlands of sufficient size to achieve desired TP reductions due to existing site constraints.
The wetland area required to meet water quality treatment objectives far exceeded the available footprint at the inlet sites due to constraints from existing residential and recreational land use.
Lessons Learned:
The feasibility study highlighted the need to properly size treatment wetlands to ensure they do not act as nutrient sources during large precipitation events. Contributing catchment area and treatment wetland size are the primary drivers of the feasibility of using wetlands for TP reduction and can be a useful initial screening tool for selecting preferred treatment solutions. The large wetland area needed for reliable TP removal is particularly limiting in retrofit situations where existing built-out environments and land uses constrain the creation of appropriately sized features to achieve treatment objectives. Instead of relying on wetland creation as an end-of-pipe solution, a distributed approach was recommended, emphasizing upstream best management practices such as channel naturalization, low-impact development technologies, agricultural BMPs, and goose management
Sitlika Creek: the Bad, the Ugly and the Really Ugly
Brad Fairley1,
Lucas Warner2,
David Bidelspach3
15 Smooth Stones Restoration Inc., Kitchener, ON, Canada
25 Smooth Stones Restoration Inc., Rocky View County, AB, Canada
35 Smooth Stones Restoration PLLC, Fort Collins, CO, USA
This project had its genesis in an excellent program run by an NGO that identifies barriers to fish migration. Through this program, the NGO identified a culvert under an abandoned rail line on Sitlika Creek north of Prince George BC as a significant barrier to salmon passage. The NGO contacted the rail company to see if they wanted to participate in the removal of the culvert and they agreed to work together. Based on the removal of more than a dozen barriers The NGO hired the same multi-national engineering firm that they had used to remove the other barriers to come up with a design. The NGO provided the design to the rail company who then engaged the firm that they had used to address fish passage issues on other culverts to finalize the design and oversee construction. Things went downhill from there. Despite the challenges, we are hoping that the NGO, the rail company, the consultants and DFO have learned some valuable lessons. The presentation will explore what went wrong and what the take-away messages were for those involved in the project.
How to Solve a Sewer Issue – The Highland Creek Story from Watershed Scale to Project Implementation
Emma Schiller M.Sc., P.Eng.1,
Momin Haque, Ph.D., P.Eng.2,
Robert Amos M.Asc., P.Eng.3
1Aquafor Beech Limited, Ottawa, Canada
2City of Toronto, Toronto, Canada
3Aquafor Beech Limited, Toronto, Canada
Highland Creek drains an urban watershed situated almost entirely within the City of Toronto’s east end, with many segments considerably straightened, realigned, and hardened to coincide with surrounding urbanization. An intricate network of buried sewer infrastructure exists throughout the valley system, using gravity to convey flows to a treatment centre located at the downstream limits of the watershed. Sanitary trunk sewers are typically inset beneath the channel and floodplains; however, intermittent exposures have become an ongoing issue due to erosion and channel enlargement. Aquafor has been working with the City for over two decades to assess and mitigate these risks.
Concerns regarding systemic channel instability and frequent infrastructure exposure along Highland Creek were documented in the 2003 Toronto Wet Weather Flow Master Management Plan. The WFMMP also evaluated the role that land based controls would have in reducing the erosion potential and existing risks within Highland Creek, concluding that channel rehabilitation and erosion restoration measures are the feasible and preferred solution at a macro / watershed scale.
Next, the Highland Creek Geomorphic Systems Master Implementation Plan was completed in 2010. The Highland Creek drainage network was subdivided into valley segments and valley segment concept plans were created to determine strategies for protecting infrastructure and stabilizing the geomorphic and aquatic characteristics of Highland Creek.
Over the last decade, the scope has narrowed to address individual valley segments through a series of studies on Geomorphology and Infrastructure Risk Analysis, resulting in prioritized conceptual plans for valley segments across the watershed. The results of these valley segment studies were then consolidated into a master implementation plan for Highland Creek.
Four sites within Valley Segment 3 have emerged as the City’s top priority area, with a unique array of sanitary sewer exposures, deteriorated grade control structures, and man-made waterfalls. Detailed design of these priority projects is nearing completion, marking the beginning of a new phase in the history of sewer exposure risk mitigation within the Highland Creek watershed.
Barefoot Box Culvert™ – 10yrs of Learning
Christopher Pfohl, C.E.T., EP, CAN-CISEC1
1R.J. Burnside & Associates Limited, Guelph, Ontario, Canada
Over the past 10 years R.J. Burnside & Associates Limited has designed, constructed and monitored a novel innovative pre-cast box culvert that can improve existing conditions for aquatic life. Based on the need to replace degraded, cast in place structures, and the concerns related to maintaining channel form and function, this unique culvert design has been proven to support sensitive aquatic life through ground water input. Over the last 10 years various methods of monitoring and testing have been used to confirm the potential to support thermal stability and create critical spawning habitat for sensitive coldwater species such as Brook trout (Salvelinus fontinalis). Methods used to determine form and function include water temperature, groundwater pressure, eDNA and videography. Observations and results may prove that the Barefoot Box Culvert™ could be the first of its kind in the World used to support aquatic life and provide critical habitat for cold water species. The benefit of using the Barefoot Box Culvert™ relates to ease of construction, time and cost savings to clients and most importantly, providing a solution to maintain or improve thermal stability in stressed aquatic environments. The Barefoot Box Culvert™ has been designed, approved, and installed in 30 locations across Southern Ontario and within 8 Conservation Authority Watersheds. Regulatory acceptance and industry knowledge are key aspects that need to be advanced, and the results of this pilot study will support this process. A video will be provided at the end of the presentation that will prove the success of this novel innovative box culvert design.
Fish Habitat Banking at DFO: Lessons learned and next steps
Sarah Matchett1
1Fisheries and Oceans Canada, Burlington, Canada
The Department of Fisheries and Oceans (DFO) in Canada has been working with proponents to ‘bank’ fish habitat restoration, enhancement and creation projects for more than 30 years. The concept builds on the 1986 Fish Habitat Policy, which introduced the guiding principle of “No Net Loss (NNL) of productive capacity of habitats”, requiring proponents to balance unavoidable habitat losses of a project with replacement habitat (i.e. compensation or offset), a principle that has since guided DFO.
Offsetting measures are the actions taken by a proponent to counterbalance the residual effects to fish and fish habitat that are caused by their project, after avoidance and mitigation measures have been applied. Habitat banks are a specific type of advance offsetting that have 3 main elements: 1) subject to a Habitat Banking Arrangement between DFO and the proponent, 2) consultation with Indigenous Peoples about proposed fish habitat banks and their proposed conservation projects is carried out by DFO, and 3) the project must be demonstrated to be functioning as intended via monitoring before credits can be withdrawn. DFO has administered dozens of banks Canada-wide, in diverse habitats (marine, riverine, palustrine, estuarine) and with varied proponents. Previous science advice on habitat banking has recommended methods for measuring productivity and ecological function of different habitats, calculating ecological equivalence, and appropriate monitoring requirements (baseline, as-built and long-term). Criticism of the habitat banking approach has included misapplication of the mitigation hierarchy, proponent noncompliance, a lack of monitoring on environmental impacts or project success, and weak scientific basis underlying compensation or practices. In the context of condensed project review timelines, habitat banking has the potential to enable a more flexible, efficient, transparent and predictable approval process. This will enable a more timely administration process to meet fish and fish habitat protection requirements under the Fisheries Act; and provide better habitat offset outcomes for government agencies, the public and industry. Moreover, the Habitat Banking approach underscores the importance of early engagement and collaboration with all partners to identify restoration priorities and support informed decision-making about projects affecting fish and fish habitat.
Tuesday
Management of Toronto’s Watercourses over nearly three Decades
Bill Snodgrass1,2,
Adam Zietara1,
Kumar Sivakumaran3,2,
Daniel McCreery3,
Rod Anderton1,2,4
1Toronto Water (TW), City of Toronto, Canada
2Retired from Toronto
3Engineering & Construction Services, City of Toronto, Canada
4Consultant
This paper traces factors that have influenced the evolution of Toronto’s watercourse management particularly by Toronto Water which is supported by the water (/ wastewater) rate. The earliest period includes the post- 1998 amalgamation of 7 municipal governments which also financed water and sewer infrastructure from the water rate. Next, the Wet Weather Flow Master Plan (WWFMP) of 2003 established a watercourse restoration plan in 5 year blocks with a budget of ca 100 million over 25 years as a part of the total WWFMP budget (stormwater ponds and underground tanks, basement flooding, combined sewer overflow (CSO) controls etc) of ca $1 billion. The WWFMP demonstrated the need to intervene in streams because land based hydrological and water controls were inadequate to address the impacts of stream erosion to water infrastructure from stormwater (and flood flow) runoff.
The WWFMP concept for stream restoration focused on 1 km length of project units to rebuild geomorphically stable channels. But subsequent extreme storms, starting with the Aug 19th 2005 storm necessitated that Toronto Water focus particularly on protecting exposed sanitary sewer crossings, using a shorter length of watercourse than 1 km. This 2005 ‘Act of God‘ caused a break in the East Highland trunk sewer, releasing raw sewage to Lake Ontario over the three day period of the event, before it was stopped by our internal watercourse construction crews. To ensure the integrity of natural channel liners, the approach is to address immediate shorter stretches, and then to link the re- constructed sections around sanitary crossings with a subsequent project at a future date.
Since 2005, master plans are prioritized for water courses in most need of restoration to protect Toronto Water infrastructure while in parallel rebuilding shorter stretches of creeks/ river to protect highly exposed infrastructure. The Geomorphic Systems Master Plan (GSMP) first completes a study of the whole stream’s geomorphology from headwaters to its confluence within Toronto (using the 2003 guideline). Then the GSMP defines separate projects which focus on the appropriate stream length needed to protect infrastructure or address O. Reg 588/17 asset plans for stream channels.
This paper summarizes other formative management aspects, including: (i) cost estimation of the WWFMP(1 million/km) through the late 2000s(6M/km) to the 2021 time frame(11.M/km), (ii) design guidance ( 2 m of cover over a sanitary sewer in Highland, 0.5 to 1 m of cover in other water courses; 0 m of cover in certain limited cases), (iii) coordination of scheduling planning studies and construction projects with Parks and Recreation (trails, recreational buildings in valleylands), Metrolynx and MTO(Ontario Line and 400 series highways ), Toronto Transportation (culverts and bridges) and TRCA (private property erosion, wetland and restoration projects) and Solid Waste (old land fills near creeks), (iv) succession planning and administration (TW is the planning unit; ECS(Engineering and Construction Services) manages most Consultant (EA and Design) and Construction (tenders, post construction) contracts.
The ultimate achievement has been to move from having designs and construction with a horizon of one to three years, to having a 10 year capital (in 2021) and then to having a capital plan with a 20 year focus (10 year capital plan plus projects defined for 10 to 20 years in the future). Simultaneously (i) Inspections of all Toronto Water related erosions issues with field walks on all water courses every three years plus (ii) post construction monitoring to estimate the design life of constructed natural channel liners (using visual inspection and quantitative assessments of riffle longevity) have commenced to provide information for Asset Management and Adaptive Management, the philosophy of the Provincial 2003 Guideline. Significant research questions remain; for example, ‘how many riffle-pool sequences upstream and downstream of a sanitary sewer crossing will provide a stable natural channel liner for a 30 year period, before sufficient riffle material is lost through erosion and requires rehabilitation project for a riffle?’
Bridges (et cetera) Over Troubled Water: Region-Scale Erosion Hazard Screening to Support Municipal Asset Management
Andrew Doherty, P.Eng1,
Peter De Carvalho, P.Eng.1
1Stantec Consulting Ltd, Waterloo, Canada
Approaches to infrastructure planning near watercourses have evolved substantially over recent decades. Today, greater recognition is given to the dynamic nature of river systems, including channel migration and erosion, and their implications for long-term infrastructure performance. However, infrastructure built in the past has left municipalities with a legacy of assets near natural channel systems that are vulnerable to erosion, access loss, and service disruptions.
Municipalities face the challenge of understanding, managing, and mitigating risk across extensive infrastructure networks that interact with natural channel systems, including roads, water, gas, and wastewater infrastructure. Defining and forecasting risk is a complex undertaking, further complicated by the increasing frequency of high-magnitude flood events driven by climate change.
This presentation will discuss and explore the application of a region-wide erosion hazard assessment in the Region of Peel. This assessment was used to support infrastructure planning for more than 56,000 sanitary sewer maintenance holes and 7,500 water distribution valve chambers, helping Regional staff identify at-risk assets and informing requirements for monitoring, mitigation, or decommissioning. The assessment integrated geomorphological principles with asset location and function to identify infrastructure at risk across multiple planning horizons and to support informed decision-making.
Applying a proactive, region-wide approach to assess erosion risk and manage municipal assets can reduce reliance on reactive emergency response while instead supporting defensible, long-term infrastructure planning. The concepts and approaches that will be explored in the presentation are transferable to municipalities managing a wide range of infrastructure within dynamic urban channel systems.
Protection of Municipal Sewer and Water Assets Around Urban Watercourses
Robert Chan1,
Rob Amos2,
1City of Toronto, Toronto, Canada
2Aquafor Beech Ltd., Mississauga, Canada
The City of Toronto (City) has kilometers of assets (e.g. sanitary trunk sewers, storm outfalls etc.) within the ravines of the city. These assets are frequently located adjacent to or under natural or straightened watercourses. Watercourse erosion, which has been exacerbated by urbanization, causes vulnerability to the structural integrity of these assets.
This presentation will provide a summary of the City’s extensive watercourse management program to protect water and sewer assets. Key program elements will be discussed, such as the on-going monitoring program to inspect sewer and water assets near watercourses, the prioritization of capital projects from geomorphic studies and inspections, and an overview of the current capital plan. The presentation will offer insights into the municipal perspective on the planning and development of watercourse projects. Included would be a discussion on some of the challenges and opportunities of addressing risks to infrastructure in urban watercourse systems. Highlights will include a summary of the new tools developed to improve the tracking, planning, and coordination of projects and at-risk sites between City departments and the Toronto and Region Conservation Authority.
Erosion control assets, such as armour stone bank structures and engineered natural channels, have been implemented over decades throughout the City’s 450 km+ of watercourses to protect public and private interests from erosion. As part of the requirements to meet O.Reg 588/17(ASSET MANAGEMENT PLANNING FOR MUNICIPAL INFRASTRUCTURE) , the City developed its first asset management plan for erosion control (EC) assets. Completion of the plan improved the management of erosion control assets by creating an inventory of assets, providing awareness of asset conditions, and streamlining electronic data accessibility. This presentation will discuss some of the methodology and results of the different elements of the plan including a) Inventory; b) ConditionAssessment; c) Service Level; d) Risk Framework; e) Lifecycle Activities, and f) Cost. A useful planning level tool which estimates cost of implementing different types and scales of erosion control projects in urban environments will be presented.
Watercourse Asset Management and DFO Habitat Banking: Kitchener’s Model
Nick Gollan1,
Sarah Matchett2
1The Corporation of the City of Kitchener, Canada
2Fisheries and Oceans Canada, Burlington, Canada
Stormwater management in Kitchener is funded through the Stormwater Utility, established in 2010, which allocates costs to all public and private property owners based on the amount of runoff they generate, with impervious area serving as the rational nexus – a first for Canadian municipalities. The creek naturalization program demonstrates how municipalities can manage watercourses as core assets under Ontario’s asset management regulations while delivering measurable ecological outcomes. Through its 2025 Corporate Asset Management Plan, the City defines stormwater service performance, resiliency, regulatory compliance, and community value, and uses condition and risk assessments, along with service performance, to prioritize lifecycle interventions for both grey and green infrastructure.
A foundational step was the formal recognition of watercourses as an asset class in 2013. Kitchener inventoried approximately 126 km of watercourses and valued them alongside pipes, ponds, and culverts, enabling transparent tradeoffs between conventional channel rehabilitation and engineered natural channel solutions. Natural channel projects restore geomorphic stability, improve flood conveyance and erosion control, and reduce long‑term maintenance liabilities while supporting broader watershed objectives. Other benefits for the watershed include renaturalized form and function of watercourses with habitat heterogeneity (riffle-pool morphology, woody structure, undercuts) and improved water quality. This approach also supports climate adaptation by improving floodplain connectivity, creating thermal refugia, and augmenting public realm benefits that residents and regulators increasingly expect locally.
Beyond local hydraulic and infrastructure benefits, these works produced quantifiable gains in fish habitat. Critically, Kitchener established Canada’s first municipal proponent‑led Habitat Banking Arrangement with Fisheries and Oceans Canada (DFO) (signed August 15, 2016), generating an estimated 15,349 m² of habitat credits. Habitat banking is a formalized approach to offsetting in which a proponent proactively restores or creates fish habitat in exchange for credits to offset anticipated future impacts requiring Fisheries Act authorization. Embedding this credit ledger into the LOS framework will reframe habitat creation as both a service outcome and a financing tool: credits can offset future project impacts and reduce the need for costly letters of credit.
Municipal Watercourse Projects: Approaches and Cost Considerations
Daniel McCreery1,
Devin Coone1
1City of Toronto, Toronto, Canada
Over a decade ago the City of Toronto created a Stormwater Management Group in its Engineering and Construction Services Division to implement stormwater and watercourse restoration projects. Since then, numerous watercourse restoration studies and design and construction projects have been completed. This presentation will provide an overview of the City’s approaches to watercourse work over the last decade while highlighting trends and cost considerations.
The presentation will provide a review of the following areas from the past 10 years:
- A high-level review of watercourse restoration professional and construction services costs and overall trends observed over the previous decade.
- A look at the ever-evolving permitting landscape and costing.
- The City’s approaches to watercourse studies, including watercourse restoration alternatives and evaluations.
- City approaches to tendering and construction for watercourse work.
- Concepts and tools used to highlight watercourse restoration benefits to financial and asset management staff.
Following the above review, the presentation will look ahead at anticipated changes to City watercourse projects, given anticipated regulation changes. It will also include a discussion on future City design and construction initiatives to be more efficient by bundling watercourse projects to improve project delivery rates.
A canopy variety hotspot metric to guide riparian forest planning and planting design decision-making
Corey Dawson1,
Kai Zuo1,
Ana María González Calderón2,
Mathieu F. Bilodeau1,
James Veres3,
Chris Smith3,
Brandon Heung1
1Dalhousie University, Truro, Canada
2Pontifical Javierian University, Bogotá, Colombia
3Maritime Aboriginal Peoples Council, Truro, Canada
Storm-driven windthrow increasingly alters riparian forest structure and function, highlighting the need for scalable metrics that quantify canopy heterogeneity linked to resilience. This study presents a Canopy Variety Hotspot (CVH) metric for measuring and mapping statistically significant clusters of canopy height variability using LiDAR-derived canopy height models (CHMs). The approach applies the dimensionless Focal Statistics type “Variety” combined with Hot Spot Analysis to identify structurally complex riparian canopy clusters across multi-temporal datasets. We tested neighbourhood window sizes and spatial distance parameters to evaluate sensitivity and scalability across four riparian zones in Nova Scotia, Canada. Windthrow impacts from Hurricane Fiona (2022) were used as a reference for comparing structural canopy changes from CHMs collected in 2013 and 2024. We propose the metric as an adaptive strategy for monitoring riparian vegetation responses to natural and anthropogenic disturbances.
Results showed that smaller circular windows (r = 3) were most sensitive to proportional canopy change, while Inverse Distance Squared with a 7.5 m threshold distance refined statistically significant clusters. Multi-temporal comparisons quantified cluster loss, gain, and areas that remained significant over an 11-year period, identifying canopy structures potentially resilient to storm-driven windthrow. A proof-of-concept framework was also developed, where field-based tree inventories and complementary metrics demonstrated correspondence between canopy height variety and richness–greenness performance. The framework translated CVH outputs into a conceptual climate-adaptive riparian planting design emphasizing deep-rooted species and structural diversity. The CVH metric provides a scalable, flexible, and repeatable approach for integrating structural canopy variability into spatial and temporal river corridor monitoring, while providing target maps for guiding site-specific riparian restoration design.
Community-Based WASH Interventions as Indirect Drivers of Natural Channel Resilience: Evidence from Rural Uganda
In rural Uganda, limited access to reliable groundwater infrastructure compels households to depend on nearby rivers, ephemeral streams, and shallow surface sources for domestic water supply. This dependence frequently results in bank destabilization, sediment disturbance, and contamination from open defecation and unmanaged greywater discharge. While natural channel science often focuses on geomorphic restoration and hydraulic engineering, less attention has been given to how decentralized water access interventions may indirectly influence channel condition and watershed resilience.
This study examines the relationship between community-led water, sanitation, and hygiene (WASH) programming and natural channel use patterns. Drawing on participatory mapping, household water-use surveys, and qualitative monitoring of stream access points before and after borehole installation, the research evaluates changes in surface water abstraction, riparian disturbance, and sanitation-related pollutant pathways.
Findings indicate that improved groundwater access, combined with hygiene education and locally managed water committees, significantly reduces routine human pressure on vulnerable streambanks. Reduced reliance on direct river collection corresponds with decreased footpath erosion, lower sediment mobilization near abstraction points, and improved riparian vegetation recovery. Furthermore, structured community governance mechanisms enhance awareness of watershed protection and seasonal flow variability.
The paper argues that community-centered WASH interventions function as measurable contributors to natural channel resilience. Integrating public health infrastructure planning with watershed management frameworks offers a scalable, low-cost complement to traditional channel stabilization approaches. These findings highlight the importance of cross-sector collaboration between river engineers, hydrologists, and community development practitioners in advancing sustainable river systems in developing contexts.
Value of Information (VOI) Analysis of a Stream Power-Based Toolbox for Erosion Risk Assessment and Management
Priyanka Hire1,
Elli Papangelakis1,
Niko Yiannakoulias1
1McMaster University, Hamilton, Canada
Stream erosion is an increasing concern in many Canadian watersheds due to urbanization, land-use change, and more intense rainfall events associated with climate change. Effective watershed management requires tools that can identify erosion-prone areas and support informed decisions about mitigation strategies. Stream Power Index for Networks (SPIN) is one such tool that calculates total and specific stream power along the stream network using digital elevation models and land-use data. Although previous work has shown promise in SPIN’s ability to identify areas of high erosion risk in small, urban watersheds, its monetary value for improving watershed management decision-making is still unknown.
Value of Information (VOI) is an analysis technique that estimates the monetary costs and benefits associated with the additional knowledge provided by a model or decision-support tool when making decisions. Although it has predominantly been used in the context of healthcare management and policy, it has increasingly been applied to assess the value of environmental models. In this study, VOI was applied to evaluate how the information provided by the SPIN toolbox could improve erosion monitoring and management decisions from a monetary perspective. VOI analysis inputs were collected through an online survey of watershed management practitioners across Canada, including conservation authorities, municipalities, engineering consulting companies, and environmental agencies. Inputs included the frequency of erosion events, economic damages associated with erosion, erosion monitoring practices, and the costs and effectiveness of both traditional erosion control and nature-based infrastructure measures.
This presentation summarizes survey results to present an overview of how stream erosion is currently identified, managed, and prioritized across the country, as well as key challenges faced. Results from the VOI analysis demonstrate the financial value associated with watershed-scale erosion risk screening tools such as SPIN. Additionally, results identify the types of information most financially valuable for watershed-scale erosion management and support the ongoing development of the SPIN toolbox. Ultimately, this work aims to improve decision-support tools that enable more cost-effective watershed management strategies.
Assessing Brook Trout habitat in a peri-urban headwater stream
Ian D. Smith1,
Daniel Hu2,
Nicholas E. Mandrak1
1University of Toronto, Scarborough Campus, Canada
2University of Toronto, St. George Campus, Toronto, Canada
A population of native Brook was found to exist within a headwater channel of the Twelve Mile Creek in the Niagara Peninsula using randomized eDNA and Ontario Stream Assessment Protocol (OSAP) sampling in 2023 and 2024 respectively. Spot sampling throughout the watershed indicated that an extant native Brook Trout population was limited to one headwater channel that is relatively unimpacted by urbanization, while numerous other more impacted headwater channels within the same system were found to be devoid of Brook Trout.
In the summer of 2025, a detailed electrofishing sampling effort was undertaken within two kilometers of thalweg distance in the occupied headwater channel to determine the abundance of Brook Trout in this part of the system. This was achieved using a novel capture-mark-recapture (CMR) technique using non-invasive pattern recognition of left flank photos of all Brook Trout captured. Image processing was completed using an artificial intelligence approach with human supervision. Furthermore, all Brook Trout were sampled genetically via buccal swabs to build a close-kin analysis to further clarify abundance via a close-kin mark recapture (CKMR) approach.
The detailed assessment of 2025 was partitioned into habitat segments (consisting of either pools or riffles/runs/glides) allowing for the estimation of Brook Trout abundance by habitat type. Each of the 85 habitat segments was rated for habitat covariates that included water temperature, water chemistry, substrate, canopy cover/shading, fluvial geometry, velocity at baseflow, large woody cover, and proximity to overbank groundwater inputs. This has allowed for the determination of the relative importance of these habitat covariates in terms of measured Brook Trout density for this peri-urban coldwater stream in southern Ontario.
For the headwater reaches that are not currently hosting coldwater fish species such as Brook Trout, similar covariate analyses have occurred to determine suitability for hosting a translocated population of fishes. It is anticipated that Brook Trout from the occupied headwater channels may be used as a source population for Brook Trout translocation after stream rehabilitation via natural channel design and system mitigation on these channels has been completed.
This effort will ultimately inform restoration and rehabilitation strategies for coldwater streams in a systematic fashion, where habitat covariates that are deemed critical for a targeted species such as Brook Trout are ranked for importance. Stream restoration and rehabilitation should not only seek to stabilize systems physically but create high quality ecologically sustainable habitat.
Non-Invasive Monitoring of Brook Trout to Support Adaptive Management in River Corridors
Lexiang (Daniel) Hu1,
Nathan E. Mandrak2,
1Department of Ecology and Evolutionary Biology, University of Toronto, Canada
2Department of Biological Sciences, University of Toronto, Canada
Monitoring sentinel species like Brook Trout (Salvelinus fontinalis) in headwater streams is often limited by the invasiveness of physical tagging and the time required for manual photo matching, which can hinder dynamic adaptive management in resilient river corridors. In this study, a non-invasive photo-identification workflow was used to estimate adult Brook Trout abundance in the Effingham Branch of 12 Mile Creek, a Southern Ontario stream. Using IBEIS-assisted identification and human verification, I processed flank images from 1,494 encounter events and identified 105 verified adult recaptures between two sampling passes. A pooled Bayesian Lincoln-Petersen model yielded an estimated adult superpopulation of 466 individuals (95% HDI: 438–501), corresponding to a linear density of 0.24 adult fish/m. The adult cohort had a mean Fulton’s condition factor of 1.03, establishing a baseline reference condition. To address the scalability limits of human-verified matching for continuous monitoring, a custom Two-Stream Multi-Modal neural network was trained using the verified image set. On a blind holdout of adult fish, the model achieved 92.9% identification accuracy and reproduced the verified recapture structure without generating false-positive cryptic matches at the selected threshold. Together, these results support the use of natural pigmentation patterns for non-invasive Brook Trout monitoring and establish deep learning-assisted photo-identification as a highly viable proof-of-concept. While broader multi-basin validation is necessary, this automated workflow offers a promising pathway to equip practitioners with the scalable, data-driven tools needed to monitor ecological responses and inform adaptive management in resilient river corridors.
Managing Flood and Erosion Risk in Canadian River Systems using Nature-Based Infrastructure: A Canadian Guideline for Design and Implementation
Sean Ferguson1,
Ivana Vouk1
1National Research Council Canada, Ottawa, Canada
Nature-Based Infrastructure (NBI) are strategies or designs that depend on, or mimic, natural system processes to manage risks while delivering environmental and societal co-benefits. There is increasing interest in NBI for riverine flooding and erosion risk management in Canada, and globally, owing to their ability to manage risk while minimizing disruption of natural river systems. Furthermore, unlike conventional engineering approaches that rely on hard, immobile features, NBI often have more flexibility to adapt to long-term changes and evolving risks. Despite the growing interest in NBI, and the availability of international and region-specific guidance, NBI still remain underused in many Canadian river systems and there is often a hesitancy to adopt these approaches owing to uncertainty and a lack of authoritative, national-scale design guidance. To address this gap, the National Research Council of Canada (NRC) is leading a multi-year project to develop evidence-based, technical guidelines for NBI design and implementation in Canadian river systems. The guidelines integrate lessons-learned from Canadian case studies where NBI have been implemented, or are being considered, to address flood and erosion risks. The featured case studies encompass a range of flooding and erosion challenges in distinct geographic locations in Canada. The guideline is being composed in collaboration with approximately 30 authors from approximately 20 organizations including municipalities, watershed authorities, academia, private industry, and other government departments. Collectively, lessons-learned from each case study and contributions from the diverse authorship team will help to ensure that the guidelines are informative, practical, evidence-based, and broadly applicable in Canadian river systems. This presentation provides an overview of the draft guideline, which is nearing completion following five years of development, as well as a brief description of supporting case studies. The presentation will also highlight remaining research gaps and potential opportunities to further improve NBI guidance in Canada.
Floodplains are Nature Based Infrastructure
Bruce MacVicar1,
Sally Betts2,
Christina Bright3,
Corey Dawson4,
Sean Ferguson5,
Mike Gallant6,
Hossein Kheirkhah Gildeh7,
Allison Matfin6,
Rachael Messenger-Lehman1,8,
Elli Papangelakis9,
Colin Rennie10,
Thiruni Thirimanne1
1University of Waterloo, Waterloo, Canada
2Credit Valley Conservation, Missisauga, Canada
3Toronto Region Conservation Authority, Toronto, Canada
4Dalhousie University, Halifax, Canada
5National Research Council Canada, Ottawa, Canada
6Kerr Wood Leidal Associates Ltd, Canada
7Barr Engineering Co, Calgary, Canada
8Stantec, Waterloo, Canada
9McMaster University, Hamilton, Canada
10University of Ottawa, Ottawa, Canada
Floodplains are infrastructure because they ensure drainage of the landscape in times of flood and provide a location for sediment storage such that the intermittent processes of sediment supply and transport can be buffered. Both of these ecosystem functions reduce hazards for human lives and built infrastructure in floods. Floodplains also provide innumerable other ecosystem services. For river restoration and sustainable management, it is important to place channels within a floodplain context, to prioritize space and connectivity where feasible, and restore dynamism where possible. Nature-based management of floodplains as infrastructure says that we should consider the time and spatial scales of these natural landscapes and allow them to evolve over time. However, historical evidence and reviews of engineering practice shows that river floodplains are frequently constrained or eliminated.
The goal of this review is to accelerate the adoption of techniques, many of which are already being applied in Canada and around the world, that enhance the physical and ecological resilience of floodplains and rivers. Specific objectives are to a) review research literature on the principles of nature-based infrastructure as applied to floodplains, b) outline different approaches that are being applied around the world, and c) summarize best-practices for design and implementation of floodplain restoration techniques. For the first objective, we used the key function of floodplain sediment storage to structure the review that touches on the distribution of floodplains in a watershed, longitudinal and lateral connectivity, dynamism, and ecosystem engineers. For the second objective, floodplain classification, the definition of an adequate width of a floodplain corridor, tools available for floodplain analysis, and specific examples of approaches used to enhance lateral or streamwise connectivity are discussed. Best practices are summarized with design recommendations and examples from across Canada. The work from this presentation will be integrated into a guidance document on Nature-based infrastructure for riverine flood and erosion risk management led by the National Research Council Canada – Ocean, Coastal, and River Engineering.
What Does Channel-Scale Nature-Based Infrastructure Aim to Do?
Elli Papangelakis1,
Sally Betts2,
Christina Bright3,
Sean Ferguson4,
Mike Gallant5,
Hossein Kheirkhah Gildeh6,
Bruce MacVicar7,
Allison Matfin5,
Colin Rennie8
1McMaster University, Hamilton, Canada
2Credit Valley Conservation Authority, Mississauga, Canada
3Toronto and Region Conservation Authority, Toronto, Canada
4National Research Council Canada, Ottawa, Canada
5Kerr Wood Leidal Associates Ltd, Canada
6Barr Engineering and Environmental Services, Calgary, Canada
7University of Waterloo, Waterloo, Canada
8University of Ottawa, Ottawa, Canada
Nature-based infrastructure (NBI) for riverine flood and erosion risk management encompasses a diverse set of solutions that span several spatial scales, from the entire watershed down to a single rocky ramp. At the smallest scale, channel-based NBI approaches include structures implemented within the channel boundaries that offer localized solutions to identified problem areas. Channel-scale NBI approaches encompass a huge diversity of solutions with varying goals, materials, and design approaches that can often make it difficult to choose the appropriate measures for a given flood and/or erosion challenge. Moreover, channel-scale approaches can only be successful if they are designed and implemented within the boarder floodplain and watershed context in which they are built. Consequently, identifying the best channel-scale NBI solution is not a trivial or easy choice.
This presentation provides an overview of commonly employed channel-scale NBI and introduces tools to help classify, choose, and design these approaches appropriately based on the flooding and erosion processes occurring. Specifically, it aims to 1) place seemingly diverse channel-scale NBI solutions onto a unified framework centered on the hydraulic and geomorphic processes driving riverine flooding and erosion, 2) classify NBI solutions based on their goals and materials to place them on a decision-support matrix, and 3) provide an overview of best-practices for designing and implementing selected NBI solutions. Examples of successfully implemented channel-scale NBI projects will be highlighted. The aim is to both summarize the diversity of NBI approaches available for managing riverine flood and erosion, and to provide watershed management practitioners with useful tools to help them choose between different solutions and implement them following best practices. The work from this presentation is also being integrated into a chapter in the new guidance document on Nature-based infrastructure for riverine flood and erosion risk management led by the National Research Council Canada – Ocean, Coastal, and River Engineering.
Using processed based restoration techniques to create natural systems infrastructure in support of salmon habitat restoration in costal British Columbia
Leif Burge1,
David West1,
Leah Ballin1,
Joe Kennedy1,
Patrick Walshe1.
1Trinity Consultants Canada, Courtenay, Canada
The use of natural systems infrastructure in restoration can improve geomorphic and ecological function in impacted rivers. Historically and currently, many systems in coastal British Columbia were impaired by logging, climate change and water diversion. Process based approaches to restoration using nature-based techniques can help guide a channel to improve its function by letting the river do the work.
We employed a rage of nature-based techniques in the toqʷanən (Theodosia) and the Oktwanch watersheds in coastal British Columbia over the last year. These systems are historically important salmon streams with degraded habitat and depressed salmon populations. We employed large wood features (LWF), and riparian gravel bar planting instead of large excavations, complex channel designs or engineered logjams within the two systems.
Large wood placements restore key geomorphic functions that were once supplied by old-growth forests. In the toqʷanən logs were placed by helicopter and ballasted with large stones. These LWF were designed to create scour pools, enhance cover, promote sediment storage, and concentrate low-flow channels to improve salmon passage at low flows. They mimic natural tree‑fall processes and address critical deficits in habitat complexity caused by decades of riparian logging. In the Oktwanch, small LWF were constructed on gravel bars using nonfunctional wood scavenged from within or adjacent to the channel. The purpose of these LWF were to provide a velocity shadow to encourage deposition and protect plantings.
Gravel bar planting using live stakes, bioengineering, and conifer/deciduous plug plantings accelerates natural bar succession, stabilizes over‑widened channels, enhances shading, adds roughness, and builds future sources of woody debris.
Projects on the Oktwanch and toqʷanən rivers show that vegetation establishment drives channel narrowing, deeper thalwegs, improved fish passage, and increased organic matter supply, directly benefiting salmon spawning and rearing habitats.
These examples demonstrate how natural systems infrastructure can restore watershed function, rebuild geomorphic processes, and enhance fish habitat resilience. The approaches are low‑tech, culturally aligned, scalable across watersheds, and designed to build long‑term community capacity, offering a robust model for salmon habitat recovery across coastal British Columbia.
Erosion and Flood Management in Agricultural Streams: Nature-Based Infrastructure in the Nottawasaga River Watershed
Laura Wensink1,
Don Little1
1Nottawasaga Valley Conservation Authority, Utopia, Canada
Nature-Based Infrastructure (NBI) is gaining traction as a resilient alternative to conventional flood and erosion management. Recent NBI funding in Ontario have emphasized wetlands and stormwater systems, but excluded natural channel systems. This presentation highlights the Nottawasaga River Restoration Program (NRRP), led by the Nottawasaga Valley Conservation Authority (NVCA), as a multi-year, partnership-driven case study advancing NBI implementation.
The project demonstrates how severe bank erosion, water quality degradation, and habitat loss in agriculturally impacted systems can be improved. Historically degraded by intensive livestock access, channel instability, and rapid erosion, this site also supports species at risk and sportfish spawning grounds. Following 3 years of rehabilitation, Sheldon Creek now features stable stream banks, terraced floodplain shelves, and several oxbow wetlands which support flood and erosion mitigation. This work could not be accomplished without private landowner partnership, which allowed 1.5km of livestock exclusion fencing, 15 m vegetated buffer, and a stabilized stream crossing that maintains farm operations while protecting aquatic habitat.
Restoration techniques combine engineered design with natural materials, including toe protection using anchored woody debris, terraced bank grading, and floodplain reconnection. These measures dissipate energy during high flows, reduce erosion rates, and enhance sediment retention. Complementary features such as constructed oxbow wetlands, low-flow bypass channels, and in-stream habitat structures improve hydraulic diversity and support fish habitat. Completing this project in multiple phases, has allowed for lessons learned to be incorporated into subsequent design phases.
The largescale restoration efforts leveraged the work of heavy equipment with community engagement to ensure that even projects on private property can involve and benefit the local community. Volunteer-based planting and bioengineering has enabled scalable restoration and stakeholder engagement. Since 2019, over 4.6 km of streambank has been stabilized, nearly 1 hectare of wetlands created, and thousands of native trees planted, supported by strong community engagement.
Hydrological Reconstruction of Flood Discharges Using Palaeostage Indicators in the Kaveri Gorge, Southern India
Pramodkumar Hire1
1HPT Arts and RYK Science College, Nashik, India
(Affiliated to Savitribai Phule Pune University, Pune, India)
Flood hazard management in monsoon-driven rivers is hindered by high spatiotemporal rainfall variability and scarce long-term hydrometric records across the Indian subcontinent. In such data-limited settings, palaeoflood hydrology offers a rigorous framework for reconstructing the magnitude and frequency of extreme flood events from pre-instrumental periods, encompassing recent, historical, and prehistoric times, through detailed analysis of geomorphic and sedimentary flood archives. Quantitative palaeoflood discharge estimates are commonly derived using two principal approaches, palaeo-competence analysis, which infers flow strength from the calibre of coarse bedload transported during the flood, and hydraulic reconstruction, which calculates discharge from the elevation of flood deposits relative to prevailing channel geometry.
This study integrates multiple palaeo-stage indicators (PSIs), including laterally continuous tree lines, slackwater deposits (SWDs), palaeo-competence analysis of coarse bedload, and historical maximum stages from documented and anecdotal sources, to constrain palaeoflood stages at five sites within the bedrock gorge section of the Kaveri River. Discharge estimation was supported by upstream and downstream gauging records, applying the slope-area method and supplementing it with one-dimensional steady-state hydraulic simulations in HEC-RAS. To assess the effects of large-magnitude floods, parameters of the hydraulics were computed.
A sensitivity analysis across a range of Manning’s n values representative of bedrock-confined channels yielded palaeoflood discharges between 5,641 and 13,420 m³s⁻¹. Validation against gauged peaks at Kollegal (upstream) and Biligundulu (downstream) shows strong concordance, with reconstructed magnitudes closely matching the 2019 flood. The historical inflow maximum at Mettur Dam (12,912 m³s⁻¹) aligns with the upper bound of the reconstructed envelope. The highest values of stream power (59,643 Wm⁻²) and bed shear stress (3,225 Nm⁻²) indicate high erosive capacity, Froude number straddling unity denote subcritical and supercritical flows, while high Reynolds number confirms extreme turbulence. These findings provide critical insights for flood hazard management in data-sparse fluvial systems.
Thermal Regimes of Stormwater Management Ponds and Their Influence on Instream Temperatures
Shauna Henderson1,
Karine Smith1,
Patrick Padovan1,
Paul Villard1
1GEO Morphix Ltd, Campbellville, Canada
Stormwater management facilities and natural channel designs are widely implemented in new developments to protect and enhance environmental features while mitigating hydrologic and water quality impacts on downstream watercourses. Stormwater management ponds, in particular, are used to attenuate peak flows and reduce total suspended solids (TSS) and other contaminants in runoff before discharge to receiving streams. Over the last decade, design approaches for these ponds have increasingly explored opportunities for enhanced thermal mitigation.
This study examined the thermal dynamics of three SWM ponds and a downstream enhanced natural channel in Milton, Ontario, to assess how pond outlet temperatures compare with, and influence, temperatures in the receiving watercourse. The analysis focused on water temperature responses to precipitation events and periods of thermal stress immediately following channel realignment, when thermal signals are most pronounced and shading from riparian vegetation and the surrounding urban landscape is minimally developed.
Continuous water temperature and water level data were collected at 5-minute intervals from April 1 to November 30 during pre- and post-channel realignment and post-construction compliance monitoring of three SWM ponds (2015–2022). Instream loggers were installed upstream and downstream of each pond outlet to assess how temperature regimes change along the receiving watercourse. Within each pond, sensors were deployed at the inlets, in the sediment forebay, and at the outlet, and a separate continuous temperature chain was installed near the bottom draw to characterize main-cell thermal stratification and better understand how SWM facilities influence the receiving watercourse. Comparisons of inlet, in-pond, outlet, and instream records indicate that pond outflows were consistently cooler and lacked the pronounced diurnal fluctuations observed instream, resulting in a net cooling effect on downstream watercourses. That said, the cooling effects were less pronounced in downstream sensors as instream temperatures were more strongly driven by atmospheric conditions than by pond releases. This study offers insight into the ability of SWM ponds to provide thermal mitigation, highlighting how stormwater engineering solutions can also deliver additional environmental benefits.
2D Hydraulic Modelling in the Consulting Environment: Practical Applications in River Restoration
Lukas Mueller1,
Ahmed Siddiqui1
1GEI Consultants Canada Ltd., Guelph, Canada
Two-dimensional (2D) hydraulic modelling is increasingly available to practitioners and is routinely referenced in guidance for natural channel design and river restoration. As its use becomes more common, there is growing interest in how 2D modelling can be applied effectively and proportionately within consulting practice to support design decisions that balance process understanding, constructability, and environmental function. We explore practical applications of 2D hydraulic modelling drawn from real world consulting projects, with a focus on aligning modelling effort with project objectives and constraints.
We begin with a brief overview of commonly used 2D modelling approaches commonly used in fluvial geomorphology practice. Typical input datasets are discussed, including drone-derived topography, publicly available LiDAR, and conventional survey data from field assessments. Emphasis is placed on selecting data sources that are appropriate for the scale and purpose of the analysis, and on making informed trade-offs between resolution, cost, and accessibility.
Applied case examples are then presented showing how 2D models were used to test and refine specific design components. These include evaluation of fish passage, hydraulic connectivity of online and riparian wetlands, functionality of dropped-bank ingress channels, and performance of rock vortex weirs. Spatial mapping of outputs such as water depth, velocity, and shear stress is used to assess hydraulic and ecological performance, providing additional insights that extend beyond what can be obtained using one-dimensional approaches alone.
The presentation concludes with a discussion of the role of 2D modelling in the consulting environment. Drawing on precedent applications, the discussion highlights how proportionate use of 2D modelling can enhance design confidence, provide insight into potential impacts of climate change, and support environmentally sound outcomes without requiring expanded scope or specialized research level analyses.
Impacts of Dam-Induced River Flow Changes on Vegetation in the Draa River (Morocco): Insights from Hydrological Modeling and Remote Sensing
Ali Meskour1,2
Sonia Hassini2
Jihane Ahattab1
Saad Bensallah1
Moulay Driss Hasnoui1
1The Laboratory of Civil Engineering, Climate, Water, Environment and Transport (LaGCET), Hassania School of Public Works, Casablanca, Morocco.
2Departement of Civil Engineering, Faculty of Engineering, McMaster University, Hamilton, Ontario, Canada
River flow regulation by dams significantly alters the natural hydrological regime of arid and semi-arid river systems, with important consequences for riparian and agricultural vegetation. This study investigates the impacts of dam-induced river flow changes on vegetation dynamics in the Draa River basin in southeastern Morocco. The river system is strongly influenced by the operation of the Mansour Eddahbi Dam, which regulates downstream water availability and plays a key role in sustaining oasis ecosystems and agricultural activities. The analysis combines hydrological data, dam release records, and remote sensing observations to assess the relationship between flow variability and vegetation response. Vegetation dynamics were monitored using satellite-derived indices, particularly the Normalized Difference Vegetation Index (NDVI), derived from multi-temporal satellite imagery. Hydrological modeling was employed to characterize flow variability and evaluate the influence of dam-controlled releases on downstream hydrological conditions. Results highlight a strong relationship between regulated flow patterns and vegetation variability in the river corridor and surrounding oasis areas. Periods of increased dam releases are generally associated with improved vegetation conditions, while reduced flows and prolonged dry periods contribute to vegetation stress and decline. These findings emphasize the critical role of dam management in maintaining ecological and agricultural sustainability in arid river systems. The study provides valuable insights for integrated water resources management and highlights the importance of combining hydrological modeling and remote sensing to better understand the interactions between water regulation and ecosystem dynamics.
Flood Susceptibility Mapping Using Hydrogeomorphology: A Case Study of the Humber River Basin, Ontario
Jasper Wong1,
Adeyemi Olusola1
1Faculty of Environmental and Urban Change, York University, Toronto, Canada
Flood susceptibility mapping (FSM) is a crucial tool for hazard mitigation and land-use planning. However, flood-generating processes often vary across different landscapes and are not always fully captured by traditional terrain-based methods. This study develops a hydrogeomorphologically informed FSM framework for the Humber River Basin in Ontario, focusing on the contrasting environments of the rural Main Humber and the urbanized Lower Humber. Using a regulatory 100-year fluvial flood extent as the dependent variable, two sets of predictors are created: a baseline set that includes topographic, land-cover, and permeability variables, and an enhanced set that incorporates hydrogeomorphic and sediment-related indicators, such as stream power, sediment connectivity, channel morphology, and valley confinement. These datasets are used to evaluate and compare multiple modelling approaches, including logistic regression, machine learning, deep learning, and hybrid convolutional neural network–machine learning models, with respect to predictive accuracy, spatial consistency, and interpretability. To support the physical interpretation of model outputs, basin-scale modelling is complemented by reach-scale geomorphological assessments. Selected areas of high and low susceptibility are analysed to characterise channel and valley conditions, including confinement, channel stability, sediment storage, and human modifications, and to evaluate their consistency with dominant flood-generating mechanisms identified through explainable AI techniques. This integrated approach acknowledges that river channels are dynamic systems, where processes such as sediment transport, aggradation, and bank erosion can significantly influence flood behavior. The study aims to improve FSM by enhancing both predictive performance and process-based understanding across a variety of riverine environments.
Wednesday
Classifying Complexity and Mapping Meaning in Fluvial Geomorphology
Roger Phillips1, 2
1University of Toronto, Toronto, Canada
2SLR Consulting, Guelph, Canada
Classification has long been a central tool in fluvial geomorphology, providing a means to organize complexity, compare systems, and support decision-making in river management, restoration, and design. Yet classifications do more than describe rivers: they shape what is measured, what is emphasized, and ultimately how risk, resilience, and intervention are understood. In practice, these interpretive frameworks underpin commonly applied tools such as reach delineation, erosion risk assessment, and prioritization methods, shaping how river systems are evaluated and managed. This presentation frames these tools as expressions of underlying interpretive choices that influence how river behaviour is understood and acted upon.
This presentation reflects on the role of classification as a form of interpretive infrastructure in river science—a necessary simplification that both enables and constrains interpretation. Drawing on research from low-relief, glacially conditioned river systems in southern Ontario, the talk examines how inherited landscape controls, sediment supply legacies, and spatial discontinuities challenge widely applied classification frameworks and assumptions of equilibrium behaviour. These examples are used selectively to illustrate how different interpretive framings can lead to different conclusions about system behaviour and risk. Multivariate floodplain and reach-scale classifications illustrate how meaningful structure can emerge from data without implying fixed types or universal trajectories.
Beyond specific methods, the presentation situates river classification within broader questions of practice: how frameworks become standardized, how particular variables are privileged over others, and how successful approaches can inadvertently narrow the scope of inquiry—a process described here as epistemic capture. In a session context, this provides a foundation for considering how subsequent approaches to reach delineation, risk assessment, and process interpretation build on and extend these choices. While often unintentional, such capture has implications for natural channel design, hazard assessment, and regulatory review, particularly under conditions of climate change and non-stationarity.
Rather than advocating a single “better” classification, the talk argues for a pluralistic and purpose-explicit approach to classification—one that treats frameworks as provisional, contextual, and revisable. In the context of resilient river corridors, resilience is framed not only as a property of channels and floodplains, but also of the knowledge systems used to interpret them. This framing is intended to set up the session’s progression from system definition, to risk interpretation, to process-based understanding.
Reframing the Definition of a “Watercourse”: Implications for Interpretation and Assessment in Watershed Studies
John McDonald1,
Roger Phillips2, 3
1Onterris, Oakville, Canada
2SLR Consulting, Guelph, Canada
3University of Toronto, Toronto, Canada
In 2024, the Province of Ontario issued the Provincial Planning Statement (PPS) to provide policy framework and guidance for land use planning and management. Several changes are included within the PPS that impact the approach to planning and management at the watershed and subwatershed scales, and through detailed levels of study. For environmental practitioners and regulators, changes were made to the Conservation Authorities Act through the introduction of O.Reg. 41/24. Notably included is the revised and enhanced definition of a “watercourse”, from “an identifiable depression in the ground in which a flow of water regularly or continuously occurs” to “a defined channel, having a bed and banks or sides, in which flow of water regularly or continuously occurs”. This shift represents a change not only in terminology, but in how fluvial systems are interpreted, classified, and brought into regulatory and planning frameworks. While this definition is an improvement, it can add a layer of rigidity in the application and can lead to issues at the project planning and early stages of execution in scoping and identifying watercourses and headwater drainage features for their required analyses.
The prior, more flexible definition often necessitated practitioner-led interpretation in defining watercourses and other drainage features based on form, process, and function. Desktop scoping at the preliminary level would then allow for field confirmation of feature type and extent(s), then appropriate characterization, leading to discipline-integrated evaluation at the reach scale and supporting management recommendations. However, inconsistencies across jurisdictions were common. The updated definition shifts this balance, potentially reducing interpretive flexibility while increasing consistency, with implications for how systems are classified, assessed, and prioritized. The new definition can present challenges in project planning, execution, and collaboration as approaches and perspectives have potentially adjusted, and adds a layer of complexity to watershed assessment and management.
This presentation considers how evolving policy definitions influence the interpretation of fluvial systems in applied settings, and how these interpretations propagate through subsequent steps such as reach delineation, erosion risk assessment, and prioritization. An overview of prior approaches, recent experience, and considerations going forward will be shared, with the intent to gather insight and feedback to maintain process-informed, scalable, and defensible approaches to watercourse and headwater feature assessment while respecting current policy.
Revisiting Proper Reach Delineation Protocols to Avoid Misguided Erosion Risk Management and Channel Restoration Initiatives
Michael Brierley 1,
Kelsey Serviss2,
Robin McKillop1
1SLR Consulting, Toronto, Canada
2SLR Consulting, Ottawa, Canada
Reach delineation is a fundamental step in studies of fluvial geomorphology. It facilitates grouping of stretches of watercourse with relatively consistent geomorphic controls – principally hydrology, gradient, confinement, and geology – such that they can be studied, assessed and managed in a physically meaningful way. Misplacement of reach breaks introduces analytical errors that cascade through planning of stormwater management (erosion thresholds), mapping of erosion hazard limits (upstream/downstream extents), and prioritization of channel restoration initiatives (rankings). This presentation uses case studies from different settings in southern Ontario to illustrate how improper placement of reach breaks at road crossings, property boundaries, and other locations unrelated to the drivers of fluvial geomorphology is misguiding assessment and management of natural channel systems. It highlights how imprecise reach delineation appears to reflect property access considerations, overemphasis of visually obvious differences in riparian vegetation in orthoimagery, underuse of LiDAR data for visualizing slope-breaks in longitudinal profiles, overreliance on regional-scale geological mapping, and failure to account for historical disturbances and legacy effects. An updated, process-based reach delineation protocol that takes advantage of readily available datasets is outlined to ensure placement of breaks is geomorphologically defensible and subsequent reach-scale assessments are reliable.
Time to Exposure: Methodology and Policy Approaches
Kayla Goguen1,
Natasha Cyples1,
Roger Phillips1
1Onterris, Guelph, Canada
Managing fluvial risk can be resource intensive, requiring significant fiscal and physical resources to mitigate. Understanding the severity of these risks and how risks at various sites compare is key in ensuring resources are well allocated in a timely manner. One of the risk assessment tools at our disposal is time to exposure (TTE), a means of estimating time (in years) for an active channel to come into contact with a feature at risk, resulting in either exposure or failure. TTE provides a relative basis for comparing erosion-driven risks across sites and supporting City-wide prioritization. This tool has been applied to help rank features at risk (i.e., infrastructure) as part of geomorphic system master plans among other studies. Ranking these features using TTE allows for the prioritization of sites based on relative severity and time to impact.
The first half of this presentation will look at the different methods applied to estimate the TTE for both vertical and horizontal erosion hazards. Generally, TTE is calculated by the horizontal distance to feature divided by the erosion hazard rate for horizontal risks, while analogous approaches are used for vertical risks based on depth to exposure and rates of degradation or scour. The presentation will discuss data requirements, analysis and interpretation, and key assumptions and sources of uncertainty associated with estimating erosion rates and channel response.
The second half of the presentation will discuss the application of erosion control credit in combination with TTE to determine the risk rankings for various feature types. Features that are already protected by erosion control structures could benefit from erosion control credit when determining the risk ranking. This concept assumes that while erosion control structures do have a functional design life, that their presence can effectively extend the time to impact by accounting for structure performance and condition. This would allow for a longer timeline before intervention/mitigation is required. Both TTE and erosion control credit, when combined, support more transparent prioritization and timing for interventions for infrastructure and assets within watercourse corridors.
Improvements to the Rapid Geomorphic Assessment for Preliminary Evaluation of Channel Stability
Robin McKillop1,
Michael Brierley1
1SLR Consulting, Toronto, Canada
The Rapid Geomorphic Assessment (RGA) was published by the Ontario Ministry of the Environment in 2003 as a field-based method for preliminarily evaluating channel stability in association with land development planning. The results of the RGA are commonly used to identify reaches most sensitive to upstream changes in land use prior to estimation of their erosion thresholds as a principal input to the establishment of stormwater management criteria. The method also informs prioritization of reaches for municipal erosion risk mitigation and habitat restoration projects and, in some cases, supports monitoring of changes in channel stability over time. The RGA remains in widespread use in southern Ontario where it maintains a profound influence on the management of natural channel systems, despite reviews of its limitations and weaknesses by practitioners at the Natural Channel Systems conference in 2016 (e.g. McKillop, 2016) and by researchers (e.g. Papangelakis et al., 2023).
A series of modifications to the RGA are proposed to address four key limitations of the original method and to serve as an interim improvement until a more rigorous, practical replacement tool is developed: 1) indicators of each of the four modes of channel adjustment have been updated to ensure applicability to all reaches, including those with cohesive channel boundaries and non-urban settings, alleviating the statistical bias introduced by indicators deemed “not applicable”; 2) indicators have been refined to provide a more objective and definitive representation of each mode of channel adjustment; 3) the strength of indicators is evaluated, based on prescribed determinants, thereby resolving limitations of the presence/absence approach; and 4) evidence of channel pattern change has replaced evidence of planimetric form adjustment for consistency in the identification of reaches in a state of morphological stress or disequilibrium. Application of the modified RGA is demonstrated as part of a pilot study along rural and urban streams in the Ottawa area.
Linking mobility to morphology: Sediment transport characteristics along gravel-bed channel bedforms
Michael G. Chislett1,
Bruce J. MacVicar1,
Frédéric Liébault2
1Department of Civil & Environmental Engineering, University of Waterloo, Waterloo, Canada
2Université Grenoble Alpes, INRAE, CNRS, IRD, Grenoble INP, IGE, 38000 Grenoble, France
Despite decades of research, there remains disagreement around sediment routing and sorting through channel morphologies, such as the pool-riffle. Pools are energy-dissipating depressions in the bedform, while riffles are shallower, faster flow regions comprised of coarser bed sediment. Their collocation, the pool-riffle sequence, is most ubiquitously found within meandering channels comprised of scroll and chute bars. These definitions of the bedform, however, lack a broader process-based explanation for their development. Debate also persists around the exact mobility behaviours that result in the riffle evolving into an interlocked unit that resembles a step-pool sequence. A variety of process mechanisms may result in the formation of these morphologies, placing them within a gradient of development conditions that may not necessarily encapsulate the complete range of formation scenarios. Here, we interpret observations from a database of 20 years of bedload sediment tracer studies compiled by Liébault et al. (2024). We use a phase diagram based on stream power and particle size as a quantitative framework to analyse sediment transport distances within various gravel-bed morphotypes and planform patterns to better understand the likely connection between stream morphologies and sediment mobility. Relationships that define critical characteristic grain sizes for mobility and morphologic transition are used to visualize physical site attributes that lend to the evolution of meandering channels dominated by a mixture of scroll and chute bars.
Results show that pool-riffles in single-thread channels most often occur within the morphologic transition zone, with an immobile D84 sediment size. Multi-thread channels may contain pool-riffles that do not fall within or beyond this morphologic transition, despite being described by the literature as having higher energy, and therefore, more mobility of coarse sediment. Some step-pools are not found within a high energy river context, despite their common association with steep and high mobility systems. A more comprehensive collection of diverse hydrologic sites, such as flashy urban channels, represents an opportunity to define the processes that result in a wider diversity of morphologic sequences. Emergent trends allow for a new hypothesis around the ability to describe specific mobility scenarios under which gravel-bed morphologies tend to develop, and the specific form they are likely to take.
Adaptive Management of the Mollie River Channel Realignment: A Case Study from the Côté Gold Project
Matthew Iannetta1,
Jeff Hirvonen1,
Cal Jefferies1,
Ben Plumb1
1GeoProcess Research Associates Inc., Dundas, Canada
From a practitioner’s perspective, executing a true adaptive management approach during the monitoring phase of a natural channel construction project can be met with barriers and challenges. Developing and implementing a tailored adaptive management plan typically requires unanticipated project resources and securing buy-in from Regulators. This is particularly true for proposed adaptive measures that may be novel or uncommonly applied. These barriers are often coupled with limited external regulatory drivers, resulting in action being initiated only when necessary to remedy a major failure, a process which can be better described as reactive instead of adaptive. In this session, we present a real-world case study of a collaborative adaptive management approach undertaken for a constructed naturalized channel at the Côté Gold Project Site.
The Côté Gold Project is an active open-pit mine located within the Mollie River watershed in Northeastern Ontario. Initial development of the open-pit and associated mine infrastructure necessitated the realignment of a segment of the Mollie River and the creation of supplemental fish habitat offsets. This resulted in the design and construction of over 2 km of naturalized watercourses and 26 ha of new lake habitat. The project is unique in that there is shared mutual interest and accountability in undertaking a true adaptive management approach to sustain a healthy, functioning system. This is attributed to the proponent’s commitment to environmental stewardship and Regulatory agreements that require demonstration of constructed habitat performance in promoting fish habitat productivity.
Here, we share our methodology in developing an adaptive management framework to mitigate performance concerns related to instances of riffle drying observed during periods of low-flow along the constructed naturalized watercourse. We further share our experiences and lessons learned in navigating the intersection of science and policy, collaborating with Regulators to establish agreement and authorization for novel sediment augmentation mitigation measures implemented in wet working conditions. Finally, we present the results of rigorous spatiotemporal turbidity monitoring undertaken during the execution of in-water repair works, as well as preliminary findings of mitigation measure effectiveness. In sharing our findings, experiences, and lessons learned throughout this case study, we intend to demonstrate a collaborative approach to sustaining healthy and functional naturalized river systems through adaptive management.
Largescale River Corridor Restoration: A Case Study of the Sheep River Watershed in Southern Alberta
Greg Courtice1,
Liv Hundal2
1Applied Ecohydraulics, Kelowna, Canada
2WSP Canada Inc., Calgary, Canada
We present a case study of a series of restoration activities from the Sheep River watershed in southern Alberta that demonstrate how multiple, independent projects can build on one another when restoration is viewed through a channel-floodplain corridor perspective. Restoration measures were developed with adaptive management in mind and implemented on the Sheep River and one of its tributaries (Threepoint Creek) required to mitigate numerous independent drivers/disturbances, including: flood response, preventative flood mitigation, and the construction of watercourse crossings for a major infrastructure corridor. Rather than pursuing isolated, piece-meal restoration projects, a broad understanding of channel-floodplain interactions and the interdependence of tributary and mainstem processes within the Sheep River watershed revealed interconnected opportunities that could build on one another through learning outcomes. This understanding led to a simplified process for identifying opportunities for restoration of nearly 60 hectares of riparian corridor on Threepoint Creek and Sheep River. We present how this framing informed project selection, design, and monitoring, within an adaptive management framework. Lessons learned will be discussed, from both successes and unanticipated circumstances, which were captured within the adaptive management approach leading to successful outcomes. These results demonstrate how adaptive management may be successfully applied to future riparian restoration opportunities and how the adaptive management process can be used to reduce project cost and improve outcomes
Thinking Outside the Active Channel: Evaluating Water and Carbon Retention in a Low-Order, Designed River Corridor
Alex Scott, M.Sc.1,
Jaclyn Cockburn, Ph.D.2
1GeoProcess Research Associates Inc., Dundas, Canada
2Departrment of Geography, Environment, and Geomatics, University of Guelph, Guelph, Canada
Modern channel designs aim to mitigate the negative impacts of anthropogenic watershed modification, such as elevated flood risk and decreased carbon storage, by implementing features that promote material retention. This research evaluates water and carbon retention within a low-order, designed tributary of East Morrison Creek in Oakville, Ontario, during the first two years post-construction. The study reach utilizes a “string and bead” morphological framework, implementing design features such as online, offline, and offline-connected wetlands alongside large wood structures to impede downstream conveyance.
A field campaign was conducted from September 2019 through November 2020, during which water levels were recorded continuously and bed sediments were sampled discretely to determine particulate organic matter (POM) content. Results indicate that water retention is primarily facilitated by surface storage within online wetlands and vertical transport mechanisms, including infiltration and evapotranspiration, during dry periods. Large wood structures were identified as critical for carbon retention, with the highest POM concentrations observed in depositional zones immediately downstream of these features.
The system’s retention capacity was heavily influenced by antecedent moisture and rainfall magnitude. During summer 2020, a threshold of 20 mm of rainfall within the previous 24 hours was identified, above which in-channel retention capacity was exceeded and longitudinal connectivity was established. When in-channel capacity was exceeded, wood structures promoted lateral connectivity, transporting water to the longitudinally discontinuous floodplain for secondary retention. These findings highlight the importance of spatial heterogeneity in reach-scale management and provide a baseline for how retention performance may evolve as vegetation matures and channel morphology adjusts over time.
Long-Term Monitoring of River Restoration Projects in South Ontario
Kate Pearson1,
Elli Papangelakis1
1McMaster University, Hamilton, Canada
Urbanization, channel modification, and subsequent channel degradation have prompted a proliferation of river restoration projects in Southern Ontario, from hardened, disconnected channels to natural channel designs with riparian plantings and wooden grade-control structures. Short-term (2-3 years) post-implementation monitoring is standard to evaluate the design’s stability and to establish the project’s ability to meet the geomorphological and ecological objectives. However, geomorphic adjustments can continue for several years to decades following the implementation of a river restoration, limiting our understanding of how urban river restorations perform long-term, and of the ability of the design to provide stable and diverse habitats for native aquatic species. This study assesses the relative successes of four river restorations across Southern Ontario with a range of ages (9-14 years), design techniques, external factors, and project objectives. To assess the geomorphic and ecological condition of the restorations, the Ontario Stream Assessment Protocol (OSAP) was used along with discrete water chemistry measurements, sediment sampling and analysis, and topographic surveys. The gathered parameters were used to supplement previous short-term monitoring efforts provided by the respective participating agencies to evaluate how the designs have performed over time, and to explore how increasing the prevalence of standardized long-term monitoring can improve and potentially redefine our understanding of design success in urban systems. In the face of climate change and rapid urban growth, understanding how river restoration designs support native species while maintaining channel stability long-term will be essential to improving the practice of river restoration to focus on lasting channel stability and ecological success.
Alluvial Channel Design – Taplow Creek 8 Years Later
Emma Schiller, M.Sc., P.Eng.1,
Diana Michalakos, C.E.T.2
1Aquafor Beech Limited, Ottawa, Canada
2Town of Oakville, Oakville, Canada
Taplow Creek is a partially confined and semi-alluvial channel in the Town of Oakville with boundary materials consisting of gravel and finer alluvial materials derived from local exposures of Queenston shale on the bed and banks. An erosion mitigation project was undertaken to address threats posed to private property by valley wall erosion at valley wall contact points, with a design approach of locally realigning Taplow Creek away from the toe of slope while also providing habitat features and wetland pockets. What differentiates this project is that these objectives were achieved using alluvial channel design.
With a unique design approach comes unique monitoring considerations. In many urban erosion mitigation projects immobility is a measure of success, but this design was constructed using native materials and is expected to adjust naturally through gradual erosion and sediment transport over time.
A detailed monitoring plan was developed spanning a period from pre-construction to five (5) years post-construction. Additionally, a turbidity monitoring plan was developed during construction to aid in refining the adaptive flow transfer plan required to manage excess fine sediments associated with the lack of coarse and engineered materials introduced to the system.
The post-construction monitoring plan included monitoring for channel form and vegetation in years 1, 2, and 5 post-construction. Field assessments addressed planform, profile, cross-sections, pocket wetlands, planting success, photographic inventories, and recommendations for any required mitigation measures. Profile and cross section adjustments were assessed each monitoring year, and qualitative observations on channel substrate were collected.
This presentation will provide a brief discussion of the design and construction process, followed by an overview of the monitoring plan and results with a focus on channel adjustments observed both in the immediate post-construction period and over the five (5) year monitoring period. The successes of this alluvial channel design approach will be reviewed, including photo comparisons of Taplow Creek over the past decade.