TRACK 2, DAY 1
Vegetation Controlled Riffles
Michael Dhanraj and Heather Amirault, Stantec Consulting
Tuesday, March 31, 2026 | 3:45 p.m. to 4:15 p.m. | Hall F
ABSTRACT
Channel design often relies on robust measures such as extensive stone armouring and large, fixed woody-debris structures to maintain a stable planform. Although these treatments can increase local geomorphic complexity, they may also constrain natural processes, particularly lateral migration.
Lateral migration is one of the key geomorphological drivers of meander development and long-term ecological function within dynamic systems. In contrast, vegetation-controlled riffles offer a more flexible approach. These simple, bioengineered elements are designed to work with fluvial processes rather than against them.
This presentation will explore how vegetation controlled riffles use vegetation to provide structure and shape flow patterns, creating hydraulic diversity and guiding sediment sorting without restricting natural channel adjustment. In appropriate contexts, they help maintain dynamic stability, enrich habitat quality, and promote resilient ecological responses.
Features such as vegetated controlled riffles often rely less on heavy equipment and detailed structural engineering, they also provide a cost-effective way to achieve system-wide ecological benefits.
As restoration approaches continue to shift toward prioritizing stability with natural variability and lower reliance on fixed, hard features, vegetation-controlled riffles represent a promising tool within the ever-changing field of natural channel design.
ABOUT THE PRESENTERS
Michael Dhanraj, Stantec Consulting
Michael Dhanraj is a Restoration Technician who specializes in the areas of stream restoration and beneficial re-use alternatives for contaminated soils and sediment. His work includes natural channel designs, scour assessments, reference reach surveys, geomorphic assessments, erosion and sediment control inspections, fish habitat compensation and channel realignments. Michael works to design solutions that are functional, constructable, cost effective and provide ecological and habitat benefits.
Heather Amirault, Stantec Consulting
Heather Amirault is a Water Resources Engineer whose main project focuses are in the areas of stream restoration and geomorphic assessment. She has completed several courses in applied fluvial geomorphology and natural channel design. Stream project work includes natural channel designs, meander belt assessments, reference reach surveys, geomorphic assessments, erosion assessments, sediment transport analyses, fish habitat compensation projects, and channel relocations.
Heather works with clients and regulators to develop design solutions that are functional, constructible, cost effective to build, and provide ecological and habitat benefits. She is proficient at data collection, geomorphic assessment, and reporting results in clear and understandable language. She is very experienced in preparing a variety of permit applications as part of a multi-disciplinary team of scientists, planners, and engineers.