Methodology

1. Fieldwork

Fieldwork will be conducted during the open-water seasons in 2025 and 2026: September 2025 and May–September 2026. The activities will include:

Sample Collection. Collection of water and sediment samples from various depths in channels and lakes. Water samples (20–100 ml) will be stored in vials, and sediment samples will be collected in plastic bags. The maximum amount of water collected for analysis per field trip will be 50 litres.

We will implement pre- and post-sample collection cleaning protocols to prevent the spread of invasive species and pathogens among water bodies. All field equipment sampling tools will be thoroughly cleaned before entering and after leaving each water body. We will use environmentally safe cleaning products, as aquatic biosecurity guidelines recommend. All team members and local collaborators will be briefed on biosecurity measures to ensure strict adherence to cleaning protocols.

On-Water Measurements. Suspended fine sediment concentration using a laser sensor (measured from a boat). Acoustic scanning of channel and lake beds using an echo sounder (measured from a boat). Water flow velocity measured with an Acoustic Doppler Current Profiler (ADCP) (measured from a boat). Geodetic water surface elevation measurements using GNSS equipment (measured from a boat). Drone imagery captured by a licensed local service provider authorized by the Government of the Northwest Territories (NWT). We are going to implement pre- and post-fieldwork cleaning protocol for all field equipment, including waders, rubber boots, sampling tools, and boats, will be thoroughly cleaned before entering and after leaving each water body. We are going to dedicated equipment for specific locations. Whenever feasible, we will assign specific equipment to distinct study areas to further minimize the risk of cross-contamination.

Logistics. Fieldwork will consist of several hours of motorboat trips rented from local providers in Inuvik, with no land-based activities (without camping and going ashore).

2. Laboratory Analyses

Laboratory analyses will be conducted in two phases: in a rented facility in Inuvik and in a European laboratory following sample transport. Methods will include:

• Sediment settling velocity tests in water columns.
• Laser-diffraction-based particle-size analysis of fine-grained sediments suspended in the water.
• Gravimetric analysis of suspended sediment concentrations (SSC) in water samples.
• Analysis of dissolved organic carbon (DOC) content in water samples.

These analyses will provide detailed data on the physical properties of sediments transported in the waters of the Mackenzie Delta.

3. Computer-Based Analyses

Computational analyses will leverage field data, laboratory results, and satellite imagery. Key activities will include:

• Remote Sensing. Utilizing Wetland Interferometric Synthetic Aperture Radar (InSAR) technology and remote-sensing indices to analyse major sediment transport pathways in lake-rich deltas, based on collected satellite imagery and purchased drone images. GIS analysis of spatial sediment transport and deposition patterns in channels and lakes using remote sensing indices.
• Hydraulic Modelling: Simulations of water and sediment flow in channels and lakes using 2D models (MIKE 21 by DHI, SMS by US Army Corps of Engineers). Particle tracking of sediment transport paths using the Lagrangian approach, with 3D modelling in SMS. Statistical calculations of sediment load and net deposition in individual channels.

4. Summary and Conclusions

The conclusions will be based on:

• Results from remote-sensing analyses and 2D and 3D hydrodynamic and sediment transport simulations.
• Sediment trapping efficiency calculations using mathematical models