The Peace River – Frozen in Time

• Location: Peace River, Alberta
• Company: BGC Engineering

The Sentinel-2 satellite captured this stark midwinter snapshot of the mighty Peace River and its rich floodplain near Garden Creek in northern Alberta. The river emerged from the Rocky Mountains at the end of the last ice age between 15,000 and 10,000 years ago, carving its way through shale and limestone formations. The first known human habitation can be traced to First Nations who followed the retreat of glaciers during the Last Glacial Maximum. Their descendants continue to sustain their livelihoods through traditional fishing, hunting and trapping. Roughly one hundred kilometres downstream (to the right of the image), the river supplies sediment and nutrients to the Peace-Athabasca Delta, one of the world's largest inland deltas, a Wetland of International Importance, and a UNESCO World Heritage Site.

The Peace is restless — its course forever changing, its floodplain ceaselessly evolving — though hydroelectric dams upstream have partially tamed its floods. U- and crescent-shaped oxbow lakes form when meanders lose their connections to the main channel through deposition and erosion of sediment. Their ephemeral nature is obscured by the thick ice cover that traps fish and beavers for the long, cold winter. Scroll bars, preserved as curved ridges on the inner bends of the meanders, accrete as the channel migrates across the floodplain over the millennia. Floods overflow channels, further reworking sediments. This complex terrain sustains myriad diverse habitats. Some are old, some are new; some are permanent, some will disappear as the Peace continually reinvents the landscape of its floodplain.

The image, with ground dimensions of roughly 90 km in width and 50 km in height, was captured on November 28, 2020. The image was assembled by Jeanine Engelbrecht, a remote sensing specialist with BGC Engineering, and Gord McKenna, a landform designer with McKenna Geotechnical.

Authors: Jeanine Engelbrecht (BGC Engineering), Gord McKenna (McKenna Geotechnical), David Wylynko (West Hawk Associates)

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