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British Columbia residents facing a flood emergency this weekend can partly blame 19th-century gold miners for their woes.
Two Canadian scientists have shown how the Fraser River — the waterway at the heart of British Columbia’s history, and currently the focus of a flood threat in Abbotsford and elsewhere in B.C.’s Lower Mainland — was significantly altered by 19th-century fortune seekers, whose dumped mine tailings from the Fraser’s gold-rich banks and tributaries accumulated at critical points along the southern course of the river and continue inching toward its Pacific outlet today.
The study of the ongoing “geomorphic impact” of 1800s-era placer mining in the Fraser watershed, co-authored by UBC researchers Andrew Nelson and Michael Church and published in the latest Geological Society of America (GSA) Bulletin, argues that present-day flood and fishery management for the 1,375-kilometre river — B.C.’s longest — need to account better for the “legacy effects” of the Gold Rush and carefully distinguish between the pre-1858, “natural” state of the Fraser’s riverbed and its post-Rush condition.
Millions of tonnes of gravel flushed into the Fraser by miners as early as 154 years ago have been “accumulating in the river in the Lower Mainland throughout the 20th century,” Church told Postmedia News.