Glaciers are muddying rivers, with drought to blame

https://www.flickr.com/photos/ericleslie/8212279250/in/photolist-cCuW6s-dndS9U-edti9N-5CUoh2-dFUvMh-4YfzPv-cnpRiA-963PNi-dvG5vy-dGjfwN-61HCUp-cE8Vrf-eyqfiG-nXoKTN-6BUxNx-3pWnxe-cE8UT1-28USLJ-28USLj-abgYeY-6BYE3S-6BUxFV-6BYj6E-6BUcMP-4A9txp-kyMExc-8GmWUy-47PCcj-8scuUp-a8KUSA-5CYFmQ-4AdKGC-4LYtr9-81CDP4-nXh4gG-8gbnvM-3wUuC-52FeVn-5cMp6m-3K1an6-8iHxMK-6Sdi8N-cE8Uts-cE8TW9-NMktt-aKU4XH-8iAb3u-7LZc1C-cE8NYh-5hWkDf
Rivers off of California’s Mount Shasta are increasingly becoming brown. (Eric Leslie/Flickr)

Water flowing off snow-capped mountains has the image of being absolutely pure, but the rivers and streams of California’s Mount Shasta are unusually brown, and geologists are pointing at drought as the cause.

News surrounding the drought in California inundates the media, but we often hear about dying crops and brown lawns. This time it’s the tourism and fishing industries that are up in arms.

Paradoxically, the heavy river flows are caused by the same climatic variations that have created drought throughout the state. A dry winter left California’s glaciers exposed to the sun, without their usual protective cover of snow. Hot weather in the summer is rapidly melting them, particularly on Mount Shasta, home to the state’s largest glaciers. The mountain’s porous volcanic soils can absorb some meltwater, but their capacity has been overwhelmed this summer, and the meltwater is causing debris flows, muddying rivers and streams. More commonly known as mudslides, debris flows are flows of water, rock, soil and other organic material that course downslope, becoming destructive torrents when they enter streambeds. They can muddy the waters of rivers that are usually pristine.

http://www.climatecentral.org
Saying California’s drought is spreading quickly is a small understatement. (Climate Central)

This year, the rapid melt of the mountain’s south-facing Konwakiton Glacier has left the McCloud River opaque with volcanic ash. These highly turbid rivers are not novel phenomena. In the past century, severe debris flows like the current one have been witnessed seven times, particularly in the 1924, 1926 and 1930, other dry years for the region, when debris flows blocked roads and railroads, rendering them impassible for days. During this period in the 1920s, the McCloud River was unfishable. The murky waters do not harm the fish, but simply make them nearly impossible to catch.

https://www.dfg.ca.gov/fish/Resources/WildTrout/Waters/images/LowerMcCloudRiver-1200x900.jpg
Fly fishing in California’s McCloud River is one of the many activities to be affected by brown rivers caused by drought. (California Department of Fish and Wildlife)

Fly fishermen, fly fishing tour guides, and local businesses that relying on tourism fear that the current drought, and the associated glacial melt, debris flows and cloudy waters, will be detrimental to the local economy during the fishing season this fall and in the future years. Some fly fishing groups have already cancelled tours that they had booked—another sign of the cascading effects of glacial melt around the world.

For another story on the effects of glacial melt on fisheries, click here.

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