Grand Canyon Ecosystem - even flows help out the bugs - Mountain Buzz

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Old 06-05-2019   #1
Andy H.'s Avatar
Wheat Ridge, Colorado
Paddling Since: 1995
Join Date: Oct 2003
Posts: 3,720
Grand Canyon Ecosystem - even flows help out the bugs

This may affect GC flows on the weekends through August. Here's the summary:

...low, steady flows of water from Glen Canyon Dam over the weekend gives the eggs that bugs lay on rocks, wood or cattails just below the water’s surface a better chance of survival. Otherwise, they might dry out and die within an hour.

“It’s a powerful reminder that flows really matter, that just a couple days a week of steady flow can illicit massive emergence,” said Kennedy, a research ecologist with the U.S. Geological Survey.
Full article here:

Changes were made to water flow out of the Glen Canyon Dam. And that led to more bugs in the Colorado River.

It's good to know they're looking after the bottom of the food chain in the Grand Canyon.

I strongly support helping the ecosystem down there, however, it's worth pointing out there's nothing remotely natural about a low flow (or clear, cold water) down there at this time of year. Late in the summer and through the rest of the year would be more appropriate for this experiment. The fact they're using low flows for bugs during what was once the peak of spring runoff indicates that the managing agencies have given up trying to mimic the natural system. Without Glen Canyon Dam the flow today (6/5/19) would be a muddy 30,000 cfs and rising steadily to about 60,000+ over the next month. The flow may even top 90,000 cfs this year with the snowpack we have.

Nothing in the world is more yielding and gentle than water. Yet it has no equal for conquering the resistant and tough. The flexible can overcome the unbending; the soft can overcome the hard. - Lao Tse
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Old 06-06-2019   #2
Boulder, Colorado
Paddling Since: 1988
Join Date: Apr 2017
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Let's not throw the baby out with the bathwater here. I fail to see the science that says its necessary that low flows happen at a specific time of year, particularly on one of the busiest stretches of river in America. To me its rather a testimony that management agencies are aware and interested in testing the hypotheses regarding the importance of flow variability on trophodynamics. It's also an interesting result regarding to the sensitivity and adaptability of benthic invertebrates as well as the cascading effects up the food web downstream.

My understanding is they do the High Flow Experiments during a less busy period so as to not overly challenge permit-holders, and for the low flow that is less than an issue. Although this also suggests the agencies are also aware of balancing usage with ecosystem and environmental integrity, so lets not cast dispersions or make dubious claims what they're not doing. Since nobody is complaining about restoring sand bars, lets also recognize the role of gravel bars as habitat...even if it doesn't directly benefit river runners or give them as wild a ride as expected.
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