Dust in the wind and the water

by Paul Larmer

One morning last week, I woke up and couldn't see the mountains. Was it snowing? No, it was dusting … again. The wind, which had howled all day and night, had finally died down, but the dry and loose soils it had borrowed from Arizona and Utah were still precipitating all over our Colorado cars, lungs and what precious little snowpack we have left in mid-May.

I counted at least four dust storms in western Colorado over the past month, and it's been even worse in Arizona. Over a period of six weeks this April and May, Interstate 40 was closed seven times between Winslow and Winona due to blowing dust that created gray-out conditions and toppled vehicles and signs. Last year, I-40 was closed five times.

What's going on here? Weird weather patterns, drought, reduced vegetation due to overgrazing and oil and gas development, global warming? Probably all of the above, according to University of Colorado biogeochemist Jason Neff.

"It's really difficult to pin this year's activity on a single use," says Neff, the co-author of a 2008 study that found the West has become 500 times more dusty over the past two centuries, based on evidence from sediment layers in alpine lakebeds. "But there is no way to explain the long-term increase in dust activity without paying attention to cattle grazing," which has broken up fragile desert soils and made them readily available for airborne transport.

Of course, airborne dirt is just one half of the West's spring sediment load. The other half is currently racing downhill in the region's rivers and streams. Some creatures even thrive in these conditions. Unique and relatively obscure native fish have evolved with the Colorado River's seasonal flows of muddy waters. But as Hillary Rosner reports in this issue's cover story, many of those fish have been in steep decline ever since Westerners constructed dams and reservoirs, which tame the flows, trap much of the silt, and provide great habitat for non-native competitors like rainbow trout and striped bass — which also happen to be favorites of sport fishermen.

Along the lower Colorado River, the amazing razorback sucker, a native fish that can live up to 50 years and grow to more than three feet long, is now dependent on captive breeding programs and the slim hope that the funding and political will can be mustered to re-engineer parts of the river to function more as they did in the pre-dam era. That's a long shot, given that we have yet to remove dams for wild runs of endangered salmon, a much more photogenic fish with a lot more human fans than suckers and chubs can boast.

But it's an important effort nonetheless. As we head into what may be an extremely volatile period of climate change, creatures like the razorbacks that have survived the extremes of the West for tens of thousands of years are more than ever worth our attention.

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