Roaring Fork Conservancy takes to the water for macroinvertebrate study
Post Independent Contributor
Glenwood Springs, CO Colorado
GLENWOOD SPRINGS, Colorado – Late Wednesday afternoon, Chad Rudow, Roaring Fork Conservancy water quality coordinator, found himself knee-deep in the Roaring Fork River. And that’s exactly where he wanted to be.
“The reason we really like this spot is because it’s really close to the USGS [U.S. Geological Survey] gauge,” Rudow said of the spot near the confluence of the Roaring Fork and Colorado rivers. “Then we can really test the quantity versus quality of the water.”
Rudow, his Roaring Fork Conservancy colleague Heather Tattersall, and volunteer Zuleika Pevec were sampling a variety of macroinvertebrates – aquatic insects such as mayflies, caddisflies and stoneflies – for a 2012 study of the Roaring Fork and Crystal river basins. In August, the watershed conservation organization published a 2011 study showing overall healthy conditions in the river and many of its tributaries.
“Our overall goal is to show a pretty comprehensive sampling of the whole watershed,” he said. “This is a very targeted study where we’re trying to pinpoint what’s going on with the overall health of the water.”
Rudow said aquatic insects are good indicators of river health because of their long aquatic life stage before hatching out into adults.
“I’m amazed at all the caddisflies,” Rudow said to Tattersall, as they used a portable stream bottom sampler to collect the aquatic insects from the river.
“This is one of the sites where we regularly see a lot of the stoneflies. You can get a lot of mayflies, too. These species are good indicators because they don’t tolerate pollution well. That’s one of the main things we look at is ratio of pollution-tolerant insects and species diversity,” he said.
This week’s sampling has included the Roaring Fork River in Glenwood, Four Mile Creek above the Sunlight Ski Area, lower Four Mile Creek where it joins the Roaring Fork, and upvalley locations such as Brush Creek in Snowmass Village and the Roaring Fork in Basalt and El Jebel. Rudow said the conservancy teamed up with the U.S. Forest Service to also collect samples on the Crystal River.
“For some species, it’s truly looking at absence versus presence,” he said. “We’re seeing a lot of caddisfly larvae, stoneflies – we’re interested in everything here, especially diversity.”
Rudow said a notable aspect of the study is the ability to compare between two consecutive years of high streamflow versus drought conditions.
“The reason we’re repeating a lot of the sites that we did last year for the study is because we can do a back-to-back study,” he said. “We can compare a real sustained wet year and a very low-flow drought year. In a lot of the sites where we’ve sampled this year, it’s just real obvious there were low flows.”
The two Four Mile Creek sites sampled Wednesday showed the impact of the 2012 drought.
“They were a real challenge to follow our protocols of collection because of the small amount of water,” he said.
As land, water and policy coordinator for the Roaring Fork Conservancy, Tattersall said she appreciated the opportunity to have hands-on experience in helping with the study.
” I think it’s a good balance to do what I do as well as be out here in the river, and touching what you’re studying,” said Tattersall, who holds a master’s degree from Johns Hopkins University in environmental science and policy. “I like being part of the first part of the study, the sampling. And I get to play with the bugs.”
Pevec, a native of the valley, said she was interested in helping the conservancy as a steward of the region’s rivers.
“I like field work in general,” she said. “Being outside, particularly in the water – I just like to be outside, that’s all.”
Rudow said the macroinvertebrates collected this week will be preserved in bags of alcohol and shipped to a lab in Fort Collins. There, lab technicians will meticulously study the thousands of aquatic insects collected to complete the 2012 study to be published next year.
“We were joking that we wondered what it would take to surprise one of the lab techs with a new species,” he said. “That’s probably not easy – they have seen a lot.”
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