From The Pueblo Chieftain (Chris Woodka):
Two researchers say Fountain Creek has a rich aquatic environment that would benefit from flood control structures such as a dam.
“This is an extremely diverse biological stream and needs to be continuously studied,” said Scott Herrmann, a retired biology professor from Colorado State University-Pueblo.
“A large dam could provide better understanding of what’s happening in the watershed, and be a good recreational benefit to the entire watershed of Fountain Creek,” said Del Nimmo, who has worked with Herrmann on Fountain Creek projects for the past decade.
The pair presented a suite of studies to Pueblo County commissioners, who have funded their recent work, last week.
Those studies began in 2007 and continued for five years, providing a baseline of conditions before the Waldo Canyon and Black Forest fires, and the growth impact of the Southern Delivery System. They track selenium and mercury concentrations moving through the food chain in plants, insects and fish.
“A large dam on Fountain Creek would give us the flood control capability that we need, but also provide recreational opportunities that are primary, with a pool of water as well as a tailwater. So we would have a fishery and fishing benefits from such a structure,” Her- rmann said.
The studies began in 2007 when the Lower Arkansas Valley Water Conservancy District purchased equipment for CSU-Pueblo that allowed measurement of minute concentrations of contaminants in tissues.
Herrmann led a team that identified how bryophytes (moss) absorbed selenium.
“What it told us was that selenium is there and available (to life forms), and there is more of it as you go downstream,” Nimmo said. “But not too many people care about bryophytes, so we began to look at fish.”
Further studies looked at the impact on fish and insects, particularly chironomid midges.
Some of the studies have only been published in the last six months.
“One of the surprises was that we also found mercury in all but one of the 111 fish we tested,” Nimmo said.
Selenium may act as a protection against harmful effects of mercury for the fish, because it reduces toxicity, Herrmann said. But the presence of both elements points to the need to monitor levels in species to measure how development in El Paso County is affecting the creek.
The main reason Nimmo supports a dam on Fountain Creek is to reduce erosion, which is the primary reason for selenium making its way into the water. The Pierre shale that underlies Fountain Creek is known to contribute selenium when it comes into contact with water.
“We’re on a selenium dome,” Nimmo said.
“Nobody has tied selenium to erosion, but every time it floods there is not only damage by erosion, but to water quality.”
The studies found that Fountain Creek exceeded EPA selenium levels at all measuring points.
The insects, which provide food for the fish, are the subject of the most recent study, and the most fascinating for Herrmann.
“Fountain Creek is not a dead stream,” Herrmann said. “It’s rich in biota.”
Scientists found at least 150 species of insects on Fountain Creek, including 24 new species. The same methodology — pupal exuvia, or identifying casts left behind by adult males as they hatch — was used in an earlier study of the Colorado River through the Grand Canyon, and found just 38 species, Herrmann said.
“The question is what effects will increased SDS return flows and runoff have on the species diversity of midges?” he said.