The indicator species vs. development: How construction runoff is muddying fish habitat
It’s just a small fish, and in comparison to a rainbow trout, not particularly pretty. But the wide-headed mottled sculpin has a certain kind of power. Aquatic biologists have found that it is less active in areas where there is freshwater acidification (the increase of acidity due to excess carbon in the environment), and therefore have deemed the slimy sculpin a good indicator species for changes in acidification in lakes, ponds and streams.
It turns out, the sculpin is also a good indicator species for changes in water quality and habitat health in the Fraser River. Sculpin are a primary food source for brown trout, which live in those waters. Without the sculpin, the trout won’t grow to the “quality fish” sizes (beyond 14 inches long) that draw anglers to the region. Fishing is the No. 2 driver, after skiing, of tourism dollars in Grand County. So in a very real sense, a healthy sculpin population in the Fraser River pours dollars into the economy.
Sculpin were also the topic of a presentation Colorado Parks and Wildlife aquatic biologist Jon Ewert gave the Fraser Town Board on Feb. 16. He’d come on the invitation of Town Manager Ed Cannon, and laid out why sculpin in the Fraser River might be in trouble.
Ewert has been collecting data on the fish since 2007, continuing a study that began in 2003. The reason Parks and Wildlife has been analyzing them is because sculpin indicate when excessive sediment has been infiltrating a river, making it harder for them to survive.
Sculpin numbers fluctuate from year to year based on things like varying water levels, habitat availability and runoff intensity. But Ewert began to worry when his team of volunteer researchers, each wielding nets for collecting sculpin, brought back data last autumn showing that numbers had dwindled from 202 in 2020 to 56 in 2021, the latter being the lowest number recorded since data collection began. One cause of this, Ewert said, could be fine sediment pouring off construction sites and settling in the rocky bottom that is sculpin habitat.
Parks and Wildlife has pictures that various residents have sent of construction sites along the river where sediment events have clouded the water.
“I don’t want to be too hasty to jump to conclusions, because correlation doesn’t necessarily mean causation,” Ewert said at the board meeting. “However, it is a concern that we’ve fielded more calls in the last two years than ever before about these sedimentation events coming off construction project sites and turning the Fraser River the color of chocolate milk.”
“This is a naturally occurring event at times with rain events and storms,” Ewert added. “But over the last two years, it seems that this has occurred far more frequently. I’ve seen them myself. … I’ve seen these events coming off of at least three different construction site locations, three different active projects. There is an open violation process going on with one, with the Colorado Water Quality Control Division, as we speak.”
Ewert emphasized that his reason for attending the meeting was to call attention to the issue rather than to point fingers at any one project.
Following Ewert’s presentation, however, Clark Lipscomb, a developer with multiple construction projects underway in Winter Park and Fraser, expressed concern.
“I do construction, and in all of the sites I’ve been in, we’ve had detention and water quality sites put in,” Lipscomb said. “The roads around (Fraser) are dirt. You also have Old Town Fraser, Ptarmigan, Winter Park Ranch — none have detention facilities, no water quality (control). On County Road 72, you have water coming off into Elk Creek … so I don’t think it’s fair to single out construction. It’s probably a very small part of the problem given the detention facilities and water quality.”
Lipscomb also pointed out that he’d seen Eisenhower Road in Fraser “running brown in front of the taco stand in the middle of summer. And it’s going straight into the Fraser River.”
He went on to say that the broader picture is more than just construction site runoff.
“I think if you really want to address it, let’s address all of the problems, including dirt roads, all of the roads, and neighbors in town that don’t have detention or water quality ponds, where you have mass runoff events that go straight into the river,” Lipscomb said.
Ewert said Parks and Wildlife had never received a report of the “mass runoff” Lipscomb described and added that an issue like that would be an “appropriate opening for a conversation about the need for infrastructure to be modernized.”
Cannon said the Fraser Town Board is keen to address all of the factors impacting the health of the Fraser River, though the board isn’t working on an ordinance at the moment. That work is pending coordination and discussion with county officials and community members, he said.
“It’s not that it’s not important,” Cannon said. “But we have other issues, like Victoria Village and the regional housing authority.”
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