How’s the river? In Aspen, that’s difﬁcult to gauge
The Aspen Times
Aspen, CO, Colorado
ASPEN – How much water is flowing in the Roaring Fork River through Aspen is anybody’s guess.
That’s why a local conservation group is spearheading an effort to better measure river flows in the Roaring Fork watershed and focusing this fall on two critical stretches – the Roaring Fork through Aspen and the lower Crystal River south of Carbondale. Both of those reaches can be reduced to more rock than water in the summer months, thanks to water diversions.
On Tuesday, Pitkin County commissioners endorsed a $23,875 expenditure from the county’s Healthy Rivers and Streams fund for a “snapshot assessment” of both reaches. The total cost of the work, $47,750, also will require contributions from Friends of Rivers and Renewables and the Roaring Fork Conservancy as well as other donors.
Hydrologists will be taking streamflow measurements and sampling water temperatures on both rivers this fall, in part to determine the ideal locations for additional gauges that would provide ongoing streamflow data. The goal is to work with landowners along both reaches to gain access to key spots in the rivers – above and below diversion points – to collect data that will help determine where the new gauges should be placed.
The ultimate goal is an integrated system of gauges to better track what’s happening with flows in the Roaring Fork and its tributaries and, ideally, to manage use of the water better, according to Chelsea Congdon Brundige, director of Friends of Rivers and Renewables, which applied for the county appropriation.
The organization, an offshoot of the Public Counsel of the Rockies, was formed last spring amid debate over the city of Aspen’s proposed Castle Creek hydropower facility. Its focus is facilitating civil and informed discussion about water and energy issues. The stream-gauge initiative is among Friends of Rivers and Renewables’ efforts.
There are already about 35 streamflow gauges in the Roaring Fork watershed, according to Brundige. They were installed and are maintained by different agencies for various purposes, but tracking river flows in connection with transmountain diversions is a key use. River runners and anglers also consult the streamflow data in connection with their particular recreational pursuits.
The gauges provide points of information but not the bigger picture, according to Brundige.
“If all you have are gauges that are dedicated to providing bits of information unrelated to other bits of information, you don’t have that picture,” she said. “They’ve got their mission, but they’re not helping you understand what’s going on in the rest of the Roaring Fork.”
Friends of Rivers and Renewables’ goal is an integrated system that includes many existing gauges plus 10 additional ones, strategically placed to help monitor the impact of major diversions like the one just east of Aspen.
The U.S. Geological Survey streamflow gauge on the Roaring Fork just above town measures flows above a major diversion, the Salvation Ditch. The next station is below Maroon Creek’s confluence with the river, downstream from Aspen. It provides data to the Colorado Division of Water Resources.
There is no gauge in the reach through town, where diversions take water from the river, and Castle Creek adds water back in, noted Sharon Clarke, land and water conservation specialist for the Roaring Fork Conservancy. A series of gauges would allow everyone from water managers to the public (via data uploaded to a website) to assess what’s happening with the river on a daily basis.
The hope is for new gauges on the Roaring Fork in town at Mill Street and Cemetery Lane, one in Woody Creek and one on Independence Pass at Lost Man. Gauges on Castle Creek, Brush Creek, Coal Creek, two on Maroon Creek and one that functions year round on the Crystal above Carbondale also are envisioned.
The stations also would collect other data, such as water temperature, Clarke said, and could help assess what’s happening with water quality as well as quantity.
“The more you know about your rivers, the better you’ll be able to take care of them and manage them,” Brundige said.
As an example, she offers the city of Aspen’s proposal to divert water from Maroon Creek for its proposed hydroelectric plant. Without a streamflow gauge, there’s no way to determine how much water is flowing in the creek and no way to know how much of that flow would be diverted, Brundige said.
“We can’t make very informed decisions if we don’t have a baseline to start with,” she said.
While there is no USGS-style gauge on Maroon Creek, the city does measure flows from the creek into its municipal water system and takes measurements on the creek with a hand-held meter just below the diversion and near Maroon Creek’s confluence with the Roaring Fork.
This fall’s work will ideally lead to the installation of the additional gauges next year, Brundige said. The estimated cost is $116,000 for installation and operation of the new monitors for a year. A source of that funding is not yet confirmed.
Ongoing, annual costs of $55,000 to $60,000 to operate the gauges are a concern that county officials have expressed, Brundige said.
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