Castle Creek Hydro Meeting Set, New Data to be Presented
The City of Aspen will be holding a public meeting Wednesday evening to discuss the Castle Creek Hydro Project and a recently completed environmental report on the topic.

The meeting will be from 5 to 7:30 p.m., June 16, at the Aspen Center for Environmental Studies at 100 Puppy Smith Street.

“The City of Aspen has been undertaking a vigorous environmental analysis of the hydroelectric project,” said Phil Overeynder, director of utilities for the City of Aspen. “Aspen has consulted with the Colorado Division of Wildlife on the hydro project since July of 2008 and has received input from the public and interested parties in a series of meetings, as well as in written form.”

The City followed the Division of Wildlife’s requests for additional studies and hired an ecological consulting firm to perform additional measurements and studies, with a goal of making sure this project provides exceptional protection of the river environment.

Miller Ecological Consultants, Inc., a full-service ecological consulting firm specializing in aquatic ecosystems that has worked in most of the major river systems in the West, specifically studied the stream flows, fish population data on Castle and Maroon Creeks, winter habitat data for Castle Creek and boreal toad surveys.

The study found that the stretch of Castle Creek from the diversion structure for the Thomas Reservoir to where this water returns at the power plant located on Power Plant Road, should have no less than 13.3 cubic feet per second (cfs) to protect the river ecosystem. From the power plant to the confluence of Castle Creek and the Roaring Fork River, that amount should be no less than 17.2 cfs.

The study also found that the habitat would not be degraded and that there are no boreal toads, a state endangered species, in the area that would be harmed as a result of the project. 

“We are absolutely committed to the health of Castle Creek and will ensure that the project will never cause the stream to go below the 13.3 stream protection flow based on the study’s findings. We are completely committed to keeping this a beautiful, healthy river,” said Overeynder, adding that the original City proposal before the completed additional study was for 12 cfs in that stretch.

Currently the state requires 12 cfs in Castle Creek.

“We can easily meet that difference between the 12 and 13.3 minimum flow. We are also having discussions about how to go above that number and what that might mean operationally for the hydroplant,” Overeynder said.

On Maroon Creek, where the City already operates a hydro facility, the federal government required flows that were actually lower than the state’s requirements, meaning less stringent environmental controls. The City has opted to voluntarily uphold the state’s higher standards for the 25 years the plant has been in operation. 

The maximum amount of water the City would be able to divert from Castle Creek for hydropower is 25 cfs, due to the size of the pipeline that will divert the water from Castle Creek to Thomas Reservoir. After the water travels from Thomas Reservoir to the hydropower facility, it will be returned to Castle Creek and eventually the Roaring Fork River.

“By diverting a maximum 25 cfs, it’s a very tiny percentage of the average 700 cfs we see in June,” Miller said. “And during times of lower flows, like in the winter, if you maintain 13.3 cfs in Castle Creek, you would meet all the criteria for a very healthy stream that would be preserved into the future with the Castle Creek Hydro Project.”

And the project isn’t like Shoshone, the hydroproject on the Colorado River near Glenwood Springs where the operation creates drastic changes on the river, visible to anyone. The Castle Creek hydroproject will divert a much lower percent of the water in the river. The City has the ability to adjust hydropower in times of low flow when it would damage the stream to divert water for hydropower, and in other times, it will be hard to visibly tell the difference when the hydropower facility is operating. 

“The only similarity between this project and Shoshone is that it will be a valuable way, in terms of Colorado water law, to keep water here on the Western Slope,” Overeynder said.

Under Colorado water law, if you don’t “use” water, you lose it. A non-consumptive use, like hydropower production, is unique in that it is enough to protect the water rights as a use, but it also returns the water to the stream.

Years ago, there was a private hydroplant that operated on Hunter Creek in Aspen in the 1800s. The hydroplant was eventually abandoned and the water rights were as well in the early 1900s.

“Today, the water is being diverted to the Front Range,” Overeynder said, adding that 20 to 25 cfs would have kept the creek alive. “If we had been able to keep that water right active, Hunter Creek would be a different stream today. It’s just an artifact of how Colorado water law works, and it’s another reason the Castle Creek Hydro Project makes sense for Aspen.”

The City operated a hydropower facility on Castle Creek in much the same fashion and location as is being proposed now with the Castle Creek Hydro Project. The original facility operated from the early 1890s to the 1950s, with no record of degradation of stream habitat.

A 2007 vote by Aspen citizens supported the new Castle Creek hydroelectric project, with 77 percent of voters voting for it. The project will produce a net 5.5 million kilowatt-hours of environmentally responsible electricity annually. That power production will prevent more than 5,000 tons of carbon dioxide from entering the atmosphere each year.

More details on the project, as well as a full copy of the Miller study, are available here.

Posted on Monday, June 14, 2010