Concerns flow over diverting water for Aspen hydro power
November 14, 2009
ASPEN – Environmentalists and Aspen residents are preparing to hold the city of Aspen accountable for any negative effects that might occur as a result of the city diverting water from Castle and Maroon creeks to create hydroelectricity.
Nearly two dozen people attended a public meeting held Friday concerning the Castle Creek Hydroelectric Project. City officials, paid consultants, hydrologists and aquatic biologists were on hand to explain the project and answer questions about the project.
The purpose of the meeting was to determine whether the city should circumvent a full environmental review through a permit process with the Federal Energy Regulatory Commission (FERC).
As it stands now, the city plans to apply for what’s known as a “conduit exemption,” which wouldn’t require a full-blown environmental review. But the city’s public works director Phil Overeyender said if public comment, which will be taken for the next 60 days, raises enough concern or potential effects that the city hasn’t considered, a full environmental review could be possible.
Paul Noto, an Aspen-based water attorney, representing several residents who live along Castle Creek and near the proposed facility, said if the city of Aspen touts itself as an environmental leader, it ought to engage in a full environmental review of its proposed project.
Noto said the question that must be fully vetted is whether the city’s environmental goal to create hydropower doesn’t come at the expense of the streams, the wildlife and individuals who own water rights in those bodies of water.
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Several people are concerned about a decreased flow in Castle and Maroon creeks because water will be drained out of both to generate power.
Under an agreement with the state, the city of Aspen would never go below 12 cfs in Castle Creek and 14 cfs in Maroon Creek.
Resident Michael Lipkin pointed out that if the hydropower plant goes forward, there would be about one-third of the water left in Castle Creek in early November, for example.
City officials and representatives said during low flow times of the year, the city might not be able to divert water from the streams because there isn’t enough available. During an average year, Castle Creek peaks at 700 cfs and the base low is 30 cfs, according to Kerry Sundeen of Glenwood Springs.
If approved, the water would travel down a 42-inch pipe, supplying the hydro plant with approximately 25 cubic feet per second (cfs) coming from Castle Creek and 60 cfs out of Maroon Creek.
The size of the pipe limits the city on how much it can take from either stream.
“You just can’t take that much water,” Sundeen said.
The city diverts water from both creeks for the primary purpose of supplying municipal water and maintains the in-stream flow of 12 and 14 cfs. The third priority would be for hydroelectricity, but if there isn’t enough water available in a dry year or during certain times of the year, it wouldn’t be diverted, Sundeen said.
“We don’t have enough stream flow during winter because hydropower is the last priority,” he said.
The proposal is to build a 1,880-square-foot hydropower plant under the Castle Creek Bridge. The project would utilize existing water rights, head gates, and water storage of the original Castle Creek hydroelectric plant, which met all of Aspen’s electric power needs from 1892 through 1958, when the plant was decommissioned.
The facility’s turbine and generator would be designed to convert the force of falling water into electric power. The water comes from the Thomas Reservoir, which is located at the top of Doolittle Drive and is the home of the water treatment facility.
The electricity would be placed on the city’s grid and taken up to the water treatment campus to power those facilities, and to potentially produce hydrogen for hydrogen fuel cells and hydrogen vehicles.
When completed, the 1.05 mega-watt facility is expected to increase electric production by 5.5 million kilowatt hours annually. It would generate renewable energy for the city and increase its supplies by 8 percent over its current level of about 75 percent.
City officials say that switching from primarily coal-fired energy purchases to hydroelectric power production would eliminate an estimated 5,167 tons of CO2 emissions – representing a 0.6 percent community-wide reduction in carbon emissions based on the 2004 greenhouse gas emission inventory.