March 23, 2015

Aspen water plan emphasizes a potential need for storage

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The City of Aspen's diversion structure on Castle Creek.

Brent Gardner-Smith/Aspen Journalism

The City of Aspen's diversion structure on Castle Creek.

A graphic in Aspen's draft water efficiency plan shows that the city has generally been using less water over time.

City of Aspen

A graphic in Aspen's draft water efficiency plan shows that the city has generally been using less water over time.

A draft water-efficiency plan for the city of Aspen places a strong emphasis on the potential need for the city to develop water-storage facilities, including large dams and reservoirs on both upper Castle and Maroon creeks.

While Aspen’s draft plan makes repeated references to the city’s lack of water storage, it also repeatedly concludes that the city has adequate water supplies for at least the next 20 years without storage.

“Through this plan, the city has established that its raw water supply is adequate to meet anticipated future growth, although lack of existing storage means that Aspen remains at risk of shortages when streamflows are low, or when emergency conditions prevent or limit use of one or more sources of supply,” Aspen’s plan states. “Moreover, the demand projections in this plan do not factor in impacts of additional future climate changes.”

The city owns senior pre-1900 water rights for 160 cubic feet per second of water from Castle Creek and 65 cfs from Maroon Creek.

Aspen’s water-efficiency plan, which has been submitted to the Colorado Water Conservation Board for review, also includes references to two potential dams on upper Castle and Maroon creeks, which would be 170 and 155 feet tall, respectively.

“The potential need for surface storage of snowmelt runoff from Castle and Maroon creeks has been included in the city’s water management Program since the 1960s,” the draft plan states. “The development of surface water storage at specific sites identified in conditional water rights held by the city for this purpose is expected to eliminate water shortage conditions.”

The city’s conditional rights for the two dams are set to expire in 2016. The city is expected to tell the state water court it can and will build the two dams someday, and it will likely include its water-efficiency plan as part of its case.

And while Aspen’s water-efficiency plan places significant emphasis on the potential need for storage, similar draft plans for Basalt, Carbondale and Glenwood Springs — prepared by the same consultants who developed Aspen’s plan — lack the same emphasis.

While the plans for Basalt, Carbondale and Glenwood contain the same reference to the general need for water storage in the West, the word “storage” is otherwise used sparingly.

For example, Basalt’s plan uses the word “storage” six times. Glenwood’s plan uses it five times, and Carbondale’s plan uses it three times.

And none of the uses is in the context of future potential reservoirs, even though those communities would presumably share the same hot, dry and crowded future that would prompt Aspen’s need for it.

In comparison, the word “storage” is used 15 times in Aspen’s plan, and it is used at least eight times in the context of Aspen’s lack of reservoir storage.

It’s hard to miss Aspen’s repeated emphasis on the potential need for storage despite the consistent conclusions that it also likely has enough water without it.

“On an annual basis, the dry year yield of the city’s water rights appears to be more than sufficient to meet current and forecast future demands,” the plan states. “However, the city does not have storage … ”

“While the historical dry year yield of the city’s water rights appear sufficient to meet current and forecast future demands, the dry year supply figure is misleading,” Aspen’s plan states. “The city, unlike many Colorado municipalities, does not have a significant water storage component to its water system. (Though) the city’s supplies appear to be sufficient for current and future demands under historical hydrology conditions, without storage … ”

Consulting engineers with Element Water Consulting in Denver and WaterDM in Boulder prepared the four plans.

“Our team used a similar planning approach with the four efficiency plans that we prepared, but each plan was tailored to the individual water provider’s specific water-supply system, current and projected water demands and customer base,” said Beorn Courtney of Element Water Consulting.

Lee Ledesma, the utilities operations manager for Aspen, also was asked about why Aspen’s plan includes storage but the other local plans don’t.

Ledesma said via email that “we have not reviewed the individual water efficiency plans for Snowmass, Carbondale, Glenwood and Basalt, so we really cannot comment on those cities’ long-range water service plans and supplies.”

A recent water-efficiency plan was completed recently for Snowmass Village.

It was prepared by SGM, an engineering firm in Glenwood Springs. The plan does not include the same type of warnings about a future potential need for storage as the Aspen plan, but it does include a reference to additional water rights in Ziegler Reservoir.

Editor’s note: Aspen Journalism is collaborating with The Aspen Times and the Glenwood Springs Post Independent on coverage of water and rivers. The Times published this story on Monday, March 23, 2015.

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