From Aspen Journalism (Heather Sackett):
Wildfire, infrastructure failure and persistent drought are the three biggest risks to the city of Aspen’s main water sources of Castle and Maroon creeks, according to consultants Carollo Engineers.
“The (risks) you worry about most are the ones that are fairly likely to happen and would have a pretty high consequence if they did,” said John Rehring, senior project manager and vice president of Carollo Engineers.
The risks to Aspen’s water supplies are just one of many topics consultants are taking into account as they develop a roadmap for the next 50 years of the city’s water management. As part of consultants’ data-gathering process, the city is holding the third and final community engagement session from 5 to 6:30 p.m. Wednesday.
The first two sessions were lightly attended, but city officials are hoping more citizens will show up Wednesday.
“I always like to see more people be involved,” said Steve Hunter, utilities resource manager for the city of Aspen. “We want to be completely transparent with the public.”
Carollo is working toward a final water integrated resource plan, or IRP, which they are expected to release by mid 2021. A main component of the plan will be how to address Aspen’s potential water shortages.
Although numbers are still preliminary, according to a presentation engineers gave to the city in January, the city’s estimated shortage is about 2,500 acre-feet on an annual basis. A shortage is defined as an inability to meet all demands at the same time, for example if prolonged drought cut streamflows such that the city could not provide enough water for outdoor irrigation or meet instream flow requirements.
One potential solution would be to bring online three groundwater wells in downtown Aspen, which are currently not being used because of water quality issues like too much fluoride. Having different water sources that might not be subject to natural disasters like wildfires and avalanches the same way Castle and Maroon creeks are would make Aspen’s water supply less vulnerable.
“Having the groundwater in there would help with diversity and risks and vulnerabilities,” Rehring said.
The city has a portfolio of water rights on various local waterways, ditches and wells. But it’s main source of potable water is Castle Creek.
Consultants also are working on finding a location to which to move Aspen’s conditional water-storage rights and determining whether the city needs storage at all. After a lengthy water court battle, in June 2019 the city gave up its rights that could have someday allowed it to build dams and reservoirs on upper Castle or Maroon creeks.
The city has identified five other locations where it could possibly store water. Those sites are the city golf course, the Maroon Creek Club golf course, the city’s Cozy Point open space, the Woody Creek gravel pit and a 63-acre parcel of land next to the gravel pit, which the city bought in 2018.
Previous consultants have come to different conclusions about how much water storage the city actually needs. A 2017 report by Deere and Ault Consultants, which was based on conclusions in a risk analysis by Headwaters Corporation, said Aspen needs 8,500 acre-feet of water storage. But a 2016 study by Wilson Water concluded Aspen does not need any storage.
“We are trying to identify just what the storage needs are and better define just how much storage is needed or maybe how to phase in that storage capacity over time,” Rehring said. “We have not zeroed in on any particular site at this point.”
Wednesday’s meeting will take place on Zoom. To register and for more information, go to aspencommunityvoice.com.
Aspen Journalism covers water and rivers in collaboration with Swift Communications newspapers. This story ran in the March 1 edition of The Aspen Times.