From email from the Colorado Water Trust (Kate Ryan, Rick Lofaro, Brendon Langenhuizen, and Rob Viehl):
Colorado Water Trust and Roaring Fork Conservancy have teamed up with the Colorado River Water Conservation District (Colorado River District) and the Colorado Water Conservation Board to purchase and release water from Ruedi Reservoir to mitigate the impacts of anchor ice on the Fryingpan River. On Friday, December 16, the first release of water from Ruedi Reservoir will begin. The project aims to release 1.26 billion gallons of water (or 3,866 acre-feet) between December 16, 2022, and March 1, 2023, to the Fryingpan River, maintaining flows around 65 cubic-feet-per-second (cfs) in order to diminish ice buildup.
Anchor ice is a natural occurrence, but can have serious consequences on the hydrology of the river and the health of the ecosystem within. When there are low flows in the river during the cold winter months, large amounts of anchor ice can form on the bottom of the river, negatively impacting fish and macroinvertebrate function and diversity. Maintaining minimum winter flows between 60 to 70 cfs increases ecological resilience in the river through mitigating the formation of the anchor ice, and improving recovery from previous anchor ice impacts.
The partners will monitor the flow levels in the Fryingpan River, water temperature, air temperature, and anchor ice presence, from December through March. Anchor ice survey results will be compared to previous two years to continue to observe trends and build a long- term data set. “Roaring Fork Conservancy’s unique anchor ice monitoring program will allow us to objectively document anchor ice over time. This allows us to continue to promote management of Ruedi Reservoir with local benefits in mind” says Rick Lofaro, Executive Director of Roaring Fork Conservancy.