Anglers fishing the trophy tailwater fishery below Reudi Reservoir dam in the fishing hole known as the Toilet Bowl

Donald Anderson, Upper Colorado River Endangered Fish Recovery Program
February, 2020

Numerous water interests on Colorado’s West Slope collaborate with the Upper Colorado Program to augment streamflows for endangered fish. Every irrigation season, weekly calls are held with reservoir managers and water users in the Yampa and Colorado River basins to coordinate operations that best meet the needs of irrigators, power generators, recreationists and municipalities as well as the fish. Programatic Biological Opinions (PBO) for each of the rivers establish agreements that allow program collaborators to promote recovery of the four species while ensuring that water users can continue developing water resources and exercising water rights in compliance with the Endangered Species Act.
The drought year of 2018 is a good example of what makes this collaboration so valuable. Disappointing winter snowpack was followed by hot and dry conditions that set in early and persisted for most of the irrigation season. The 2017-2018 Water Year was the warmest in 124 years of recorded Colorado history, and the second-driest. River flows dwindled and reservoirs were drawn down to alarmingly low levels.

Drought conditions threaten endangered fish recovery too. Low river flows and high water temperatures in early summer stress native fish by reducing their food base and forcing them to seek refuge in scarce pools and backwaters. Problematic nonnative species like smallmouth bass get a jump-start under warm conditions. They eat young endangered fish, and grow to a size that promotes over-winter survival, allowing them to wreak more havoc in subsequent years.

The Upper Colorado Program accesses substantial amounts of water from reservoirs annually to boost flows for endangered fish during low-flow periods of the year. However, in years when augmentation water is most crucial, less is available. Thousands of acre-feet accessible in a “normal” year from West Slope reservoirs like Green Mountain and Ruedi are unavailable in very dry years. As a result, flow conditions for endangered fish grew particularly dire in 2018, especially in the lower Yampa River and in the ’15-Mile Reach’ of the Colorado River above the Gunnison River confluence.

The good news: Upper Colorado Program partners stepped up to provide extraordinary support for maintaining instream flows in 2018. In the Yampa River basin, the Colorado River Water Conservation District (CRWCD) leased water from Elkhead Reservoir to help prevent the dismally low flow conditions in the lower Yampa from becoming worse. In the Colorado River above the 15-Mile Reach, multiple partners stepped up and voluntarily provided desperately needed water. The CRWCD advantageously timed their maintenance releases from Wolford Reservoir to provide maximum benefits for endangered fish. The Ute Water Conservancy District of Grand Junction leased their unused water in Ruedi Reservoir to support flows. ExxonMobil subsidiary XTO Energy released their hold on 5,000 acre-feet of contract water in Ruedi Reservoir, enabling an equivalent amount to be released for endangered fish. Note that without these collaborative efforts, the 15-Mile Reach likely would have gone completely dry for approximately 12 days in late September and early October. Not good.

Others making these water deliveries possible included the Colorado Water Conservation Board, the U.S. Bureau of Reclamation, the Colorado State Engineer’s Office, and agricultural water users like the Grand Valley Water Users Association, Grand Valley Irrigation Co., and Orchard Mesa Irrigation District in Palisade, Colorado. The Upper Colorado Program is fortunate to count these entities among its partners.