The organization that has made it its mission to create river restoration and aquatic habitat improvements along the Rio Grande and Conejos River acknowledges its mistake to minimize river flows during a canal diversion project that resulted in a mass fish kill and potential impacts to other species along the Rio Grande corridor.
Daniel Boyes, executive director of the Rio Grande Headwaters Restoration Project, said a combination of factors, including a tight construction timeline and changing weather, contributed to the decision that led to a dry riverbed on a 7.2-mile stretch of the Rio Grande east of Del Norte.
It is in this area, where the north and south channels of the Rio Grande diverge, that the Farmers Union Canal Diversion and Headgate project is underway. The project ironically is intended to “improve fish passage, enhance aquatic habitat into both the north and south channels of the Rio Grande, and modernize critical irrigation infrastructure.”
“The Rio Grande Headwaters Restoration Project (RGHRP) and San Luis Valley Irrigation District (SLVID) are deeply saddened by the fish mortality that occurred during construction of the project,” said Boyes.
He further explained: “The original construction plan involved keeping the work area dry by directing higher-than-normal flows into the north channel of the Rio Grande. However, as conditions changed, the project team grew concerned that elevated flows from fall rains, combined with potential ice jams, could cause significant damage to bridge infrastructure, multiple other ditch diversions, and separate concrete work occurring along the Farmer’s Union Canal.
“In response to these risks, the team made the decision to minimize flows into the north channel. Unfortunately, this resulted in areas of unintended dry up and an associated fish kill. In hindsight, the decision to limit flows was a mistake.”
Aquatic biologists with Colorado Parks and Wildlife, after reviewing the damage and collecting as many of the dead fish as they could, estimated it could take three to five years to recover the fishery, said John Livingston, southwest region public information officer for CPW.
“A significant number of the fish populations in that stretch died across all age classes. Brown and rainbow trout as small as two inches and up to 24 inches have been found, along with all sizes in between. Brown trout also spawn in the fall, and this year’s eggs laid in the rocky bottoms of the river most likely have been lost,” Livingston said.
As soon as the project team was aware of the impacts to the fishery, Rio Grande Headwaters Restoration Project and San Luis Valley Irrigation District communicated with Colorado Parks and Wildlife (CPW) to determine how best to restore flows, Boyes said.
He added the project team used pumps and pipes to return water to the north channel, which is now flowing normally along its full length. Flows will continue to be maintained in the north channel for the remainder of construction, which is expected to be completed by early April.
Boyes, who was away when the decision was made, met last week with CPW staff to continue to remedy the problem. The canal diversion and headgate project is funded through the U.S. Bureau of Reclamation.
“The existing diversion structure will be replaced with a new structure that is fish-friendly and the headgates will be upgraded and automated. Once complete, the project will create a more connected river system, allowing fish to move freely past the Farmer’s Union diversion, and will result in healthier fish populations,” Boyes said. “The new diversion and automated headgates will also improve water management efficiency and help farmers.”