An infrequent “administrative call” on the Dolores River by the Colorado Water Conservation Board is preventing two creeks from filling Groundhog Reservoir until Nov. 1.
The call was initiated to satisfy in-stream flow rights below McPhee Dam of 78 cubic feet per second, but local water managers say the water will never get there.
In-stream flow rights are administered by the water board to preserve the natural environment in state rivers to a reasonable degree. They are a priority water right senior to some, but junior to others.
A call is made to maintain a water right’s priority in the Colorado system of prior appropriation, commonly referred to as “first in line, first in right.”
Because of the call initiated this month, a man-made ditch diverting water from Little Fish creek and Clear creek to Groundhog was shut off, allowing the creeks to flow naturally into the Dolores River via the West Fork.
Marty Robbins, District 32 water commissioner for the Department of Natural Resources, said the call caused water administrators to enforce Groundhog’s one-time fill system that legally allows the reservoir to only fill from Nov. 1 to May 1. Groundhog Reservoir, owned by the Montezuma Valley Irrigation Co., typically diverts the streams into the reservoir year-round.
“Just because it has been done before, does not mean it can when there is a call,” Robbins said. “These calls may happen more regularly.”
On Nov. 1, the reservoir will go back on priority for filling, and the diversion ditch will be reopened, officials said.
The administrative call sends the creek water into the upper Dolores River and McPhee Reservoir, managed by the Dolores Water Conservancy District.
But Dolores Water Conservation District general manager Mike Preston says the extra water will stay in the reservoir and not flow through the dam to the lower Dolores River.
“McPhee’s water rights are senior to that in-stream flow right, and we have a storage right that allows for refill,” he said.
The in-stream flow water right on the Lower Dolores River is intended to preserve habitat for native fish, including the round-tail chub, bluehead sucker, and flannelmouth sucker. Federal and state biologists have reported that an increase in flows below the dam is needed to improve native fish habitat.
But the unexpected call by the state for delivery of in-stream water rights had an unintended consequence of threatening trout elsewhere, said Montezuma County Commissioner Larry Don Suckla.
The diversion ditch from Clear Creek to Groundhog Reservoir supports trout population, he said, but they became doomed when the water was cut off.
“Explain to me how water can be diverted for native fish, but is allowed to hurt trout?” he said.
Brandon Johnson, manager for the Montezuma Valley Irrigation Co., said the Colorado Water Conservation Board’s administrative “call presents issues at Groundhog we were not anticipating.”
The Colorado Water Conservation Board also made administrative calls for in-stream flows rights on other rivers in the state to establish that the rights exist and to reveal if any water users are out of priority, officials said. The calls were made after irrigation season so they would be the least disruptive.
The additional water flowing into McPhee as a result of the call will be divided among allocation holders in 2017, Dolores Water Conservation District officials said.