GLENWOOD SPRINGS — Although Four Mile Creek is currently running near the brink with early season runoff, a private water company that has been voluntarily diverting water from the next drainage over for more than 20 years plans to end that practice this year.
The potential impact of the decision is uncertain at this time, and may not be known until the next dry year when smaller tributaries such as Four Mile experience low late-season flows.
But Sunlight Water Co. will halt extra deliveries of water from its private Flannery Reservoir in the Three Mile watershed to Four Mile on a regular basis starting this season, according to company manager Cain Mahan.
The only exception will be water necessary to satisfy the company’s own needs and that of its current and future customers. The decision is due mainly to a lack of customer demand for the water, he said.
“We have, at this point, about six customers with varying amounts of water apportioned,” Mahan said, adding that extra water beyond that amount has been diverted from the high-mountain reservoir since the early 1990s, and has basically been free for the taking.
“As soon as we can get up to the siphon, we will shut it off,” he said of the remote area southwest of Glenwood Springs that remains deep in snow.
Historically, he said he and his family, including father Jim Mahan who built the reservoir, have been releasing a constant flow of about 1 cubic feet per second (cfs), or 724 acre-feet per year, since around 1992.
The reservoir itself covers about 24 surface acres, according to state water court records, and has a capacity to hold 105 acre-feet of water.
A siphon system pulls water from the deep part of the reservoir and diverts it into the Four Mile drainage, where it enters Four Mile Creek just above the Atkinson Ditch head gate, Mahan explained.
The idea was to market water to prospective customers on the Four Mile side, but much of that water ended up being diverted for free as other providers came in and were successful in selling water to individual users, he said.
“We have a bunch of water up there that we put over to Four Mile, and in Colorado any water that is not being used can be claimed,” Mahan said.
So the decision was made to end the voluntary diversions.
“The probable impact to Four Mile water users is evident in the fact that, even before we added water the creek, it regularly ran dry at the Atkinson Ditch, according to the state’s records,” Mahan said.
William Zilm, who heads up the company overseeing the Atkinson Ditch, said he was awaiting legal confirmation of the Mahans’ decision, and declined to comment.
Other water users in the Four Mile area said they would also have to wait and see how the Mahans’ decision might impact flows.
“We hadn’t heard about it, but I don’t think it will impact us,” said Randy Walther, president of the Oak Meadows Homeowners Association, noting that domestic water supplies for Oak Meadows, situated upstream from the Three Mile diversion point, has augmentation from other reservoirs in the area.
The decision also doesn’t affect West Divide Water Conservancy District customers in the area, said the conservancy’s legal counsel, Glenwood Springs attorney Ed Olszewski.
Mahan said his company remains interested in marketing its water to help augment Four Mile water needs in the future, “for an agreed upon amount.”
“There has always been, and always will be, demand for water on Four Mile, as well as a shortage of supply,” he said.