Roberts Tunnel open, affecting Blue |

Roberts Tunnel open, affecting Blue

BOB BERWYNsummit daily news

SUMMIT COUNTY – Boaters who still haven’t dipped their oars into the waters of the Lower Blue might want to hurry up.Recent bountiful flows in the river will begin to recede, as Denver Water opens the Roberts Tunnel today for the first time in several months. “By Monday, we will not have raftable flows anymore in the Lower Blue,” said Denver Water engineer Marc Waage. “Things are changing quickly. Inflows into Dillon Reservoir are dropping.”By the end of the day, 200 cfs will be flowing through the 24-mile underground aqueduct. The water will pour under the Continental Divide and into the South Platte drainage near Grants, along Highway 285, to bolster flows and storage on the Front Range side of the Divide.By Thursday, inflow from the Snake, Blue and Tenmile drainages combined was down to about 695 cfs, down from near 1,000 cfs early in the week.The last of the snowpack is melting, and flows on the South Platte have dropped, with downstream demand on South Platte water growing, Waage said, explaining that water from Dillon Reservoir is now needed to augment those flows and to meet downstream calls.The news of the Roberts Tunnel diversion comes just a day after water officials touted the “free river” status of the Colorado and Blue. But even with the 200 cfs diversion, Dillon will continue to spill, at least for a while, and the Blue River and Colorado River basin is still in a “surplus” situation, with more than enough water flowing through the system to meet all adjudicated water rights.Waage said he’s informed commercial raft operators about the changes. “We’ll try to keep the outflow from the reservoir above 500 cfs through the weekend, but Monday is looking iffy,” he said. Flows below that benchmark are generally not considered adequate for commercial rafting. “I know people aren’t going to believe it, but we really tried to keep the tunnel off as long as we could to extend the rafting season,” he said.In the past 10 years, the Blue River has only sustained raftable flows for short stretches of time, notably during Labor Day weekend 2004, when Denver Water scheduled a release to help meet that recreational demand. Bob Berwyn can be reached at (970) 668-3998, ext. 228, or at

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