Crews working to replace mile-long pipeline after testing reveals wrong type of pipe was used in construction last summer
The Old Dillon Reservoir in mid-construction, summer, 2012. Bob Berwyn photo.
By Bob Berwyn
SUMMIT COUNTY — Local water officials say there’s still enough runoff coming down from the mountains to fill the newly enlarged Old Dillon Reservoir by Aug. 1 — even after an unexpected setback delayed the start of fill.
As engineers started to pressure-test the diversion pipeline late last summer, they discovered that the contractor used the wrong kind of pipe for the job, preventing completion of the project.
“Some of the gaskets would not seal,” said Dillon utilities superintendent Trevor Giles, explaining that crews are currently in the process of replacing the 24-inch-diameter pipe, which runs about 5,000 from the lower Salt Lick Gulch area in Wildernest, beneath I-70 and into the reservoir.
“The gist of it is, we put the pipe in, went to pressure test it, and realized the pipe wasn’t substantial enough for the pressures we were encountering. The pipe was not the correct material for that application,” he said. “Pending any weather and runoff delays, we should have this done by the end of June.”
Giles said the contractor was able to resell the pipe. It will be used in some development projects in the Grand Junction area, and won’t end up in the landfill, Giles said. Under the terms of the contract, local entities and taxpayers won’t be on the hook for any additional costs for the replacement work, which could cost between $400,000 to $500,000.
The $7 million project was initially scheduled for completion July 31, 2012 but encountered delays last spring, when the contractors started work without having all the needed equipment on-hand at the start of construction, Summit County manager Gary Martinez said last spring.
Old Dillon Reservoir will provide more local water storage by expanding the existing reservoir from 62 acre feet to 308 acre feet. The reservoir is administered by a locally formed authority with representatives from several local towns and the county. The original reservoir was built in 1936 and stored water for Dillon until the town was relocated when Dillon Reservoir was created by Denver Water.
According to a county fact sheet, the water will be used to meet demand from new growth in Summit County and a variety of other purposes, potentially including ball fields and other recreational open space, wetlands restoration, new community facilities and augmentation of well water usage in the Blue River Basin. Late in the construction process, the reservoir authority decided to raise the dams by one foot, so the finished storage volume will be 308 acre feet.
In particular, the storage will benefit Dillon, which relies on surface water from Straight Creek, running down from its headwaters near the Eisenhower Tunnel. Straight Creek is potentially vulnerable to pollution and low flows, so Old Dillon Reservoir will be a good backup.
When the work is done and and inspections are completed, the reservoir could fill in as little as two to three weeks, depending on how much runoff is still flowing in Salt Lick Gulch. The diversion intake in the Gulch is just a couple feet higher than the reservoir, so the water flows via gravity through an inverted siphon.
Golden trout pond?
Once the reservoir is filled, it could become home to a population of golden trout, native to California and a close relative of native Colorado cutthroat trout. Local water officials discussed the fishery with Colorado Parks and Wildlife last year, and now, there are several thousand six-inch goldens in a hatchery, waiting for a new home.
Since Old Dillon Reservoir is mostly a closed body of water, it will be suitable for creating a broodstock of golden trout. The pipeline going into the the reservoir will be screened to prevent any other fish from entering the water, helping to maintain a population of pure golden trout.
The fishery would give Summit County a unique angling opportunity that could be a statewide draw, as the state’s only golden trout fishery. Golden trout are native to a drainages in California like the Kern River. They look a bit like cutthroat trout but with more of a golden color. They aren’t be mistaken for so-called albino rainbows that also have a yellow hue, said Colorado Parks and Wildlife biologist Jon Ewert.
Since golden trout aren’t native, they aren’t subject to any special protections, and Ewert envisions a put-and-take fishery. Initially, the fishery would probably be managed as catch and release, but once some of the trout have grown to 12 inches or larger, anglers may be able to take some of the fish home for dinner.
Giles said there have been reports of deer already moving back through the surrounding forests. Most of the area will be allowed to regrow naturally, and the reservoir authority will maintain a small wetlands at the west end of the reservoir.
