County looking at road, bridge goals

Start with Washington Gulch culvert, end with Gothic Road bridge—and use a shoofly

By Katherine Nettles

Gunnison County is looking to make culvert improvements to the Washington Gulch drainage under Gothic Road in 2020, and to replace the Gothic Road bridge crossing the Slate River between Crested Butte and Mt. Crested Butte in 2021. Public works director Marlene Crosby gave an overview of the county’s road and bridge conditions as part of a performance and strategic plan review with county commissioners on October 8.

The Gothic bridge was built in 1983, and is now showing signs of its age. Crosby said it’s the busiest of all the bridges owned by the county, with engineering and traffic studies reporting more than 5,000 cars crossing it daily. The public works department collected estimates of what it would cost to rehabilitate or replace the bridge to aid in its recommendation to the board of commissioners, and Crosby said the best option appears to be total replacement given that the estimated cost of a brand new bridge would be only slightly more than the cost of rehabbing it.

The rehab requires two new steel girders which are very expensive, said Crosby. A new bridge would use concrete girders at a much lower cost, for a total of about $2 million, of which the county would likely need to contribute $462,000.  She said the best option is to use a shoofly, or a legally standard temporary bridge that serves as a detour during construction. This allows the project to get done faster and avoids closures and traffic congestion.

“So you keep traffic moving, and it allows you to use existing bridge approaches as the construction staging area,” said Crosby. Her recommendation would be to submit an application to the CDOT Off-System Bridge program during the next grant cycle for the bridge’s reconstruction with a two-lane shoofly. She recommended the county wait to submit for the project until the following year’s grant cycle (2021), and use the time to allocate money for engineering and potential wetlands identification in that area as well.

Currently, the area around the bridge floods, she said, but holds potential for better flow guidance between the Slate River and Coal Creek. The Crested Butte Land Trust owns property on the northwest side of the bridge, and Crosby suggested conducting a wetlands survey this fall and working with the Land Trust to help enhance the wetland area.

The county has settled on prioritizing improvements on a culvert under Gothic Road just below the sewer plant in Mt. Crested Butte during its 2020 budget cycle. The bottom has washed out, says Crosby, and needs to be slip-lined with plastic as a measure that will “last a lifetime.”

“We need to do it before the top collapses,” said Crosby. “That’s our busiest road. We can’t afford a failure.” The commissioners agreed.

Part of the strategic plan as Crosby outlined it is that “By December 31, 2020, Gunnison County will have an additional funding stream that ensures sufficient support for road and bridge infrastructure, construction and maintenance…”