The City of Golden purchased the Vidler Tunnel and collection system in 2000, which provides western slope water from the Peru Creek Basin in Summit County into the Clear Creek Basin (Guanel-la Pass). IMEG has worked with the City over the past two decades on several improvement projects and maintenance programs.

One significant issue with the tunnel was the existing flow mea-surement flume located approximately 300-feet into the western portal of the tunnel. The interior location of the flume was prob-lematic in that it was subject to icing early in the year, did not allow visible access to verify flows, and the satellite communication of flow data was unreliable.

To remedy this, IMEG in coordination with the City designed a new flume structure for the western portal. This new flume was located at the exterior of the western portal and provided greater accuracy, reliability, and operability for the City. Design for any improvement at Vidler means considering remote 4 x4 access, and the limited construction window inherent with an asset at 11,650-ft of eleva-tion. To accommodate these unique challenges the flume structure was designed utilizing a number of precast structures that could be delivered and assembled in place rather than trying to cast a complex concrete structure. In addition, to the physical challenges the portal is located within the White River National Forest which requires environmental permitting and coordination on any project.