Interstate 70 Tunnels East Portal, Colorado

Interstate 70 crosses the Continental Divide inside the Johnson and Eisenhower Tunnels. The Eisenhower Tunnel, now the westbound lane, was built first, opening in 1973. Six years later the Johnson Tunnel opened next to it, and the highway was divided. The tunnels are just under two miles long, and cross 1,470 feet underneath the Divide. At more than 11,000 feet in elevation, it is the highest point on the Interstate Highway System, and they are the highest vehicular tunnels in the nation as well. The tunnels also carry water over the Continental Divide, from the western slope to the eastern slope. A series of infiltration points collect water from above the western portal into an underground tank, which is connected to a channel that runs into the tunnel. The rights to much of this water were claimed, when the tunnels were proposed, by the Adolph Coors Company, which sought more sources of water for its primary brewery in Golden, on the eastern slope. The water joins with surface drainage around the tunnel portals, including from the roadway drains and tunnel seepage. Some of this water is held at the tunnel for cleaning and firefighting use by the Department of Transportation, but most of it is treated in a treatment plant inside the east portal building, and discharged. The water flows out of the tunnel into a small pond next to the highway, then joins Clear Creek, a once wild creek, now pushed to the side of Interstate 70, which uses the valley carved by the creek, to get to Denver.