Twin Lakes Tunnel East Portal, Colorado

The four-mile long Twin Lakes Tunnel emerges from the other side of the Continental Divide at its eastern portal. It is said to be as straight as a rifle barrel, and that you can see one end all the way to the other—a pinprick of light 4 miles away. The tunnel was built in the 1930s, and around 40,000 acre-feet per year flow through the tunnel as measured by the Parshall Flume at the east portal. It is owned by the Twin Lakes Reservoir and Canal Company, whose shareholders are the city of Colorado Springs, the Pueblo Board of Water Works, the city of Aurora, and other eastern slope communities. The water flows into Lake Creek and to the Twin Lakes Reservoir.