Learn about the Colorado-Big Thompson Project, Alva B. Adams Tunnel, and visit East Portal on this guided history hike!

Join the Rocky Mountain Conservancy for a hike exploring the history beneath Rocky Mountain National Park. This 5-mile round-trip hike from East Portal to Sprague Lake gains 750 feet in elevation and highlights the remarkable story of the Alva B. Adams Tunnel and the Colorado-Big Thompson Project.

Built during the New Deal era, the project diverted water from the Colorado River to the eastern plains—providing irrigation, hydroelectric power, and economic relief during a time of national hardship.

Along this moderate hike, we’ll discuss the ongoing balance between preservation and progress in the Park’s history. Our hike begins with a steep climb over a short distance, with occasional areas of loose ground, before leveling off for the remainder of this out and back route.

Who: Participants ages 16 and up.

Program Level: Challenging – These programs are ideal for people accustomed to hiking longer, steeper trails at elevations above 8,000 feet. Programs will include travel over rough, loose, and uneven terrain. Participants should be able to hike at a pace of 1.5 miles per hour while carrying their own food, water, and layered clothing.

This program is entirely field based.

When: Friday, September 18th from 9:00am to 3:00pm. Ending time is approximate and depends on traffic conditions and the pace of the group. Please leave yourself some free time after the hike in case we get back later than expected.

Where: We will meet at the Estes Park Visitor Center at 500 Big Thompson Ave, and travel together to the trailhead in Conservancy vehicles. Look for a large white van with Rocky Mountain Conservancy logos in the visitor center parking lot. Registration includes all park fees and permits.