Krista Driscoll

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October 31, 2013
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Take a boat tour to learn about the history of Dillon Reservoir

Learn about the history of Dillon, the rise of Denver Water and the construction of the Dillon Dam on the “Explore Lake Dillon” boat tour, offered every Tuesday during the summer.

The tours, led by Jim Estelle, a volunteer with the Summit Historical Society, embark from the Dillon Marina and loop around the reservoir as Estelle explains how it was constructed and why.

“It’s a great way to see Dillon from a different perspective, a different view,” said Shannon Jakoby, office manager at the Dillon Marina.

For the first time this summer, those on the tour are encouraged to disembark and continue their journey by heading up the hill to the Dillon Schoolhouse Museum on LaBonte Street. The schoolhouse, open at 10:30 a.m. on Tuesdays, is free to tour and loops a 10-minute DVD that shows the construction of the reservoir, including a photo of the schoolhouse building being hauled on the back of a flatbed truck from old Dillon to new Dillon, Estelle said.

Diverting water to the east

Tour participants board a pontoon boat at the Dillon Marina and head off on their excursion.

“As we leave the dock, we start out talking about the unique situation that exists here in Colorado in that Colorado exports all its water,” Estelle said. “So we either consume it, store it or it goes away.”

The population centers in Colorado are concentrated on the Eastern Slope of the Continental Divide, but most of the water in the state resides on the Western Slope.

“So the first function of the reservoir is the dam,” Estelle said. “We need a diversion to get the water from the West Slope to the East Slope. We talk about the Roberts Tunnel and how it was built, the size and its history; it had its 50th anniversary late last August.”

Water flows through the 23.3-mile Roberts Tunnel at up to 1,000 cubic feet per second, sending the contents of the reservoir to the Front Range, where it is processed by Denver Water.

Moving the town of Dillon

After studying the Roberts Tunnel, Estelle delves into the history of Dillon, how it got its name, how it came to be and how it was moved from the bottom of the reservoir site to its current location. Originally, Dillon was a railroad town.

“What they were trying to do was position themselves to where they thought the railroad would come in,” he said. “We discuss the rails coming in and how that made Dillon a transportation hub, with cattle and lumber coming down from the north or from Montezuma.”

Dillon’s fate eventually fell into the hands of Denver Water, as it began buying up property in the valley at the confluence of the Snake River, Blue River and Ten Mile Creek.

“Denver Water quickly moved into the valley,” Estelle said. “The drainage of the three rivers — where the three rivers meet — they bought property because they wanted to do a diversion project or both storage and diversion.”

After reviewing several designs for the dam, one was settled upon in 1958-59, and letters went out to the approximately 80 residents of Dillon telling them they would need to relocate by the spring of 1962.

“If you wanted to walk away from your property, they would give you a lot in new Dillon, or you can accept what they paid you and not get a lot,” Estelle said. “A few people had the resources that they got the new lot up in Dillon and also moved their structures up.”

About 14 private residences were moved from the valley to the site of new Dillon, along with a few commercial structures such as the Lake Dillon Theatre, which was formerly the town hall building at the old site, and the Arapahoe Café building.

Summit County and the dam

The tour also delves into a brief history of Summit County, through hard-rock mining, surface mining and dredging, railroading and, finally, morphing into a tourism-based economy in the 1960s.

“By that time, we’re kind of cruising around and a little ways up the Blue arm and then we turn and make our way over to the dam and I talk about how you construct this dam,” Estelle said.

There are two main types of dams, Estelle said. The larger ones, such as Hoover Dam and Glen Canyon Dam, have an arch design.

The Dillon Dam is a gravity design, which is held in place by its sheer weight — 12 million tons. Estelle then reviews the stats of the dam and explains how it diverts water through the Roberts Tunnel to the Front Range.

Estelle said the tour is important so people can understand how and why the reservoir was built and how it moves water.

“I think a lot of people are aware of the reservoir, but I don’t think they necessarily understand the nuances of how it works and why the reservoir goes up and down so much,” he said.

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The Summit Daily Updated Oct 31, 2013 04:29PM Published May 8, 2015 12:24PM Copyright 2015 The Summit Daily. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.