GRANT — Fifty years ago this week, Denver Water opened the spigot on the Harold D. Roberts Tunnel and began delivering water from Summit County to the Front Range.

The water-diversion tunnel, still one of the largest in the world, is responsible for sustaining upward of 1.3 million people. Denver Water hosted an anniversary celebration Wednesday.

The tunnel’s construction began in 1956, during one of the worst droughts in Colorado’s history. The 23.3-mile tunnel, which diverts water from Dillion Reservoir under the Continental Divide to Grant, west of Bailey, was completed in 1962.

Constructing the tunnel, then the second largest in the world, cost $50 million. When it opened, it served 335,000 Denver residents.

Read more of the article Denver water honors water tunnel that began flowing in 1962 at SummitDaily.com.