Denver (west of town), August 3, 1933

On the evening of August 3, 1933, Elsie Henderson's urgent voice raced down the Sullivan Telephone Exchange's wires, outpacing Cherry Creek's northbound floodwaters. Notified by a Douglas County sheriff that Castlewood Dam had burst and that everything along the stream's path from Franktown to Denver was in danger, the operator told farmers and ranchers to gather their families and head for higher ground.

At that time, rural telephone customers often shared single wires called "party lines." The telephone company assigned phone numbers made up of unique ring patterns to each customer (for example, one short ring followed by two long rings). Elsie, one of only two people available to operate the Sullivan switchboard that night, alerted people with one long ring, the universally recognized sound for an emergency. She and fellow Sullivan Exchange employee Ingrid Mosher worked through the night and into the following afternoon, saving lives, livestock, and property. Though five thousand fled the lowlands, only two people died in one of the worst floods in Colorado history.

In time, Elsie's deeds might have been washed downriver and forgotten. The story survives thanks to George Madsen, a friend who took the time to answer a 1994 letter from Castlewood Canyon State Park staff requesting personal reminiscences about the flood. Madsen, a former telephone company employee, wrote down his own memories, along with the stories told to him by Elsie and Ingrid years earlier. Dozens of other Coloradans answered the call too, typing their recollections on legal-sized sheets of paper headed by the question, "Where Were You When the Dam Broke?" In 1997 Castlewood Canyon State Park staff members assembled these memories into a compelling book called, The Night the Dam Gave Way: A Diary of Personal Accounts .

Funded in part by a $3,750 State Historical Fund grant, the publication helps Coloradans understand the relationship between Castlewood Dam and the people and environment its failure affected. The Castlewood diary tells how developers built the dam thirty miles south of Denver in 1890, hoping to facilitate agricultural development in Douglas County. It goes on to chronicle the immediate controversy over alleged defects, citing proclamations by its engineer that "the Castlewood dam will never, in the life of any person now living, or in generations to come, break to an extent that will do any great harm." But before the walls crumbled during the 1933 downpour, discrediting the engineer, Castlewood Reservoir drew thousands of vacationers. Mildred Sas of Broomfield recalled camping, fishing, and playing near the dam as a child:

We used to go up to the dam and sit and talk about it. Often we wondered how long it would last. It was amazing how the big slabs of rock were put together. It was God's Country then, and about five years later when we stopped going to the dam it broke my heart.

After the dam collapsed, Leota Bostrom of Littleton remembered seeing "a wall of water" coming down Cherry Creek. The ten-year-old girl saw tree branches, bushes, a dead cow, and a dog float by as she watched from West Seventh Avenue and Speer Boulevard. She remembered the stench of death, writing, "The smell was unique to a flood and if you ever smell it you will never forget. Awful!"

Documented memories like Mildred's and Leota's may be just as important to a historic site's preservation as bricks and mortar. Although the Army Corps of Engineers considered rebuilding Castlewood Dam as part of a Cherry Creek flood-control project as late as the 1970s, citizens opposed the idea, arguing that the new Cherry Creek dam built in 1946 was sufficient. Today, thanks to the creators of this publication, visitors to the old dam's ruins in Castlewood Canyon State Park can dip into a reservoir of shared experiences that offer personal perspectives on an important part of Colorado's history.

BY BEN FOGELBERG, Editor, Colorado History NOW