Castlewood Dam failure, 90 years later: When Denver was hit with a wall of water

FRANKTOWN, Colo. — In the early morning hours of Aug. 3, 1933, following two days of heavy rain, Castlewood Dam keeper Hugh E. Paine was awoken by a horrendous noise described by him as sounding like a tornado. Grabbing his kerosene lamp, Paine walked out to the dam to see what was causing the noise.

What Paine saw that morning was the making of a disaster that, in a matter of hours, would take the lives of two people and ravage farms, ranches and parts of Denver—causing nearly $23 million (in today’s dollars) in damages in the midst of the Great Depression. But it may have been a lot worse if it weren't for the actions of the 48-year-old caretaker that morning.

Aug. 3, 2023, is the 90th anniversary of the collapse of the Castlewood Dam, which was constructed in 1890 near Castle Rock and held back the Cherry Creek. It's construction created a reservoir — called Lake Louisa by many — with a capacity of 5,300 acre-feet of water. It's a little-known piece of Colorado history that had lasting impacts on the region.

Today, what's left of the dam — the right and left abutments and part of its crest — sits quietly like an ancient Roman ruin in front of a now-dry reservoir bed inside Castlewood Canyon State Park, 40 miles southeast of Denver. It became a state park in 1964 and expanded another 792 acres, to include the former dam and reservoir, in the 1970s.

Cherry Creek still meanders through the canyon, now unobstructed, carving an even deeper canyon through 90 years of erosion. Flood control is now handled by the Cherry Creek Dam, which was built in 1949 as part of a $275 million New Deal program.

Ron Claussen, a former park employee and volunteer, said Castlewood Dam may have been doomed from the beginning because of how and where it was constructed.

"All the rocks is Castle Rock conglomerate. It was quarried from the cliff faces on both sides. So, the material was handy. The problem is, when you look around here, this is Dawson Arkose, very crumbly, soft sandstone. So it was probably not the best place to put it," Claussen said.

Built in 1889, the 600 feet long, 70 feet tall Castlewood Dam provided irrigation water for surrounding farms and a new agriculture development in the town of Melvin, Colorado, which is now underwater in the Cherry Creek Reservoir.

“They were selling 40-acre lots for apple trees at cetera. Well, they needed irrigation water because it's hot and dry around here in July and August. So, this thing was supposed to supply water down to those folks down there,” Claussen explained.

With a width at the base of about 50 feet, it took 11 months and 83 men to complete the dam which was started by the Denver Water Storage Company. A.M. Welles was the chief engineer and designer of the project. The reservoir it created was a recreational destination for many in the Denver area.

But almost immediately after its completion, the dam began having problems.

“It leaked from the very beginning when they finished it 1890,” Claussen said. "And in 1902, there was a big fix. And if we walk around to the other side, you'll see the whole other side of the dam is just filled in with dirt, because they just put tons and tons of dirt up against the dam."

Fears of the dam breaking and damaging homes and businesses downstream began spreading when news of the leaks made headlines in Denver. In an April 17, 1900, article in the Rocky Mountain News, Welles tried to dispel those fears. He told the paper that if the dam were to break, it wouldn’t have much of an impact on Denver.

“Now, as a matter of fact, if the dam broke, and I don’t care how large a break it was, by the time the head of the flood had reached Denver the last drop would not be out of the dam. Not by any means. If the whole contents of the lake were allowed to spread out, allowing for the removal of the portions of the dam that would be carried away in front of the flood, the water would not do much more than fill the channel of the creek.” Wells is quoted as saying in the article.

But of course that wasn't the case. The 1933 flood as a result of the break was devastating blow to the city of Denver.

The Castlewood Dam stood for 43 years up until 1:30 a.m. on Aug. 3, 1933. Two days of non-stop rain was too much for the dam to handle. Paine, the dam caretaker, knew it too. His attempts at opening several of the dam's valves to relieve the pressure, wasn't going to stop what was 43 years in the making.

The eastern section of the dam was the first to break, followed by the middle and western sections. The dam's foundation was weakened by years of erosion. The collapse released more than 1 billion gallons of water downstream and sent an eleven foot wall of water thundering down Cherry Creek. By 7 a.m., that wall of water arrived in Denver, taking out several bridges and flooding homes and businesses along the way.

"When you're driving down Speer Boulevard, you've got that beautiful little concrete channel with a bike path down there and a nice slowly running creek. The water was going up over the top. There was a log that floated into the lobby of Union Station and bumped into stuff," Claussen explained.

News accounts at the time painted a frightful picture. In an Aug. 3, 1933 article in the The World-Independent, the Associated Press reported on the casualties and the devastation: "Mrs. Claude Hill, 50, mother of seven, was drowned near Mathieson near Colorado Springs and her body was found several miles down the gulch. Her home was swept from its foundation and carried several hundred yards by the torrent. Hill and the children escaped."

A second victim — 81-year-old Tom Casey — was taken by the floodwaters. "He stepped off his back porch into a hole, water, and he couldn't get out. He drowned," Claussen said.

The flood continued to ravage Denver, spreading to downtown shops and Union Station. The AP article continues: "The flood carried tons of debris into Denver and isolated several sections. Police patrol automobiles sounded the alarm after the dam broke, and about two o’clock this morning the police rescued several marooned families. The water supply in many sections of the city was demoralized. Telephone and light service is impaired. Six inches of water covered the floor of the Union Station. Merchandise stores and scores of store basements were damaged. Prisoners were removed from the city to the county jail, and several feet of water covers the low level downtown streets."

Denver remained flooded for several days. The break caused extensive property damage throughout the area, leaving a trail of destruction to highways, crops, livestock, railroads and buildings. It was estimated to have caused damage to 1,100 pieces of property.

Severe weather continues to wreak havoc in some parts of the park. Heavy rainfall in June destroyed every bridge crossing over Cherry Creek. More than 14 inches of rain has fallen over Castlewood Canyon since Jan. 1, according to the National Weather Service. On June 22, the high level mark was 9.5 feet. Normal creek levels are typically between 2 to 3 feet. Crews are working at restoring the bridges but it will take weeks and may not be completed before August.

Paine and Nettie Driskill, a Parker telephone operator, were hailed as heroes for the actions they took that August morning in 1933. The warning Paine provided to Driskill who then conveyed it to those downstream is credited with saving several lives.

"He tried to get out and ride to Castle Rock, but the rod was washed out. So the dam took out the road. So he had to go up and he started calling people. Then there was Nettie Driskill, who lived up in Parker, she was a telephone operator. When she got wind of it, she started calling police departments, fire departments on downstream. So that's how everybody knew what was coming and why nobody else really got killed," Claussen explained.

Paine was born in Douglas County and lived all his life in Castle Rock, according to a March 2, 1939, article in The Englewood Herald. He died on Feb. 28, 1939 at St. Joseph’s Hospital. The paper reported that Paine had "long suffered from a stomach ailment. He went to the hospital February 18, and underwent an operation."

Driskill received national acclaim and was even featured in Time magazine.

In the late 90s, park officials published a booklet — written and researched by Sharon Randall, Tracy Dixon and Patty Horan — that chronicled personal accounts of the 1933 flood. Many were young children or teenagers, but area citizens remember the night the Castlewood dam gave way.

Below are some examples from the publication titled, The Night the Dam Gave Way, A Diary of Personal Accounts:

Gone fishing, a green horse & Lake Louisa

Telephone Rang in the Night

A Young Man’s Adventures