DENVER (KDVR) – The construction company responsible for work on the Central 70 Project said an error in its drainage pump system prevented the pumps from turning on automatically Sunday, which caused massive floods and stranded at least 11 people.

“Kiewit regrets that many motorists became stranded in flood water around the Central 70 Project,” Matt Sanman, the public information officer for Kiewit Infrastructure Co., said in an email.

“We are grateful to the Denver Fire Department for their quick and effective response and that no injuries were reported,” he said.

Sanman said the pumps worked as they were intended after they were turned on manually, and the area “was drained in a short period of time.”

He said the company is working with the Colorado Department of Transportation to investigate what led to the error. According to CDOT, the system was designed to handle a “100-year storm event.”

Both CDOT and Kiewit said the project is still incomplete.

“The drainage system of the project isn’t complete, but we are confident it can and should work properly to successfully handle this and other more significant rain events,” Sanman said.

Stacia Sellers, a spokesperson for CDOT, said the situation was a little chaotic over the weekend, but the engineers handled everything very calmly.

“This is active construction,” she said. “We are not scheduled to be done with the project until the end of this year, so this is not going to be the final product. It’s not fully functioning as of yet. For any construction project, you are going to have things like this happen, but we do have a drainage system that is able to withstand a 100-year flood.”

Sanman said the company is “in the process of reaching out to the motorists who we ordered tow trucks for to assess the damages they incurred.”

Central 70 Project schematics

The Central 70 Project was a plan to completely redevelop a 10-mile stretch of Interstate 70 through Denver and remove an aging viaduct in the area. The cost of rebuilding the interstate through Denver is $1.2 billion.

The area that experienced flooding was between York and Steele streets, and CDOT shut down traffic between the two until it was cleared.