Dallas delays Mill Creek tunnel project, extending timeline to 2029

Dallas’ Mill Creek Tunnel project was originally scheduled for completion in 2024. Now, it likely won’t be finished until 2029. 

The Mill Creek Tunnel project has been in development since March 2018. It was designed to create a drainage tunnel stretching five miles long that would help reduce flooding between Fair Park in the south and the Federal Reserve Bank in downtown Dallas by flowing out to the Trinity River. The 30-foot-tall tunnel (which is being constructed 100 feet below ground) was originally scheduled for completion sometime in 2024. Now, though, Assistant City Manager Dev Rastogi has announced that substantial work is projected to be done in 2028, but the project likely won’t be fully completed until 2029.

In a memo addressing the new timeline, Rastogi wrote, “DWU is committed to completing the project as expeditiously and economically as possible to deliver the flood relief benefits of the Mill Creek Tunnel project. Staff is diligently working with the contractor to maximize the tunnel lining productivity, while maintaining safety and quality.” Despite the extended construction period, Sarah Standifer, the Director of Dallas Water Utilities, emphasized that the project would not exceed its originally projected budget of $300 million.

What’s been slowing the project down?

Several factors have contributed to the Mill Creek Tunnel project falling behind schedule. Despite construction starting in 2018, it wasn’t until April 2020 that major excavation began in earnest. That work didn’t wrap up until July 2022, which led to an initial round of delays. The city said many of those issues could be attributed to COVID-19-related interruptions in the supply chain, as well as changes in city permitting. The construction company also had to wait to receive a manufactured “tunnel boring machine” to begin excavation.

Another major issue facing the project was the estimation of how quickly progress could be made. Initially, the city believed that workers could excavate around 80 feet of tunnel per day. Once work began, workers realized they could realistically only clear about 45 feet per day, which caused its own delays. On average, they could also only complete about 70 feet per week of the concrete lining. Estimates originally had them completing 400 feet every week. When making the announcement addressing the new project completion date, the city noted that workers were averaging up to 146 feet per week now.

In June 2025, it was announced that the city was eyeing a 2027 completion date. Over the last six months, it became increasingly apparent that the timeline would have to be pushed back even further.