CDOT says it’ll get to the bottom of why I-70 flooded, stranding motorists

“It was so cold.”

A truck is submerged in a work area next to the new I-70 underpass that flooded during heavy rain. Aug. 7, 2022.

A truck is submerged in a work area next to the new I-70 underpass that flooded during heavy rain. Aug. 7, 2022.

Kevin J. Beaty/Denverite
Nathaniel Minor, CPR News

UPDATE: A faulty pump system could be responsible for Sunday night’s flooding on I-70. More on that here.


Torrential rain caused widespread flooding across northeast Denver Sunday afternoon, sending water gushing down streets and stranding hundreds of motorists on a newly rebuilt section of I-70 for several hours.

One video on social media shows people walking through waist-high water near York Street.

I-70 reopened at about 10 p.m.

Gerald Louis was stuck in traffic when his Mercedes suddenly filled with water up to his lap.

“It was so cold,” Louis, who was later helped by firefighters, said.

Gerald Louis tries to rescue items from his newly purchased Mercedes, which was sumberged on the new I-70 underpass through Elyria Swansea as heavy rains flooded the area. Aug. 7, 2022.

Gerald Louis tries to rescue items from his newly purchased Mercedes, which was sumberged on the new I-70 underpass through Elyria Swansea as heavy rains flooded the area. Aug. 7, 2022.

Kevin J. Beaty/Denverite

We don’t yet know why the highway flooded, but CDOT says its new drainage system isn’t fully online yet.

The $1.2 billion Central 70 highway expansion project demolished crumbling viaducts that used to carry drivers and sunk part of it below grade. While the project is mostly done, its drainage system is not yet complete, Colorado Department of Transportation spokeswoman Stacia Sellers said in an email.

“Once our drainage system is fully complete, the lowered section of I-70 where flooding happened this evening is expected to withstand a 100-year storm event,” she said. “Every construction project runs the risk of flooding while it’s in an interim phase.”

CDOT and its contractor, Kiewit, will conduct an investigation into the flood’s cause, she said. One area of attention will be an under-construction section of 46th Avenue directly above the flooded section of I-70.

“This section is not yet paved, creating exceptionally muddy conditions that may have contributed to flooding,” she wrote.

Rain falls on the I-70 underpass through Elyria Swansea. Aug. 7, 2022.

Rain falls on the I-70 underpass through Elyria Swansea. Aug. 7, 2022.

Kevin J. Beaty/Denverite

The Central 70 project was highly controversial and has disrupted life in Elyria Swansea for years.

It’s also spawned multiple lawsuits. One was over the city’s plan to use City Park Golf Course, about two miles south of I-70, for stormwater retention and to reduce the water that would end up on I-70. That suit failed and the golf course was ripped up to make room for new infrastructure.

On Sunday, a social media post showed water flooding the course.

Still, neighborhood streets and I-70 flooded, which frustrated long-time Central 70 opponent and Denver City Council member Candi CdeBaca.

“We told you so,” she tweeted.

Firefighters block traffic for tow trucks collecting cars abandoned on the new I-70 underpass through Elyria Swansea during heavy rain and flooding. Aug. 7, 2022.

Firefighters block traffic for tow trucks collecting cars abandoned on the new I-70 underpass through Elyria Swansea during heavy rain and flooding. Aug. 7, 2022.

Kevin J. Beaty/Denverite

Drew Dutcher, a community advocate who fought against the project with CdeBaca, said it has proved “more problematic at every turn.”

“There are many issues, many questions we need answered,” he told us.

Denverite’s Kevin J. Beaty contributed to this report.

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