Concrete spill at Millcreek stream 'resolved' after cleanup and heavy rain, officials say

Mill Creek is pictured on Thursday, July 29, 2021. According to state officials, some concrete was spilled into Mill Creek near 3800 South and Upland Drive this week during an I-215 reconstruction project. Biologists have confirmed that the increased PH levels in the water from the spill have caused a pretty significant fish kill.

Mill Creek is pictured on Thursday, July 29, 2021. According to state officials, some concrete was spilled into Mill Creek near 3800 South and Upland Drive this week during an I-215 reconstruction project. Biologists have confirmed that the increased PH levels in the water from the spill have caused a pretty significant fish kill. (Patrick Fink)



MILLCREEK — Heavy rains over the weekend helped clear up a stream that was contaminated by a concrete spill in Millcreek last week, state environmental officials said Monday.

The Utah Department of Environmental Quality said the issue at Mill Creek is now "resolved" after a mixture of cleanup efforts and rain. The agency lifted its recommendations that people or pets avoid the water.

Erica Gattis, director of the Utah Division of Water Quality, told KSL NewsRadio that 60 50-gallon bags of "potentially contaminated material" were removed from the creek through the help of a few dozen people from multiple state, county and local agencies. At the same time, the National Weather Service reported that 1.35 inches of rain fell at I-215 at Olympus Cove — near the site of the concrete spill — Sunday and Monday. That also helped clear up the stream.

"The material that was released has largely been recovered or has been diluted and washed downstream so we don't see any immediate concern," Gattis said.

The spill happened late Thursday afternoon as crews from a company contracted to work on the Utah Department of Transportation's I-215 reconstruction project. For an unknown reason there was a spill, and concrete ended up in Mill Creek, which flows below the freeway near 3540 South in Millcreek.

State officials said Saturday anywhere between 2 to 5 cubic yards of concrete spilled into the stream. That equates to a range of about 400 to a little more than 1,000 gallons. It led to water discoloration and a foam build-up in some areas, as well as a change in the pH levels and a call for residents to avoid it.

The spill also led to a "pretty significant" fish kill-off in Mill Creek. Biologists with the Utah Division of Wildlife Resources estimate that a good portion of fish at the point of the spill and downstream died. Gattis said at least 300 fish were cleared from the stream, but a spokesperson for the division said it's still unclear how many fish died as a result of the spill. Its investigation is ongoing.

Effects from the spill reached as far downstream as 500 East in South Salt Lake. Despite fears it could reach as far as its confluence with the Jordan River, Gattis said Monday there was no evidence that the spill reached the river.

While pH levels returned to healthy levels Monday and recommendations were lifted, Gattis said the spill did have a "big impact" on the aquatic life that called the creek home and the cleanup disturbed some of the stream bottom. She said the Division of Water Quality plans to work with UDOT to investigate any long-term impacts of the spill.

"We'll be working over the next few months to try and bring it back to a restored condition," she said, "but the water quality has returned to pre-spill conditions and should be appropriate for irrigation and recreation."

The Utah Department of Environmental Quality said anyone who has questions about the spill and cleanup should call an incident hotline at 844-909-3278.

Contributing: Jeff Caplan, KSL NewsRadio

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