Avon looks into recovery, future mitigation efforts following July mudslides
The town knew about some of the drainage issues, but is now solidifying a plan for the future.
The town of Avon is looking at improvements and mitigation efforts after monsoon rains caused mudslides on July 22.
The rain event dropped between 1 and 1.5 inches of rain within an hour, causing water and mud to flood and overwhelm the town’s roads, sidewalks, residences and drainage infrastructure.
“Within minutes, most of our culverts and pipes were clogged from all the mud and debris and then we started having that migrate to other areas and cause issues throughout town,” said Town Engineer Justin Hildreth at the Aug. 10 Town Council meeting. “We had a bit of a mess.”
This event has been classified as a 20-year event, which Hildreth clarified means that it has a 5% chance of occurring each year, not that it will happen once every 20 years.
But, Hildreth also pointed out at Tuesday’s meeting that these types of events could occur with more frequency as the effects of climate change are fully realized.
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“We are going to look at it in terms of climate change. I think we’re all concerned that the weather is changing and see if that’s going to impact future rain events and what we should predict those rain events will look like,” Hildreth said.
Going forward, the town has identified several priority areas that it will focus on to make improvements. This includes the drainage areas that go to Beaver Bench, the drainage between the Sonnen Halde complex and Sherman Meadows, a section on Wildridge Road East as well as Avon Road. Hildreth said that these are the highest priorities because of the damage to public and private property on July 22.
The town is currently working with engineering firm Tetra Tech to better analyze and understand the storm and its impacts. This will include an evaluation and inventory of all the town’s existing drainage pipe infrastructure to prevent future clogging, make site specific recommendations to provide to the home owner’s associations of the effected residences as well as develop regional mitigation measures along Nottingham Road, Swift Gulch Road and West Beaver Creek Blvd.
According to Hildreth, even as a priority, these plans could take a while to be implemented completely.
“These are going to take time,” he said, adding that no improvements will be made this year but if the analysis, surveys, obtaining necessary easements and required work goes smoothly, the necessary work will happen next summer.
Existing issues, future actions
July’s mudslides certainly won’t be the last extreme weather events in Avon, nor were they the first.
“We’ve known we’ve had these issues in town,” Hildreth said. “When the town was developed in the 70s, they never really planned for these type of rainfall events.”
Ahead of the July 22 event, Hildreth pointed to several examples of mitigation efforts constructed by the town — most of which withstood the event with little damage.
This includes two erosion control projects above Nottingham Road — with another on track to be constructed next year.
“Since we can’t stop the rain, because we have nowhere to retain it, we just can lessen the amount of erosion that occurs,” Hildreth said, adding that the erosion control projects were successful in lessening the amount of damage done downstream.
Another example of successful mitigation efforts was with new development, the Buffalo Ridge Apartments, where as part of the development agreement two large sediment ponds were constructed to collect sediment.
However, Hildreth noted that the town may require mitigation efforts, like these sediment ponds, in future developments, but not everywhere has the space for it, or the slope is too steep to make effective improvements.
“We really don’t have room to construct something like this on Nottingham Road or Swift Gulch Road because it’s already developed,” he said. “We’ve been doing what we can with the land that we have.”
One of the main complications during the July 22 event was that the town’s entire underground infrastructure — culverts, storm sewer pipes, etc. — clogged within 10-15 minutes, Hildreth said. Going forward, the town will be looking to make improvements above ground, not only as a way to move water, sediment and debris during these events but also to make it easier to clean once these events occur.
While no specific projects of this nature have been identified, this will likely include building new above-ground drainage ways as well as widening existing drainage.
Asking the town to step up
Several residents of the impacted properties — namely Beaver Bench and Sonnen Halde condo complexes — shared their experiences during and after the storms.
“The water just rushed over Nottingham Road and right into our parking lot. The first line of defense failed, the second line of defense failed, the culvert failed; Public Works was very responsive in cleaning up the mess but they weren’t very preventative in maintaining these culverts,” said Anthony Sekinger, one of the residents of Sonnen Halde impacted by the event. “This is not something that was in any way mitigated, there were failures above us that just absolutely killed us and smoked us.”
The residents urged the Town Council to make improvements and properly maintain the town’s ditches, culverts and overall drainage system.
“I just urge you to do everything in your power to advocate for improvements,” Sekinger said. “Please continue to push the town of Avon, I know it’s a 20-year event, but as Justin is saying, I’m not quite comfortable betting that it’s going to be — it’s probably going to be sooner than that.”
Outside of the residences most impacted from the events, other residents asked the town to step up.
“My ask of the town is — I understand you have to also mitigate these mudslides — but you also have to mitigate or at least examine, what is the town’s liability and possible negligence for not cleaning out these ditches,” said Neal Henzler, a Wildwood resident, asking the town to identify and work with properties to understand responsibility in managing these flooding risks.
Directly following the event, the town’s public works department mobilized to clear the roads and remove debris. The town also offered assistance to residents for mud removal and furniture disposal. Hildreth estimated that the cleanup efforts, including the cleanup of culverts and ditches by a private contractor, will be completed by the end of August.
According to Town Manager Eric Heil, the town has started to work with the Salvation Army to partner on some form of relief and funds for the impacted residents, similar to what the town did after the fire at Sunridge Apartments earlier this year.
Town Attorney Paul Wisor also noted that the most direct line for relief is through local Rep. Joe Neguse and the federal government, which “has pools of money for these events.”
Heil echoed that the town has been in contact with Neguse’s office to coordinate efforts.
Some residents at Tuesday’s meeting have taken matters into their own hands, starting GoFundMe pages. This includes pages for residents Jason and Jennifer Lance and Krysta Gardner as well as property owner Chris Lai.