Avon issues flood mitigation recommendations to local homeowner’s associations

Last July, Avon experienced a significant rain event that overwhelmed town infrastructure and caused rain and mud damage to multiple residential properties in town.

In the months since, the town has been working with engineering firm Tetra Tech to better analyze the storm and its impacts as well as to identify future mitigation actions the town can take.

As part of the work, the town released a written report — including a report of recommended improvements from Tetra Tech — identifying a list of actions that local homeowner’s associations can take to reduce the risk of damage from flooding.

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The recommendations were primarily created for the two main properties impacted in July: Sonnen Halde and Beaver Bench condominiums in Avon. In addition to some site-specific actions, the report from Tetra Tech includes general recommendations also “applicable to other areas within the town.”

General recommendations

These general recommendations include exterior maintenance to drains and drainage rights of way that should be “conducted periodically.” Some of these items include removing sediment and debris from drains, keeping gutters and downspouts clear, maintaining clear drainage rights of ways, pumping sediment out of culverts and drain gates after events and ensure areas around drains slope into them.

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While the recommended actions are directed at homeowners associations, the town itself is also making moves to keep its drainage infrastructure clean. Following the July 2021 rain event, the town did do a widespread cleanup of its drainage infrastructure, including its culverts. Going forward, in order to keep its storm water infrastructure clear and clean, the town is investing in a vacuum truck, which it expects to be delivered in August.

The second part of the general recommendations is exterior improvement efforts, meant to improve existing drainage.

This includes making improvements to lot grading to encourage flow away from buildings, grading to improve drainage to easements and rights of way, and improve grading to drains. It also includes elevating utilities and items — like air conditioning units, fuel tanks and patio furniture — above flood levels to prevent damage and eliminate items that could disrupt primary flow paths.

The final area of general improvements is recommendations for interior improvements for rebuilding and for new construction. This includes using flood-resistant materials for floors, doors, windows and walls as well as elevating utilities like boilers and furnaces away from the ground floor when possible and/or typical highwater marks.

Site-specific improvements

The report also gives recommendations to both the Sonnen Halde and Beaver Bench properties. While some of these align with the general recommendations, most are more site-specific.

Some of these include the addition of berms to divert flow away from buildings, raising sidewalks for additional flood protection, regrading certain parts of the sites, installing flood-proof walls at entrances and replace patio fences with flood-proof fencing. Specific direction is given in the report to exact locations and recommended materials for these barriers and improvements.

Among these specific improvement recommendations is the modification of a sidewalk at Beaver Bench to include three additional steps. This, according to a written report from Town Engineer Justin Hildreth in the March 22 Town Council packet, would create an 18-inch high barrier that would prevent water flow into the downstairs units.

The report states that while this improvement — like the other site-specific recommendations in the report — is the responsibility of the Beaver Bench Homeowner’s Association, the town plans to discuss a cost sharing agreement on the project to “expedite its installation.”

Town-wide efforts

In addition to these recommendations, the Tetra Tech consultants and town staff have identified several mitigation efforts for the town.

To start, the town is working on creating a comprehensive map and catalog of the town’s infrastructure so it can assess current conditions, track maintenance and find areas for improvement. It will also look at existing drainage pipe infrastructure — which was clogged with mud and debris during the July 2021 event — to identify ways to reduce clogging and therefore flooding damage.

In the longer-term, the town has also identified a need to “develop regional mitigation measures along Nottingham Road, Swift Gulch Road and West Beaver Creek Boulevard,” according to Hildreth’s memo. These measures would be designed and implemented to reduce future damage to private developments and public infrastructure on Avon Road, he wrote.

These mitigation plans also mention specific improvements with relation to Beaver Bench Condominiums. According to Hildreth’s report, the town needs to create a drainage swale — or an open channel that collects water — near the condos and along an existing drainage easement. However, this easement is blocked by a trash enclosure constructed by Beaver Bench, “without town approval,” Hildreth wrote.

“Town staff will initiate legal proceedings to require Beaver Creek West Condominiums to locate the trash enclosure outside of the drainage easement,” he added.

As most of these town-wide efforts and improvements will take time and money, Hildreth’s report also identified that seeking federal and state grant opportunities will be part of its future mitigation steps.

Specifically, Hildreth’s report mentions the Building Resilient Infrastructure and Communities grant, which is a Federal Emergency Management agency grant intended for helping communities reduce risks from disasters and natural hazards.

The town is expected to continue to share its plans, reports and findings this spring as it prepares for the upcoming summer and the possibility of future rain events. At the Feb. 22 Town Council meeting, Town Manager Eric Heil referenced future reports on Public Work’s plans for maintenance this spring and summer, expert analysis of the rain event itself and more — all of which the residents impacted are anxiously awaiting.

“I would implore you to stay on top of this,” said Josh Hall, a Beaver Bench resident, at the Feb. 22 Town Council meeting. “Our big fear is that it happens again this summer.”