City updates council on stormwater work

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City updates council on stormwater work
At its most intense, the storm on Aug. 15 dumped 4.11 inches of rain on the city in 40 minutes. (Photo/Alex Snyder)
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By Cody Mello-Klein | [email protected]

During Tuesday night’s City Council legislative meeting, staff from the city’s Department of Transportation and Environmental Services presented a timeline for the city’s large scale stormwater projects that involves construction starting in 2024.

For residents who experienced the impacts of several intense summer rainstorms, from widespread flooding to sewage backup, the news may prove frustrating, especially after another series of intense summer storms.

The two most significant storms that occurred over the last couple of months swept through Alexandria on Aug. 15 and Sept. 16. The storm on Aug. 15 was the most intense of the two, dropping three to six inches of rain in about 30 minutes in some areas of the city, according to Yon Lambert, director of T&ES. The storm caused flooding, power outages, sanitary backups and road closures and resulted in a total of 5.5 inches of rain falling over the course of six hours. The city received 155 service requests related to the storm’s impact through the 311 service.

The Sept. 16 storm lasted less time but brought down about two inches of rain in 30 minutes in Rosemont and about 2.6 inches total.

Lambert characterized the Sept. 16 storm as a 10- year storm, meaning the kind of storm that would typically have a 10% chance of occurring annually, while he said a storm with the intensity of what occurred on Aug. 15 would typically have less than a 0.5% chance of happening annually.

“Obviously, given what’s happening with climate change, we are all experienced with seeing these storms more frequently now,” Lambert said.

According to Terry Suehr, director of project implementation in T&ES, the city is making progress on the first three larger stormwater capacity projects that the city has invested in. Council’s approved 10-year capital improvement program budget includes $267 million for stormwater projects, with $27.5 million set aside for projects in FY2022.

The first two projects – one at Glebe Road and Commonwealth Avenue and the other at Ashby Street and Glebe Road – are entering the design phase, while a third project at the Hoofs Run culvert bypass is “right behind that,” according to Suehr.

“We anticipate design award to be this coming spring. [The] design process typically goes about 18 months, and then we go straight into construction after that,” Suehr said. “So, we’re looking at construction award around the spring of 2024 and then proceeding with construction on those three projects that we have going.”

Shovels will not enter dirt on the city’s larger flood mitigation efforts for a few years, but the city is implementing a series of smaller spot improvement projects and maintenance efforts in the meantime, according to Lambert. There are currently three spot improvement projects being designed and five projects in the preliminary design phase.

“Obviously, with the new funding, we’re able to do now more projects annually than we were able to do previously,” Lambert said. “… Two of those are on Mount Vernon Avenue … and both involve replacing of inlets, extending some storm sewers and adding new inlets.”

T&ES staff have also cleaned out about 5,000 linear feet of storm pipes over the summer, repaired 14 stormwater structures, completed cleaning on the lower portion of the Hooffs Run culvert and inspected 15 miles of sanitary sewer pipes, according to Lambert.

Although residents continue have continued to feel the impacts of these storms and the resulting flooding, Lambert said the city has been better able to analyze the rainfall from these storms using new rain gauges. The hope is that the data provided during storms like this will help staff target specific areas of the city for upcoming projects in its new Flood Action Alexandria program.

“I would say that with the addition of the city’s rain gauges … that has provided us with additional data to be able to monitor and understand what’s happening with these storms and how localized some of these events really have been,” Lambert said.

The program launches this week and with it will come a new public data portal where residents can view the data collected by the city’s expanded network of rain gauges.

As part of the program, the city announced on Tuesday that it had hired Daniel Medina as Alexandria’s first Flood Action Alexandria program manager. The new position will involve work across city departments in order to successfully implement the city’s flood mitigation program and manage the city’s growing list of stormwater capital projects. Medina will also serve as a liaison to the Ad Hoc Stormwater Utility and Flood Mitigation Advisory Group.

Medina was virtually present at the meeting on Tuesday and said he was glad to hear council asking about flooding in other parts of the meeting on Tuesday. Medina stressed how vital it is to assess flood mitigation in every part of city policy.

“It’s going to continue raining. It’s going to rain more, so we all need an approach that starts with the ground up and constitutes a holistic solution to the problem,” Medina said.

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