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Inside Alexandria’s race to install new floodwater mitigation projects before the next big storm

As rainfall travels down the hills of the Parkfairfax neighborhood, the momentum sweeps it past the slim gutters meant to catch the water, propelling it further downhill to devastating effect. But fortunately, with a surge of political and financial interest being poured into flood mitigation over the last few years, stormwater isn’t the only thing gaining momentum.

Among the larger flooding infrastructure projects going around the city are a handful of smaller “spot improvements” that could play a big role when the next major storm hits.

In the Parkfairfax neighborhood, the Department of Transportation and Environmental Services has been installing 13 inlets that the city hopes will help catch some of the stormwater the current storm drains aren’t getting.

Last week, civil engineers Brian Rahal and Ehsanullah Hayat were overseeing the inlet project, the largest of the stormwater spot improvements in the city to date.

“The biggest problem with this area is it’s steep,” said Rahal. “The inlets were put in decades ago and are small, so the gutters get filled with runoff quickly.”

Every flooding issue needs its own diagnosis and in Parkfairfax — unlike Old Town’s massive stormwater infrastructure project — Rahal said the issue isn’t one of capacity.

“There’s capacity here, but we need to get [the water] in,” Rahal said.

The city is installing 13 inlets: nine are redone inlets designed to make the current storm drains significantly larger and four are completely new inlets. The larger inlets are designed to divert more of the stormwater that momentum currently carries past the antiquated ones built decades ago in Parkfairfax. Last year, the city worked on around seven inlet projects across the city.

“That should capture most of it,” Rahal said. “That should drastically reduce the impact.”

Stormwater also tends to have a snowballing effect, where water can flow down to the same locations from different locations and the problems can quickly escalate. The intersection of Holmes Lane and Martha Custis Drive, where a few of the new inlets are being installed, is one such confluence of watersheds.

Rahal has worked in stormwater management in Alexandria for 12 years and said the increase in flooding problems has been gradual but increasingly noticeable.

“It increase really started in rainfall around 2010, but we started noticing it in 2015,'” Rahal said. “It was spotty, then we had record rainfall in 2018 and in 2019 we had the big storms.”

There was torrential flooding across the region in 2019, but Alexandria’s seen continued heavy rainfall every year since. New rainfall records were set in Alexandria last July.

The battering of the city from back-to-back flooding caused intense public scrutiny of the city’s stormwater mitigation, drawing backlash from sources ranging from the former sheriff to a locally popular Twitter account. The city worked to fast-track flood mitigation projects, but the speed of progress was limited by the design process.

Rahal said the stormwater utility fee helped give the city the resources it needed to move more quickly on some of these projects.

“That really changed the narrative,” Rahal said. “In 2014 we were concerned about the water quality mandate and focused more on water quality, then the narrative shifted to a higher priority for flood mitigation.”

Now, Rahal said the city is juggling larger and longer-term infrastructure projects with shorter-term spot improvements.

“We’ve taken a two-pronged approach,” Rahal said. “There are big projects that take time and we’re busy designing them, but at the same time we’re making spot improvements as much as we can in the time we have to affect change.”

Looking at the slim inlets they’re replacing, Rahal says he thinks back to their initial installation and has to remember how much the rainfall levels have changed since they were installed.

‘They had no way of knowing the stormwater issues we’d face,” Rahal said, “so it’s up to us to mitigate them.”