Monday evening’s deluge around the D.C. area caused flooding issues on some major roadways, including the Capital Beltway both in Virginia and Maryland.

According to local highway officials, the volume and force of the water caused mud and debris to be dislocated and sucked into drainage pipes.

With enough notice, local road crews can try and clear as many drains as possible. But when a severe summer storm pops up, drains can get clogged and water can back up into the roadways — as it did Monday on the Inner Loop between Connecticut and Georgia Avenues; near River Road and the exit for the Baltimore Washington Parkway in Maryland and in Virginia; the Outer Loop of the Beltway near Georgetown Pike; as well as the Dulles Toll Road.

“It’s sometimes like holding the ocean back with a broom,” said Maryland State Highway Administration spokesman Charlie Gischler. “What we’ve been doing is going out with our (vacuum) trucks … and trying to get as much of that litter from the drainage inlets to make sure we have positive drainage.”

Drainage is especially poor in long term work zones, like on the Beltway in McLean, where storm drains and culverts are still under construction and concrete walls blocks runoff. The torrent of water that rushed across the Beltway near Old Dominion Drive banked against the concrete walls and was more than half-a-foot deep in some areas.

In Vienna and McLean, more than four inches of rain fell in just over an hour, inundating storm drains.

The extreme rainfall rates led to flash flooding on the George Washington Parkway south of Route 123 as well. Some of the construction barrels in that work zone actually floated away.

The National Park Service said 90% of the drainage work is complete, and ponding is better than it was last year, but there are still places where water pools deeply.

When you have such exceptionally heavy rainfall, the storm drains can only accept so much water before they’re overwhelmed.

In recent years, we’ve had heavy rainfall events with extreme rainfall rates, coupled with aging infrastructure.

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