Clear ‘leaf traffic jams’ to help prevent localized flooding

Mountlake Terrace resident Tam Nguyen clears a storm drain.

Residents can play a powerful role in helping prevent localized flooding at this time of year, according to local stormwater experts.

Falling leaves, branches, cones and needles, and the stray piece of garbage can accumulate around and clog storm drains (also known as “catch basins”), especially after a big rain event.

These “leaf traffic jams” obstruct the flow of stormwater into underground pipes and can result in puddling on streets. If not cleared, the puddle can enlarge to become localized flooding.

These conditions slow down traffic and are potentially dangerous for drivers, cyclists and pedestrians.

Residents can pitch in by visually monitoring nearby drains and clearing them with rakes and brooms when necessary. In fact, the City of Lynnwood encourages people to learn more and sign up to volunteer for their Adopt-A Catch Basin program. Likewise, the Mountlake Terrace offers an Adopt-A-Drain program.

“We want to empower people to be extra sets of eyes at our over 7,000 catch basins,” said Kayla Grattan, the City of Lynnwood’s surface water technician.

Stewarding catch basins not only mitigates localized flooding, but “benefits our downstream neighbors like invertebrates and salmon,” Grattan said.

“It’s easy to think that something natural like leaves can’t be problematic, but when they’re falling and decomposing all at once, it decreases the oxygen available to life in our waterways,” Grattan added.

A storm drain cleared of debris can prevent numerous future problems.

Stormwater, unlike sewage, is not treated, points out Patrick Johnson, senior stormwater engineering technician at the City of Edmonds. Instead, it flows directly into nearby streams, lakes and ultimately – depending on where you live – into the Puget Sound and Lake Washington.

“There’s no filter. Whatever goes in, goes out,” Johnson said.

Here are some key things to know:

• Prioritize your personal safety: Clear drains in daylight hours, work from the sidewalk rather than the road and wear protective gear like gloves and a reflective safety vest.

• Rake or sweep leaves onto the sidewalk or place in the appropriate yard waste or garbage bin.

• Do not put hands into grates.

• If you see oil, paint, soapy water or other contaminants at drains, contact your local municipality right away to have them clear it out, advises Laura Reed, the City of Mountlake Terrace’s stormwater program manager.

And the added bonus: Adopting and clearing drains is a rewarding way to get outdoors, do some physical activity and contribute to your community.

Mountlake Terrace Mayor Kyoko Matsumoto Wright has adopted two drains and checks them daily as she drives to work.

“Whenever I have to clean out the drains it’s a happy day for me – it really gives me a sense of purpose,” Wright said.

— Story and photos by Clare McLean

  1. For over twenty two years I’ve cleared the drain in front of my home of neighbor’s Fir needles that really clog. Hazardous, overgrown, nuisance trees, shedding along OVD, fill the drains all Fall and Winter. Sidewalks on OVD approaching 168th in Meadowdale area are nasty too – dangerous for walkers and bicycles. But of late, it’s become too dangerous to keep my drain clear on this heavily traveled arterial, as speeds are uncontrolled and lack of driver attn is very real. City of Lynnwood has the control and they’re failing miserably.

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