C oupons for compost and car washes will be given to Maple Valley residents who come to a healthy soil workshop at Lake Wilderness Lodge on Tuesday night — but the well-being of everybody who uses the lake may be at stake.
Participants will learn how to build lush lawns and landscaping without relying on chemical fertilizers and pesticides. Experts will also discuss how to keep phosphorus and other harmful chemicals out of local streams and lakes, especially Lake Wilderness, where recent toxic algae blooms have prompted health warnings.
It takes one phosphorus atom to create an algae molecule
Jami Burke, a certified erosion control specialist from Cedar Grove Composting, will explain how to create deeper root systems that reduce the need for watering and chemicals.
The workshop is part of a big push in Maple Valley to monitor stormwater and educate residents about how their actions affect lakes and streams. Chemicals from pesticides, fertilizers and even car washing reach local waterways and can cause serious damage to the ecosystem.
City Engineer David Casey says that many residents don’t realize how easy it is to wreak havoc on recreational areas such as Lake Wilderness by making simple mistakes such as washing their cars in their driveways.
“A good part of our town does flow into Lake Wilderness,” Casey says.
Though Washington has banned phosphates in laundry and dishwasher detergents, it still may be present in other soaps and fertilizers. A law banning phosphorus in lawn fertilizers takes effect next January.
When phosphorus makes it to a lake through storm drains, it encourages algal blooms. The algae feeds off the oxygen, killing the fish. The algae can also kill pets and pose serious health risks to humans, especially children, who tend to swallow more water while swimming or playing in lakes.
Casey says he carries car wash coupons and often pulls over for some “one-on-one” teaching when he sees somebody washing a car in a driveway, which could send phosphorus-laced soap straight to the nearest storm drain.
“I’ll say, ‘Do you like Lake Wilderness?’ and they’ll say, ‘Oh yeah, that’s a great place,’ and I’ll say, ‘Did you know we have toxic algae bloom?’ and they’ll say, ‘Oh yeah that’s a really bad thing.’ Then I’ll say, ‘Did you know it takes one phosphorus atom to create an algae molecule?’”
Cars should be washed at a commercial car wash or in the yard — because grass can act as a natural filter for harmful chemicals, Casey says.
Two years ago, the city stamped storm drains with the phrase, “Only rain down the storm drain.” This year and last, they have been carefully mapping and inspecting the storm drain system, neighborhood-by-neighborhood, to determine the path of possible contaminants.
“If there’s a spill, we have a map where we can say quickly and easily, this stuff is going to head in this direction,” Casey says. The inventory can also help the city identify trouble spots in housing developments and other areas.
At the Healthy Soils Workshop, to be held at 7 p.m. Tuesday at Lake Wilderness Lodge, the first 100 residents will receive a coupon for a free bag of Cedar Grove Compost at Johnson’s Home and Garden. Car wash coupons also will be available.
Ed note: Updated to correct that Washington has banned phosphorus in most detergents.
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