More than water goes through storm drains. Trash, pet waste, fertilizers, herbicides and other pollutants are washed into the system by rain, or by people overwatering. Used motor oil, automotive fluids like leaking antifreeze, soap from people washing their cars, and even pollutants from worn-down tires all end up in the stormdrain system. This toxic soup of water and pollution is called stormwater, or urban runoff. Urban runoff is the main source of pollution to California’s coast.
Unlike the soil and vegetation in natural watersheds, most urban areas are covered in impermeable surfaces, such as asphalt or concrete. As a result, instead of rainwater slowly percolating through the ground, getting filtered and cleaned along the way, that water is rushed along streets. Along the way it picks up trash and pollution and flows into stormdrains and out to the ocean, unfiltered.
In much of coastal California, the stormdrain system is different from the sewer. Stormwater is not captured and thoroughly cleaned, like sewage is.
The pollutants in urban runoff include sediment, oil and grease, metals and other toxins. All of these can severely impact freshwater and marine habitats. Toxic metals are a major problem in many rivers and bays in the Los Angeles area, threatening public health and killing animals that live there.
Swimming in water that’s been contaminated by bacteria means that you can contract a skin rash, respiratory or stomach infection. Swimmers can even contract hepatitis from sewage-contaminated water.
Marine life also suffers from contaminated water. Bottom-dwelling fish, like halibut and croaker develop skin lesions, tumors and other problems. Even highly mobile animals, like dolphins, develop skin problems when exposed to concentrated, untreated sewage.
Urban runoff also carries trash directly into our oceans, where animals mistake it for food or get tangled in it.
So what can we do to make it better? There are a lot of things we each can do to help:
Keep trash and chemicals off the streets. That means picking up litter when you see it, even if it’s not your own, and avoiding the use of harsh chemicals.
Make sure your car is in good working order.
Pick up after your dog. You don’t want to swim in its waste the next time you go to the beach!
Be a community advocate. Report full or clogged stormdrains to your department of public works.
The less water that gets into our stormdrain system, the cleaner our beaches stay. Keep water on your property by not overwatering, and consider investing in rain barrels or other catchment systems. You’ll get a solid supply of water for your garden, and you’ll be doing your favorite beach a favor too.