Heal the Bay is an environmental nonprofit dedicated to making the coastal waters and watersheds of Greater Los Angeles safe, healthy and clean. To fulfill their mission, they use science, education, community action, and advocacy. healthebay.org

Storm Drain System

The Los Angeles County storm drain system is a 5,000 mile network of open channels, gutters, and drain pipes which collects runoff from Los Angeles County streets. The network drains to more than 70 major outfalls that empty into the ocean. While the primary purpose of the system is to prevent flooding in the approximately 1,060 square miles of urban area it drains, it unintentionally moves pollution directly to our bays and beaches.

Catch basins are the curbside openings leading into the storm drain system. There are roughly 250,000 catch basins in Los Angeles County. Each year, an average of 30 billion gallons of storm water and urban runoff flow through the storm drain system and are discharged into Santa Monica Bay. Runoff has increased because roads, buildings, and pavement cover land that once absorbed and filtered rainfall. Without anywhere to go, the rainfall must flow into the storm drain system.

Unlike other areas of the country, sewage and urban runoff within the Los Angeles area are carried through two entirely separate systems. This means that sewage gets treated, while most runoff does not. Things that fall, pour, or are dropped onto our region’s streets end up in the storm drain system and eventually make their way into Santa Monica or San Pedro Bays untreated.


Impacts of Urban Runoff and Storm Drain Pollution

Trash, motor oil and other automotive fluids, animal and human waste, toxic chemicals, pesticides, dirt, aerial fallout, and other pollutants collect on sidewalks, roads, roofs, and other surfaces. Heavy rains wash the pollutants from these surfaces into the catch basins, down through the storm drain system, eventually emptying out through outfall pipes along the coast into our coastal waters. Human pathogens of unknown origins have also been found in storm drains.

Chemicals in the storm drain system are also a concern. PCBs (polychlorinated biphenyls), a carcinogenic group of industrial chemicals, have been found in storm drains. They are virtually indestructible in the environment and can accumulate in higher levels of the food chain.

Storm drain pollution is toxic to marine life. Animals can choke and/or get entangled in marine debris. Pollution affects food webs, animal reproduction, algal blooms, and the overall health of the marine ecosystem.

Swimming Health Risks

Storm drain pollution is also toxic to humans. County health officials and Heal the Bay advise swimming at least 100 yards away from flowing storm drains. Experts agree that the entire beach should be avoided after a major storm for at least 72 hours because of the potential risks to human health. Swimmers are also advised to avoid contact with storm water where it pools or streams across the beach. Near flowing storm drain outlets, bacteria indicator counts are approximately 10 times higher at ankle depth, where small children play, than at chest depth.

Frequently Asked Questions

How come they don’t put screens over the gutter openings and storm drain outlets to catch all the trash before it gets to the ocean?

There are a few locations where screens and nets have been put up to catch trash, but there are too many gutters and drains for screens to be installed everywhere. The first problem is that screens clog up with trash very quickly, which is dangerous because a clogged gutter can lead to serious flooding. Secondly, there are over 250,000 gutters in L.A. County—it would take an enormous amount of time and money to clean out each one on a regular basis.

What is causing the high bacteria levels in Los Angeles County coastal waters?

Leaky sewer and septic systems, horse ranches, illegal RV dumping, feces from people who do not have access to bathrooms, waste from dogs, cats and birds are all sources of bacteria.

Reasons to keep the ocean clean (even if you don’t go to the beach):

  Animals mistake trash for food on the beach and in the ocean. Popped balloons look like sea jellies, Styrofoam bits look like fish eggs, etc.

  As a part of the water cycle, the ocean generates the rain necessary to sustain life on earth. The rain nourishes our crops, and all Earth creatures, big and small, need water to survive.

  The ocean provides over 70% of the oxygen we breathe. The phytoplankton and algae that live in the ocean produce oxygen.

  The ocean is an important source of food: fish, clams, lobster, sushi, seaweed, etc.

  Seaweed is an important ingredient in many different products, such as ice cream, toothpaste, beer, pudding, chocolate milk, shampoo etc.

  A healthy ocean has plenty of biodiversity. The wide range of interesting marine creatures in the sea enriches our lives.

  Scientists use marine organisms in their search for lifesaving medicines. Many of these organisms are becoming endangered due to pollution from runoff.

  Many tourists come to visit our beaches, pumping money into our economy. According to the Los Angeles Convention & Visitors Bureau in 1998, direct spending by overnight visitors throughout Los Angeles County was $11.9 billion dollars.

Want to help protect our oceans?  Join Heal the Bay!

Donate, volunteer, speak up, or educate others!  healthebay.org/take-part

For more info:  HealtheBay.org


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