Even a simple thing such as over watering your garden can be a health hazard nowadays. The leftover water runs over the driveway, curb, and parts of the road trying to find its way into the stormwater system. Along the way, it gathers fertilizer, pesticides, dirt, and grit and carries it through local streams straight to the ocean, creating health hazards for fish. Although stormwater initiatives are currently in effect, stormwater runoff is a major problem as it may ruin aquatic ecosystems and also bring harm to humans.

Urban runoff is the runoff of water due to storms or human action (such as washing the car, watering the lawn, etc.) that runs over impermeable surfaces into local streams, which turn into rivers, and then into the ocean. Along the way, it picks up various pollutants on the curbs, roads, and lawns of the city.

These pollutants include motor oil, fertilizers, pesticides, litter, and pet waste, to name a few. They all end up in bodies of water throughout the world. According to the National Oceanic and Atmospheric Administration, 80 percent of water pollution mostly comes from runoff.[i] You would think the number one source of water pollution would be treated, right?

For the most part: no.

The storm drain system, which is separate from the sewage/wastewater system, takes rainwater straight to the ocean, preventing flooding, however it does not take into account the contaminants carried by it. This can pose major problems for aquatic life in local bodies of water. One of these problems, Eutrophication, leads to damages of about $2.2 billion annually  in the U.S.[ii] Eutrophication is the unnatural growth of algae and other plants caused by the increase of certain nutrients, like nitrogen and phosphorous. Both just so happen to be found in fertilizers and pet waste, contaminants carried by stormwater.

The overgrowth of algae blocks sunlight from other plants, killing them. Later, the algae itself dies, and bacteria use the leftover oxygen to digest the plants, creating carbon dioxide.[iii] Two of the largest problems for oceanic ecosystems, anoxia and ocean acidification, can partly be traced back to stormwater runoff, which can partly be traced to the pet waste that someone decided not to pick up.

Sediment found in stormwater can also affect underwater habitats in a negative way. Created by erosion in streams or, mainly, construction sites, it may suffocate fish eggs and bottom dwelling organisms as well as cloud vision.[iv] Sediment also can clog fish gills and easily transport nutrients that promote eutrophication.[v] The degradation of local water bodies and the destruction of ecosystems is unacceptable. The lack of treated stormwater also may impair drinking water quality, the fishing economy, and affect recreational areas.

Some pollutants affect human populations as well, such as the bacteria in pet waste or the chemicals in pesticides. According to a case study of Southern California beaches done by researchers at UCLA and Stanford in 2006, more than 627,000 excess gastrointestinal illnesses occur every year due to contaminated waters, costing up to $51 million in health costs.[vi] When so little is done to  prevent such a large problem, the health of the public, and of their bank accounts, is put at risk. When someone litters, hoses off their driveway, does not clean up after their pet, harm might be gradually, inadvertently, and indirectly brought to marine and human life.

There are many possible large scale solutions that can be implemented to help fight this problem. One such solution, although costly, would be the creation of stormwater treatment facilities, which would be placed at the outflow points of watersheds. Take Los Angeles County, for example, which has trash nets set up at Ballona Creek and the LA River. They alone capture 200 tons of litter each year, which is only a small portion of litter that ends up in the ocean.[vii] Considering it does not rain here as much as other places, that is a lot of garbage, and it is still not counting the other contaminants that flow through each day. Stormwater treatment plants, being separate from sewage treatment, would take on the problem all at once.

Another solution that can be done both on a small or large scale is quite typical for environmental problems, but not usually for underwater environments: plant trees. In a natural forest, only 10 percent of rainwater becomes runoff, but in a city, it can be up to 55 percent.[viii] A dense population of trees can capture rainwater and release it into the atmosphere through evapotranspiration and also increase rainwater infiltration by creating better soil conditions through its roots and leaf litter.[ix] This would not be as effective for strong storms, but provides a simple, cheap solution that comes with many other benefits.

It would be ridiculous to tell you to stop washing your car, but there are many things an individual can do to prevent stormwater pollution. After all, most polluted runoff starts in the average person’s yard. First of all, do not sweep, hose, dump, throw, or otherwise put anything into storm drains. You should know by now that they are not trash cans. Also, check your vehicle for oil leaks and dispose of oil properly. An Environmental Protection Agency estimate states that approximately 193 million gallons of used oil is dumped improperly in the U.S.[x]

Fixing the stormwater pollution problem will take time, as nearly everyone is contributing to it, one way or another. A large cause of most of the pollutants is human habits. The “stop littering” demand has been in effect for many years, yet some people still do it. So long as they are not caught, there are no consequences. However, that should not stop your civic duty to do what is right and set an example.