Runoff

Whether it be point or non-point source pollution, anthropogenic runoff is a heavy contributor to the ocean pollution off the coast of southern California. From inadequate waste water treatment to storm water runoff, the human effect on the ocean and its creatures is evident. Run off originates when the drain systems cannot keep up with higher rainfall, and the water runs along the concrete of developed cities such as Los Angeles, and collects a long list of toxins ranging from sewage and agriculture wastes to hazardous industrial sources. Even though southern California is historically stricken with drought, runoff is still a dominant problem. In 2013 Los Angeles had the driest year on record with only 3.6 inches of rainfall, but for every inch of rain 3.8 billion gallons of runoff was produced[1], most of which flows to the ocean. Wetland destruction is likely one of the substantial forces behind the rise in harmful runoff entering the Pacific Ocean from California today. In California’s Central Valley it has been estimated 95% of wetlands have been lost[2]. These are wetlands that, until destroyed, gathered storm runoff and recycled the water back into the groundwater cycle and collected the harmful effluents that would have otherwise flowed to the coast.

Image result for industrial runoff into the ocean

The past historical mistakes have made it possible for high amounts of toxic chemicals and waste to make their way to the ocean. A scientific article written by Johnathon Puritz investigated how anthropogenic runoff affected the population structure of the bat star. The contributing scientists to the experiment were able to find evidence on the correlation between a decrease of genetic diversity in the species and the proximity to known storm water runoff and wastewater effluent sources around San Diego, California. It was found that human runoff acts as a barrier for larval dispersal to this starfish species that is otherwise not harvested by humans[3].

Along with the Bat Star, many other marine species are affected by runoff into the oceans. The ocean is a crucial part of all Earth’s processes so conserving it is a must. Possible ideas for reducing anthropogenic runoff include, but are not limited to, permeable concrete, artificial wetlands, wetland conservation, and advanced dumping control in coastal cities. Each resolution itself only chips away at the problem, but all together can make a substantial impact in saving the Pacific Ocean.

[1] Ashoka and Michael Zakaras, “Why Does California Let Billions of Gallons of Fresh Water Flow Straight into the Ocean?” Forbes (Forbes), April 15, 2015

[2] Walter G. Duffy and Sharon N. Kahara, “Wetland Ecosystem Services in California’s Central Valley and Implications for the Wetland Reserve Program,” Ecological Applications 21, no. sp1 (April 2011): S19

[3] Jonathan B. Puritz and Robert J. Toonan, “Coastal Pollution Limits Pelagic Larval Dispersal,” Nature Communications 2, no. 226: 1-7 (August 18, 2010)