How Atmospheric Rivers Influence Water Pollution on the California Coast

SW CASC Investigator Alexander Gershunov (Scripps Institution of Oceanography at UC, San Diego) recently co-authored an article that quantifies the impacts of atmospheric rivers (ARs) on coastal water pollution and waterborne diseases. The article, entitled “Atmospheric rivers impact California’s coastal water quality via extreme precipitation,” was published online this month in Science of The Total Environment.  Dr. Gershunov and his colleagues used precipitation data from the National Climatic Data Center’s Hydro-Climatology Network, a catalog of atmospheric rivers making landfall from 2003 to 2009, and water quality data collected from the California Environmental Data Exchange Network repository. They found that spikes in coastal water pollution containing fecal bacteria from runoff and raw sewage runoff were associated with atmospheric rivers—narrow bands of concentrated moisture in the atmosphere that resemble rivers—about 75% of the time. This association was strongest in densely populated Southern California. Pollution can happen when storm runoff is collected and transported to streams and the ocean. Waste water treatment plants can also flood causing raw sewage to be sent downstream. Contact to these contaminants via surfing, swimming, or eating shellfish can cause eye and ear infections as well as gastrointestinal issues. Extreme precipitation events, such as AR events, are expected to intensify in the future due to a changing climate, and these findings suggest that coastal pollution could increase as a result. The authors hope this information can be used by public health officials so they may be able to issue warnings to residents to protect themselves from contaminants. Read Article