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Association of Urban Runoff with Coastal Water Quality in Orange County, California
Author(s) -
Dwight Ryan H.,
Semenza Jan C.,
Baker Dean B.,
Olson Betty H.
Publication year - 2002
Publication title -
water environment research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 73
eISSN - 1554-7531
pISSN - 1061-4303
DOI - 10.2175/106143002x139776
Subject(s) - environmental science , water quality , surface runoff , hydrology (agriculture) , indicator bacteria , stormwater , urban runoff , precipitation , pollution , discharge , storm , drainage basin , geography , ecology , fecal coliform , geology , geotechnical engineering , cartography , meteorology , biology
The associations between storm events, urban runoff, and coastal water quality have not been well investigated. A temporal and spatial analysis of 2 years of data was conducted to determine associations between urban river discharge and indicator bacteria levels for Southern California beaches and evaluate the contribution of anomalous precipitation to the association. Data show beaches next to rivers had the highest bacterial levels in both wet and dry seasons. Bacterial levels rose substantially across all sites during wet months, and river discharge and bacterial levels were all highest during the winter with the most rainfall. Precipitation was significantly associated (Spearman rank bivariate correlation, P < 0.01) with water discharged from the rivers. River discharge was significantly associated with bacterial levels at 20 out of 22 beaches, with the strongest associations at sites next to rivers. The results indicate that urban river discharge is a primary source of Southern California's coastal water pollution and, as a result, swimming at beaches near rivers may pose a significant public health risk. The strong association found between precipitation and water pollution may be relevant to studies of potential health effects associated with climate change.