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Mississippi Water Science Center

Bacteriological and Water-Quality Data Collected at Coastal Mississippi Sites Following Hurricane Katrina, September-October 2005

By Richard A. Rebich and Richard H. Coupe

U.S. Geological Survey
Data Series 174


On August 29, 2005, Hurricane Katrina devastated coastal Mississippi with 150 mile-per-hour winds and a storm surge in excess of 20 feet. Katrina moved inland and wreaked destruction on a broad swath of eastern Mississippi. Some eastern Mississippi counties were left without power and water and some major roads were impassable for weeks. The possibility of disease transmission from contaminated water and contamination caused by chemical spills were major concerns.

As part of a multi-agency response to the disaster, the U.S. Geological Survey (USGS), in partnership with the Mississippi Department of Environmental Quality (MDEQ), established a network of sampling locations to determine the effects of the storm on surface-water quality along the Mississippi Gulf Coast.Water samples were collected weekly at 31 estuarine tributary sites and 13 beach monitoring sites in coastal Mississippi Counties Hancock, Harrison, and Jackson for a period of 5 weeks beginning September 19, 2005. Samples were collected by MDEQ and USGS, were transported to a temporary laboratory established at a USGS facility at Stennis Space Center near Bay St. Louis, MS, and were analyzed within 6 hours of collection. USGS analyzed the samples primarily for enterococci, which is the standard fecal indicator bacteria for brackish waters and can be used as a fecal indicator for freshwater. Enterococci densities were determined by the most probable value method. About 14 percent of the enterococci densities were less than the detection limit, and 81 percent were lower than U.S. Environmental Agency criteria for the protection of public health. Densities at several of the bacteriological sites increased during the second week of sampling possibly due to runoff associated with Hurricane Rita rainfall that occurred September 23-24, 2005. Quality-control data were reviewed to ensure that methods performed as expected.

USGS also collected 19 water-quality samples at 12 inland freshwater sites for a period of 2 weeks starting on September 19, 2005. Sampling sites were located near established USGS stream gages. Physical properties of the streams were measured on site.Waterquality samples were collected, processed, and preserved on site according to standard procedures and then shipped to the USGS NationalWater Quality Laboratory in Denver, CO, for analysis--except for biochemical oxygen demand samples, which were analyzed by the MDEQ laboratory in Pearl, MS. Each sample was analyzed for multiple constituents including nutrients, major ions, trace metals, modern-use and polar pesticides, wastewater compounds, volatile organic compounds, and degradate organic compounds. Most detections were below available State and Federal water-quality criteria for Mississippi streams. Overall, the results from the bacteriological and water-quality samples indicated no systematic contamination in the sampled streams in the aftermath of Hurricane Katrina.

Table of Contents



Site selection

Bacteriological sampling sites

Water-quality sampling sites

Sample collection and analysis methods

Bacteriological samples

Water-quality samples

Quality-assurance procedures

Bacteriological sample processing and analysis

Water-quality sample processing and analysis


Bacteriological results

Water-quality results






1-5. Maps showing

1.   Bacteriological sampling sites in three coastal Mississippi counties
2.   Bacteriological sampling sites in Hancock County, Mississippi
3.   Bacteriological sampling sites in Harrison County, Mississippi
4.   Bacteriological sampling sites in Jackson County, Mississippi
5.   Water-quality sampling sites in southeastern Mississippi

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