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Publications—Data Series

Data Series 143

Bacteriological Water Quality in the Lake Pontchartrain Basin, Louisiana, Following Hurricanes Katrina and Rita, September 2005

By  Donald M. Stoeckel, Rebecca N. Bushon, Dennis K. Demcheck, Stanley C. Skrobialowski, Christopher M. Kephart, Erin E. Bertke, Brian E. Mailot, Scott V. Mize, and Robert B. Fendick, Jr.


    The U.S. Geological Survey (USGS), in collaboration with the Louisiana Department of Environmental Quality, monitored bacteriological quality of water at 22 sites in and around Lake Pontchartrain, La., for three consecutive weeks beginning September 13, 2005, following hurricanes Katrina and Rita and the associated flooding. Samples were collected and analyzed by USGS personnel from the USGS Louisiana Water Science Center and the USGS Ohio Water Microbiology Laboratory. Fecal-indicator bacteria (Escherichia coli, enterococci, and fecal coliform) concentrations ranged from the detection limit to 36,000 colony-forming units per 100 milliliters.  Data are presented in tabular form and as plots of data in the context of available historical data and water-quality standards and criteria for each site sampled.  Quality-control data were reviewed to ensure that methods performed as expected in a mobile laboratory setting.

Table of Contents



Description of Study Area

Methods of Study

    Site Selection and Description

    Sample Collection

    Onsite Physical and Chemical Measurements

    Bacteriological Analyses

    Quality-Control and Quality-Assurance Practices

Water-Quality Characteristics


References Cited


1. Index map showing general location of the study area in and around Lake Pontchartrain, La.

2. Map showing location of data-collection sites in the Lake Pontchartrain, La., area. (Graphical displays of bacteria-concentration distributions may be viewed by clicking on the map near each site.)


1. Site descriptions.

2. Onsite physical and chemical water-quality measurements at a 1-m depth at 22 sites in and around Lake Pontchartrain La.

3. Bacteriological data from the Lake Pontchartrain area, Louisiana.

4. U.S. Environmental Protection Agency (2004) criteria for recreational waters.

5. Summary of quality-control analyses for bacteriological water-quality sampling in the Lake Pontchartrain area, Louisiana.

This report is available online in Portable Document Format (PDF). If you do not have the Adobe Acrobat PDF Reader, it is available for free download from Adobe Systems Incorporated.

View the text and tables in PDF (375 kb)

View figure 2 (area map and graphs of bacteria-concentration distribution) in PDF (2.0 MB)

Note: All data displayed in the graphs in figure 2 can be found in tables 1 through 4 in the main part of the report.

Document Accessibility:  Adobe Systems Incorporated has information about PDFs and the visually impaired. This information provides tools to help make PDF files accessible. These tools and the accessible reader may be obtained free from Adobe at Adobe Access.

For more information about USGS activities in Louisiana contact:


USGS Louisiana Water Science Center

3535 S. Sherwood Forest Blvd., Suite 120

Baton Rouge, LA 70816

Telephone: (225) 298-5481

Fax: (225) 298-5490

or access the USGS Louisiana Water Science Center home page at:

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