Louisiana 2012 Beachwater Quality Summary
Reported Sources of Beachwater Contamination
(number of closing/advisory days; does not include extended or permanent days)
- 516 (97%) unknown contamination sources
- 15 (3%) Gulf of Mexico oil spill
While most of Louisiana's coastline consists of wetlands, coastal beaches line nearly 30 miles of Gulf of Mexico and estuarine shoreline, including beaches on the barrier island Grand Isle as well as some near the Texas border and on the shore of the Lake Pontchartrain estuary. The state's coastal monitoring program is administered by the Louisiana Department of Health and Hospitals (LDHH).
Louisiana Water Quality Challenges and Improvements
In August 2012, Hurricane Isaac hit eastern Louisiana and caused several beach closures. Additionally, some of the beaches monitored by the LDHH are still experiencing lingering impacts from Hurricanes Katrina and Rita (August and September 2005, respectively) and Hurricanes Gustav and Ike (September 2008). For example, although use of Cameron Parish beaches is increasing as the area is rebuilt, it still remains below pre-storm levels. In 2012, Hackberry Beach remained inaccessible due to road damage.
BP Oil Spill
Louisiana's coastal beaches in the eastern half of the state were severely impacted by the BP oil disaster, which began on April 20, 2010, with the explosion of the Deepwater Horizon rig. Oil flowed from the damaged well for nearly three months until it was capped on July 15, 2010. Three years after the disaster, the long-term impacts from the spill are still difficult to determine.
The beachwater quality monitoring program in Louisiana through the BEACH Act does not test for oil, and thus the LDHH does not have monitoring data on oil to report. However, other entities are still engaged in oil spill cleanup activity in some regions, including Fourchon Beach, which is currently closed to the public due to ownership issues. At Fourchon Beach, Louisiana State University (LSU) researchers are investigating oil aggregates from the BP spill. Aggregates look like benign rocks but reveal a dark, oily interior when broken open. Cleanup efforts are difficult because although a beach may appear free of aggregates, hurricanes and other storms can wash away top layers of sand, uncovering oil that remains behind. Researchers at LSU are concerned that the public could be exposed to the oil aggregates once the beach is reopened.
Louisiana beaches have a wide range of salinity conditions, and most are relatively remote from urban runoff. These factors reduce the direct association between environmental conditions and enterococci densities and make the use of predictive models very difficult. Using data collected between 2004 and 2009, the LDHH Center for Environmental Health Services (CEHS) performed a study to determine how indicator organism density was influenced by environmental factors at Louisiana coastal beaches. Researchers found that environmental factors explained only a small fraction of the total variability in indicator organism density, and thus statistical models of environmental variable-indicator organism relationships were not sufficient to be used as predictive models on which to base precautionary advisories.
In 2011, Louisiana BEACH program managers conducted a similar analysis of data collected during the 2011 monitoring season. Like the 2009 study, the LDHH found the relationship between environmental variables and enterococci density changed from year to year, and that the enterococci density was not explained by differences in environmental variables. Because of the large year-to-year differences in enterococci densities and annual variance within beach segments, and annual differences in the relationship between enterococci density and the environmental variables, the study's authors concluded that developing useful predictive models that go beyond finding a general pattern of environmental conditions that are associated with higher/lower enterococci densities is not possible for Louisiana's more remote beaches. It may be possible to create a reliable predictive model for beaches near urban areas, such as the Lake Charles beaches, when additional monitoring data are available for analysis.
What Does Beachwater Monitoring Show?
In 2012, Louisiana reported 31 coastal beaches. Of these, 25 (81%) were assigned a monitoring frequency of once a week, 1 (3%) once a month, and 5 (16%) were not monitored. In 2012, 6% of all reported beach monitoring samples exceeded the state's daily maximum bacterial standard of 104 colonies/100 ml. The beaches with the highest percent exceedance rates of the daily maximum standard in 2012 were Fontainebleau State Park in St. Tammany Parish (18%), Rutherford Beach in Cameron Parish (17%), Cypremort Point State Park in St. Mary Parish (16%), Grand Isle State Park 2 in Jefferson Parish (13%), North Beach–Lake Charles in Calcasieu Parish (11%), and Grand Isle State Park 3 in Jefferson Parish (11%). St. Tammany Parish had the highest exceedance rate of the daily maximum standard in 2012 (18%), followed by St. Mary (16%), Orleans (14%), Lafourche (13%), Calcasieu (9%), Jefferson (6%), and Cameron (5%) parishes. NRDC considers all reported samples individually (without averaging) when calculating the percent exceedance rates in this analysis. This includes duplicate samples and samples taken outside the official beach season, if any.
An ongoing ownership dispute over Fourchon Beach restricted public access to the beach during 2012 and limited the LDHH's ability to conduct regular monitoring at stations along that beach. Stations 2 and 4 were not monitored at all during 2012.
Enterococci density was extremely low compared with prior years at Constance Beach Complex, Holly Beach, and Lake Charles beaches and was low at Hackberry-Rutherford Beach, Grand Isle Beach, and Cypremort Point State Park. The low enterococci densities may in part be explained by corresponding extremely high salinty at those beaches, but the exact cause of the improvement is unknown. Salinty at Lake Charles beaches in 2012 was comparable to salinity in prior years, suggesting that other, unknown factors affected enterococci densitites. At Fourchon Beach, Grand Isle State Park, Fontainebleau State Park, and Pontchartain Beach, enterococci density was comparable to that of prior years.
Louisiana Percent of Samples Exceeding the State's Daily Maximum Bacterial Standard for 23 Beaches Reported 2008-2012*
* Please note that only samples from a common set of beaches monitored each year from 2008-2012 are included in the bar chart.
What Are Louisiana's Sampling Practices?
Monitoring is conducted from the beginning of April through the end of October. The LDHH determines sampling practices, locations, standards, and notification protocols and practices at Louisiana beaches monitored through the BEACH Act. Samples are collected 6 to 12 inches below the surface in water approximately 3 feet deep. Levels of beach use and perceptions of water quality determine monitoring priorities. Monitoring frequency does not increase after a beach is placed under advisory unless the contamination source has been identified and corrected, in which case more intensive sampling may be conducted.
How Many Beach Closings and Advisories Were Issued in 2012?
Total closing/advisory days for 51 events lasting six consecutive weeks or less increased 17% to 623 days in 2012 from 531 days in 2011. For prior years, there were 91 days in 2010, 472 days in 2009, and 221 days in 2008. In addition, there was 1 extended event (65 days total due to Hurricane Isaac) but no permanent events in 2012, a substantial reduction in both extended and permanent events from prior years. Extended events are those in effect more than six weeks but not more than 13 consecutive weeks; permanent events are in effect for more than 13 consecutive weeks. For the 51 events lasting six consecutive weeks or less, 79% (495) of closing/advisory days were due to monitoring that revealed elevated bacteria levels, and 21% (128) were due to Hurricane Isaac.
How Does Louisiana Determine When to Warn Visitors About Swimming?
The LDHH issues beach advisories based on water quality but does not have the authority to close a beach. Local governments, however, can issue closings. Water quality standards are not met if any of the following are exceeded: an enterococcus single-sample maximum standard of 104 mpn/100 ml, an enterococcus geometric mean of 35 mpn/100 ml for samples taken over a 30-day period, or a fecal coliform geometric mean of 200 mpn/100 ml for samples taken over a 30-day period. Multiple samples are sometimes taken during a sampling event, and when they are, the results are averaged before comparison with the standard. An exceedance of any of these three standards can trigger an advisory. The public is notified about advisories through the LDHH beach advisory website, press releases, and signs posted at the beach.
Other than taking a resample to verify exceedances when results are in doubt, there is no protocol for forgoing an advisory when an exceedance is found. It is noteworthy that the majority of advisories in Louisiana result from an exceedance of the enterococcus geometric mean criterion. Louisiana's percentage of monitored station-weeks that were in compliance is different from that of states using other criteria. If Louisiana issued beach advisories based only on the enterococcus single-sample maximum criterion, as many states do, its noncompliance during 2012 would have been reduced by 64%.
Nine beach closures were issued in 2012 due to Hurricane Isaac, which affected areas on the eastern portion of the state in late August. Impacts varied by beach, with Elmer's Island and Grand Isle Beach closed for 7 days, Grand Isle State Park closed for 25 days, and Fontainebleau State Park closed for 65 days.
Louisiana 2012 Monitoring Results and Closing/Advisory Days