Bayou Lafourche

Bacteria
Bacteria criteria are established to protect water quality commensurate with the most
stringent designated use assigned to the subsegment. In Bayou Lafourche, the most
stringent designed use during the period of May 1 through October 31 is primary contact
recreation. From November 1 through April 31, secondary contact recreation criteria
apply.
Primary contact recreation: No more than 25 percent of the total samples collected on a
monthly basis shall exceed a fecal coliform density of 400/100 mL. This primary contact
recreation criterion shall apply only during the defined recreational period of May 1
through October 31.
Secondary contact recreation: No more than 25 percent of the total samples collected
on a monthly or near monthly basis shall exceed a fecal coliform density of 2,000/100
mL. In Bayou Lafourche, this secondary contact recreation criterion applies year round.
Drinking water supply: No more than 30 percent of the total samples collected on a
monthly or near-monthly basis shall exceed a fecal coliform density of 2,000/100 mL.
Bayou Lafourche is listed in the Louisiana Water Quality Inventory Integrated Report as
being impaired for primary contact recreation due to recurring violations of fecal coliform
criteria. Unlike dissolved oxygen, data shows no seasonal pattern in fecal coliform
concentrations. While dissolved oxygen fluctuations are driven largely by seasonal
temperature changes, fecal coliform fluctuations are more likely caused by rainfall
events that result in sewer and onsite disposal system effluent being washed into Bayou
Lafourche, as well as domestic and wild animal waste being carried by runoff.
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