Modeling microbial levels using precipitation data and seasonal analysis

This paper presents models for estimating fecal coliform concentrations in the Bogue Falaya and Tchefuncte Rivers as a function of basin average preci pitation. Fecal coliform data from the Louisiana Department of Health and H ospitals were available for a period of 15 years (1975 through 1991). Preci pitation data from the Louisiana Climate Center at Louisiana State Universi ty were available for 49 years (1943 through 1991). The climate of the area is characterized by different precipitation/runoff mechanisms for the summ er and winter seasons. This seasonal effect has been successfully applied i n modeling fecal coliform in the Tchefuncte River as a function of discharg e (Barbe and Francis, 1995). Even though a seasonal effect was found for th e Tchefuncte River, no seasonal effect was evident for the Bogue Falaya Riv er. A reason for this difference is discussed. Statistical analysis entaile d regression analysis to determine the relationship between precipitation a nd fecal coliform concentration and testing for seasonal differences in fec al coliform concentrations.