The Mississippi River Basin Initiative (MRBI) Watershed Water Quality Monitoring in Bayou Chene and Lacassine Bayou in Louisiana.

In order to assess surface water quality of Bayou Chene and Lacassine Bayou watersheds under the MRBI program in southwestern Louisiana, weekly surface water quality monitoring at nine locations was done from June 20, 2012 to May 15, 2014. Dissolved oxygen, turbidity, conductivity, pH and surface water temperature were determined in the field using a YSI Sonde and the surface water samples were analyzed for TS, TSS, TDS, BOD₅, NO₃-N, NO₂-N, TKN, Cl, Fl, SO₄, PO₄, and TP in laboratory. As expected, a wide range of values for water quality parameters were observed. While DO values ranged from 0.32 mg L^-1 and 13.94 mg L^-1, the turbidity, TSS, TDS, and TS values ranged respectively from 3.2 NTU and 1,650 NTU, 3.4 mg L^-1 and 2,997 mg L^-1, 29 mg L^-1 and 5,125 mg L^-1, 63 mg L^-1 and 6,374 mg L^-1. Similarly, NO₃-N, TKN, SRP, and TP values ranged from 0.07 mg L^-1 and 2.3 mg L^-1, 0.08 mg L^-1 and 15.04 mg L^-1, 0.03 mg L^-1 and 1.06 mg L^-1, 0.01 mg L^-1 and 3.59 mg L^-1, respectively. Monthly analyses of the water quality data showed peak median values for turbidity (611.1 NTU) and TSS (151 mg L^-1) in March and peak median values for TDS (612 mg L^-1), TS (773 mg L^-1), TP (0.63 mg L^-1), TKN (2.94 mg L^-1), and BOD₅ (5.79 mg L^-1) in April.  The months of March and April also showed elevated median values for NO₃-N. These results clearly indicate that the impairment of surface water quality in these watersheds are closely related to the drainage water of newly planted rice fields and crawfish ponds, which typically occur in the months of March and April. Therefore, attention should be given to the management of surface drainage water from rice fields and from crawfish ponds for effective nonpoint source pollution control in these watersheds.