A research was to determine the water quality in the drainage ditch, and the area under investigation was in Kg Wang Ulu near Perlis. Five parameters of surface water quality physical and chemical characteristics were assessed, and pH, dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), and ammonia nitrogen (NH3-N) were analyzed. Water sampling was carried out during the time before planting, during planting and after planting in a single season. Results shown at NH3-N at point 1 varying from 1.18 to 4.82 mg/L, pH of 6.18 to 7.38, DO of 3.06 to 9.06 mg/L, BOD of 6.45 to 19.16 mg/L and COD of 18 to 28 mg/L. At point 2, 1 NH3-N ranging from 1.52 to 4.89 mg/L, pH values ranging from 6.13 to 7.38, DOs ranging from 3.19 to 8.63 mg/L, BOD ranging from 7.06 to 14.98 mg/L and COD ranging from 19 to 30 mg/L. Finally, point 3 results for NH3-N ranging from 2.50 to 5.92 mg/L, pH values ranging from 6.19 to 7.41, DO ranging from 3.06 to 9.06 mg/L, BOD ranging from 6.18 to 12.78 mg/L, and COD ranging from 18 to 42 mg/L, respectively.
