Abstract: The seasonal variations of Rakh Branch canal were studied. Air and water temperature varied from 17-43 and 15-410C, respectively. The other variables were varied as light penetration 16-29 cm, pH 7.8-8.5, electrical conductivity 0.15-1.4 dsm‾1, dissolved oxygen 1.9-3.4, total alkalinity 237-290, carbonates 46-80, bicarbonates 189-210, total hardness 167-237, calcium 31-44, magnesium 17-37, sodium 14-25, potassium 1.6-5.4, phosphates 0.0-0.103, nitrates 0.43-3.46, total solids 925-1178 and total dissolved solids 796-983 mg l‾1 . Productivity based on dry weight of planktonic biomass was ranged from 111-229 mg l‾1. The total twenty two genera of phytoplankton and zooplankton were recorded which varied significantly during different periods of the study because of season.