Central Department of Botany, Tribhuvan University, Kathmandu

 We present an extensive investigation of physico-chemical parameters of water samples of Tinau River at Butwal. Water samples under investigations were collected from Jhomsa, Dobhan  Chidiya Khola and Butwal Tinau sampling station during pre monsoon (April-May), monsoon (July-August) and post monsoon (October-November) seasons in the year 2012. The observed values of different physico-chemical parameters like pH, temperature, turbidity, total hardness (TH) Chloride, total dissolved solids (TDS), total alkalinity (TA), dissolved oxygen (DO), total nitrogen, total phosphorus, electrical conductivity of samples were compared with standard values recommended by world health organization (WHO). The result indicated the various ranges with temperature 14.05-30.95°C, transparency 26.2 to 119.65 cm, TDS ranged from 163.8 to 265.7 mg/L,  turbidity from 8.81 to  9.72 NTU, electrical conductivity varied from 91 to 94.5 µs/cm, pH from 7.45-7.77, alkalinity from 29.55 to 33.95 mg/L, total hardness from 113.5 to 172.2 mg/L, DO 6.81 to 8.23 mg/L, chloride value  ranged from 7.33 to 8.24 mg/L and  total nitrogen from 0.629 to 0.76, total phosphorus ranged from 0.76 to 1.13 mg/L. All the physicochemical parameters are within the standard for drinking water except turbidity and pH (Butwal station) and raw water source for potable abstraction.

Key words:Physiochemical parameters; Seasonal variation, Tinau River; Water quality.