68 Seasonal VariationsFig.1. Maps showing the location ofthe study site and 3 sampling locations inthe Rivers Ganges,Brahmaputraandtheir confluence area.3. ResultsSPM concentrations varied from 0.4 mg l -1 to 900 mg l -1 and 5 mg l -1 to 400 mg l -1 inGangesandBrahmaputra River respectively. In the G-B confluence, SPM concentrationswere much less variable, showing range from 20 mg l -1 to 400 mg l -1 (Table 1 and Fig. 2).In the surface water ofGanges River, Brahmaputra River and G-B confluence, TDS,electrical conductivity (EC) and temperature varied during the observation periods (Table1). The pH and DO (Dissolved Oxygen) values were almost similar intheGangesandBrahmaputra Rivers as well as in G-B confluence (Table 1) during the entire observationperiod and values were approximately 8.0 and 7.0 mg l -1 respectively. For theGanges, theBrahmaputra River andtheir confluence, TDS values varied from 121 to 261, 75 to 121and 80 to 128.5 mg l -1 respectively. EC values varied from 238 to 495, 121 to 260 and 155to 270 µS cm -1 for Ganges, Brahmaputraand G-B confluence respectively. Watertemperature showed strong seasonal variationsinthe studied rivers with minimum valuesin winter (December to February) (22 °C) and maximum values in summer (April toOctober) (30 °C).