Phytoplankton collection was carried out from the Godavari river at Kopargaon for one year. Four sampling sites were selected near the confluence of the Godavari river and Gardi nallah. Two sites were located at upstream of Gardi Nallah and two are downstream of nallah. The monthly collection of phytoplankton from selected sampling sites was carried out during the period June 2017 to March 2018. Present studies revealed that a total 38 species from 29 genera belonging to 4 class namely as Chlorophyceae , Cyanophyceae, Bacillariophyceae and Euglenophyceae were encountered during the investigation period. Chlorophyceae was found to be the dominant group. Many planktonic and epiphytic algae were encountered during investigation period at four sampling stations The commonly occurred genera were Ankistrodesmus, Scenedesmus, Coelastrum ,Chlorella, Tetrastrum, Crucigenia, Selanastrum. Bacillariophyceae was second largest group encountered during study period. This group comprised 16 species belonging to 10 genera. The commonly recorded genera of this class are ,Fragilara, Nitzschia, Navicula, Mastogloia and Synedra . Cyanophyceae was represented by 4 genera and 4 species . The recorded genera were Microcystis, Merismppedia Oscillatoria and Chroococcus .Euglenophyceae was represented by 2 genera i.e. Euglena and Phacus and 2 species. The downstream sampling stations shows luxurious growth and population of phytoplankton as it receives Sugarcane Factory effluents and domestic wastes from that region .

Keywords : Phytoplankton, Confluence, Gardi Nallah, Godavar River, Kopargaon.