River Gomti runs across the major parts of Uttar Pradesh, various industries are pouring effluents directly into Gomti and domestic waste water are also discharged into this river. As Suheli River of Dudhwa National Park travelled through the forest, it was found almost to be pollution free. The extent of water pollution in both the rivers and the possible impacts of pollution on plant, Pistia stratiotes and fish, Wallago attu in both the regions were analysed and compared in pre monsoon, monsoon and post monsoon seasons. The physico chemical properties of water at different sites and morphological, physiological properties of Pistia stratiotes and haematological properties of Wallago attu were studied. The present research was aimed to study the ecosystem and trend of Suheli river in Dudhwa National Park and Gomti River of Lucknow city and conservation of precious ecosystem of Dudhwa National Park and Gomti river. The water quality of Gomti river was found to be more polluted as compared to that of Suheli river which was found to be good for the flora and fauna of the area.