Phytoplankton (microscopic algae) usually occurs as unicellular, colonial or filamentous forms and is mostly photosynthetic and is grazed upon by the zooplankton and other organisms occurring in the same environment. The phytoplanktons stand at the baseline of food webs in aquatic environments and are very sensitive to changes in the environmental conditions. Plankton, particularly phytoplankton, has long been used as indicators of water quality. They flourish both in highly eutrophic waters while a few others are very sensitive to organic and/or chemical wastes. Some species have also been associated with noxious blooms sometimes creating offensive tastes and odours or toxic conditions. Because of their short life cycles planktons respond quickly to environmental changes, and hence the standing crop and species composition indicate the quality of the water mass in which they are found.

Most of the biochemical and metabolic activities have been studied in land plants and also work has been done in the case of aquatic plants especially submerged hydrophytes, hence it was considered as interest to study Hydrilla with the objectives such as physico- chemical parameters of water, growth pattern and biochemical changes of Hydrilla plant and Correlation between physico-chemical parameters of water and biological parameter of Hydrilla

Hamisar is central to the social and cultural consciousness of Bhuj city. This heritage lakes speaks of the suffering of the drought years, and the joy of the good years.Lake studies are conducted to meet specific purposes like Protection of present water quality, Water Quality Impacts associated with Eutrophication and Restoration of former water quality.After complete investigation the result of physical and chemical parameters were compared with WHO (1971) and BIS (1991) standard. After comparing the 98 result it was found that many number of parameters were above desirable limit, which indicate that water of Hamisar lake show some level of pollution