Study of the physico-chemical parameters such as colour, turbidity, dissolved oxygen, nitrate content, fluoride content, etc shows a marked difference between the two streams. Further when biomonitoring was done, it was observed that the macroinvertebrates inhabiting Umkaliar stream were pollution tolerant such as aquatic worms (Tubificidae), midge larvae (Chirominidae) and fish fly larvae (Nigronia) etc. During this study a dead fishes were also found from this stream. In Lwai stream, macroinvertebrates which are pollution sensitive (i.e. residing in clean water) such as variety of species from taxonomic orders of Ephemeroptera (mayflies), Plecoptera (stoneflies) and Trichoptera (caddisflies) were found to be more dominant. Umkaliar stream have high anthropogenic activities along its bank and during field work for one year it was observed that there was a permanent anthropogenic activity. Sewage was observed to be directly release in to the stream from the houses. Washing of clothes and vehicles were seen to take place almost every day. Unlike Umkaliar stream, Lwai stream is far from human impact making it still pollution free. Thus, it can be concluded that due to anthropogenic activity there is a change in composition in both physicochemical and biological properties in Umkaliar stream which indicates water pollution as compared to Lwai stream.
