author(s)
Mamta Rani, H.S. Bhamrah

abstract
A comparative study of biological water quality in ecological segment of River Yamuna the water quality improved from slight pollution to clean in Himalayan segment during 2011. In upper segment the biological water quality of River Yamuna changed from moderate pollution to slight pollution during 2011 and moderate pollution was observed in Delhi segment, Eutrophicated segment and Diluted segment during all season. Arthropods dominated by 87.5% and 12.5% dominated by the Mollusca in Himalayan segment of River Yamuna. Arthropods communities reduced to 62.5% and Mollusca, annelids and Platyhelminthes 12.5% were equally distributed in Upper segment and Eutrophicated segment. As compare to upper and eutrophicated segment Arthropods communities again reduced to 60% and Mollusca and annelids increased to 20% each in Delhi segment of River Yamuna. In Diluted segment, Arthropods community increased 83.3% and Mollusca 16.5% were observed in River Yamuna.