Sothuparai reservoir is located at the foothills of the Western Ghats. The water quality parameters such as water temperature, PH, turbidity, total dissolved solids, total hardness, electrical conductivity, magnesium, calcium and chloride were analyzed and are within the permissible limits and can be used for irrigation and domestic purpose. A total of 2,670 individuals of aquatic entamofauna were represented by 43 genera categorized under 32 families and 9 orders during the study period. The diversity, evenness and the Ephemeroptera, Plecoptera and Trichoptera families were higher in upperstream than in downstream. Ephemeropteran was most diverse and its presence is an indicative of good water quality. The abundance of organic pollution tolerant Baetis species was found in downstream. To compare with the upperstream has the better water quality than the downstream of the reservoir. This may be due to the interruptions by anthropogenic activities in the downstream. The diversity and structure of bird communities is essential to delineate the importance of regional or local landscapes for avian conservation. Total count method was used and a total of 1,348 individuals belonging to 38 species of 25 families were observed in Sothuparai reservoir. Out of 25 Families, Muscicapidae dominated with 4 species and Culicidae with 3 species. Thus the present investigation depicts that the Sothuparai reservoir supports variety of bird's population and aquatic insect communities. Regular monitoring of the reservoir using aquatic insects and birds as indicators will facilitate better conservation and management.