Limnology is the study of aquatic ecosystems. The quality of water is extremely variable in physical, chemical and biological characteristics.This book is describes about 02 water bodies of Bhalki and Bidar, India in special reference to inter relationship of physico-chemical and biological factors. Which include collection of data pertaining to meteorological conditions like temperature, rainfall and humidity; methodology, data preparation and interpretation with statistical tools of physico-chemical status of water, Primary production and phytoplankton composition such as pH, alkalinity, hardness, calcium, magnesium, chloride, sulphate, nitrite, phosphorous, silicon, organic content, dissolved oxygen, free carbon dioxide, biological oxygen demand and chemical oxygen demand, primary productivity of water bodies consists of grass primary productivity, net primary productivity and community respiration and periodicity and abundance of phytoplankton. Book consist 166 identified algal species photographs of studied water body. It also reveals about polluting sources, ecology of the water body and management.