tion:several geological phenomenon result in the formation of the lakes but most of the lakes are formed due to glacial activity 100 are actually basins or depressions on the the earth's crust when the Glacier melted water filled in those basins ...this is the origin of lakethere are various ways of classifying a lake...oligotrophic lakes are generally deep and clear with few AQUATIC plant life eutrophic lakes are COMPLETELY the opposite of oligotrophic Lake they are not so deep and support a large number of aquatic plant life they are highly productive .they can support only warm water fihes mesotropic Lake fall in between them they are moderately covered by aquatic life other form of classification of lakes include temporary lake , freshwater lake, saline lake ,PERMANENT lake, tectonic lakes,RIFT valley lakes,etc. The physico-chemical parameters  include temperature, pH, electric conductivity, turbidity, alkalinity, dissolved oxygen, total dissolved solid, calcium, magnesium, sodium, chloride, phosphate, biological oxygen demand, nitrate and total hardness of water .