Surface Water Sources:

Natural Quiescent Water as in Lakes and Ponds

The quality of water of natural ponds and lakes are more uniform in quality than any other flowing sources of water and does not need much purification. If the catchments of the lakes/ponds are protected and non-erodible, it normally does not get in touch with surface contamination and thus its water may be safely supplied just after disinfection. Larger and older lakes permit self purification of water due to sedimentation of suspended matter and removal of bacteria to a greater extent as compared to smaller and newer lakes. However, in still water of lakes and ponds the algae, weed and other vegetation grow freely, causing bad smell, taste and color etc. Due to low catchment area of the lake basin, quantity of available water is normally less, hence these are not considered as principal source of water supply except in hilly and small towns, where there is no other source of water.