IMPONDED ESERVOIR Def. – An artificial structure constructed across the valley containing water course to impound or store the water stream so that it may be used for water supply. It has 3 parts……. 1. Dam to hold the water 2. Spillway to release the extra water 3. Gates to regulate the flow of water supply
LOCATION FACTORS # Quantity of water # Quality of water # Shortest dam size # Suitable elevation (height) # density & distribution of population around catchment area # Location of consumer population # Location of nearby highways, electric lines, bridges, rail lines etc. # Geological stability
QUALITY V/S QUANTITY OF SURFACE WATER - Ensure quantity first - Availability for longer period - Up streams can give good quality water - Surface waters are more contaminated
SUB-SURFACE WATER Definition :- It is the available stock of water under the ground surface in flowing or static condition due the continuous percolation of rain water or water from surface sources like river or lakes. It is also called under-ground water. It is a natural phenomenon.
OCCURANCE OF SUB-SURFACE WATER Depends upon…….. …..Amount & intensity of rainfall …..Distribution of rainfall ……Slope of ground …..Permeability of ground surface
QUALITY V/S QUANTITY OF SUB-SURFACE WATER OLD VIEW – GROUND WATER IS PURE MODERN VIEW – NO NATURAL SOURCE IS PURE
SUB-SURFACE SOURCE OF WATER SPRINGS WELLS ARTESIAN WELL INFILTERATION GALLARIES INFILTERATION WELLS