Dark zones are human made
Groundwater sustains almost 60 per cent of the irrigated land in India. Most districts in India today have larger shares of irrigated land under groundwater irrigation than under surface-water irrigation. This ominous change in water use patterns in India has been extremely rapid since the 1970s.
Extensive groundwater usage has caused depletion of water levels in many areas. This has had concomitant effects such as drying up of dug wells and shallow wells, springs and wetlands becoming arid and intrusion of seawater along coasts. The quality of groundwater has also deteriorated greatly following depletion in its levels.
The Maheshwaram watershed, located about 35 kilometres from Hyderabad in Andhra Pradesh, was extensively monitored between 1999 and 2002 by the Hyderabad based Indo-French Centre for Groundwater Research (ifcgr)