The primary objective of ground water regime monitoring is to record information on ground water level and quality through representative sampling in space and time. Board regularly monitors ground water level through a wide network of ground water observation wells located all over the Country. Water level is measured four times in a year i.e., in the month of January, April/May, August and November and ground water quality samples are collected once in a year i.e., during April/May.
Ground Water Level Scenario in India during January, 2014
Perusal of Depth to water level map of January,2014 indicates that in Sub-Himalayan area, north of river Ganges, Assam, Bihar, Chhattisgarh, Maharashtra, Jharkhand, Madhya Pradesh, Odisha, Bihar, Gujarat, Tripura and Coastal Tamil Nadu generally the depth to water level varies from 2-5 meter below ground level(mbgl). Shallow water level less than 2 mbgl have also been observed as isolated patches in Maharashtra, Andhra Pradesh, Assam, Northern Uttar Pradesh, Madhya Pradesh, Gujarat and Odisha. In major parts of north-western States, depth to water level generally ranges from 10-40 mbgl. In the western parts of the Country, deeper water level is recorded in the depth range of 20-40 mbgl and more than 40 mbgl. In some parts of Delhi and Rajasthan, water level of more than 40 mbgl is recorded. Along the eastern & western coast, water level is generally less than 10 mbgl. Central part of the State of West Bengal recorded water level in the range of 5-10 mbgl and also 10-20 mbgl. In Central India, water level generally varies between less than 2 mbgl to 5 mbgl, except in isolated pockets where water level less than 10 mbgl has been observed. The peninsular part of Country, generally, recorded a water level in the range of 5 to 20 mbgl depth range. Depth to Water level Map of India of January, 2014 has been depicted in Figure - I.
A comparison of depth to water level of January,2014 with decadal mean of January (2004-2013) indicate that 7607 no. of wells i.e., about 62% wells are showing rise in water level, out of which 46% wells show rise of less than 2 m, about 11% wells show rise in water in the range of 2-4 m; and about 5% wells show rise in the range of more than 4 m. 4618 no. of wells i.e., about 38% wells are showing decline in water level, out of which 28% wells show decline in the range of 0-2 m, 5% wells are showing decline in water level in 2-4 m; and remaining 2% wells show decline of more than 4 m. Decline in water level of more than 4 m is mostly prominent in Delhi, Gujarat, Haryana, Karnataka, Punjab, Rajasthan and Tamil Nadu. Rise in water level of more than 4 m is observed mostly in Andhra Pradesh, Gujarat, Himachal Pradesh, Madhya Pradesh, Maharashtra, Rajasthan and Uttar Pradesh.
Decadal Water Level Fluctuation Map of India for January, 2014 with the mean of January (2004-2013) has been depicted in Figure - II.