Monitoring of ground water regime is an effort to obtain information on ground water levels and chemical quality through representative sampling. The important attributes of ground water regime monitoring are ground water level, ground water quality and temperature.  The primary objective of establishing the water monitoring network stations is to record the response of ground regime to the natural and artificial conditions of recharge and discharge with reference to geology, climate, physiography, land use pattern and hydrologic characteristics. The natural conditions affecting the regime involve climatic parameters like rainfall, evapo-transpiration etc. and the artificial conditions including pumpage from the aquifer, recharge due to irrigation system and other manmade causes like waste disposal etc.

Ground water levels are being measured four times a year during January, April/ May, August and November since 1969 by Central Ground Water Board through a network of about 15000 observation wells located all over the country. Ground water samples are collected through these observation wells once a year during the month of April/ May to create background information of ground water quality changes on regional scale. The database generated forms the basis for planning the ground water development and management programme. The ground water level and quality monitoring is of particular importance in coastal as well inland saline environment to assess the changes in salt water/fresh water interface as also the gradual quality changes in the fresh ground water regime. This data is used for assessment of ground water resources and changes in the regime consequent to various development and management activities.

            A perusal of depth to water level map of India during Pre-Monsoon (May 2006) reveals that in sub-Himalayan area, north of river Ganges, generally the depth to water level ranges from 2-10 meter below ground level (mbgl). In the eastern part of the country in the Brahmaputra valley water level generally ranges from 2-5 mbgl, except in isolated pockets where depth to water level is less than 2 mbgl. However, in upper Assam, isolated pocket of deeper water level, 5-10 mbgl has been observed. In major parts of Indus basin, depth to water level generally ranges from 10-20 mbgl. In the western part of the country covering states of Gujarat and Rajasthan deeper water level is recorded in the range of 10-20 mbgl. Depth to water level more than 40m has also been observed in Jodhpur, Churu, Jalore, Nagaur, Jhunjhunu and Jaipur district of Rajasthan In the west coast, water level generally ranges from 5-10 m. Western part of Maharastra recorded water level less than 5m. In the east coast i,e coastal Andhra Pradesh and Orissa, generally the water level ranges between 2-5m. However, isolated pockets of water level less than 2m have also been recorded. Eastern most part of West Bengal recorded water level in the range of 5-10 mbgl. In central India water level generally varies between 5-20 mbgl, except in isolated pockets where water level is more than 20 mbgl. The peninsular part of country generally water level ranges between 2-10 mbgl except in pockets where water level is more than 10 mbgl. Isolated patches of deeper water level in the range of 20-40m and more than 40m have also been observed in various parts of the country.

A perusal of depth to water level map of India during Pre-Monsoon (May 2006) when compared with decadal mean (1996-2005) reveals that there is general rise in water level in the range of 0-4m in the peninsular India, coastal Andhra Pradesh and Orissa. However, in isolated pockets, fall of water level has also been recorded. In Northern India there is general fall in Water level in the range of 0-2m. However there is rise in water level in the northern part of Bihar and Uttar Pradesh. In Central India there is mixed trend of Rise and fall in water level. In addition, isolated patches of rise or fall of water level in the range of 0-2m have been observed through out the country.

A perusal of depth to water level map of India for the Post-Monsoon period (November 2006) reveals that in sub-Himalayan area, north of river Ganges, generally the depth to water level ranges from 2-5 mbgl. Isolated pocket of shallow water level less than 2m has also been observed. In the eastern parts of the country in the Brahmaputra valley water level generally ranges from 2-5 mbgl, except in isolated pockets where depth to water level is less than 2 mbgl. However in upper Assam isolated pocket of deeper water level, 5-10 mbgl is observed. In major parts of Northwestern states- Indus basin, depth to water level generally ranges from 10-20 mbgl. In the western parts of the country covering states of Gujarat, Rajasthan deeper water level is recorded in the range of 10-20 mbgl. In the state of Rajasthan, the depth to water level more than 60m has been noticed in the districts of Jaisalmer and Barmer. Isolated pockets of such deep water levels were also observed in Jodhpur, Churu, Jalore, Nagaur, Jhunjhunu and Jaipur district. In the west coast water level is generally less than 10 m and in western parts of Maharastra State isolated pockets of water level less than 2m has also been observed. In the east coast i,e coastal Andhra Pradesh and Orissa, shallow water level of less than 2m have been recorded. In eastern states water level in general ranges from 2-5 mbgl. However eastern most part of West Bengal recorded water level in the range of 5-10 mbgl. In central India water level generally varies between 2-10 mbgl, except in isolated pockets where deeper water level more than 10m.bgl.has been observed. Similarly pockets of shallow water level of less than 2 m is also observed. The peninsular part of country generally recorded a water level in the range 5-10 mbgl. In some patches water level ranges from 10-20 mbgl. Isolated patches of water level of 10-20 and 20-40 have been observed as well.

Water level of November 2006 when compared with decadal mean (1996-2005),   it was observed that the States of Uttar Pradesh, Rajasthan, Karnataka, Madhya Pradesh, Chandigarh, Punjab and Haryana show a decline in water level of more than 2m. In Uttar Pradesh in some parts of Aligarh, Bahraich, Balrampur, Bijnor, Chandoli, Banda, Kanpur, Mathura, Pratapgarh, Moradabad and Varanasi districts falls in this category. In Rajasthan districts of Bikaner, Jaisalmer, Barmer, Jodhpur, Churu, Jalore, Nagaur, Jhunjhunu and Jaipur fall in this category. In Uttar Pradesh fall more than 2m is observed in Agra, Allahabad, Banda, Hamirpur, Kanpur, Mathura and Pratapgarh districts. In Karnataka water level fall is observed in Bellari, Bijapur, Shimoga and Mangalore districts.  In Madhya Pradesh the districts of Morena, Bhind, Gwalior, Datia, Sheopur and Central part of Guna shows a fall in water level. In Punjab ground water level falls in Amritsar, Bhatinda, Hoshiarpur and Rupnagar districts.  In Haryana, the districts of Ambala, Faridabad, Jind, Fatehbad, Mahendragarh and Rewari shows a falling ground water level.  Majority of the well in the states of Tamil Nadu and Bihar shows a rise in water level when compared with Decadal mean.  In Tamil Nadu, Coimbatore, Dindigul, Erode, Kanyakumari, Karur, Madurai, Nilgiri, Perambatore districts shows rise in water level.  In Bihar rise in water level is observed in Kishanganj, Lakhisarai, Madhopur, Nalanda and Purnia districts. In addition isolated patches of rise or fall of water level in the range of 0-2m have been observed through out the country.

SK/BS