R& D in Hydrogeology
During X plan, R&D Studies /Special Studies are being undertaken in various fields of ground water in collaboration with premier Academic /Research institutions, Govt. Agencies. Memorandum of Understanding with NIH has been signed in the field of ground water modeling for planning ground water development in Yamuna flood plain area of Delhi and in Western Yamuna Canal Command area , Haryana. Isotope studies in arsenic affected areas of Bihar are being undertaken in collaboration with BARC. Project on exploration of deeper aquifers in Ganga basin have been undertaken with ONGC. During AAP 2005-06, 22 R & D studies have been proposed in various parts of the country through Regional offices of the Board
Key Issues
Ground water management is the key to combat the emerging problems of water scarcity. Ground water being a hidden resource, is often developed without proper understanding of its occurrence in time and space and threatened by overexploitation and contamination. There is an inherent linkage between development and management of ground water resources.
For an effective supply side management, it is essential to have full knowledge of hydrogeological controls which govern the yields and behaviour of ground water levels under abstraction stress. The effects of ground water development can be short term and reversible or long term and quasi-reversible which require a strong monitoring mechanism for scientific management. There is need for scientific planning in development of ground water under different hydrogeological situations and to evolve effect management practices. Demand driven development of ground water resources by different user groups without any scientific planning and proper understanding of local ground water regime behavior, leads to sharp depletion of the resources and quality degradation. Signals of mis- management of ground water resources are seen in areas where ground water extraction rate has exceeded the natural recharge.
It has been strongly felt that ground water management is the foremost challenge being faced by the Organizations dealing with ground water in India. The activities of the Organizations and policies affecting ground water need to reflect the priority issues with the overall objective to provide water security through ground water management in major parts of the country.
Central Ground Water Board being the apex organization at the central level with vast experience in the ground water sector has taken the proactive role in identifying various key issues on ground water management .
Supply side Management - Scientific development of ground water
In view of the reducing availability of fresh water resources and increasing demands, it is essential that stress is laid on development of ground water in areas with prolific aquifers and low stage of development; conservation of fresh ground water resources through development of ground water in water logged areas and promoting use of saline/ brackish ground water. Therefore, the following thrust areas are identified for ground water development.
Development of groundwater in areas with low stage of ground water development
There are many areas in different parts of the country, where potential for development of ground water still exists. To tap this potential, a concept paper for development of ground water has been prepared. It is proposed to develop ground water resources in safe (low stress) areas throughout the country except in the States of Haryana, Punjab and Rajasthan and Union Territories of Chandigarh, Delhi, Lakshadweep, Pondicherry and Daman & Diu, where there are problems of either continuously declining ground water levels or that of quality deterioration. Shallow tubewells are proposed to be constructed in alluvial areas and in areas underlain by hard rocks, borewells and boring in dugwells are proposed.
Development of deeper aquifers
As per the National Water Policy, the development of ground water is to be restricted to the replenishable resource. The in-storage ground water resources of the country have been assessed as 10812 BCM, which can be retained for future use/ harnessed in periods of crisis. CGWB has till now explored potential aquifers upto the depth of 400 metres in alluvial areas and 200 metres in hard rocks. However, to increase the availability of water to meet the increasing demands and to retain the same for future use, newer potential sources of ground water would need to be explored. Exploration of deeper aquifers to ensure sustainable water supply for various uses would need to be carried out, so that potential aquifers can be exploited for use.
In coastal areas, sufficient scope exists to tap deeper ground water aquifers. It is, therefore, essential that deeper ground water exploration be carried out in coastal areas to ascertain the safe yield of these aquifers for sustainable development.
Development of ground water in flood plain areas
The flood plains in the vicinity of the rivers act as repositories for ground water. To meet the additional demands, ground water from the flood plains can be withdrawn during non-monsoon period. The dewatered aquifer zones would be recharged during the subsequent monsoon period through flood water. Recharge to ground water can be enhanced by adopting appropriate artificial recharge practices including construction of additional barrages.
Integrated use of surface and ground water - conjunctive use.
A total of 13 studies for establishing feasibility of conjunctive use of surface and ground water have been completed by CGWB. The Studies have established that the isolated use of surface water ignoring optimal ground water use in irrigation command has resulted into various environmental problems Optimal conjunctive use plan to be implemented by the State agencies in co-ordination with CADA has been recommended. The recommendations of the completed Conjunctive use studies needs to be implemented on the ground. Further, it is also felt that there is a need to adopt Ground Water Hydraulic Management Models (Management models) which incorporates a ground water simulation model as constraint in the Management model which can be efficiently used in planning the conjunctive use of water.
Development of ground water in water logged areas
Large areas particularly in the command areas of major and medium irrigation projects suffer from water logging due to rejected recharge. The water logging conditions have been created due to high intensity of irrigation without adequate drainage, which results in upward movement of water table. As per the assessment made by the Working Group on Problem Identification in Irrigated Area with suggested Remedial Measures (1991), about 2.46 mha of the area under surface water irrigation projects is water logged or threatened by water logging. Such areas suffer from loss of productivity. Provision of horizontal drainage in such areas is only a part solution.
The water table from such areas can be depressed by constructing wells/ tubewells and reclaimed water can be used for beneficial use. Pumping of ground water besides alleviating the conditions of water logging will also contribute to increase in irrigation intensity. Such areas, therefore, offer scope for ground water development by lowering the water table down to 5 metres or more.
Development of saline/ brackish aquifers
As mentioned earlier, many areas in the country are underlain by saline water aquifers. Yields of many crops, vegetables and fruit plants e.g. barley, dates and pomegranate, when irrigated with saline or brackish water are not significantly affected. Saline/ brackish water can be successfully used to irrigate such plants and fresh or good quality water can be saved for use by other sensitive crops of for other uses. However, there is need to develop new salt-tolerant crops and improve tolerance capacity of existing crops. Studies conducted by various workers have revealed that poor quality water could be used through drip in irrigating tomatoes and potatoes without much deterioration in yield and quality.
For domestic water supply, saline water can be used after blending with fresh water for uses other than drinking. Further development of saline water and simultaneous recharge of fresh water will also lessen the problem of salinity.
Demand side Management Strategies ~ to tackle declining water level
In demand side management the socio-economic dimensions plays an important role involving managing the users of water and land. Management options to arrest declining ground water levels are two fold viz. regulated withdrawals and augmentation of ground water. These measures can only be successfully implemented only with effective people's participation. It is, therefore, essential to educate the masses on need and ways for regulation, conservation and augmentation of ground water resources.
R& D in Water Quality
Ground Water Quality - Regional scenario :
Apart from collection and analysis of ground water samples as a part of various scientific studies and exploration of fresh water aquifers, ground water samples are collected once a year from the observation wells and analysed to create a background database and assess regional ground water quality changes. In addition, special R & D studies have been/ are being undertaken in the areas affected by arsenic in West Bengal and Bihar. Similar studies have also been taken up in fluoride and salinity affected areas of the country. Brief findings of these studies are as follows.
Ground water in most of the areas in the country is fresh. However, in some areas, ground water quality has been found to be contaminated due to hydrogeological reasons.
a) Salinity in ground water:
The salinity in ground water is of two kinds viz. inland salinity and coastal salinity.
Inland salinity : Inland salinity in ground water is caused due to geogenic sources. The problem of inland salinity has been observed in arid and semi arid regions of Rajasthan, Haryana, Punjab, and Gujarat with limited extent in the states of Uttar Pradesh, Delhi, Karnataka, Maharashtra, Madhya Pradesh and Tamilnadu. Electrical conductivity in these areas exceeds 4000 micro Siemens/ cm.
Coastal salinity : Problem of coastal salinity in ground water, that is caused due to excessive exploitation of ground water, has been observed in Mangrol - Chorwad areas and Coastal Saurashtra of Gujarat, Minjur area in Tamilnadu, Pondicherry coast, parts of Orissa, Andhra Pradesh and Kerala coast.
b) Fluoride contamination in ground water
High fluoride content beyond 1.5 mg/l in ground water has been reported from isolated pockets in the States of Andhra Pradesh, Assam, Bihar, Chhattisgarh, Delhi, Gujarat, Haryana, Jharkhand, Karnataka, Kerala, Madhya Pradesh, Maharashtra, Orissa, Punjab, Rajasthan, Tamilnadu, Uttar Pradesh and West Bengal.
c) Arsenic contamination in ground water
Occurrence of high concentration of arsenic (beyond permissible limit of 0.05 mg/l) in ground water has been reported from 79 blocks of 8 districts of West Bengal viz. Bardhaman, Hoogli, Howrah, Malda, Murshidabad, Nadia, North and South 24 Parganas. Arsenic contamination has also been recently reported from parts of Bhojpur and Patna districts of Bihar and Ballia district of Uttar Pradesh. Occurrence of arsenic in these states is associated with sediments in Ganga basin. Localised occurrence of arsenic in ground water has been reported from parts of Rajnandgaon district of Chhattisgarh due to arsenopyrite mineralization in the fracture zones in hard rock terrain.
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d) Iron contamination in ground water
High concentration of iron (in excess of 1 mg/l) in ground water has been observed in more than 1.1 lakh habitations in the country. In the eastern parts of Brahmaputra basin, the iron content is in the range of 0.4 to 4.0 mg/l while in the northwestern parts of the basin, iron is in the range of 0.3 to 3.0 mg/l in ground water. In Tripura, there is widespread occurrence of ground water with iron in the range of 0.3 to 1.2 mg/l. Ground water in Kosi river basin in north-eastern Bihar has iron in excess of permissible limit. Excess iron in ground water is also found in many places in eastern and southwestern parts of West Bengal. Sporadic occurrences of iron contamination in ground water have also been reported from Uttar Pradesh, Orissa, Punjab, Rajasthan, Maharashtra, Madhya Pradesh, Chhattisgarh, Jharkhand, Tamilnadu and Kerala.
Ministry
of Water Resources