Report on the Dynamic Ground Water Resources of Maharashtra (2011-2012)
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REPORT ON THE DYNAMIC GROUND WATER RESOURCES OF MAHARASHTRA (2011-2012) Groundwater Surveys and Development Agency, Pune Water Supply and Sanitation Department, Government of Maharashtra & Central Ground Water Board, Central Region, Nagpur Ministry of Water Resources, Government of India February 2014 DYNAMIC GROUND WATER RESOURCES OF MAHARASHTRA (2011-12) Prepared by Groundwater Surveys and Development Agency, GoM & Central Ground Water Board, Central Region, Nagpur, GoI i FOREWORD An overwhelming population of rural Maharashtra and to some extent urban population is dependent on groundwater for drinking purposes. It has been observed that prior to the year 1972 the use of groundwater was relatively insignificant in the State. Subsequently due to frequent occurrence of droughts, limitations of the availability of surface water, development of low cost drilling devices, easy availability of institutional finance, and energization etc. led to proliferation of irrigation wells. Maharashtra is one of the most well endowed States in the country in respect of rainfall. But it may soon become a State where large parts of it face perennial water shortage, if urgent institutional, policy and technological initiatives are not taken to address both the quantity and the quality issues of groundwater. Most of the discussions at National and State level as well as local level are centered on demand-side projections, supply-side shortfalls and large scale investment estimates for resource development. The fact is that good governance and better management practices along with partnership with the community can bring better and sustainable benefits. Efforts are need to be taken to empower local communities to manage their own water resources and rebuild a new relationship with water in the society. Groundwater is a natural resource with both ecological and economic value and is of vital importance for sustaining life, health and integrity of ecosystems. This resource is increasingly threatened by over-extraction which has insidious long-term effects. Scarcity and misuse of groundwater pose a serious threat to sustainable development and livelihood. The availability of groundwater is extremely uneven, both in space, time and depth and so will be the case in future. The uneven distribution of groundwater in the State can be mainly attributed to highly heterogeneous lithology and regional variation of rainfall. Around 92% of the area of the State is occupied by hard rocks and because of variations in their basic characteristics; physiography and variability in the rainfall, there are limitations on the availability of groundwater. Though there is unanimity about this, there is still considerable difference of opinion among the scientists about the precise degree of these limitations. In order to assess the availability of groundwater and to ensure maximum accuracy in groundwater estimates, the Central Government has, from time to time, appointed committees comprising groundwater experts and has laid down guidelines for this purpose. Estimates of groundwater in Maharashtra are being revised from time to time on the basis of these guidelines. The total demand for water from the groundwater ii domain is increasing day by day. The main reason for this is the self reliance being experienced by users of groundwater. But as this is leading to inexorable withdrawal, and as the status regarding total availability of groundwater is of uncertain nature, it is imperative to give more serious thought and a new direction to groundwater planning and management. While first major but adhoc attempt of estimating groundwater resources was made in 1973, the first scientific groundwater resource assessment of Maharashtra was made during 1979 on the basis of Overexploitation Committee Report. Since then various committees constituted by Government of India and Government of Maharashtra to estimate the groundwater resources have made the attempts from time to time. After due consideration of the limitations in the earlier methodologies, the Groundwater Estimation Committee (GoI), during 1997, proposed the revised methodology known as GEC 97. Little modifications have been suggested in this methodology by the R & D Advisory Committee of GoI. Based on the protocol and guidelines issued by Central Ground Water Board, New Delhi, the State has completed the exercise of Groundwater Resource Estimation of Maharashtra for 2004, 2007-08 and 2008-09. Now as per the GoI protocol and guidelines issued on 5th January 2010 and subsequently on 22nd July 2010, the exercise of estimating the Groundwater Resources of Maharashtra as on 2011-12 has been completed. As per this report, the total rechargeable groundwater resource in the State is computed as 33,94,737 Hectare Metre (Ham) or (33.95 BCM) and the Net ground water availability is 32,15,185 Hectare Metre (Ham) or (32.15 BCM). Out of these, 17,17,705 Ham is withdrawn for different uses viz irrigation, domestic & industry etc, 1,97,552 Ham or 1.97 BCM is earmarked for domestic and industrial requirement and the remaining is available for future irrigation. Compared to 2004 the groundwater use has increased by 2,09,192 ham (i.e. from 15.08 to 17.18 BCM). A note of caution is required to be placed on record, regarding the situation that may emerge from the statement in the preceding paragraph i.e. after subtracting the present groundwater draft of 17.18 BCM it appears that there is still a balance of 16.45 BCM. During the course of preparation of this Groundwater Assessment report it is observed that 2,05,685 irrigation borewells with pump sets have been accounted for the draft calculations. Around 50% of the districts have received irrigation borewell data. It is a well-known fact that the large number of irrigation borewells/tubewells are the main source of irrigation across the State and a substantative number of these are not even on record for electricity connections. If actual draft from those borewells/tubewells had been accounted for then the balance position would have certainly emerged as alarming. iii The precision of groundwater resource estimation is mainly dependent on the quality of the basic data. This assessment is carried out with the help of the secondary data. Despite the limitations of the secondary data, GSDA has taken efforts and has tried to collect more accurate well census, crop & surface irrigation data. The well census data have been cross verified with the electric connections given by Maharashtra State Electricity Distribution Company. This is followed by sample field confirmation by GSDA. The Groundwater Estimation has been carried out for 33 districts excepting Mumbai and Mumbai Suburb districts. The notified 1505 watersheds have been delineated into 1531 watershed units based on newly formed districts. On the basis of the present Groundwater Resource Assessment, out of the total 1531 watersheds, 76 watersheds are categorized as Overexploited i.e. the groundwater development is more than 100% of the recharge and the water table during either Post or Pre monsoon interval or both shows declining trend. Four watersheds are categorized as Critical where groundwater development is between 90 to 100% of the recharge and where water table, either Post or Pre monsoon interval or both, shows significant declining trend and 100 watersheds are categorised as Semi-Critical where groundwater development is between 70 and 90% of the recharge and where water table, either Pre or Post monsoon interval, shows declining trend. Out of the total 353 tahsils, 10 tahsils are categorized as Overexploited, 2 tashils are categorized as Critical and 16 tahasils are categorized as Semi- Critical. Out of 16 semi-critical tahsils, in 7 tahsils the exploitation is more than 95% i.e. they are on the verge of transformation into the Over-exploited category. It is revealed from the data that the areas which have emerged as overexploited, critical or semi-critical are predominantly from the DPAP areas, where there is highest percentage of water intensive commercial crops as well as low rainfall. Groundwater is one amongst the State’s most important natural resources. It provides drinking water to rural as well as urban community, supports irrigation & industry, sustains the flow of streams & rivers and maintains wetland ecosystem. There is significant freshwater deficit in many areas of the State. Human health, welfare and food security are at risk unless the groundwater resources are managed more effectively and efficiently by the community. It is very much obvious that over extraction of ground water over years without any compensatory replenishment is affecting large tracts of land adversely. The non-replenishment of the shallow aquifers and depletion of the deeper aquifers on account of unregulated sinking of deep borewells/tubewells, almost amounting to “water-mining” unmindful of the adverse ecological effects is one of the contributory causes for iv recurring droughts. Concerted action, therefore, is needed to reverse the present trend of periodic occurrence of droughts. Taking into consideration variation of rainfall in Maharashtra, which is the most influential factor in the dynamic groundwater estimation, it will be imperative henceforth to estimate freshly the groundwater resources every year. For this, it is necessary to make the method prescribed by the Central Committee much easier to operate and to publish in November every year the groundwater storage created in each watershed so as to apprise the community about the status of irrigation and drinking water. It would also be necessary to plan and control the use of groundwater under the prevailing conditions. Publication and distribution of annual reports and related programmes for creating awareness amongst the community and for educating them will have to be undertaken regularly. This will enable avoiding scarcity, as well as the hectic activity and excessive expenditure that has become characteristic of summer months. It is necessary to formulate and adopt a long-term policy to protect groundwater by preventing pollution and overuse. This policy should be comprehensive and implemented at all appropriate levels.