Groundwater Situation in India: Problems and Perspective

This art icle was downloaded by: [ Raj m at a Vij ayaraj e Scindia Krishi Vishwa Vidyalaya] On: 20 January 2015, At : 03: 06 Publisher: Rout ledge I nform a Lt d Regist ered in England and Wales Regist ered Num ber: 1072954 Regist ered office: Mort im er House, 37- 41 Mort im er St reet , London W1T 3JH, UK International Journal of Water Resources Development Publicat ion det ails, including inst ruct ions f or aut hors and subscript ion inf ormat ion: ht t p: / / www. t andf online. com/ loi/ cij w20 Groundwater Situation in India: Problems and Perspective Dhirendra Kumar Singh & Anil Kumar Singh Published online: 21 Jul 2010. To cite this article: Dhirendra Kumar Singh & Anil Kumar Singh (2002) Groundwat er Sit uat ion in India: Problems and Perspect ive, Int ernat ional Journal of Wat er Resources Development , 18: 4, 563-580, DOI: 10. 1080/ 0790062022000017400 To link to this article: ht t p: / / dx. doi. org/ 10. 1080/ 0790062022000017400 PLEASE SCROLL DOWN FOR ARTI CLE Taylor & Francis m akes every effort t o ensure t he accuracy of all t he inform at ion ( t he “ Cont ent ” ) cont ained in t he publicat ions on our plat form . However, Taylor & Francis, our agent s, and our licensors m ake no represent at ions or warrant ies what soever as t o t he accuracy, com plet eness, or suit abilit y for any purpose of t he Cont ent . Any opinions and views expressed in t his publicat ion are t he opinions and views of t he aut hors, and are not t he views of or endorsed by Taylor & Francis. The accuracy of t he Cont ent should not be relied upon and should be independent ly verified wit h prim ary sources of inform at ion. Taylor and Francis shall not be liable for any losses, act ions, claim s, proceedings, dem ands, cost s, expenses, dam ages, and ot her liabilit ies what soever or howsoever caused arising direct ly or indirect ly in connect ion wit h, in relat ion t o or arising out of t he use of t he Cont ent . This art icle m ay be used for research, t eaching, and privat e st udy purposes. Any subst ant ial or syst em at ic reproduct ion, redist ribut ion, reselling, loan, sub- licensing, syst em at ic supply, or dist ribut ion in any Downloaded by [Rajmata Vijayaraje Scindia Krishi Vishwa Vidyalaya] at 03:06 20 January 2015 form t o anyone is expressly forbidden. Term s & Condit ions of access and use can be found at ht t p: / / www.t andfonline.com / page/ t erm s- andcondit ions Water Resources Development, Vol. 18, No. 4, 563–580, 2002 Downloaded by [Rajmata Vijayaraje Scindia Krishi Vishwa Vidyalaya] at 03:06 20 January 2015 Groundwater Situation in India: Problems and Perspective DHIRENDRA KUMAR SINGH & ANIL KUMAR SINGH Water Technology Centre, Indian Agricultural Research Institute, New Delhi 110012, India. Email: [email protected],[email protected] ABSTRACT Overexploitation of groundwater and intensive irrigation in major canal commands has posed serious problems for groundwater managers in India. Depletion of water tables, saltwater encroachment, drying of aquifers, groundwater pollution, water logging and salinity, etc. are major consequences of overexploitation and intensive irrigation. It has been reported that in many parts of the country the water table is declining at the rate of 1–2 m/year. At the same time in some canal commands, the water table rise is as high as 1 m/year. Deterioration in groundwater quality by various causes is another serious issue. Increased arsenic content in shallow aquifers of West Bengal reported recently has created panic among the groundwater users. Summed together, all these issues are expected to reduce the fresh water availability for irrigation, domestic and industrial uses. If this trend continues unchecked, India is going to face a major water crisis in the near future. Realizing this, the Government of India has initiated several protective and legislative measures to overcome the groundwater management-related problems but, due to the lack of awareness and political and administrative will, none of the measures has made any signiŽcant impact. This paper highlights the critical issues and examines the various schemes related to groundwater development and management. Introduction Groundwater has played a major role in increasing the food production and achieving food security in India. It is an important source of water for agricultural, domestic and industrial needs. Groundwater, a renewable source of water, has the remarkable distinction of being a highly dependable and safe source of water supply. This, in conjunction with the large-scale rural electriŽcation in India and easily available credit through Žnancial institutions, has been instrumental in the uncontrolled exploitation of groundwater during the last few decades. The importance of the groundwater resource in India can be realized by the fact that about 50% of the total irrigated area is dependent upon groundwater (Central Water Commission (CWC), 2000) and about 60% of irrigated food production depends on irrigation from groundwater wells (Shah et al., 2000). Studies also suggest that productivity of groundwater is more than that of 0790-062 7 Print/1360-064 8 On-line/02/040563–18 Ó 2002 Taylor & Francis Ltd DOI: 10.1080/079006202200001740 0 564 D. K. Singh & A. K. Singh Table 1. Share of groundwater in irrigation potential of India Downloaded by [Rajmata Vijayaraje Scindia Krishi Vishwa Vidyalaya] at 03:06 20 January 2015 Source Major and medium (surface water) Minor irrigation (surface water) Minor irrigation (groundwater) Total (surface water and groundwater) Total (major, medium and groundwater) Percentage of groundwater in total irrigation potential Irrigation potential (million hectares) Created up to Utilized up to Ultimate 1997–98 1997–98 58.5 17.4 64.0 81.4 139.9 46 33.6 12.6 46.5 59.1 92.7 29.0 11.0 42.7 53.7 82.7 50 51.6 Source: CWC (2000). surface water due to the fact that it is available at the point of use, requires minimum conveyance infrastructure, is available on demand and maximizes the application efŽciency as the farmers have to pay the cost of lifting. At the national level, there is considerable groundwater resource still available for use (Table 1). However, when viewed at the micro level, there are regions where intensive development has created a critical situation. Though, in the post-Green Revolution era, the rapid expansion in use of groundwater primarily for irrigation has contributed signiŽcantly to the agricultural and economic development of the country, sustainable development and management of this resource have posed many challenges in recent years. Overexploitation of groundwater in several parts of the country has resulted in declining groundwater levels, a reduction in supply, saline water encroachment, drying of the spring and shallow aquifers, increased cost of lifting, reduction in free ow and even local subsidence in some places. In several parts of India (north Gujarat, southern Rajasthan, Saurashtra, the Coimbatore and Madurai districts of Tamil Nadu, the Kolar district of Karnataka, the whole Royalseema region of Andhra Pradesh and parts of Punjab, Haryana and Uttar Pradesh) declining water levels are in the order of 1–2 m/year. It has been reported that declining water levels could reduce India’s harvest by 25% or more (Seckler et al., 1998). Further dangerous consequences of falling water levels are an increase in arsenic levels in several regions of the country, uoride contamination of the drinking water supply and many other forms of groundwater pollution, making tubewell water unŽt for human consumption and farming. While falling water levels are a major concern in India, intensive irrigation in certain canal command areas, coupled with poor sub-surface drainage, has created problems of waterlogging and salinity, making the soils unproductive. The issue of assessment of groundwater potential is another important aspect of groundwater development and management. In many cases the groundwater potential estimated by the Central Ground Water Board of India (CGWB) deviates from reality if examined at regional levels. There are instances where CGWB estimates are on the high side (Singh, 2001). This paper critically reviews the groundwater situation in India and issues related to its development and management. Groundwater Situation in India 565 Downloaded by [Rajmata Vijayaraje Scindia Krishi Vishwa Vidyalaya] at 03:06 20 January 2015 Assessment of Groundwater Potential and its Availability The assessment of the groundwater resource in the country has always been subjected to revisions. From time to time several attempt have been made by various working groups/committees/task forces constituted by the government of India to estimate the groundwater resource of the country based on the available data and in response to development needs. But, due to a lack of scientiŽc data and incomplete understanding of the parameters in recharge and discharge processes, all the previous estimates have been tentative and at best, approximations. Even the present approaches to estimating the groundwater potential adopted after the recommendations of the Groundwater Estimation Committee (GEC) (1984, 1997), set up by the Government of India, can, at best, be said to be a scientiŽc approximation. Though the present methods are more scientiŽc in nature, there are some major drawbacks, which need improvement. The two most popular methods, which are used by the CGWB and other government agencies for assessment of groundwater potential, are the water level uctuation method and the rainfall inŽltration method, using ad hoc norms (GEC, 1984, 1997). In the water level uctuation method, utilizable recharge is estimated based on pre-monsoon (April–May) to post-monsoon (November) water level uctuations for the area receiving the South-west Monsoon. Similarly, for the area receiving the North-east Monsoon pre-monsoon (November) and post-monsoon (March) water level uctuation is taken into consideration. The speciŽc yield values of the geological formation in the zone of water table uctuation are then multiplied by the difference between pre-monsoon and post-monsoon levels to arrive at the utilizable recharge. In areas where groundwater monitoring is not adequate in space and time, the rainfall inŽltration method is adopted. The norms for rainfall inŽltration contributing to groundwater recharge have been evolved based on the studies undertaken in various regions of India and rainfall inŽltration factors have been recommended for these regions. The normal rainfall Žgures are taken from the India Meteorological Department. Besides these, norms (GEC, 1984, 1997) are available for the estimation of recharge due to seepage from canals, return seepage from irrigated Želds, seepage from tanks and lakes and potential recharge in waterlogged and ood-prone areas. In both of these methods, total subsurface inow into a region is assumed to be equal to the subsurface outow from the region. In locations where the assumption that inow and outow components are equal is not valid, as in smaller units, erroneous estimates can be obtained. Though, conceptually, the water level uctuation method appears to give better results, it fails to give the real estimate of the groundwater resource potential available for irrigation or any other use. In many regions where the water-holding capacity of the aquifers is not high and geohydrological conditions are such that the water table rises to the ground surface during the monsoon and falls to a very low level as a result of very high sub-surface outow during the non-monsoon period, the total annual groundwater recharge is not available for irrigation. This is obvious because the irrigation water demand is spread over most months and is more during the non-monsoon period. In other words, even though there is sufŽcient rainfall and groundwater recharge, its availability is not guaranteed during the non-monsoon period. This Downloaded by [Rajmata Vijayaraje Scindia Krishi Vishwa Vidyalaya] at 03:06 20 January 2015 566 D. K. Singh & A. K. Singh method gives higher estimates of a utilizable groundwater resource in cases where outow is higher than the inow. Singh (2001) determined the utilizable groundwater resource potential of Rajgarh block of Mirzapur district using the regional groundwater recharge and balance approach and compared it with the estimates of the CGWB. According to this estimate the utilizable groundwater balance is only 31.9 million cubic metres (MCM), which is far less than the CGWB estimate of 112.3 MCM. This is due to the fact that a considerable portion (79.3 MCM) of the recharged water goes as outow from the block and is not available for irrigation. Incorrect reporting of the groundwater resource potential has deprived several regions in India like this of new water resource development schemes as the CGWB has estimated surplus or adequate groundwater resources in these regions and planners treat them as ‘adequate water zones’ (white category). The National Commission on Agriculture (1976) assessed the total groundwater potential of the country as 67 million hectare metres (ha m) excluding soil moisture, of which 26 million ha m was considered as available for irrigation. When this was converted into the area to be irrigated, the ultimate irrigation potential worked out to be 40 million ha. Again in 1979, the GEC assessed the gross and net groundwater recharge as 46.79 million ha m and 32.49 million ha m. With further advancement and understanding of the subject, GEC (1984) came up with a revised methodology for assessment of the groundwater potential. Based on this and the recommendation of the working group constituted by different states, the annual replenishible groundwater resource of the country was estimated to be 45.33 million ha m. Out of this resource, groundwater for irrigation was computed as 38.34 million ha m per year and ultimate irrigation potential in terms of area was estimated as 80.38 million ha, which was double the estimate of National Commission on Agriculture (1976). This estimate was further reŽned by adopting separate norms for the estimate from canal command and non-command areas and the water requirement of the crops in different zones. Accordingly, the total rechargeable groundwater resource potential of the country was Žxed at 43.19 million ha m. The available groundwater resource for irrigation is 36.08 million ha m, of which the utilizable groundwater is 32.47 million ha m. In terms of area, utilizable irrigation potential of the country is now estimated as 64.05 million ha (CGWB, 2000). Groundwater Utilization and EfŽciency of its Use In India, groundwater development and use are restricted to the shallow zone within a 50 m depth and are mostly Žnanced through institutional sources and private efforts. The development of a deeper zone (50–300 m below ground level) is usually in the public sector for community irrigation. The shallow groundwater structure includes dug wells, dug cum bore wells, shallow tubewells and Žlter points, etc. The deeper structure includes heavy-duty tubewells and bore wells. State-wise distribution of these structures (up to 1994) is given in Table 2. Groundwater utilization statistics reveal that the irrigation potential created from groundwater up to 1993 was 35.38 million ha. The stage of groundwater development worked out to be 55.23%. The actual stage of development worked out on a volumetric basis was about 32% (Table 3). This variation was due to the fact that the area which can theoretically be irrigated from the available ground- Groundwater Situation in India 567 Downloaded by [Rajmata Vijayaraje Scindia Krishi Vishwa Vidyalaya] at 03:06 20 January 2015 Table 2. Number of groundwater withdrawal structures (up to March 1994) State/union territories Dug wells Shallow tubewells Public tubewells Andhra Pradesh Arunachal Pradesh Assam Bihar Goa Gujrat Haryan Himachal Pradesh Jammu and Kashmir Karnataka Kerala Madhya Pradesh Maharashtra Manipur Meghalaya Mizoram Nagaland Orissa Punjab Rajasthan Sikkim Tamil Nadu Tripura Uttar Pradesh West Bengal Total states Union territories Total 1 309 860 — — 509 770 102 709 070 42 420 3 570 2 779 545 156 212 814 1 307 070 1 350 020 — — — 450 593 413 93 470 853 263 — 1 470 807 — 1 149 930 54 330 10 208 294 16 857 10 225 151 113 160 — 49 597 755 142 — 8 300 463 037 374 2 087 37 837 4 103 23 886 254 10 780 — — 20 205 622 600 21 686 — 171 305 2 432 2 420 593 296 539 5 013 927 26 083 5 040 010 8 109 — 2 702 6 625 105 5 588 1 799 289 172 — 64 1 940 — 5 3 — 4 5 768 2 002 75 — — 164 28 446 4 766 68 626 797 69 423 Source: CWC (2000). water resource has to be reduced based on the availability of land for irrigation and considering the absence of suitable measures for the control and regulation of groundwater development and to account for possible reŽnements which would be required in the present methodology of groundwater resource assessment (CGWB, 1995). According to the latest estimates of the CWC (2000), the anticipated groundwater potential created and utilized up to 1997–98 is 46.5 million ha and 42.7 million ha, respectively (Table 1). EfŽciency of groundwater use is, in general, higher than that of surface water. This is due to the fact that the groundwater is available on demand at the point of use, requiring little conveyance. It has been reported that crop yield in India is up to 3 times higher than the crop yields from irrigation by canal system alone (Table 4) (Chambers, 1988; Dhawan, 1989). Groundwater Availability and Accessibility Groundwater resources vary greatly in terms of their accessibility and ease of recharge. The former depends on the structure of rocks and aquifers and the cost and availability of different water-drawing technologies in relation to local Downloaded by [Rajmata Vijayaraje Scindia Krishi Vishwa Vidyalaya] at 03:06 20 January 2015 568 Table 3. Groundwater resources and irrigation potential of India 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 State/union territories Andhra Pradesh 3.529 16 Arunachal Pradesh 0.143 85 Assam 2.471 92 Bihar 3.352 13 Goa 0.021 82 Gujarat 2.037 67 Haryana 0.852 76 Himachal Pradesh 0.036 60 Jammu and Kashmir 0.442 57 Karnataka 1.618 57 Kerala 0.790 03 Madhya Pradesh 5.088 92 Maharashtra 3.786 73 Manipur 0.315 40 Meghalaya 0.053 97 Mizoram Not assessed Nagaland 2 0.072 40 Orissa 2.000 14 Punjab 1.865 50 Rajasthan 1.270 76 Sikkim Not assessed Tamil Nadu 2.639 12 Tripura 0.066 34 Uttar Pradesh 8.382 10 West Bengal 2.309 23 Union territories 0.040 760 Total 43.188 50 Available groundwater resource for irrigation in net terms (million ha m/year) Utilizable groundwater resources for irrigation in net terms (million ha m/year) Gross draft estimated on pro rata basis (million ha m/year) Net draft (million ha m/year) Balance groundwater resource for future use in net terms (million ha m/year) 0.529 38 0.021 58 0.370 79 0.502 82 0.003 27 0.305 65 0.127 92 0.007 31 0.066 39 0.242 79 0.131 35 0.763 32 1.239 72 0.047 30 0.008 10 2.999 78 0.122 27 2.101 13 2.849 31 0.018 55 1.732 02 0.724 84 0.029 29 0.376 18 1.375 78 0.658 68 4.325 60 2.547 01 0.268 10 0.045 87 2.699 81 0.110 05 1.891 02 2.564 39 0.016 70 1.558 81 0.652 36 0.026 37 0.338 58 1.238 21 0.592 81 3.892 98 2.292 31 0.241 29 0.041 28 1.013 18 — 0.134 55 0.781 08 0.002 19 1.024 31 0.868 53 0.007 57 0.007 13 0.614 43 0.143 74 1.018 66 1.105 76 Negligible 0.002 60 0.709 22 — 0.094 18 0.546 76 0.001 54 0.717 02 0.607 98 0.005 30 0.005 00 0.430 10 0.100 62 0.713 12 0.774 03 Negligible 0.001 82 2.290 56 0.122 27 2.006 95 2.302 55 0.017 01 1.015 00 0.116 86 0.023 99 0.371 18 0.945 68 0.558 06 3.612 48 1.772 98 0.268 10 0.044 05 0.010 90 0.300 02 0.186 52 0.199 45 0.061 50 1.700 12 1.678 98 1.071 31 0.055 35 1.530 09 1.511 09 0.964 18 Negligible 0.204 47 2.251 09 0.774 83 Negligible 0.143 13 1.575 76 0.542 38 0.395 86 0.009 95 1.257 43 0.346 42 0.019 197 7.093 337 2.243 26 0.056 39 7.124 67 1.962 81 0.007 132 36.080 682 2.018 92 0.050 76 6.412 33 1.766 53 0.006 42 32.472 64 1.936 83 0.026 92 3.833 64 0.677 94 0.023 36 16.452 72 1.355 78 0.018 85 2.683 54 0.474 52 0.016 362 11.516 912 Source: CGWB (2000). Note: Bihar includes Jharkhand, Madhya Pradesh includes Chhattisgarh and Uttar Pradesh includes Uttaranchal. Level of groundwater development (% ) 23.64 Weighted average delta (m) Utilizable irrigation potential for development (million ha) 4.48 19.19 8.30 41.45 83.88 18.10 1.33 31.26 15.28 16.49 30.39 Negligible Negligible 0.047–1.472 0.018 00 1.283 0.40–0.65 0.870 0.45–0.714 0.385–0.6 0.385 0.385–0.6 0.18–0.74 0.53–0.83 0.400 0.43–1.28 0.650 0.650 3.960 08 0.900 00 4.947 63 0.029 28 2.755 90 1.461 70 0.068 50 0.707 95 2.572 81 0.879 25 9.732 49 3.651 97 0.369 00 0.035 1 0.061 50 1.556 99 0.103 22 0.528 93 Negligible 8.42 93.85 50–63 — 0.34–0.44 0.518 0.457–0.6 — 4.202 58 2.917 15 1.777 83 0.878 748 0.037 54 4.441 13 1.488 29 0.005 780 24.578 78 60.44 33.43 37.67 24.18 — 31.92 0.37–0.93 0.630 0.20–0.50 0.33–0.75 — — 2.832 05 0.080 56 16.798 96 3.317 94 0.005 405 64.050 17 D. K. Singh & A. K. Singh S. No. Total replenishable groundwater resources (million ha m/year) Provision for domestic, industrial and other uses (million ha m/year) Groundwater Situation in India 569 Table 4. Average grain yields, in tonnes per unirrigated hectare and per irrigated hectare by irrigated source in four Indian states Yield (t/ha) State Downloaded by [Rajmata Vijayaraje Scindia Krishi Vishwa Vidyalaya] at 03:06 20 January 2015 Punjab Haryana Andhra Pradesh Tamil Nadu Years 1977–79 1963–65 1950–51 1978–79 1976–77 1977–79 1957–59 1977–79 1964–66 1956–58 Unirrigated Groundwater Canal Tank 1.08 0.75 0.37 0.38 5.46 3.06 1.75 5.74 3.24 1.18 0.94 2.36 — — 0.42 0.47 0.49 0.61 0.66 5.69 3.11 6.53 4.00 3.37 3.43 2.27 2.60 2.14 1.69 1.96 1.35 2.33 2.08 1.86 Source: Chambers (1988). income and opportunities, while the latter depends on the physical characteristics of the aquifer and sources of recharge. There is no clear-cut groundwater use policy in India to ensure both access and rechargeability. The long-term consequences of overpumping of groundwater are deeper installation of pumps and associated higher cost, which will make groundwater available only to those able to mobilize the high investment cost. The depth at which the groundwater is available is a crucial parameter: if it is deep its access is limited to rich farmers only. With deep tubewells, it becomes necessary for rich farmers to economize the cost of pumping by extending the command area as far as possible by providing water to poor farmers who do not have or cannot afford a tubewell, and intensifying cropping. In these circumstances, more farmers are served and management becomes a more complex process. The majority of Indian villagers are landless. Either the farmers or Panchyat owns every inch of the village land. Even among the landholders, the majority are small or marginal farmers. As such there is no ownership right over the groundwater aquifer. In many cases, it so happens that if a large farmer sinks a deep tubewell and pumps it, there will not be enough water in the shallow tubewell of the neighbouring farmer, who is in the zone of interference. Under such a condition, there should be a general consensus to protect the interest of the rural poor and ensure that they are also able to get access to groundwater, and to oversee that this resource is not exploited and used solely by those who have access to capital and land. Depletion of Groundwater Resources Groundwater development in different parts of the country has not been uniform. During the past decades intensive groundwater development in some parts of the country has resulted in overexploitation and depletion of groundwater resources. The number of groundwater withdrawal structures has increased rapidly. There were 10.50 million dug wells, 6.74 million shallow tubewells and 0.09 million public tubewells up to March 1997 (Table 5). The number of shallow tubewells roughly doubled every 3.7 years between 1951 and 1991 (Moench, 570 D. K. Singh & A. K. Singh Table 5. Development of groundwater withdrawal structures (thousands) in India Downloaded by [Rajmata Vijayaraje Scindia Krishi Vishwa Vidyalaya] at 03:06 20 January 2015 Year Dug wells Shallow tubewells Public tubewells 3 860 4 540 6 100 6 700 7 435 7 786 8 742 9 407 10 225 10 501 3 22 260 1 138 1 749 2 132 3 359 4 754 5 040 6 743 2.4 8.9 14.7 22.0 30.0 33.3 48.2 63.6 69.4 90.0 1950–51 1960–61 1968–69 1973–74 1977–78 1979–80 1984–85 1989–90 1993–94a 1996–97b Source: Saksena (2000). (2000). a CWC (2000). b Chaddha 2000). Some of the states/union territories facing a severe problem of water level decline are Tamil Nadu, Madhya Pradesh, Uttar Pradesh, Maharashtra, Rajasthan, Gujarat, Punjab, Haryana, Karnataka, National Capital Region of Delhi and Pondicherry. In the case of Tamil Nadu, it has been reported that in the last 40–50 years, the groundwater table has depleted by 10–50 m in some districts of the state (Saksena, 2000). In some districts of western Uttar Pradesh, the decline of the water level is as high as 0.66 m/year. According to Saksena (2000), at least 20% of the area in Uttar Pradesh located outside the canal commands has shown a decline in the water table of up to 7 m during the period 1972–85. This is mainly due to overexploitation of groundwater resources through tubewells. Similarly, in Madhya Pradesh, the long-term decline of the groundwater level has been reported to be as high as 13.05 m (Saksena, 2000). Based on the norms of the CGWB, about 3.53% and 2.53% of the 7063 blocks of the country have been classiŽed as overexploited and dark blocks, respectively (Table 6). Dark or critical blocks increased at continuous rate of 5.5% over the period 1984–85 to 1992–93. At this rate, it is estimated that roughly 36% of the blocks in the country would be either dark or critical by 2017–18 (Moench, 2000). This will lead to non-accessibility of water to the poor farmers due to the increase in cost of drilling of tubewells and lifting, particularly in groundwater-irrigated areas. Rise in Groundwater Level If overexploitation of groundwater has posed problems to managers in groundwater-irrigated areas, large areas in major canal commands suffer from waterlogging and associated salinity or alkalinity problems. Singh (1993) reported that in some irrigation commands the water table rise is as high as 1.00 m/year (Table 7). On the basis of the past rate of development, according to which 1 million–2 million ha/year are brought under irrigation in the country and the assumption that 3% of the area will eventually become waterlogged or saline, the rate of spread of waterlogging or salinization in irrigated areas in coming years may be around 30 000–60 000 ha/year (Singh, 1998). According to CWC Groundwater Situation in India 571 Table 6. Categorization of blocks/mandals/talukas/watersheds as overexploited and dark on an all-India basis Downloaded by [Rajmata Vijayaraje Scindia Krishi Vishwa Vidyalaya] at 03:06 20 January 2015 State number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 State Andhra Pradesh Arunachal Pradesh Assam Bihar Goa Gujarat Haryana Himachal Pradesh Jumma and Kashmir Karnataka Kerala Madhya Pradesh Maharashtra Manipur Meghalaya Mizoram Nagaland Orissa Punjab Rajasthan Sikkim Tamil Nadu Tripura Uttar Pradesh West Bengal Total states Number blocks/mandals/ of talukas/ districts watersheds 23 8 23 42 3 19 16 12 14 19 14 45 30 6 5 3 7 27 12 30 4 21 3 63 16 465 1104 48 134 585 12 184 108 69 123 175 154 459 1503 26 29 20 21 314 118 236 4 384 17 895 341 — Number of blocks (except Andhra Pradesh, Gujarat and Maharashtra) Number of mandals (Andhra Pradesh) Number of talukas (Gujarat) Number of Watershed (Maharashtra) Number of blocks/mandals/talukas/watersheds Overexploited Dark Number Percentage Number Percentage 6 — — — — 12 45 — — 6 — — — — — — — — 62 45 — 54 — 19 — 0.54 — — — — 6.52 41.67 — — 3.43 — — — — — — — — 52.54 18.07 — 14.06 — 2.12 — — 24 — — 1 — 14 6 — — 12 1 3 34 — — — — — 8 11 — 43 — 22 — — 4272 231 107 1104 184 1503 6 12 — 24 14 34 2.17 — — 0.17 — 7.61 5.56 — — 6.86 0.65 0.65 2.26 — — — — — 6.78 4.66 — 11.20 — 2.46 — — Source: CGWB (2000). Note: Andhra Pradesh: 1104 mandals/309 blocks; Gujarat: 184 talukas/218 blocks; Maharashtra: 503 watersheds/231 talukas/366 blocks. Bihar includes Jharkhand, Madhya Pradesh includes Chhattisgarh and Uttar Pradesh includes Uttaranchal. (2000) about 8.51 million ha, 5.50 million ha and 3.58 million ha in the country are suffering from the problems of waterlogging, salinity and alkalinity, respectively. Waterlogging and salinity pose a major challenge for the engineers and managers of the irrigation commands. This has also overshadowed the planned beneŽt from the irrigation projects. Groundwater Quality Beside overexploitation and water level decline, groundwater pollution is a major concern in several regions of India. To a certain extent, recharging of 572 D. K. Singh & A. K. Singh Table 7. Rising trend of water table in irrigation commands Downloaded by [Rajmata Vijayaraje Scindia Krishi Vishwa Vidyalaya] at 03:06 20 January 2015 Irrigation command Mahi Right-bank Canal Command, Gujarat Rajasthan Canal Command, Rajasthan Western Jamuna and Bhakra Canal Command, Haryan Sirhind Canal Command, Punjab Sharda Sahayak Canal Command, Uttar Pradesh Malprabha Canal Command, Karnataka Nagarjunsagar Irrigation Project, Andhra Pradesh Sriram Sagar Irrigation Project, Andhra Pradesh Rise of water table (m/year) 0.28 0.29–0.88 0.30–1.00 0.10–1.00 0.68 0.60–1.20 0.32 0.26 Source: Singh (1993). aquifers can compensate for the overdraft but groundwater pollution is an almost irreversible process and can cause reduction in water availability. Therefore, in order to assess the groundwater development potential, its quality in relation to various uses is as important as its quantity. Excessive pumping in coastal and semi-arid regions, dumping of industrial and domestic wastes, indiscriminate use of chemicals and fertilizers, leachates from compost pits, seepage from septic tanks and seepage of sewage are posing serious threats to groundwater quality. If this continues, besides causing health problems, groundwater pollution will reduce the water availability for irrigation, domestic and industrial uses. Incidence of groundwater pollution is highest in urban areas, where large volumes of waste water are discharged in relatively smaller areas. Increased use of chemical fertilizer coupled with improper water management practices has resulted in deterioration of groundwater quality in several parts of the country. The effect of agricultural chemicals on groundwater quality is greater in shallow, unconŽned aquifers. In India, the majority of the rural population obtain their domestic water supply from shallow private boreholes which suffer the impact of nitrate pollution to a much greater extent than the deeper, public tubewells used for urban water supply. Pollution from industrial units is another major concern. Efuents in most cases are discharged into pits, open ground or open unlined drains, resulting in contamination of groundwater. Fluoride has been identiŽed as endemic in thirteen states in India due to abundance in naturally occurring uoride-bearing minerals. These states are Andhra Pradesh, Gujarat, Haryana, Orissa, Punjab, Rajasthan, Tamil Nadu, Uttar Pradesh, Karnataka, Madhya Pradesh, Maharashtra, Bihar and Delhi. There are nearly half a million people in India suffering from ailments due to an excess of uoride in drinking water. In some villages of Rajasthan and Gujrat the level of uoride is as high as 11.00 mg/l. Arsenic in groundwater has been reported in shallow aquifers from eight districts of West Bengal. Groundwater pollution in the form of saltwater intrusion into the coastal and some inland aquifers is another major concern. Excessive pumping of coastal aquifers and those inland aquifers where fresh water is underlain by saline water causes salt water to move into fresh water and contaminate it. India has a 6100 km long coastline spread in the states of West Bengal, Gujarat, Orissa, Andhra Pradesh, Tamilnadu, Maharashtra, Kerala, Andman and Nicobar and Pondichery, etc. Saltwater intrusion is a major problem along the coastline in all Groundwater Situation in India 573 Table 8. Annual requirement of fresh water (BCM) Different uses of water Downloaded by [Rajmata Vijayaraje Scindia Krishi Vishwa Vidyalaya] at 03:06 20 January 2015 Irrigation Domestic Industry Thermal power Other uses Total 2000 2025 2050 541 42 8 2 41 634 910 73 22 15 72 1092 1072 102 63 130 80 1447 Source: CWC (2000). these states. A different type of saltwater intrusion in inland aquifers has been reported from south-west Punjab and parts of the Haryana, Rajasthan and Gujarat states of India, where excessive pumping has caused upconing of salt water and saline water discharge. Future Demands With increasing demand for water for irrigation, domestic and industrial uses, India is heading for a major water crisis in the future. Per capita water availability in the country, which was 5000 m3, has dropped to 2200 m3. Even at this stage, India with 16% of world population, 2.45% of the world’s land area and 4% of the world’s water resources already has a serious drinking water crisis. According to an estimate (CWC, 2000), the present annual demand of India is 634 billion cubic metres (BCM), which is expected to increase to 1092 BCM and 1447 BCM in 2025 and 2050, respectively (Table 8). With growing opposition to large reservoirs, pressure will be on the groundwater resource. At the present level of exploitation, groundwater reservoirs will dry up entirely by 2025 in as many as 15 states in India (Jha, 2001). At the present level of overexploitation, the groundwater reserve in Delhi may dry up by 2015 and it will take just 2600 additional tubewells running at an average of 10 hours/day to exhaust the entire reserve of underground water in Delhi (Jha, 2001). Many other states, like Punjab, Haryana, Bihar, Andhra Pradesh, Gujarat, Karnataka, Madhya Pradesh, Maharashtra and Orissa, are expected to suffer the same fate. Groundwater Management Options and Policy Implementation ScientiŽc understanding of the groundwater processes and effective planning and implementation of the desired options are key to sustainable management of groundwater resources to maintain a balance between groundwater development and groundwater protection. The rational management of the groundwater resource is difŽcult without a basic understanding of the distribution and yield of aquifers and their vulnerability to pollution and overdraft and some knowledge of the existing and potential threat to the resource. Inaccessibility of the sub-surface environment is a major problem in development of a database in the case of groundwater. Surveying, drilling, water sampling and water level monitoring, etc. are important actions in building a database and keeping track of long-term trends. According to Coughanowr (1994), three independent processes involved in groundwater management are: the collection and interpret- Downloaded by [Rajmata Vijayaraje Scindia Krishi Vishwa Vidyalaya] at 03:06 20 January 2015 574 D. K. Singh & A. K. Singh ation of hydrogeological and other pertinent information; the development of groundwater management plans which articulate priorities, goals and responsibilities; and the implementation of these plans through a series of legislative, institutional and regulatory actions. Groundwater development and management have posed serious problems in India. Realizing this, the government of India initiated a series of protective, corrective and legislative measures for sustainable management of the groundwater resource in the country. Several non-governmental organizations (NGOs) are also engaged in creating awareness of groundwater development and management amongst the people. Some important measures for groundwater development and management adopted in India are presented in the following sections. Assessment and Monitoring of the Groundwater Resource As discussed earlier, the methodology for the assessment of groundwater potential is not yet perfect. There is a need to incorporate some more parameters, like inow/outow, into the recharge estimation methodology. Lack of an information base on groundwater availability and withdrawal and inadequate monitoring on a regular basis are major problems in the assessment of groundwater potential. In recent years, the government of India has given a lot of emphasis to the monitoring of the groundwater resource in the country. Currently more than 15 500 network stations of the CGWB and more than 30 000 observation wells of the state groundwater organizations are in use for periodic monitoring of groundwater levels. In 1995, the government of India launched a World Bankaided National Hydrology Project to create a hydrological information system. Currently, it is being implemented in eight states of India. The project aims at improving the existing data collection network through the construction of observation wells, the setting up and upgrading of chemical laboratories, the establishment of national and state data banks and the integration and transmission of data. Under this project so far 2200 sites spread over the eight states have been identiŽed for the installation of piezometers. About 2134 piezometers had been installed up to January 2000. With the strengthening of manpower and infrastructure and greater understanding of processes, it is expected that assessment of groundwater potential will be more realistic in future. ArtiŽcial Recharge of Groundwater ArtiŽcial recharge of groundwater reservoirs has been recognized as one of the important strategies of groundwater management to counter overexploitation. ArtiŽcial groundwater recharge reduces or even reverses the declining levels of groundwater, protects fresh groundwater in coastal aquifers against saline water intrusion and stores surplus surface water, including monsoon run-off and waste water, for future use. ArtiŽcial groundwater recharge is accomplished mainly through rainwater harvesting, recharging the aquifer with imported water and vegetative treatments of the catchments. Recharging of aquifers with imported water is a costly affair. Vegetative treatment of watersheds helps in increasing the groundwater recharge. Since long-distance transport of water for recharge is difŽcult and expensive, emphasis is being given to in situ rainwater Downloaded by [Rajmata Vijayaraje Scindia Krishi Vishwa Vidyalaya] at 03:06 20 January 2015 Groundwater Situation in India 575 harvesting and recharge. In a country like India, this method is important because the major portion of the annual rainfall is received in some 100 hours of heavy downpour, providing very little time for the natural recharging of the aquifer (Keller et al., 2000), even though a large potential for groundwater recharge exists. According to Chaddha (2000), utilizable groundwater storage potential of the country is 160 BCM. Looking at the technical and economical feasibility, the Ministry of Water Resources has initiated a programme for rainwater harvesting and recharge for which 450 million Indian rupees were earmarked in the Ninth Plan. The ministry has already sanctioned 250 million Indian rupees for the CGWB for this programme, which involves states and water agencies in rural areas. The CGWB has started artiŽcial recharge studies in the dark and overexploited blocks of Punjab, Haryana, Maharashtra, Uttar Pradesh and Jammu and Kashmir. In south India, where the three states of Karnataka, Andhra Pradesh and Tamil Nadu have over 0.2 million tanks, a strategy has been widely advocated to convert these into recharge tanks by Žlling them with canal water (Kulandaivelu & Jayachandran, 1990; Reddy et al., 1990). In Tamil Nadu alone, about 7500 percolation ponds have been constructed (Public Works Department, 1994). At many sites, artiŽcial recharge projects have started giving the desired results. In Kurnool irrigation system of Andhra Pradesh, nine percolation ponds and seven check dams constructed in an experimental recharge project increased the duration of spring ow from 75 to 207 days; and the post-monsoon water table rose by 2.5 m. In the western region of India, people supported by local NGOs have created a massive well recharge movement based on the principle of ‘water on your roof stays on your roof; water on your Želd stays on your Želd, and water in your village stays in your village’. Villagers have modiŽed some 300 000 wells and open bores to divert rainwater to them. They have also constructed thousands of ponds, check dams and other rainwater harvesting and recharging structures on self-help principles (Shah et al., 2000). Some old and traditional water harvesting structures are becoming important in India. Khadins of Rajasthan and tankas of western Gujarat are playing a major role in groundwater recharge. In the city of Rajkot in the Saurashtra region of India, 1500 new houses and apartments built during 1997 incorporated design changes for rainwater harvesting and storage found in old houses in the region but forgotten in recent decades (Shah, 2000). Roof water harvesting for groundwater recharge has given new hopes to overcome the groundwater problems, particularly in major Indian cities. The Central Ground Water Board of India (CGWB) is advising the states and municipal bodies to undertake rooftop rainwater harvesting and its recharge to groundwater by making it mandatory for every dwelling unit by amending city bye-laws. According to an estimate of the CGWB (2000), about 6 MCM of water could be made available for groundwater recharge through roofwater harvesting in the National Capital Territory of Delhi. In Delhi, the rooftop area has been worked out to be about 138 km2, which would yield about 67.9 MCM water assuming 600 mm rainfall during the monsoon. If only 10% of the rooftop area is considered for rainwater harvesting (mainly institutional areas) in the Žrst phase, the CGWB has estimated that about 6 MCM water could be made available for recharge (CGWB, 2000). Looking at the prospect of rainwater harvesting, Delhi Development Authority under the Delhi government has proposed amendments to building byelaws making it mandatory for city buildings to have inbuilt provisions for Downloaded by [Rajmata Vijayaraje Scindia Krishi Vishwa Vidyalaya] at 03:06 20 January 2015 576 D. K. Singh & A. K. Singh rainwater harvesting and recharge. Similarly, many other cities are joining this move. Recently, Coimbatore has joined the group of cities in the country which has made rainwater harvesting mandatory. Many group housing societies in the southern city of Hyderabad have already incorporated roofwater harvesting provisions. However, while implementing the groundwater recharge projects, particularly in urban areas, one has to be careful in the planning and design of such projects. It is possible that several types of pollutants, including bacteria and toxic elements, may enter into the groundwater aquifer along with the recharged water. Much more research is needed in the Želd of artiŽcial recharge for its large-scale adoption. The CGWB has undertaken several studies throughout the country to develop location-speciŽc design procedures for the artiŽcial recharge of groundwater. Groundwater Legislation As per the constitution of India, groundwater is considered as a state subject and only state governments are empowered to enact the law to control and regulate groundwater exploitation. Realizing the problem of overdraft and mining of aquifers and groundwater pollution, a model bill for groundwater regulation was circulated by the CGWB in the early 1970s. The bill envisaged the setting up of a groundwater authority and the introduction of a system of licensing for the purpose of extraction and use of groundwater in notiŽed areas, the registration of existing users in such notiŽed areas and the imposition of penalties for contravening certain provisions. However, not much has been done by the states. A lack of political will, awareness amongst the farmers, a strong farmers’ lobby in some states, appeasement policies of the subsequent governments and the non-availability of any other source of water supply in some areas have been the main hurdles in implementing the Groundwater Control and Regulation Act. However, modiŽed versions of this act have been adopted by some states. Gujarat was the Žrst state to implement the bill. More recently, Tamil Nadu has introduced a bill known as the Tamil Nadu Groundwater (Development and Management) Act 2000. Under this, it has been proposed to constitute a groundwater authority as per the provision in the Groundwater (Control and Regulation) Bill 1970. Even if the regulations are adopted by other states, their implementation would be very difŽcult and inequitable in practice (Moench, 2000). Complexities such as the existence of millions of wells across the country, prevailing conditions in the rural areas, unhindered public access to groundwater and the interlinked and often poorly understood character of the system dependent on groundwater will always pose a challenge to groundwater managers. To control water pollution, the Water (Prevention and Control) Act was passed by the parliament in 1974 and by 1990 it was adopted by all the states. Under this act, a Central Board of Prevention and Control of Water Pollution was constituted. The act also provides for constitution of such boards in all states. The functions of the central board are generally advisory while the states have the regulatory functions of inspections of efuents and plants and the power to impose penalties as per the provision in the act. Even this has not made much of an impact in reducing groundwater pollution. Thereafter, the Environmental Protection Act was passed in 1986. The Government of India Downloaded by [Rajmata Vijayaraje Scindia Krishi Vishwa Vidyalaya] at 03:06 20 January 2015 Groundwater Situation in India 577 declared the National Water Policy in 1987, which stated that water is a prime natural resource, a basic human need and a precious national asset. The policy called for control over the exploitation of groundwater through regulation and an integrated and co-ordinated development of surface water and groundwater. Even after all these actions by the state and central governments, the problems related to groundwater development and management have not changed much. From the above discussion it can be said that acts and regulation alone cannot solve the problem of groundwater management and development until and unless they are implemented in the right perspective and observed by the users. Strong political and administrative will is needed for this. There is an urgent need to educate the people about the importance of groundwater and its management, as their participation is critical for its success. Management of Groundwater in Canal Commands through Conjunctive Use and Sub-surface Drainage As discussed earlier, excessive application of surface irrigation water in combination with poor sub-surface drainage has created waterlogging and salinity problems in certain canal commands. Conjunctive use of surface water and groundwater and sub-surface drainage are important programmes for the efŽcient utilization and management of the groundwater resource. If planned and designed properly, conjunctive use can enhance the availability of water supplies, ensure advance irrigation in season prior to the availability of surface water and provide life-saving irrigation when surface water is not available. Conjunctive use of groundwater and surface water in areas with saline water needs careful planning so that saltwater upconing can be prevented. Planning of a conjunctive use project requires proper understanding of the nature and extent of groundwater and estimation of the amount of water to be pumped from an area through groundwater balance studies and economic analysis. The status of conjunctive use in canal commands (Saksena, 2000) in various states is presented in Table 9. The Indian scenario of conjunctive use programmes suggests that what is being practised in the country at the moment does not really envisage the optimal use of both groundwater and surface water resources. Most of the irrigation projects have been designed keeping in view the surface water inputs, and utilization of groundwater is being thought of only after problems of waterlogging and salinization have occurred in canal commands. The National Water Policy directs that both surface water and groundwater should be viewed as an integrated resource and should be developed conjunctively in a co-ordinated manner and that their use should be envisaged right from the project planning stage. At the same time, there is a need to undertake systematic studies for effective planning of conjunctive use. The CGWB has taken up projects on conjunctive use in almost all the major command areas. The projects have given satisfactory results so far. Studies and pilot projects on sub-surface drainage undertaken in some canal commands have proved that sub-surface drainage can be a viable management option for controlling the rising water table. Earlier sub-surface drainage was not given much importance in the country. Though the worldwide acceptability of sub-surface drainage was established long ago, in India it took decades to establish it as a technology to control the rising water table. Even after recogniz- 578 D. K. Singh & A. K. Singh Table 9. Supplemental irrigation by groundwater in surface water irrigation commands (area in 1000 ha) Downloaded by [Rajmata Vijayaraje Scindia Krishi Vishwa Vidyalaya] at 03:06 20 January 2015 State number 1 2 3 4 5 6 7 8 9 10 State Andhra Pradesh Gujrat Haryana Karnataka Madhya Pradesh Maharashtra Punjab Tamil Nadu Uttar Pradesh West Bengal Utilized potential of surface water projects Area under supplemented irrigation by groundwater 3094 873 1785 1188 1403 935 2498 1245 5703 1524 12 33 400 42 120 365 1056 250 986 145 Percentage 0.4 4.1 22.4 3.5 8.6 39.0 42.3 20.0 17.3 9.5 Source: Saksena (2000). ing it as a water table control measure, the installation of sub-surface drainage is not possible in many canal commands due to lack of funds. Haryana Operational Pilot Project for the reclamation of waterlogged and saline land was formulated in 1987 with the help of the Netherlands government. The project started in 1994 with a budget allocation of 230 million rupees. The outcomes of the project are encouraging and it has now been decided to implement a sub-surface drainage scheme in Haryana at a rate of 2500 ha/year. Rajasthan Agricultural Drainage Project was started in the Chambal Command with the help of the Canadian government (Canada International Development Agency) in 1991, and 25 000 ha area has been put under sub-surface drainage for water table control. Several studies conducted by the Central Soil Salinity Research Institute, Karnal, and the all-India Coordinated Research Project on Agricultural Drainage, Water Technology Centre, Indian Agricultural Research Institute, New Delhi, have also proved that sub-surface drainage can be a viable alternative for water table control. It is argued that sub-surface drainage should become an integral part of irrigation project planning from the very beginning, i.e. while planning for any canal command project in the country, sub-surface drainage should be included as a major component so that the implementation is done simultaneously and the situation of waterlogging does not arise. Demand Regulation By adopting suitable cropping patterns in critical and sub-critical areas, the demand for water could be regulated, providing more opportunity for groundwater recharge so that the water table decline is reversed and brought to the earlier level of the groundwater reserve. Precision agriculture and water-saving crop production technologies should be promoted in such areas. The Agriculture Department can identify suitable cropping patterns for hot-spot areas. Groundwater Situation in India 579 Downloaded by [Rajmata Vijayaraje Scindia Krishi Vishwa Vidyalaya] at 03:06 20 January 2015 Control of Groundwater Pollution Non-availability of comprehensive data sets in India is a major problem in the detection and prevention of groundwater pollution. The Central Pollution Control Board and the CGWB are engaged in monitoring water quality in the country but still the extent and distribution of pollutants across the country have not been quantiŽed. In most cases, groundwater monitoring is done in the areas from where the water quality problem has already been reported. For example, an arsenic problem from West Bengal was recognized only after the large-scale reporting of arsenic poisoning. Therefore, it is essential to establish groundwater monitoring stations throughout the country. ‘Prevention is better than cure’ is the best strategy. To control groundwater pollution, industrial and municipal wastes should be properly treated before they are discharged into surface water or groundwater. Intrusion of sea water can be arrested by maintaining the potentiometric surface of the freshwater aquifer well above sea level, which can be accomplished by reducing groundwater extraction, rescheduling pumping duration, dispersal of extraction points or artiŽcial recharge. SpeciŽc land use regulation (e.g. zoning) which includes the prohibition or restriction of cultivation and regulations pertaining to the use and application of speciŽc substances may be useful in controlling groundwater pollution. Conclusion The development and management of groundwater are complex issues for which a realistic assessment of the utilizable groundwater potential available for various uses is very important. For optimal utilization of groundwater, the difference between rechargeable groundwater potential and potential available for use has to be understood properly. If depletion of the groundwater table in some parts of India is a matter of great concern, rising water tables and salinity in many canal commands have overshadowed the expected beneŽts from the irrigation projects. It is anticipated that if these two problems are not attended to, a stage may be reached when all regions in the country could be adversely affected by one of these maladies. Deteriorating groundwater quality is another major concern, which will reduce freshwater availability in future. Increased incidences of uoride and arsenic contamination in several states of India are posing a major challenge. Annual water demand is going to increase from the present level of 634 BCM to 1092 BCM in 2025. With growing opposition to large dams, pressure on groundwater utilization is bound to increase. If attention to groundwater management is not given now, India will be facing a major water crisis in the coming years. Realizing the importance of groundwater development and management, the Government of India has started several corrective and protective measures besides introducing the bill for groundwater regulation way back in 1970. ArtiŽcial groundwater recharge, conjunctive use in canal commands and the establishment of groundwater monitoring stations, etc. are some important schemes launched by the government. However, to make these schemes resultoriented, a strong political, administrative and technical will is needed. There is a need to create awareness among the users so that groundwater development and management can be a people’s programme. 580 D. K. Singh & A. K. Singh Downloaded by [Rajmata Vijayaraje Scindia Krishi Vishwa Vidyalaya] at 03:06 20 January 2015 References CGWB (1995) Groundwater Resource of India (Faridabad, CGWB). CGWB (2000) Annual Report (New Delhi, CGWB). Chaddha, D. K. (2000) Groundwater recharge: option for groundwater management, Journal of Transport and Infrastructure, 7(4), pp. 44–57. Chambers, R. (1998). Managing Canal Irrigation (Oxford, Oxford IBH Publishing Company). Coughanowr, C. (1994). Groundwater, IHP Humid Tropics Programme Series No. 8 (Paris, United Nations Educational, ScientiŽc and Cultural Organization). CWC (2000) Water and Related Statistics (New Delhi, CWC). Dhawan, B. D. (1989) Studies in Irrigation and Water Management (New Delhi, Commonwealth Publication). GEC (1984) Groundwater Estimation Methodology (New Delhi, Ministry of Irrigation). GEC (1997) Groundwater Estimation Methodology (New Delhi, CGWB). Jha, S. (2001) Rainwater Harvesting in India, Press Information Bureau, Government of India, New Delhi, India (http://pib.nic.in/feature/feyr2001/fsep2001/f060920011.html ) (accessed 23 December). Keller, A., Sakthivadivel, R. & Seckler, D. (2000) Water Scarcity and the Role of Storage in Development, Research Report No. 39, International Water Management Institute, Colombo, Sri Lanka. Kulandaivelu, R. & Jayachandran, K. (1990). Groundwater utilizatio n and recharge through percolation ponds—a case study, in: Proceedings, Workshop on Percolation Ponds (Madras, Centre of Water Resources). Moench, M. (2000) India’s Groundwater Challenges (http://www.india-seminar.com/2000/480% 20moench.html) (accessed 26 December). National Commission on Agriculture (1976) Resource Development, Part V, Report of the National Commission on Agriculture (New Delhi, Government of India). Public Works Department (1994) Groundwater Resources of Tamilnadu. Present Status of Development (Madras, Government of Tamilnadu). Reddy, N., Rao, K. V. S. & Prakasam, P. (1990) Impact of percolation ponds on groundwater region in hard rock areas of Andhra Pradesh. in: Proceedings, Workshop on Percolation Ponds (Madras, Centre of Water Resources). Saksena, R. S. (2000) Conjunctive Use of Surface and Groundwater (Roorkee, Indian National Committee on Hydrology, National Institute of Hydrology). Seckler, D., Molden, D. & Baker, R. (1998). Water Scarcity in the 21st Century, IWMI Water Brief 2, International Water Management Institute, Colombo, Sri Lanka. Shah, T., Molden, D., Sakthivadivel, R. & Seckler, D. (2000) The Global Groundwater Situation: Overview of Opportunity and Challenges (Colombo, International Water Management Institute). Singh, D. K. (2001) Water Resources Development and Management Strategies for Rajgarh Block of Mirzapur District (New Delhi, Water Technology Centre, Indian Agricultural Research Institute). Singh, O. P. (1993) Drainage problems and design criteria for land drainage systems, in: Proceedings, National Workshop on Sustainable Irrigation in Saline Environment, February 17–19, CSSRI (Karnal, Central Soil Salinity Research Institute). Singh, O. P. (1998) Salinity and waterlogging problems in irrigation commands, in: O. P. Singh & P. S. Minhas (Eds) Agricultural Salinity Management in India (Karnal, Central Soil Salinity Research Institute).