State Wise Water Resources Situation in India
Sustainable development and efficient management of water is an increasingly complex challenge in India. Increasing population, growing urbanization, and rapid industrialization, combined with the need for raising agricultural production, generates competing claims for water. There is a growing perception of a sense of an impending water crisis in the country. India with 2.4% of the world’s total area has 16% of the world’s population; but has only 4% of the total available fresh water. This clearly indicates the need for water resource development, conservation, and optimum use. The first step towards formulation of a policy that will deal with these aspects is to have a clear perspective of the water resource situation in the country. Hence, what follows is a brief state-wise review of water availability and demand in India, along with various policy initiatives undertaken by the respective state governments to tackle the water problem.
Irrigation schemes are generally classified into three classes:
- Major and medium schemes – surface schemes irrigating over 2,000 hectares;
- Minor surface schemes – diversion or reservoir schemes irrigating less than 2,000 hectares;
- Life schemes – tube well or small river lift irrigation schemes.
Till March 2008, a potential of 28.63 lakh ha has been created through 15 major and 78 medium schemes and 10 major and 3 medium ongoing schemes. There are also about 40,000 minor surface irrigation works, of which 747 are formally recognized as schemes and the remainders are ahars (small tanks). There are 2,074 river lift-irrigation schemes, 5,791 deep tube wells, about 600,000 shallow tube wells and about 400,000 dug wells used for irrigation. Irrigation provided during Kharif (2007) in bihar stood at 1222.00 th ha, while that during Rabi (2007-08) stood at 231.00 th ha. Canal irrigated area has declined by 2 lakh hectares during last 6 years. Moreover, canal water is not available to the tail end of command area. An attempt has been made to organize Water Users Association (WUAs) to improve efficiency of canal irrigation system, but majority of them are not functioning properly. About 97 per cent of tube wells are diesel operated and farmers are making irrigation expenses at the rate of Rs 1500 to 2500 per hectare in normal year making crop production uneconomical. In Bihar the majority of farmers provide survival irrigation to crops, resulting in low level of crop productivity. In addition to this,Bihar had a variety of traditional irrigation infrastructure such as ahar, pyne and ponds for water harvesting but now almost all of them have depleted.
Annual rainfall is the main source of water in the state. The average annual yield from rainfall is 230.76 Billion cubic meters (BCM). As per 2001 assessments, the average annual availability of surface water resources is about 120.40 BCM & annual replenishable ground water resource is about 21.01 BCM. Thus, the total water resources of the state stand at about 141.41 BCM.
Orissa is in a comfortable position with regard to rich water resources, with a total ultimate irrigation potential of 8.8 million hectares. In per capita terms, it is second only to Madhya Pradesh (undivided), while Madhya Pradesh has 0.30 hectare per capita ultimate irrigation potential, it is 0.24 for Orissa. The net irrigation potential created by the end of 2002-03 from all sources was 26.03 lakh hectares, ie, 44.12 per cent of the total irrigable area of the State. Out of this about 46.91 per cent of the area, ie, 12.21 lakh hectare of land is irrigated through major and medium irrigation projects. About 4.65 lakh hectare of land received irrigation from minor (flow), 3.47 lakh hectares from minor (lift) and 5.70 lakh hectares from other sources such as private tanks, ponds, dug-wells, water harvesting structures etc.
Sikkim is a mountainous State with steep rugged hills, narrow valleys and rocky terrain. The topographical condition does not favor major or medium irrigation schemes and as such all irrigation schemes in the State fall under surface flow Minor Irrigation Schemes category. The rate of rainfall in Sikkim being very high, the irrigation channels suffer extensive damages during the rainy season due to which an appreciable chunk of plan fund gets diverted for restorative works and as such the creation of additional potential is minimal.
In the South district of Sikkim, cultivation is done both by surface and by rain water conservation. The sources of surface irrigation are Jhora (in Hilly area), river lift irrigation, and storage tank. Irrigation depends mainly on springs and Kholas. Majority of the springs dry up in the absence of sufficient monsoon. The major cropping pattern of the district is maize, rice, millet etc., in Khariff period, and wheat, barley, mustard etc., in Rabi period. The district topography is rugged in nature and steep slope, and no such water supply system for irrigation except monsoon rainfall. The farmers are forced to cultivate fruits, vegetables, cardamom, potato, ginger etc., which are favorable for the topography and climate of the district.
In the East district of Sikkim, Ground water occurs in largely disconnected localized bodies under favorable geological structures, such as joints, fractured zones in various litho logical units, weathered zones in the phyllite, schist, gneisses and quartzite. The ground water is available from source perennial springs from nallas present in all geological formations in the area. Due to higher relief and steep gradient of the area, the subsurface flow of ground water is intercepted which manifest as seepages and springs. The area is characterized by high rainfall, which is primary source of ground water. The springs are not deep seated. Direct infiltration and rainfall through joints, fracture, weathered zones of the rocks and through soil covers is the principal mode of recharge of the springs. Due to steep slope most of the precipitation in the area is lost as surface run off through streams, kholas and intermittent springs which are tapped through pipe lines and distributed by gravity method for domestic use. Precipitation is the main source of recharge of ground water but glacier melt water also recharges the ground water considerably.
- West Bengal
Teesta Barrage Project and Subarnarekha Barrage Project are currently in operation in the State. During the 10th plan 51.475 thousand hectares of irrigation potential had been created. The target for the 11th plan is to create 210.9 thousand hectares of irrigation potential. A cumulative irrigation to the tune of 1,38,520 hectares had been created from the Teesta Barrage project upto 2006-07 against the ultimate potential of 5,27,000 hectares. Subamarekha Barrage Project envisages irrigating 99248 hectares in Kharif and 30,766 hectares in Rabi seasons in the districts of Purba and Paschim Medinipur. Out of 32 medium irrigation schemes in the district of Purulia, 25 irrigation schemes have already been completed. The ultimate minor irrigation potential in the State has been estimated at 44.34 lakh hectares, out of which 31.34 lakh hectares are from ground water resources and 13.00 lakh hectares are from surface water resources. Up to 2006-07, 38.64 lakh hectares minor irrigation potential was created, out of which 81.96 per cent could be utilized during the year, amounting to 31.67 lakh hectares. The level of groundwater development in the state varies from as high as 84.6% in Nadia district, to as low as 5% in Jalpaiguri district, the average for the state being 41.3%.
As per groundwater estimation carried out jointly by the State Water Investigation Directorate (SWID) and the Central Groundwater Board following the GEC 97 methodology, of the 269 blocks in the state, as many as 231 blocks (or 86% of the blocks) were declared ‘safe’, while 37 blocks were declared ‘semicritical’ and only 1 block was put in the ‘critical’ groundwater category. Contrast this to recent statistics from the state of Punjab: of the 137 blocks inPunjab, 103 blocks (or 75%) are overexploited; five blocks are in ‘critical’ stage, four blocks are in ‘semicritical’ stage and only 25 blocks are in ‘safe’ category. Or the state of Gujarat: 45% of 184 blocks were in the category of ‘overexploited’, ‘dark’ and ‘grey’ in the year 1997, a number that has almost certainly gone up by now.
In the past decades, Haryana witnessed an impressive increase of crop yields. For instance average wheat grain yields in India rose from 1350 kg/ha in 1975 to 2450 kg/ha in 1998. Haryana participated in the Green Revolution, and current wheat grain yields in irrigated farmer fields stand at around 3900 kg/ha. In an extensive farming system analysis and planning study for sustainable food security in Haryana, it was found that the availability of water is a major constraint to further food production increase in Haryana. In the central and north-western region of Haryana, where the groundwater is brackish and no drainage outlets are available, canal irrigation has led to problems of rise in water table, water logging and flooding, and secondary salinization. In the eastern region and other areas with fresh groundwater, the water table is continuously declining. There are three canal commands. Yamuna command, including Gurgaon and Agra Canal Systems with CCA of 0.288 and 0.158 Million Acres, is the oldest system having CCA of 2.910 Million Acres with Average Irrigated Area of 2.171 Million Acres. Bhakra canal command came into existence in 1954 having CCA of 3.565 Million Acres and Average Irrigated Area of 3.029 Million Acres. Lift irrigation system was the pioneer work, an era of providing irrigation water to higher areas having CCA of 1.265 Million Acres and Average Irrigated Area of 0.167 Million Acres. Total CCA of the state stands at 7.740 Million Acres and Total Average Irrigated Area at 5.347 Million Acres per year (1999-2004). Of the total 104 blocks, 55 blocks are over exploited, 11 others are critical and 5 are in a semi critical stage. 48% of deep groundwater is saline, while 41% of shallow water is marginally saline. 35% of deep ground water and 55% of shallow ground water is fresh water. Before canal irrigation was introduced in SIC during the sixties, the crops were mainly grown with rain water and conserved soil moisture. Gram (chickpea) in the rabi season and Bajra (pearl millet) in the kharif season used to be the major crops grown. Due to the development of the canal irrigation system and increased groundwater exploitation during the last thirty years, there is a continuous shift in the cropping pattern towards more water demanding crops. During the period from 1975-76 to 2000-01, the area under rice increased by more than 200%, wheat by about 190% and cotton by 170%. On the other hand the area under pearl millet and chickpea decreased by about 95%. At present, wheat in the rabi season and cotton and rice in the kharif season are the main crops. Other important crops are oil seeds, gram (chickpea) and fodder. Cotton-wheat and rice-wheat are the most dominant crop rotations.
- n Himachal Pradesh
Irrigation and Public Health Department (IPH) has divided the State of Himachal Pradesh in to four zones viz. North (Dharamshala), Central (Mandi), South (Shimla) and Shah Nehar Project (Shahnehar). Till the end of March 2003, around 1.99 lakh ha of land had irrigation facilities. Out of this, about 46% area was covered by community system. Under Major Irrigation Sector, there’s only one sanctioned on-going project of Shahnehar. Under Medium Irrigation Sector, Sidhatha Project in Dlstt. Kangra and Anandpur Hydel Project in Distt. Bilaspur are in progress. Minor Irrigation schemes under NABARD assistance and AIBP assistance are in progress apart from some schemes under state sector.
- n Punjab
Punjab has a very well developed and interlinked river system and widespread 14500 kms long Canal Systems. Total cultivable command area in Punjab is 42.90 lakh hectares out of which 30.88 lakh hectares have been brought under command of canals networks. The state experienced a phenomenal increase in agricultural production during the last three decades, mainly due to extensive adoption of rice-wheat cropping system with assured irrigation facilities and has helped India in achieving self-sufficiency in food. Punjab contributes 65 per cent of wheat and 42 per cent of rice to the central pool. The cropping intensity has increased from 133 per cent in 1971 to 186 per cent in 2005 mainly due to expansion of irrigation facilities and rapid mechanism of various agricultural operations. The net area under irrigation in Punjab is 95 per cent of the total cropped area. The dominance of rice-wheat system has caused reduction in area under low water requiring crops, which led to over exploitation of groundwater resource, as the surface water is not adequate to meet the irrigation needs of the state. The number of tube wells has increased from 0.19 million in 1971 to 1.17 million in 2005. The average annual rainfall is 580 mm and is ill distributed in time and space. The total water supply of 3.13 m ha m falls short by 1.27 m ha m of the total water demand of 4.40 m ha m.
Punjab could be divided into three zones viz. north-eastern, central and south-west part with reference to water management issues. The north-eastern part comprising 19 per cent of geographical area has the problem of soil erosion, flash floods and deep water table with erratic distribution of rainfall. Some of the water conservation measures like water harvesting structures (excavated farm ponds and small earthen dams), vegetative measures, land leveling, terracing, contour cultivation, mulching are being adopted in this region. The rainfall varies from 800 mm to 1200 mm and 80 per cent is runoff-producing rainfall. Quality of ground water in northeastern undulating region is good with low salinity and low alkalinity hazards for irrigation use. During rabi season at the time of sowing there is very less rainfall and the probability of occurrence of drought is also very high. So, the harvested water is utilized at that time.
The central part of the state comprising 47 per cent of state geographical area faces the problem of reduction in ground water at the rate of 0.5 m per year since last two decades. It is mainly due to change in cropping pattern and over-exploitation of groundwater to meet the irrigation needs of crops. The main source of irrigation in this part is the groundwater. In this plain region, the water quality is good except few pockets adjacent to south-west part, where the groundwater has high residual sodium carbonate.
The southwest part of Punjab comprising 34 per cent of area faces severe groundwater quality problems that prevent its withdrawal. In this region, the poor quality of groundwater is due to salinity, alkalinity or both. Presence of salt impregnated strata below these soils is responsible for the poor quality of underground water in these areas. Conjunctive use of good and poor quality waters along with use of amendments like gypsum and organic manures are encouraged for sustainable crop productivity.
- n Rajasthan
- The State of Rajasthan is one of the driest state of the country and the total surface water resources in the State is only about 1% of the total surface water resources of the country The rivers of the state are rain fed and identified by 14 major basins divided into 59 sub-basins. The surface water resources in the state are mainly confined to south and southeastern part of the State. There is a large area in Western part of the State, which does not have any defined drainage basin. Thus the water resources in the state are not only scarce but have highly uneven distribution both in time and space. The situation of ground water exploitation is also not satisfactory as in areas where surface irrigation is provided there is a tendency of not using ground water for agriculture which creates problem of water table rise and even water logging. On the contrary, in large areas of the State ground water is being over exploited and the water table in some areas is going down at the rate of 3 meter per year. Rainfall in the state varies from a high of 900 mm in the south east to a low of 190 mm in the western districts. The rainfall is further characterized by frequent dry spells and uneven distribution, which seriously affect the crop and livestock production. In the relatively high rainfall areas, (such as eastern districts of Jhalawar, Banswara, Kota, Baran, and parts of Chittorgarh and also an area covered by Gang, Bhakra and IGNP canal system, Chittorgarh) expansion of ground and surface water irrigation has helped farmers in making the transition to high input based commercially oriented farming. In contrast, change has been slow in the low rainfall, arid and semi-arid non-irrigated areas, where productivity has remained low on account of uncertain provision of water, poor levels of technology adoption and a steadily weakening natural resource base.
- Despite the gains registered in terms of gross irrigated area (with an increase of 173 percentage between 1958-59 and 1996-97), and area under canal irrigation (with an increase of nearly two-fold between 1970-71 and 1996-97), in 1995-96 only 32.3 percent of the cultivated area was under irrigation. Further, nearly 70 percent of cropped area was still heavily dependent on rainfall. The dominant source of irrigation continues to be open dug wells that, together with tube wells, contribute nearly 56 percent of the irrigation potential in the state. The total utilizable groundwater for irrigation in Rajasthan is estimated to be 11,028 mcm, of which about 6,494 mcm (58.88 percent) is being exploited. In regions where agro-climatic conditions favor intensive commercial cultivation, private investments in development and extraction of ground resources have been high. Dug and tube wells have been sunk without reference to groundwater potential and recharge requirements, leading to rapid depletion and lowering of the water table. The State has been divided into 594 groundwater potential zones. Out of these, 322 zones fall in the ‘White’ category where ground water development is less than 65 percent, 71 zones fall in the ‘Grey’ category having 65 percent to 85 percent stage of development. The remaining 201 zones have been categorized as ‘Dark’, where the stage of ground water development is more than 85 percent. Out of these, 173 zones are over-exploited, having a stage of development that is more than 100 percent. There are significant differences and variations in the irrigation endowment of regions and districts. Nearly 21 percent of the State’s irrigation potential is, in fact, concentrated in two districts, namely Ganganagar (where 73 percent of the cropped area is under irrigation) and Hanumangarh (where 37 percent of the gross cropped area is under irrigation). At the other end of the spectrum there are desert districts (viz. Barmer, Jaisalmer, Churu, and Jodhpur) where less than 10 percent of the cropped area is under irrigation. Bikaner is the only desert district which, due to the Indira Gandhi canal, has more than 10 percent of its cropped area (14 percent) under irrigation. Differences in irrigation endowment have a strong impact on agriculture production and technology. Irrigated areas have intensive cropping systems involving two to three crop cycles. Farmers give preference to the production of high input based cash crops such as cotton, chilies, coriander, oilseeds, and cumin, and benefit from the agriculture services and markets that develop in the region (Ganganagar, Kota, Bharatpur and Jhalawar).
- Uttar Pradesh
Average rainfall in the state ranges from 100-200 cm in the east to 60-100 cm in the west. The Central Plain Zone comprises 13 districts (Farrukhabad, Fatehpur, Hardoi, Kanpur Dehat, Kanpur Nagar, Lakhimpur-Kheri, Lucknow, Kannauj, Sitapur, Rae Bareli, Pratapgarh, Allahabad and Etawah) and falls in between these two regions, where more than two-third of area is irrigated by shallow tube-well (groundwater). About 90 percent of the rainfall occurs during the southwest monsoon, between July and September. Canal and tube-wells are the main source of irrigation in Uttar Pradesh due to technological advancement and more reliability of groundwater (tube-well) irrigation. In Uttar Pradesh, share of canal irrigation has declined from 35.42 per cent during 1965-75 to 25.18 per cent during the period 1995-2003 while that of tube-well has increased significantly from 30.37 to 66.94 per cent. This may be mainly due to private ownership of tube-well, which makes it independent of Government’s regulation and control. Furthermore, canal being poorly managed, the delivery of irrigation water to the farmers are not in sufficient amount as well as on time, when it is needed. According to Irrigation department of Uttar Pradesh state, total replenishable ground water resource of the state is 84 BCM, out of which 72 BCM (85.7%) is exploitable for irrigation purposes. Out of the total replenishable resource, present total extraction is about 40.95 BCM and the net exploitation is 27 BCM which is 65.9% of total extraction. Thus, the ground water resource available for future exploitation is about 43.95 BCM. However, this resource is unevenly distributed in space. Out of 819 blocks in Uttar Pradesh/ Uttaranchal, there are 85 “Dark” block, 214 “Grey” blocks in the state, of which 15 dark & 38 grey blocks fall in Central Plain Zone (CPZ). Furthermore, out of 13 districts in CPZ, in 9 districts (Farrukhabad, Fatehpur, Hardoi, Kanpur Dehat, Kanpur Nagar, Lucknow, Rae Bareli, Allahabad and Etawah), groundwater level has declined by more than 4 meters during 1981-2000 @>20 cm/year. Seriousness of the issue of falling groundwater level in the region can be evidenced from the panic among the public due to several incidents of 4-8’’ wide land cracks in many districts of CPZ (Allahabad, Etawah, Kanpur, Lucknow) alongwith in Bundelkhand region on June 16-18, 2008. According to Geological Survey of India (GSI), exploitation of ground water was the main reason behind these cracks as the region had deficient rainfall during the past 4-5 years. Excessive withdrawal of groundwater created tension in the aquifer and due to sudden recharge of groundwater following heavy rainfall over a very short duration, these cracks have developed.
- Andhra Pradesh
Andhra Pradesh is endowed with very rich water resources and has three large rivers Krishna,Godavari and Pennar, as well as Nagavalli and Vamsadhara along with several minor rivers. The state is divided into three major agro-climatic zones – the Telengana region, the Rayalseema region and the coastal region along the Bay of Bengal. The major rivers are seasonal with more than 90 per cent of the total flows occurring between June and December. The ultimate irrigation potential from all sources is estimated to be 9.50 m ha. It includes 7.30 m ha from surface water and 2.20 m ha from groundwater. Systemic problems related to the irrigation sector are prevalent in the State of Andhra Pradesh. The net irrigational potential created through large financial investments is under-utilized with a gap of nearly 33%. Some of the main reasons for this gap are the non-compliance of farmers to the designed cropping pattern, the poor conditions of the irrigation systems, and the lack of operational plans. In addition to this gap, water distribution within the command areas is often neither reliable nor equitable with large differences in water availability between the head and tail end of the irrigation canals. Area under irrigation is shrinking in many of the major and medium commands. By improving the conductor system and drainage network, considerable water can be made available for additional ayacut (irrigated area). Farmers in the head reaches of major and medium irrigation schemes are drawing water far in excess of their allocation and as a consequence, water is not flowing to the tail end areas. The average annual rainfall of Andhra Pradesh ranges from 500 mm annually in the South–West to 1,100 mm in the North-East. Andhra Pradesh is having 27.5 million hectares of geographical area with gross and net cropped area of 13.2 and 11.5 million hectares respectively and forests occupying 22.6% of the geographical area and irrigated area occupy 5.77 million ha (2004-05). The net irrigated area is 3.88 m ha of which 34.7% under canals, 12.3% under tanks and 53% under tube wells and other sources. The irrigation potential in Andhra Pradesh has been estimated to be 11.3 million ha. In Andhra Pradesh, the total irrigated area (net) increased from 27.47lakh ha in 1955 to 45.27 lakh ha in 2000. Much of the growth in irrigated area in A.P. since 1985 has come from tube wells and the area under tanks has decreased. There was no improvement in irrigated area from 1975 to 2000 under canal system. Rice is the most important irrigated crop in A.P, large parts of new irrigated area are being cropped with rice and the proportion of rice area that is irrigated is increasing. The area under food and non-food crops accounts 63 and 37 % respectively of total cultivated crop area. In Andhra Pradesh, at present 98.8% of Sugarcane, 95.8% of Turmeric, 95.2% of Rice, 64.2% of Chillies and 12.7% of Cotton is irrigated. However, rice consumes 67%, groundnut 8.4% and sugarcane 5.4% of irrigation water. The water supplied for domestic and industrial purposes constituted only 0.9% and 0.45% respectively of the total water utilized in the State in 2001. By 2025, the total assessed water yield from the surface and groundwater will have to be exploited to the fullest extent, as the water requirement for the domestic and industrial sectors is estimated to reach 3% and 1.27% respectively of the State’s available resources. By 2025, no additional demand of water for any of the sectors can be met from the available fresh water sources of the State. Even to barely meet the projected demands, there will have to be 100% exploitation of the annual assessed water yield. Given the present population and the total assessed annual water yield, Andhra Pradesh has a water availability of 1400 m3 per capita per annum, which brings the State into the water scarce category (<1700 m3 per capita per annum is categorized as water scarce).
Karnataka state, with more than 75 percent of its arable land in the rainfed regions, is the second largest drought-prone area in India (after Rajasthan). The net sown area in Karnataka is normally about 11.2 million hectares. Only 24 percent of the arable area is under irrigation, so most of the cultivable area depends on the occurrence and distribution of pre-monsoon and southwest monsoon precipitation. Karnataka over the past 43 years (1960–61 to 2002–03) has had a rainfall deficit in an average of 1 out of every 4.3 years. Rainfall deficits occurred in 12 out of the 43 years during Kharif season (the main cropping season, June to October), and in 21 out of the 43 years during Rabi season. Normally, 65 percent of the net sown area is planted with crops during Kharif depending on pre-monsoon and southwest monsoon rains. Similarly, about 30 percent and 5 percent of the area is sown during Rabi, the northeast monsoon season (November to March) and the summer season (April to June), respectively, depending on the quantum of residual moisture. According to 1999–2000 data, 45 percent of the net sown area in Karnataka is under cereals, 14 percent under pulses, and 20 percent under oilseeds. The Kharif crops in Karnataka comprise millets, paddy (rice), maize, moong (pulses), groundnut, red chillies, cotton, soyabean, sugarcane, rice, and turmeric. The major Rabi crops of Karnataka are wheat, barley, mustard, sesame, and peas. Karnataka is one of the major producers of rice among all other states in India. Rice is the food crop harvested by Karnataka and sugarcane is the cash crop. Other cash crops sown in Karnataka apart from sugarcane are cashews, cardamom, betel (areca) nut, and grapes. The cool slopes of Western Ghats are well-known for coffee and tea plantations whereas the eastern regions are widely known for producing sugarcanes, a bit of rubber plants, and fruits such as oranges and bananas. The north-western region of Karnataka has black soil which supports oilseeds, cotton, and groundnuts. Two-thirds of Karnataka’s geographical area is arid or semi-arid. Out of 27 districts, 18 districts are drought prone with annual normal rainfall of less than 750 mm. The normal annual rainfall of the state is 1,139 mm, received over 55 rainy days. Of the annual rainfall, 71 percent is received during the Kharif season, 17 percent during the Rabi season, and the remaining 12 percent during the pre-monsoon season. Because rainfall is highly variable over space and time and irrigation is limited, agricultural production is correspondingly variable. Even during the good rainfall years, at least 25 percent of the taluks [district subdivisions] in the state are affected by uneven distribution of rainfall, and even the assured rainfall areas like the coastal region can experience drought-like conditions.
Northern Karnataka has well diversified cropping including rice, cotton, maize, and chili (red pepper) during kharif season, and wheat, chickpea, sorghum, and sunflower during rabi season. Only 13% of the area is currently irrigated. Rice is mainly grown in the Bellary District under the Tungabhadra irrigation project and the remaining crops are scattered over all districts both under rainfed and irrigated ecosystems. The productivity of important crops like rice, wheat, and chickpea is low if compared with state and national averages.
- Tamil Nadu
Tamil Nadu enjoys semi arid climate, which permits higher crops productivity under irrigation. Out of 13 million hectares of geographical area, which is 3.95 per cent of total geographical area of India, the cultivable area in Tamil Nadu is around 7 million hectares, 55 per cent of which is dryland. Monsoon rainfall is the basic resource for water availability in Tamil Nadu. Based on annual rainfall of Tamil Nadu and total geographical area, the tentative annual water availability is 12.285 Mha.M and out of which the annual availability is 4.74 m.ha.M. The dominant monsoon for rainfall is north-east monsoon (Oct.-Dec.) which contribute about 42 to 48 per cent to total annual rainfall of each district of Tamil Nadu (30 districts). Neverthless the contribution from south-west monsoon (June-September) to Tamil Nadu is around 32 per cent and it benefits Dharmapuri, Salem, Namakkal, Kanyakumari, The Nilgiris, Vellore and parts of Villupuram, Cuddalore, Karur, Thiruvallur and Perambalur districts. If any negative deviation from normal rainfall occurs in Tamil Nadu either during North East monsoon season or during south west monsoon season, in an year, the water availability in Tamil Nadu would affect three major water sources of irrigation viz., canals, wells and tanks. The normal rainfall in Tamil Nadu is 46.4, 140.9, 334.0 and 459 mm respectively for cold weather period (January-February) hot weather period (March- May), south-west monsoon period (June-September) and north east monsoon period (October-December). The net area irrigated by different sources during 05-06 was 2919545 ha as against 2637198 ha in 04-05 showing an increase of 282347 ha or 10.71% over the previous year. The net area irrigated during 05-06 constituted 55.7% of the net area sown in the state. Villupuram district is at the top with 243141 ha net area irrigated. However the highest percentage of the net area irrigated to the net area sown was recorded in Thiruvarur District with 96.3% followed by Kancheepuram District with 88.7% whereas the lowest percentage was recorded in The Nilgiris district with 0.9%.
Wells are the principal source of irrigation in Tamil Nadu. During 05-06, open wells and tube-wells continued to be the main source of irrigation. The net area irrigated by open-wells and tube-wells together accounted for 1536808 ha (about 52.6 % of the total net area irrigated) in 05-06 as against 1400394 ha in 04-05 showing an increase of 136414 ha i.e. 9.7%. The net area irrigated by wells during the year 05-06 was the highest in Villupuram district with 11.41% of the total net area irrigated by the wells in the state followed by 7.5% in Coimbatore district and 7.0% in Thiruvannamalai district.
Canals are also one of the major sources of irrigation in Tamil Nadu. As the system tanks get supply from a permanent storage like reservoirs, dams etc. the area irrigated by this source is classified under canals. During 05-06, Canal irrigation accounted for 27.4% of the net area irrigated by all sources in the state. The net area irrigated by canals including system tanks during the year under review was 800161 ha as against 753819 ha in 04-05 recording an increase of 46342 ha i.e. 6.1%. The net area irrigated by canals is the highest in Thiruvarur district with 147564 ha (18.7%) followed by Thanjavur district with 134634 ha (17.4%) and Nagapattinam district with 125014 ha (15.7%) of the total net area irrigated by canals in the State.
The non-system tanks which are fed partly from their independent catchment areas and partly from the diversion of river water and jungle streams depend fully on rain. The net area irrigated by non-system tanks during the year 05-06 is 575352 ha as against 465355 ha in 04-05 registering an increase of 109997 ha or 23.6% over previous year. The extent of area irrigated by tanks during the year is the highest in Sivagangai district with 12.7% followed by Pudukkottai district with 12.5%, Villupuram district with 10.6% and Kancheepuram district with 10.6%.
Tamil Nadu agriculture largely depends on Southwest and Northeast monsoons and also release of adequate water in river Cauvery and comfortable storage position in the major reservoirs of the state. Taking advantage of the Southwest monsoon, large-scale coverage of oilseeds, pulses and cotton crops are taken up under rain-fed cultivation in the state. Though rice is cultivated mainly under irrigated conditions, substantial area is also brought under semi dry cultivation in Kancheepuram, Tiruvallur and Ramanathapuram districts, where sowing is taken-up utilising early rains of the South- West monsoon, later sustained by irrigation using tank water. The Northeast monsoon rains are also very crucial for recharge of sub soil water. From time immemorial due to the good soil health and plentiful water availability, Tamil Nadu farmers have had a set cropping pattern in command areas, tank-fed areas and well irrigated areas, which predominantly as in for paddy, sugarcane, coconut and other hydrophilic crops. Due to the changing rainfall pattern over the years, ground water depletion, lack of flows in the perennial rivers, scarcity of labour and hike in wages, the existing cropping pattern has ceased to be economically viable.
The average annual rainfall of the state is 3000mm, the bulk of which (70%) is received during the South-West monsoon which sets in by June and extends up to September. The state also gets rains from the North-East monsoon during October to December. However the spatial and temporal distribution pattern is mainly responsible for the frequent floods and droughts in Kerala. The average annual rainfall in the lowland of Kerala ranges from 900 mm in the south to 3500 mm in the north. In the midland, annual rainfall ranges from 1400 mm in the south to about 6000 mm in the north. In the highland, annual rainfall varies from 2500 mm in the south to about 6000 mm in the north. Kerala has got 41 west-flowing and 3 east-flowing rivers originating from the Western Ghats. The total annual yield of all these rivers together is 78.041 Million Cubic Meters (MCM) of which 70,323 MCM is in Kerala. The peculiarity of the rivers flowing across Kerala is their short length and the elevational difference between the high and the low land leading to quick flow of water collected from the river basin discharged into theLakshsdweep Sea. As a result, the state has not been able to utilise the river water sources to a major extent. The major portion of the runoff through the rivers takes place during the monsoon seasons. 67.29% of the surface water area of 3.61 lakh hectares is constituted by brackish water lakes, backwaters and estuaries. Groundwater has been the mainstay for meeting the domestic needs of more than 80% of rural and 50% of urban population besides, fulfilling the irrigation needs of around 50% of irrigated agriculture. The ground water potential of Kerala is very low as compared to that of many other states in the country. The estimated ground water balance is 5590Mm³. Dug wells are the major ground water extraction structure in Kerala. The dug wells have a maximum depth of about 10 to 15 meters and have a diameter of about 1 to 2 meters in coastal region and 2 to 6 meters in the midland and high land. The open well density in Kerala is perhaps the highest in the country – 200 wells per sq.km in the coastal region, 150 wells per sq.km in the midland and 70 wells per sq.km in the high land. The ground water withdrawal is estimated as 980Mm³. Apart from rivers and wells, sources like tanks, ponds, springs and surangams are also used in Kerala for providing water for drinking as well as irrigation. It is estimated that Kerala has approximately 995 tanks and ponds having more than 15000 Mm summer storage. The short, fast flowing, monsoon fed rivers of Kerala often encounter salinity intrusion into their lower stretches during summer months. When the fresh flow reduces, two major problems are encountered in these water bodies (i) salinity propagates more into the interior of the river (ii) flushing of the system becomes less effective. Both these have an impact on irrigation, drinking and industrial water supply schemes situated in the downstream stretches. It is found that the salinity in the Beypore Estuary propagates into a distance of 24 km upstream thereby creating problems to the water supply to the Kozhikod corporation area. The flushing time in summer from a distance of 20 km from the mouth is 20 days and more, creating pollution concentration in the lower stretches. These problems are acute in some of the estuaries nearby important cities and industrial complexes. Problems of salinity intrusion are also encountered in Periyar, Meenachil and Kuttiyadi rivers. It has also been observed that over exploitation of ground water in certain stretches has contributed to the entry of salinity into the coastal aquifers from the sea. Though this tendency is mainly observed during the summer months, when recharge is partially zero, there is a possibility of aggravation of the problem due to increase in withdrawal rate to cater to the requirements of dense coastal population. Water logging in the commands of major and medium irrigation projects is another known problem. Studies reveal that around 400 Ha of land in the commands of Malampuzha and Kuttiyadi irrigation projects are water logged. Water logging occurs mainly due to (i) high density of irrigation (ii) wrong and defective methods of irrigation (iii) improper maintenance of nature channels (iv) hydraulic pressures from saturated areas at higher elevations (v) heavy seepage losses from canals (vi) absence of drainage canals in irrigated areas and (vii) silting of canals. It has been reported that over exploitation of ground water in certain hydrological zones has contributed to permanent lowering of water table and salinity intrusion into coastal aquifers. There are some areas in Kerala where bore wells withdraw water directly from the water table because of the improper construction procedures. This has been observed in some areas near Calicut Corporation, resulting in excessive lowering of ground water table. It is also noticed that uncontrolled sand removal from the riverbeds also results in lowering of ground water table in the nearby areas.
Agriculture in Gujarat is highly dependant on rainfall – 64 percent of the area is rain fed, which is marginally higher than the all India figure, i.e., 60 percent. Agriculture is largely dependent on the south-west monsoons from June/ July to September/October, which is often erratic and unevenly distributed (Valsad district in south Gujarat received maximum rainfall of 2064 mm, while the Kutch district received minimum rainfall of 663 mm in the monsoon of year 2007).Gujarat is known to be a drought-prone state, with 70 percent of its geographical area classified as semi-arid and arid land types. The State’s gross irrigated area increased from around 3.7(1999-00) to 4.4 million ha (2006-07)- an increase of 16.9 percent. During the period, irrigated area under wheat has grown the fastest at 16.5 percent per annum (total food grains at 7 percent), followed by cotton and fruits and vegetables at 8 and 5.4 percent per annum respectively. Of total gross irrigated area, 16-17 percent is irrigated by government canals and 82 percent by privately owned tube and other wells; thus agriculture in Gujarat depends predominantly on ground water. Gujarat has seen severe ground water depletion, especially after agricultural demand for water went up after the 1960s. At present in Gujarat there are 17 major irrigation projects and 169 medium irrigation schemes across various talukas (blocks).
- Madhya Pradesh
Madhya Pradesh consists of four physiographic regions: the low lying areas in north and north-west of Gwalior, Malwa plateau, Satpura, and Vindhyan ranges. The average annual rainfall varies from 800 mm to about 1800 mm. Monsoon in Madhya Pradesh lasts from June till September. The rainfall decreases from south east and east to north-west and west. The total geographical area of the state is 30.8 M ha, of which total net sown area in 2005-06 was 14.9 M ha (48.5%) and net irrigated area was 5.5 M ha (36.9% of agricultural area). Among all other districts of Madhya Pradesh, Hoshangabad had the maximum net irrigated area (79.2% of net sown area) due to the availability of an irrigation canal and Dindori had the minimum net irrigated area (0.40%) as the district was mostly covered with forest and mountainous terrain. The majority of the crops in Madhya Pradesh were rainfed and only 36.9% of the net sown area was under irrigation. The cropping pattern in the state was much diversified and dependent on soil type, rainfall, water resources development, and socio-economic status. Millet and wheat were the major crops in the central and northern regions, paddy in eastern and southeastern regions and cotton in the southwestern parts of Madhya Pradesh.
The total irrigation potential created in the State by the end of June 2006 through major, medium and minor irrigation projects taken together was 52.90 lakh hectares. The share of major, medium, minor (State sector) and minor (Local sector) irrigation projects in the total irrigation potential created was 44.06 per cent, 13.40 per cent, 19.96 per cent and 22.58 per cent respectively. The additional irrigation potential created during 2005-06 was 1.17 lakh hectares showing an increase of 2.2 per cent over the cumulative achievement by the end of June 2005. The actual utilization of irrigation potential in 2005-06 was 20.13 lakh hectares (38.05 per cent) as against the potential of 51.73 lakh hectares created up to the end of June 2005. The State is mainly covered by the basins of Krishna, Godavari and Tapi except the west-flowing rivers of Konkan strip. A small portion on north comes under Narmada basin. There are in all 380 rivers in the State and their total length is 19269 km. Most of the land is undulating and hilly. Comparatively, continuously hilly plateau lands are very few. Because of this, flow canal systems in Maharashtra are very expensive, though there are a number of suitable sites for building water storage reservoirs. Maharashtra gets rain both from the south-west and the north-east monsoon winds. The proportion of the rainfall derived from the north-east monsoon increases towards east. The average rainfall of the State is approximately 1360 mm. Nearly 88% of the total average rainfall occurs between June to September, while nearly 8% occurs between October to December and 4% after December. There is a considerable variation in the reliability of the rains in different parts of the State. The steep decline in the rainfall to the east of Sahyadri is strikingly noticeable. In the 30 to 50 km wide belt the average rainfall is observed to be less than 650 mm (as low as only 500 mm at some places). Thereafter, the rainfall increases steadily towards east and the average rainfall in the easternmost districts is observed to be 1400 mm. The pre-monsoon rain during March to May is the highest in Western Maharashtra (5%) while in Marathwada it is 4%, in Vidarbha it is 3% and the minimum is in Konkan (1%). Out of the total cultivable land in Maharashtra about 53% is under Kharif and about 30% is under Rabi crops. These mostly comprise of food grains and oilseeds. The rainfall during June to September affects both the Kharif and the Rabi crops. The State has created 3.863 Mha irrigation potential using surface water resources by 2003 through 52 major, 206 medium and 2445 state sector minor irrigation projects. Besides 53 major, 212 medium, 885 State Sector minor projects and 22 lift irrigation projects are under construction in the State. The total investment in the irrigation sector up to March 2003 is around Rs. 300 billion. The ultimate irrigation potential, through surface water and ground water resources, has been estimated as 12.6 Mha.