II.1.- Indiscriminate and Excessive Utilisation of Surface/Canal Water
The land Environmental hazards are water logging and soil salinity/alkalinity spreading in areas of surface water irrigation projects. In India, the history of water logging and salinity/alkalinity of fertile lands can be traced mainly to the post - Independence period of fifties and sixties when the development of surface water irrigation took place to make our country self reliant in food production. The main function of successful irrigated agriculture is to develop and maintain soil zone in which moisture air and salt components are favourable for plants/crop growth. The plants must have moisture to grow, live and the presence of free air in the interstices of soil and root zone is as essential as water for plant/crop growth. The fertile land is seriously affected when water table rises into the root zone of the plant/ crop. An average and normal man requires 60 litres water, 1.4 kg food and 2.25 kg of air every day. To grow one ton of food grain requires 1000 tons of water and one ton of rice needs 2000 tons of water. The excessive and indiscriminate use of surface/canal water has led to regional environmental imbalances which caused water logging and soil infertility in irrigated commands. The water logging means 100 percent saturation of soil profile. The water in excess adversely affects the production and yield of crops by reducing soil volume accessible to their roots and excessive soil moisture prevents the formation of carbon dioxide by plant roots and other organisms and from being exchanged with the oxygen from the atmosphere a process known as 'aeration'. Without aeration, the root development and uptake capacity of water and nutrients of most plants is reduced resulting in decrease of crop yield. The magnitude of water logging associated with soil salinity/alkalinity has been progressively increasing since the inception of irrigated agriculture. It has been found a big constraint in achieving optimum agriculture production. If it is not controlled at present then there is likelihood of acquiring a situation, which may be beyond our means of combat.
As per FAO (1990) , in India salinity effected 11% of total irrigated area, which is 4.7 Mha. The National Commissions for Irrigation (1972) on Agriculture (1976) and Ministry of Agriculture (1985) have reported water logged area of 4.84, 6.00 and 8.53 Mha respectively showing a progressive increase.
The National Commission on Agriculture (1976) estimated excess salt concentration in 7 Mha area, out of which 2.50 was under alkali soil and 4.50 Mha under salinity. The Ministry of Agriculture (1985) reported 9.08 Mha as salt infested area, which included 3.58 as alkaline and 5.50 Mha with salinity proving thereby that degradation of lands are on the increase.
According to the Ministry of Water Resources (1991) an area of 5.8 Mha was suffering due to these problems in the commands of major/medium Irrigation projects in our country. This hinders the use of irrigation resource costing around Rs 24,000 crores 1 at Rs 40,000 per ha. Taking into consideration 12% interest rate, an annual loss of about Rs 2800 crores was computed. The loss of foodgrains were calculated as 17 Mtones which cost about Rs 7,000 crores at Rs 4000 per tone. High salt and water logging affected crop growth result in lower returns. It was observed that net returns of all crops in such affected areas was drastically reduced even in some cases, it was negative e.g. Sarda Sahayak command as shown below.
Crop Normal soils Water Logged area Salt Affected soils
Paddy 1844 853 245
Paddy 920 416 -104
Wheat 2061 -397 162
At 1985 price level, the Haryana State loss was estimated at Rs 40 crores and predicted Rs 100 crores by turn of this century. In SW area of Punjab State, cotton crop contribute 15 % of India's production. During 1992-93, it was 23.5 lakh bales, which declined to 15.14 lakh bales in 1993-94 and in 1997 it decreased to less than 10 lakh bales incurring a reported loss of Rs 600 crores.
During 1998, only Muktsar district of Punjab State suffered loss of Rs 200 crores cotton crop due to water logging according to Department of Agriculture. It has been computed that water logging and salt infested soils cost 422 million man days.
II.2.- Surface Water as means of Transport
of Chemical Wastes and Effluents of Industries The effect of water on almost everything in our environments is far more consequential than might be imagined. Water is often called "the Universal Solvent" because of its extraordinary ability to dissolve a broad range of substances. In fact it dissolves more substance in greater quantity than any other liquid. The salinity of the world's oceans is a direct result. An element such as calcium becomes so abundant in sea water that it precipitates out, forming crystals of the mineral calcite, that a thick layer of a sedimentary rock called "limestone" forms on the ocean floor.
Water has the highest heat of vaporisation of any liquid e.g. huge amounts of heat energy are required to evaporate even small quantities of water. The subsequent release of this energy through condensation during rainstorms provide an important energy source, which is responsible for generating tornadoes and hurricanes. It comes from the heat energy acquired by countless water molecules when they evaporate from a water surface. Within human body, water is critical in maintaining uniform body temperatures. We have a large volume of water in our bodies (about 75%), without which we would warm up or cool down much more rapidly than we do.
The industrialisation brings with it the problem of waste disposal. The effluent discharged from industries like textile mills, distilleries, fertiliser, sugar factories, tanneries, mineral and metal processing industries etc. introduce into ground water undesirable colour, odour and taste, organic matter and dissolved salts which include arsenic, cyanide, cadmium and hexavalent chromium in toxic concentrations. Ground water derived from mines producing sulphide ores of base metals is generally too acidic for use and contains appreciable amounts of metals.
The studies of effluents and ground water analyses in the industrial town areas of Punjab, Haryana and Uttar Pradesh have shown that the concentrations of chromium (hexavalent) are on very high side and are given as follows.
Locality Effluent Groundwater Inland ISI (1981)
State Cr+6 Cr+6 Surface Tolerance limits effluents Water into public sewers
High concentrations of Cr+6 to the extent of 12.9, 270.00 & 355.00 mg/litre in ground water are detrimental to human health due to toxic effects on human skin, nasal mucous membrane, larynx (a respiratory organisational containing vocal cords) and lung carcinoma (tumour, cancer). Cyanide maximum between 26 and 63 in effluents and 1.80 prescribed 2.0 mg/litre for cyanide discharge on land. The high concentration to the extent of 2 mg/l. in ground water is a health hazard in view of high toxicity of cyanide ions.
The major industries concentrated in Assam State are petrochemical located at Digboi, Noonmati, Guwahati and Bongaigaon, Paper mill at Jagiroad, Morigaon, Fertilizer Factory at Namrup, Dibrugarh District. The effluent from Noonmati Refinery in Guwahati were sampled in December 1976 at different points in Bharalu streamlet water, their analytical results are as follows.
Constituents Bharalu Streamlet Water Effluent Discharge
All these three constituents are toxic in nature and Biochemical Oxygen Demand (BOD) was more in the effluent than the prescribed ISI limit of 30. These parameters in the streamlet water indicates that it has become polluted. Their safe limits for drinking/domestic use are 0.1 mg/1 0.002 and 3 respectively.
II.3.- Over Exploitation of Ground Water Resource
A major portion (59%) of the irrigated agriculture acreage is fed by ground water resource which is an assured source of chemically safe water in Unin Territory, Delhi. Due to more demand of ground water for ever increasing population and irrigation within a short span of time, the exploitation of this precious resource has become non judicious and improper in space and time.
The increasing extraction of ground water has resulted in their water levels decline, especially in the fresh ground water areas. In Central Punjab State area, the levels have been falling at 0.2 to 0.3 m/year.
In NCT Delhi, the decline was 11.5m between during 1977 and 1995 pre-monsoons in Ghitorni area (South Delhi) depicting a decline of 0.64 m/year.
The demand for drinking water of NCT of Delhi has been increasing manifold in the last three decades due to rapid increase in the population. The population of Delhi was 62.2 lakh in 1984 which rose to 94.2 lakh in 1991 indicating a growth rate of 51%. The population of Delhi is expected to be 122 lakh by the year 2001 and 200 lakh by 2010 AD. The requirement of drinking water in Delhi during 1995-96 was 3200 mild against which the total raw water treatment capacity was only 2380 mild resulting in a short fall of 820 mild. Due to this, the stress on exploitation of ground water resource increased in Delhi during last two decades. However, the ground water availability scenario in Delhi is not very rosy since a greater part of NCT Delhi is underlain by brackish to saline ground water at depths of 30 m and below.
In early eighties, the depths to water level varied between 2 and 5 mbgl in various parts of Punjab State but presently it is 3 to 7 mbgl in 10 km belt along the rivers and up to 10 mbgl in other places. The most notable consequence of the agricultural development strategy has been the depletion of ground water resource. The water table in the State declining at an rate of 0.5 to 1 m per annum. The severity of such situation can be judged from the fact that 108 blocks (85 % blocks) are classified either dark or gray showing no further or very little scope exists for further exploitation of this resource especially in the central part of the State covering Jalandhar, Kapurthala, Ludhiana districts and part of Amritsar, Patiala and Sangrur districts. The declining water levels have resulted in failure of tubewells or deepening of ground water abstraction structures leading to higher cost of pumping.
II.4.- Water not Fit for Drinking According to School of Environmental Studies (SOES) Calcutta (1996), about 1.5 million people are exposed to 'arsenocosis' and 2 lakh people are affected by arsenic poisoning in West Bengal state only, where 4.4 million are habitats. The disease is indicated by ugly blisters in exposed parts of the body. In 1993, 35 blocks were affected by arsenic poisoning of ground water and in 1995 it spreaded to 61 blocks of seven districts of the State. It was found that indiscriminate drawl of ground water for irrigating lands has led arsenic in sub-soil creeping into deep levels of groundwater repositories. The reason could also be rich arsenic deposits in Rajmahal hills for incursion of arsenic in groundwater. Bangladesh country, adjacent to West Bengal State of India, where wells sunk in alluvium of Ganga river delta by UNICEF, World Bank and British Oversease Development Administration has been slowly poisoning villagers with arsenic waters. Tens of millions people are suffering from Cancer triggered by arsenic. Bangladesh has 3 million tubewells providing 95 % drinking water. About 30 million people are drinking water containing more than 50 pp b of arsenic, five times WHO's recommended limit of 10 ppb. As per National Institute of Preventive and Social Medicine (NIPSOM) (1988) arsenic concentration in ground water repositories is increasing year by year and 20 % of Bangladesh drinking water has more than 50 ppb of arsenic element concentration.