Environmental Issues in Conventional and Non-conventional Irrigation Projects
Conventional projects are those which use water from river, lake, streams, ponds,reservoir, surface and groundwater bodies. In non-conventional category comes irrigation projects which use water from sea, water harvested through rain catchment, municipal and domestic sewage water, industrial water effluent, effluent from hotel industry etc.
Conventional and non-conventional Irrigation projects produce different environmental issues, where the latter demands more closer examination and appraisal from the viewpoint of financial Institutions. Alam and Srivastava (1986), Srivastava and Daisley(1983) and Srivastava and Brudi (1981) have shown that the requirements of technological packets and project appraisal for conventional and non-conventional irrigation projects are different. Financial Institutions financing these projects environmental matters into consideration.
There are different methodologies used because in case of conventional irrigation project the environmental issues are seen through hydraulics and hydrology of water who'll for non-conventional irrigation projects environmental issues are analysed Hillsborough additional factors such as material (organic and inorganic matters) transport, decay and transformation.
Here, lets look into "The Environmental Issues in Non-conventional Irrigation Project". Rapid industrialization and urbanization created a large gap between supply and Mantle of conventional water for irrigation. The gap is pronounced and wider in And and Semi Arid Land (ASAL) than in humid area. As demand from priority sectors (municipal and industry) is approaching production limit of conventional water, the agriculture future may have to largely depend on non-conventional irrigation.
Juwarkar (1988) estimates 2.5 lakhs hectare can be irrigated by urban waste water. indirectly, including treated industrial effluent and domestic waste water. It can be speculated that about 69 lakhs hectare can be irrigated in this way, i.e. about 12% of total irrigated area in India.
As environmental awareness grow and Industries become responsible for treating their effluent more and more can be brought under non-conventional irrigation. Studies on availability of treated industrial effluent for irrigation are scanty, but study on domestic waste water is available. Waste water generated is estimated to be of the order of about 10,000 million litres per day from about 110 urban centres in 240 towns and cities avails population of more than 50,000 (NEERI, 1985).
The non-conventional irrigation has demand from viewpoint of economic necessity hut it also has additional issues to what is given above, namely
- hazard to health,
- toxicity to soil,
- toxic residue in the product, and
- contamination of surface and ground water.
Domestic effluent is comparatively harmless if synthetic detergents are not very In concentration but industrial effluents are dangerous in terms of chemical composition. It is pollution loading rate to soil which is of concern in non-conventional irrigation. The pollution loading rates depend on factors such as chemical and physical properties of effluent, terrain feature of the land, chemical, physical and micro-biological properties of the soil, land-use, crop and irrigation plant, etc. Shallow and deep groundwater contamination is a concerning which refrain institutions from considerable non-conventional irrigation project as an environmentally friendly venture. Thus conventionalize irrigation requires a different technological and on-farm management packages than the conventional irrigation to counteract the negative environmental impacts mentioned above. This is a typical example to show the controversial problems involved in eco-friendly projects.
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