Irrigation in India: Way Forward
Scientific and systematic problem identification is necessary to understand the requirements of a particular area. Such requirements should be studied in detail to determine the constraints involved in the improvement of water management and better agricultural production. The major strategies for improving water use in agriculture are summarized as under.
- Addressing Conveyance Loss
- Checking Application Losses and Improving Irrigation Efficiency
- Checking Over-Exploitation of Ground Water
- Creating Secondary Storage
- Creating In-situ Moisture Conservation and Rainwater Harvesting
- Effective Irrigation Development in Eastern & North-East Region
- On-farm Water Management
- Controlling Waterlogging and Soil Salinity
- Water Pricing
- Recycling of Water
- Emphasis on Awareness Generation & Training
- Coordination & Convergence Mechanism
Addressing Conveyance Loss
The operation and maintenance of irrigation systems is very poor and, therefore, water loss from canals is very high. Almost half of this loss is found in field channels. Improvement in canal operating systems is the requirement of the day.
Checking Application Losses and Improving Irrigation Efficiency
Traditional flow irrigation has very low application efficiency, and 15-90 per cent of water may be saved and significant increase in yield achieved by adopting nonconventional methods like sprinkler, drip or microsprinkler irrigation.
Compared to flow irrigation, when sprinkler irrigation is used, water saving in various crops ranges from 16 per cent to 69 per cent, and the increase in yield ranges between 3 per cent and 57 per cent. Similarly, as compared to traditional flow irrigation, drip irrigation saves water between 5 per cent to 68 per cent and increases yield between 10 per cent to 50 per cent.
Although it involves more operations and maintenance (O&M) cost for energy charges compared to surface irrigation, the microirrigation system increases water use efficiency. Irrigation efficiency in drip irrigation is about 90 per cent, compared to about 65 per cent in the case of sprinkler irrigation and about 35-50 per cent in the case of conventional method of irrigation, as per the Central Water Commission studies, 1991.
Drip irrigation technology irrigates plants at the root zone through emitters fitted on a network of pipes, called mains, sub-mains and laterals. The emitting devices could be drippers, micro-sprinklers, mini-sprinklers, micro-jets, misters, fan jets, micro-sprayers, foggers, etc., each designed to discharge water at prescribed rates. So far, under the National Mission on Micro Irrigation, an area of about 4 million ha has been covered under micro-irrigation.
Checking Over-Exploitation of Ground Water
While achieving their high food grain production targets under the green revolution, and emerging as the major contributors of foodgrains to the national pool stocks, Punjab, Haryana, Uttar Pradesh, Andhra Pradesh, etc., have experienced serious groundwater depletion.
The overexploited regions need to be given integrated treatment of the following:
- artificial recharge of groundwater;
- rainwater harvesting;
- conjunctive use of surface water and groundwater;
- management of poor/marginal quality groundwater;
- water conservation by increasing water use efficiency;
- regulation of groundwater development, etc.
Further, separation of feeders for domestic and agricultural power, and timely but controlled supply for irrigation, help regulate groundwater use. Implementation of participatory irrigation through water user associations is the way out to empower and entrust village communities with the right and responsibility to collect electricity charges in overexploited blocks to regulate access through obligation on groundwater users to undertake rainwater harvesting and groundwater recharge. A gradual withdrawal of cultivation of rice, sugarcane and other water-guzzling crops from the overexploited western region of the country is the call of the day.
Creating Secondary Storage
During the monsoon, the reservoirs reach the peak storage level, making water available even at the tail end of the system. Considering that irrigation water demand is minimum at this point of time, water should be stored in secondary storage structures constructed at feasible locations along the tail end of the canal system, and used when tail-end farmers face water shortage.
Creating In-situ Moisture Conservation and Rainwater Harvesting
An ecologically sound conservation technique is recharging aquifers. This is carried out by impounding water in surface structures like ponds, khadins, tanks, check dams, gabions, etc. This helps create micro-storage for lifesaving irrigation and for replenishment of groundwater through seepage. Similarly, practices like zero tillage and sub-soiling were found useful as in-situ moisture conservation. Yet another effective technique is shallow inter-row cultivation and contour farming for conserving rainwater in the soil. The watershed approach has been found to be the best for these interventions and should be vigorously promoted.
Effective Irrigation Development in Eastern & North-East Region
Although East and North East India is blessed with sufficient rainfall, groundwater resources lie underutilized to the extent of 58-82 per cent. There is a need for a shift in land use and cropping patterns in accordance with this region’s climatic characteristics, water availability scenarios and food requirements. Hence, in the Eastern, North Eastern and coastal pockets of India, the priority should be to exploit the abundant availability of groundwater.
In Assam, Bihar, Chhattisgarh, Orissa, parts of Jharkhand, Eastern Uttar Pradesh, West Bengal and other coastal regions and pockets, a battery of shallow and deep tube wells could be installed for withdrawing groundwater during the rabi season, which will also act as a sink for subsequent floods. For small and marginal farmers in the Eastern states, the provision of community tube wells and mobile pump sets may be encouraged.
There is need to create irrigation potential in the Eastern and North Eastern states through adequate power supply by energizing new tube wells and pump sets and through soft credit for farmers for installing tube wells and pump sets.
On-farm Water Management
On-farm water management can reduce wasteful use of water and, at the same time, lead to increases in productivity. As the rates for irrigation water are generally low, and independent of the quantity of water used, farmers have no incentive to economize water use, and resort to wasteful water use practices. The All India Coordinated Research Programmes (AICRP) of the ICAR in water management network centres have successfully demonstrated that there is great scope for economizing water use, increasing crop productivity and improving water use efficiency through transfer of available irrigation and other agro-technology to farmers in irrigation commands.
Controlling Waterlogging and Soil Salinity
Waterlogging leads to soil salinity. The problem of waterlogging is very often observed in surface irrigation systems and also in areas of poor drainage, and results in the accumulation of water. Apart from lining the canals, drainage development—through either surface, sub-surface, bio-drainage, or a combined approach—should be accorded priority, followed by appropriate agronomic measures.
Like any commodity available in abundance at little or no cost, irrigation water is heavily misused, with serious economic and ecological implications. The only way out is the adoption of volumetric, metered supply of water as soon as possible. As one of the most important natural resources, water needs a serious regulatory system of use to ensure that it is treated as a national property and used judiciously. Effective distribution and pricing is necessary for this. Not only regulation of water pricing, but also the regulation of the price of energy that goes into lifting and using water is needed to prevent its side effects on water as a natural resource.
Recycling of Water
Currently, reuse and recycling of waste water is not practiced on a large scale in India. There is considerable scope and incentive to use this alternative in irrigation.
Emphasis on Awareness Generation & Training
Awareness training on the use of irrigation water in critical stages of crop growth under different soil and environment conditions should be imparted to farmers, and be an integral part of water resource development and management. Such training should be conducted for all categories of farming personnel, and should focus on information systems, sectoral planning, project planning and formulation, project management, operation of projects and their physical structures and systems and the management of water distribution systems.
Coordination & Convergence Mechanism
The key to higher, cost-effective yield and sustainable water use is efficient water management, and its precondition is the convergence of resources of various concerned line ministries and departments. For instance, for water conservation through groundwater recharge and rainwater harvesting, the efforts of watershed development project authorities have to converge with those of the ministries of rural development, agriculture, water resources, urban development and power, etc., to enable the project to deliver results effectively. Enhancing productivity of water using micro irrigation, supplemental and deficit irrigation is possible only through the combined efforts of the Ministries of Agriculture, Water Resources and Power. A coordinated action plan needs to be put in place through the collaborative efforts of the concerned ministries not only at the Central level but also at the state level.