Water plays a critical role in meeting our needs in diverse fields – providing, inter alia, water for drinking, agricultural and industrial uses as well as maintaining the eco-system. India has a large irrigation network and has been in the forefront for establishing institutions and policies aimed at facilitating planned development of water resources including a National Water Policy. Despite the continuing concerns and efforts, the water sector in India appears to be in a bind. Withdrawal of water at four times the rate it was 65 years ago to support a population of 1210 million (in 2010) at an enhanced level of nutrition, public health parameters and living standards is to say the least, stressing the water capital. The ecosystem health has also been compromised severely. Realizing the seriousness and the importance of the water issues to our programs for national well- being, INAE decided to undertake a research study to examine a few critical aspects of water supply and demand in various sectors and come up with implementable recommendations to overcome the lacunae in the water resources sector. Mr. SS Chakraborty is the Coordinator of this study group on “Water Resources Management” with Prof. S Mohan, Dr. RR Sonde, Prof Subhash Chander and Dr. NK Tyagi as Members. The study assesses the demand for water from the various sectors of the economy, their trends and the potential shift from one sector to another in the light of the changes in the composition of the economy, the food security requirements, implications of changes in the lifestyle and other factors. This study analyses inter-alia water availability, water quality and water demands in a few sectors along with the water-energy linkages, at the river basin level.
India has a reasonably good endowment of water resources with an average rainfall of 1083 mm equivalent to 3560 billion cubic metre (BCM)/year. However, the available amount is substantially less and is estimated at 1869 BCM in the form of surface water and ground water. Climate is one of the factors that is expected to disturb the hydrologic cycle. Preserving water quality is critical for sustained economic development and it is not a quality vs development issue. Degradation of water quality affects health and productivity, thereby impacting development activity adversely. This Research Study makes an effort to estimate the gap between supply and demand of water over the medium term upto 2025 and 2050, based on data available and taking cognizance of the uncertainties inherent in such estimations.
The common issues regarding surface and groundwater are salinity, toxicity and presence of pathogens. The specific problems relating to surface water are eutrophication, oxygen depletion and ecological health; whereas groundwater specific issues are presence of fluoride, nitrate and arsenic contamination. As water quality standards differ with intended use, it is essential that while quantifying the degree of pollution, the standards and guidelines for use are kept in view. The overall gap in demand and supplies would not exist and the dependability of the system would be greatly enhanced after implementation of the various recommendations given below.
Creation of Large Storages and Linkages – It is planned to create additional live storage capacity of 170 BCM by 2050. Completion of the storage projects under construction by 2025 would provide live storage of 63 BCM.
Large Scale Rehabilitation of Irrigation Works – Such an intervention would require renovation, de-silting and setting up of management infrastructure for irrigation works, creating an additional potential of 5 mha.
Last Mile Irrigation Infrastructure – This will set up the command area management structure and rehabilitate the system to bridge the gap of 9 mha (approx) between the irrigation potential created and that utilized.
Small Scale Irrigation Infrastructure – Minor irrigation infrastructure projects, such as dams built closer to the community for using water during dry spells, will have a potential of irrigating 1.5 mha.
Aquifer Recharge – This would require construction of percolation tanks, check dams, contour bunds etc. to saturate the catchment area and increase abstraction efficiency to 90%, and recharge efficiency to 75%.
Rain Water Harvesting – This involves harvesting rain water in the watersheds and using it for micro-irrigation in rain-fed cultivated areas. This will increase the yield of various crops by 25-40%.
Use of Waste Water in Irrigation – Recycling and reusing waste water, in lands near urban areas for irrigation and other purposes need to be ensured, through appropriate regulations, as necessary.
Demand Management Technology interventions identified for maximizing productivity are listed below:
Laser Levelling – Use of laser levelling equipment for quicker and better levelling of the fields will contribute to water saving and increase water use efficiencies, besides reducing energy used in pumping water.
Zero or Minimum Tilling – This technology involves direct planting of the crops without any or minimum tillage of lands. It not only reduces water use by 20-30%, but also reduces cost of cultivation, increases yield by 10-20% and decreases greenhouse gas emission.
Sprinkler or Drip Irrigation – Use of sprinkler or drip irrigation saves 20-40% of water and increases yield by 10-40%.
System of Rice Intensification (SRI) – This envisages transplanting seedlings of lesser age with more spacing and less water application only at saturation size.
Land Surface Modification, Bed and Furrow Irrigation and Drainage– Bed and furrow Irrigation permit growing of crops on beds with less water, reducing chances of plant submergence due to excessive rain.
Biotic and Abiotic Stress Management – The objective is to encourage better management of plant stress by optimum use of pesticides and innovative crop protection technologies.
Improved Germplasm – This would increase yield potential by using higher yielding seed varieties that are best adapted for specific conditions.
Increased Fertilizer Use – This would involve increasing fertilizer use to reduce mineral exhaustion and improve yields in irrigated lands. The yield of all crops will increase by 25-50%.
Irrigation Scheduling – The objective is to determine the exact amount of water for application to the field as well as the exact timing for application. The yield of all crops will increase by 5-20%, saving 10-15% of water.
Piped/lined Water Conveyance from Tubewells – This reduces the losses in the conveyance system. Use of piped/lined water conveyance from tube-wells saves 20-40% water and increases yield by 10-40%.
Subsurface Drainage – A subsurface drain is a perforated conduit of tile, pipe or tubing, installed below the ground surface to intercept, collect and/or convey drainage water. The yield would increase by 20-30%.
Water Security for Domestic, Industrial and Other Requirements
The requirement of 261 BCM by 2025 and 373 BCM by 2050 will be met by utilizing perennial ground water resources as well as from the storages created.
Sustainability of Ecosystems
The total environmental demands to maintain the ecosystem is estimated as 353 BCM. A Scientific Panel consisting of Biologists, Ecologists, Geomorphologists and Hydrologists needs to be constituted to assess the water needs after taking care of the species composition in the riverine Wetlands. The Panel would define the capacity to support and maintain a balanced, integrated, adoptive ecosystem having the full range of elements (genes, species and assemblages) and processes expected in the natural habitat of a region.
AIBP to be renamed as PABA – An effective institutional framework and sustained policy support are also required. The current Accelerated Irrigation Benefit Programme (AIBP) of the Govt. may be renamed as Programme for Accelerated benefits for Agriculture (PABA) which may adopt the technologies for effective execution on the ground.
Development of Water Technology Hubs – These hubs will be useful for benchmarking the available technologies to provide a clear picture of the benefits to private entrepreneurs.
Engaging Local Users in Water Management – All stakeholders, including members of the public, need to be given full opportunities to share their views and influence the outcome of water projects impacting them.
Strengthening Technology Diffusion Network – The technology diffusion network needs to be strengthened. To start with, each Krishi Vigyan Kendras should have a water technologist.
Climate Change – Adaptation to climate change would require speedy action on implementation of supply and demand measures.
Private Participation – Private participation in development and management of water resources, especially in large industrial clusters, needs to be encouraged.