Rainwater Harvesting: Why Rain is a Gain You Can’t Let Drain

Stop wasting free water and start securing your home’s future with simple collection systems

Chinmoy Kumar Sarma

Water is life, and saving it is our shared responsibility. The Ministry of Jal Shakti’s “Catch the Rain” campaign encourages everyone to harvest rainwater “where it falls, when it falls.” This focuses on saving and conserving rain water to meet the water crisis in the country by creating rain water harvesting structures suitable to the climatic conditions and sub soil strata with people’s active participation. With millions facing water scarcity due to climate change and aging infrastructure, we need to act now. By building smart harvesting systems and improving irrigation-which accounts for 80% of our water use-we can secure our future. Join the movement: every drop counts.

Even with heavy irrigation, advanced fertilizers, and modern techniques, farming still hasn’t fully escaped its reliance on rain. Because of this, rain-dependent agriculture remains the primary method used across the globe. A study revealed that rain-fed agriculture is in practice in 80 per cent of the world’s agricultural land area and generates 65-70 per cent of the world’s staple foods. It produces most of the food for the poor communities in developing countries.

India transformed from a food-scarce nation in the 1960s to a food-surplus one today, driven by significant leaps in agricultural production and a steady decline in rural poverty.But the impact of green revolution remained confined to well endowed and irrigated areas and also in some selected crops and yet, many backward regions mainly rainfed areas remain untouched in the country.

India’s rain-fed regions are incredibly diverse, spanning from high-potential agricultural zones to resource-limited areas. Because these farms rely on unpredictable rainfall, they face constant risks and lower productivity. The primary hurdles are stabilizing crop yields despite shifting weather patterns and implementing effective water management to protect harvests during dry spells.

Assam is rich in surface water, including rivers, lakes, and wetlands, with rainfall serving as the primary source for both surface and groundwater. While monsoon rains are essential for rural and urban supply, inconsistent rainfall patterns often lead to runoff, erosion, or flooding. When this happens, “green water” is lost to the landscape rather than being absorbed by plants, reducing agricultural productivity.Our state receives average annual rainfall of more than 2000 mmwhich equates to around 183236 MCM of rain per year, out of which approximately 31 per cent is lost to the atmosphere in the form of evapo-transpiration, 10 per cent moves into the ground for ground water recharging and 53 per cent flows over the soil surface as surface runoff.

If available surplus runoff wateris harvested and utilized efficiently, then it will definitely help in increasing the cropping intensity as well as crop productivity and will encourage crop diversification in the state.Rice- fallow areas offer good scope for crop intensification and diversification in the state.

One of the reasons behind keeping rice areas fallowduring rabi season is the lack of irrigation facilities.So, the soil moisture deficit condition and the stress associated with rabi crops are solely responsible for instability in crop yield. The success of rainfed farming always depends on rain water harvesting, moisture conservation and proper utilization of moisture but the whole approaches should be on watershed basis.

Rain water harvesting measures involves the optimum utilization of rain water in order to reduce the pressure on ground water. The techniques of water harvesting are different for different physio-topographical conditions and rainfall pattern, but all practices aim at collecting and storing the maximum available rain water and/or surface run-off, so that the same can be used during the lean period for irrigation, drinking and other purposes. The water so conserved also infiltrates and percolates into the soil whichcontributes ground water recharge and improves soil moisture status.

Assam has a rich history of use of traditional systems of water harvesting in the form of pond, well etc. In fact, ponds represent an important community resource for water in rural areas even today. The basic concept of rainwater harvesting for agricultural purpose is to capture precipitation falling on the ground either in storage structure for life saving irrigation or in the crop field itself through some moisture conservation measures.

Construction of farm-pond or community water reservoirs to harvest excess rain-water during rainy season is a feasible strategy to provide life saving irrigation which can be useful for the farmers especially during the winter season (rabi season) to grow crops when rainfall is not so abundant or almost negligible. Rain water harvesting can also be useful for those farmers which depend on rainfall for irrigating crops during monsoon season (kharif season) as the climate is changing and necessary amount of rainfall even during the kharif season is becoming scarce.

Utilization of harvested rain wateras supplemental irrigation at moisture sensitive stages of crop is very much critical for improving the productivity in rainfed agriculture rather than providing stress free period throughout the crop growing period. Proper irrigation scheduling and enhancing the irrigation water use efficiency for per drop more crop are the keys for efficient utilization of harvested water.

Conservation of rain water in the field itself is another important area of rain water harvestingwhich can be achieved by several agronomic and engineering approaches. Soil and crop management practices such as conservation tillage, deep summer ploughing, levelling, bunding, contour cultivation, improving water holding capacity of soil through addition of organic manures, adoption of suitable crops and cropping system for reducing surface runoff, following suitable planting method etc. are some of the approaches for in field moisture conservation in rainfed areas.

Dr. Chinmoy Kumar Sarma, Assam Agricultural University, Jorhat, Mobile- 9957130225

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