Dr Mandeep Singh Azad and Dr Manmeet Motan
Crops are like babies. They have very specific requirements growing up, viz temperature, pH, moisture etc. Most crops require water during or shortly after the growing season. They are susceptible to water logging in the harvesting season. The recent rains in parts of India have been detrimental to precisely these crops. Water logging saturates sub-soil, suffocating plant roots. It also creates very conducive conditions for pests and microbes to thrive, effectively washing away whatever pesticide, insecticide has been sprayed upon the crops. The moist produce is difficult to harvest, harvesters are known to have consumed more diesel, after light rains.
This year the worst affected crop has been potato. Mustard, gram, wheat, coarse grains and onions have been badly damaged as well. Today, India ranks second worldwide in farm output. Agriculture and allied sectors like forestry and logging accounted for 16.6% of the GDP in 2007, employed 52% of the total workforce and despite a steady decline of its share in the GDP, is still the largest economic sector and plays a significant role in the overall socio-economic development of India..India’s population is growing faster than its ability to produce rice and wheat. It is predicted that India will soon be able to sustain and stabilize its food demand and supply by the year 2020!.But untimely heavy rains are making it difficult for farmers to save their produce.
Water Harvesting the need of hour
Our country gets about 4000 billion cubic meters of water from the sky. Out of which only about one-fourth of this is actually usable, as the rest runs off into the sea and evaporates. This quantum remains more or less constant, though there are regional variations subject to local landforms and rock structures. Whatever we could do for impounding water has been done to a large extent, there are about 4500 large dams in our country and thousands of small water-holding structures. Over the last century or so, India’s population has quadrupled. The average availability of usable water has correspondingly decreased from about 6000 cubic meter per capita per day to 1500 to 1800 meter per capita per day. Since ages, natural water bodies have been satisfying the quench, of the inhabitants of this state. Unfortunately, in the last 4-5 decades owing to negligence and greed of ‘we’ the consumers, fresh water resources have witnessed a considerable decline in their water quality and quantity. The ever-increasing groundwater depletion is a major threat to people. Studies have revealed that there is a decrease of 1ft. to 4ft. annually in the ground water level of this region. We have to stop being the victims of the vagaries of nature, it calls for tightening our belts and starting a mass revolution.
Some of the common queries that play on the minds of people are, What is rain water harvesting? Does it work? Can we harvest rain in our own house? Who benefits? What will be the quality of water? How much does it cost? To put it simply, Rain water harvesting means catching and holding rain where it falls and using it. We can store it in tanks or can use it to recharge groundwater. Our ancestors harvested rain just as naturally as they tilled the ground to grow crops. We lost touch with these local solutions. But now, as the taps dry up, more and more people are reviving this age-old system and practicing it very successfully. Structures to harvest rain require little space. A dried bore well, a row of soak pits or a tank concealed below the ground are all that we need. The open spaces, rooftops and ground can be used as catchment (surface to catch rain). By this, our groundwater will be recharged, and as groundwater moves, our neighborhood will gain too. While doing it we have to be careful not to direct sewage water into it. Rain water is like distilled water. Water is in its purest form as rain, if we do not mix it with other contaminants. Cost is calculated based on the size of the building and various other considerations. We have to realize the importance of conserving water and take it as our own responsibility to rectify the situation and not look towards the Government for everything. It is so easy to sit comfortably in our homes and criticize others and the government for not doing anything, we have to awaken to the fact that we are the ones creating the problem so we should be the ones to solve it. Unless each and every one of us do our little bit the problem will worsen.
Easy Ways to harvest rain water: Roofs made of corrugated iron sheet, asbestos sheet or tiles can be utilized for harvesting the rainwater. If the roof is thatched, polythene sheets can be used for collecting the rainwater The collected rainwater is filtered through a filter filled with pebbles in the bottom and coarse sand on the top. The filtered water is collected either in storage tank of existing sump and the overflow water may be diverted to percolation pit nearby.
Individual houses Existing Open well: Rainwater from the terrace is diverted to the existing open well using PVC pipes through a filter chamber. The minimum size of the filter chamber is 2.5′ x 2.5′ x 2.5′ filled with broken bricks/ blue metal / pebbles and sand on the top. The chamber may be covered with RCC slab.
Existing Bore well: Settlement / filter tank of required size has to be provided. Overflow water may be diverted to a percolation pit nearby .The rate of recharge through bore well is less effective than open well. Defunct bore wells may also be used.
Multi-storied complexes Percolation Pit with Bore method: Construct one unit for 300 sq.ft. area (approx.).Construct a chamber of size 1 m x 1m x 1m.A bore hole is to be drilled at the bottom of the percolation pit. Bore hole size 150 – 300mm dia with 10 – 15 ft. depth (approx.).Filled with broken bricks/blue metal/pebbles. Suitable for clay area
Recharge well (shallow / small):This is meant for large area with heavy run-off.Size : 3′ dia with 5′ – 15′ depth. Constructed with concrete well rings. Side walls must be perforated. Bottom 1′ is filled with broken bricks (for cushion).Covered with RCC slab/man hole. Suitable for sandy sub-soil area.
Many areas that experience drought, also have excessive rainfall during the rainy season.If the rain is saved, it can provide enough water to irrigate a farmer’s land throughout the dry season. Capturing this water and storing it as surface water is called rainwater harvesting. By conserving the monsoon rain, farmers can increase the area they irrigate, grow crops in the dry season, support livestock and even recharge groundwater. This means better food provision for their families and higher incomes. Stored rainwater also provides families with water for their household needs. Ex-situ, or decentralized, rainwater harvesting refers to any structures built to capture rain. These could be ponds, tanks, or reservoirs and can be owned individually or communally. They are all shapes and sizes, depending on the amount of rainfall and the size of land available, the suitability of the location and above all, the needs of the farmer.There are other practices which help conserve the rain as it falls in the field. Building bunds or terraces increases the moisture retention of the soil and keeps rainwater where it is needed, around the crops. This is known as in-situ rainwater harvesting.
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