Efficient Harvesting and Conserved Rainwater Utilization for Sustainable Agriculture

摘要

The objectives of rainwater harvesting are essentially aimed at conservation and efficient utilization for sustainability of living beings. Rainwater can be stored for direct use or can be re-charged into ground. Over extraction of groundwater resource and indiscriminate use of groundwater caused a drastic depletion of the water table and which resulted a lot of serious problems. Groundwater reservoir was primarily replenished by the annual precipitation received in a particular area. The rate of entering water to under ground reservoir was depended on pattern of rainfall, run-off, stream flow, permeability of the soils and earth materials present prior to reach the water up to the zone of saturation. Under these stated conditions, increasing groundwater recharge substantially could only be assured the greater recharge of the aquifers. The upper limit of the groundwater extraction should be not more that annual amount of recharge. But actually, introduction of intensive agriculture with high yielding fertilizer and irrigation responsive photo-insensitive short duration cultivars particularly of rice that grow three/four times a year that required high volume of water, which are being extracted from the groundwater. The upper limit has already been crossed and posed severe problems due to draw down effect and thereby lowering the water table. The problems of arsenic, iron concentration and heavy metal contaminations have increased severely. The natural springs abolished from the farmers' field. The hand pumps are not workable at various places. The sands are coming with ground water extraction through submersible pumps. The deep tube wells are being inaction at several places. The use of surface water would become also to be more effective and helpful to mitigate the arsenic like problems. As the possibility of contamination of arsenic are very less in surface water, only the flowing surface water is the safest source that is free from arsenic. So there was an endeavor to add the groundwater as much as possible taking all possible measures for its purification (avoiding all sorts of contamination following de-germs chambers to be constructed for the purpose) and taking off water at need without hampering the water table.