The technology and engineering of the traditional water harvesting systems differed, depending on whether they were to provide drinking water or to be used for irrigation.Those meant for drinking water were generally smaller, sometimes covered and with steps leading down to the water.C., while the “Great Bath” was probably a water storage tank.The Indus Valley cities had excellent systems of water harvesting and drainage.Dholavira, laid out on a slope between two storm water channels, is an example of sophisticated engineering.A tank excavated at Sringaverapura near Allahabad, Uttar Pradesh, dates back to the 1st century B. Rama began his 14 year exile from here and could well have drunk water from this tank.The history of India tells us that floods, droughts or both were a perennial occurrence.
Water wheels (araghatta) were used to lift water from the Jhelum.
The structures became more sophisticated and much bigger when the streams turned to rivers. In the arid and semi-arid regions, where the streams are more seasonal, the diversion channels first led the water to a storage structure like a tank for later use.
Storage systems to collect just runoff from the watershed were also built. In the flood plains, several unique systems to control and harness the floodwaters were devised. In regions with good groundwater aquifers, dugwells with innovative methods to lift the water were in use.
Trans Himalayan Region Water from melting snow and ice is the only source of water here. The people made intelligent use of their limited resources and made agriculture possible in this dry and barren land.
The snow and ice melt slowly through the day and water is available in the streams only in the evening, when it is too late for irrigation.