Many thought that given the disadvantages and rising resistance against the multipurpose projects, water harvesting system was a viable alternative, both socioeconomically and environmentally. In ancient India, along with the sophisticated hydraulic structures, there existed an extraordinary tradition of water-harvesting system. People had in depth knowledge of rainfall regimes and soil types and developed wide ranging techniques to harvest rainwater, groundwater, river water and floodwater in keeping with the local ecological conditions and their water needs. In hill and mountainous regions, people built diversions channels like the 'guls' and 'kuls' of the western Himalayas for agriculture. Rooftop rainwater harvesting was commonly practiced to store drinking water, particularly in Rajasthan. In the floodplains of Bengal, people developed inundation channels to irrigate their fields. In arid and semi-arid regions, agricultural field were converted into rain fed storage structures that allowed the water to stand and moisten the soil like the 'khadins' in Jaisalmer and 'johads' in other parts of Rajasthan.