New Delhi: In an initiative to strengthen water security in India's arid and semi-arid regions, the scientists of Indian Council of Agricultural Research (ICAR)-Central Arid Zone Research Institute (CAZRI) have developed innovative rainwater-harvesting models that can help farmers capture and store rainwater from intense rainfall for use during dry periods.
Explaining the innovation of rain water at arid zone, Deepesh Machiwal, principal scientist in ICAR-CAZRI told “The institute has developed two models – a single-pond system and a double-pond cascade system comprising two interconnected ponds – to harvest and conserve rainwater. The models are designed to capture runoff during heavy rainfall and store it for subsequent agricultural use, particularly in regions where rainfall is limited, erratic and increasingly concentrated in intense weather events.”
The initiative has resulted in the construction of three ponds at the institute, with a combined storage capacity of around 38 lakh litres, he added.
Scientists believe that the cascade-based model could offer practical advantages to farmers, particularly in terms of maintenance, operational convenience and management of water losses. The technology is also expected to provide an additional source of water security in areas where farmers frequently face shortages during prolonged dry spells.
Two-Pond System For Easy Maintenance
Principal Scientist Machiwal said that one of the important features of the initiative is the comparison between a conventional single large pond and a cascade system in which the same storage capacity is divided between two smaller ponds.
Explaining the advantages, he said the single-pond model developed at the institute has a top surface area of approximately 35 metres by 20 metres. Maintaining such a large water-harvesting structure can be challenging because water remains spread across a relatively extensive surface area. In comparison, dividing the storage capacity into two interconnected ponds makes maintenance easier. If one pond requires cleaning, repairs or other maintenance work, the activity can be carried out without disturbing the other pond, which can continue to retain water.
The scientist pointed out that the construction costs of both models are almost similar. Expenses associated with excavation through JCB machines and installation of plastic or high-density polyethylene (HDPE) sheets do not differ significantly.
"From the perspective of maintenance and operational efficiency, I find the cascade system more useful. We can undertake maintenance work in one pond while keeping the other pond intact," the scientist described.
ICAR is also examining whether the arrangement of two interconnected ponds can help reduce evaporation-related water losses compared with a single large pond. This is particularly relevant for arid regions, where high temperatures and prolonged dry periods can result in substantial water loss.
Harvesting Rainwater From Intense Storm
A major challenge in arid regions is that rainfall is often irregular and concentrated in a few intense spells. A large volume of runoff may be generated during a single storm, making it essential to have adequate infrastructure to capture and store the water before it flows away.
According to the scientist, rainfall patterns have changed considerably over the years, with the region increasingly experiencing high-intensity rainfall events.
Based on observations during the last six to seven years at CAZRI, the scientist said they receive at least one major rainfall every year that has the potential to generate around one crore litres of harvestable water. However, the current rainwater-harvesting infrastructure has a combined storage capacity of only around 38 lakh litres. Consequently, a single intense rainfall can be sufficient to fill all the ponds.
"It is not necessary that one rainfall event fills the ponds partially and another event adds more water. A single storm can be sufficient to fill all the ponds. If we miss that rainfall event, we may lose the opportunity to harvest such a large volume of water," Machiwal said.
The performance of the system during 2026 has provided an encouraging observation. Machiwal said that despite relatively low rainfall during the year, which he associated with El Niño conditions, all the ponds at the institute were full. He described this as an encouraging indication of the potential of rainwater harvesting in water-stressed regions.
For farmers, the ability to capture a large volume of rainwater during available rainfall events could provide an important buffer against subsequent dry spells. Stored water can potentially be used for protective irrigation, crop establishment and other agricultural requirements, depending on the available quantity and farm-level requirements.
Benefits For Farmers In Drought-Prone Regions
Taking the initiative beyond the institute and making the technology accessible to farmers is one of the important objectives of the project. Under this component, CAZRI plans to organise field days and workshops to bring farmers to the institute and demonstrate the rainwater-harvesting models.
The objective is to familiarise them with the construction, functioning, maintenance and potential agricultural applications of the structures. The scientists also intend to implement the technology on the fields of at least three farmers as part of efforts to demonstrate its practical application under actual farming conditions. CAZRI aims to expand the reach of the technology and take rainwater-harvesting solutions directly to farmers' fields.
For farmers in arid and semi-arid areas, rainwater harvesting can play an important role in reducing dependence on uncertain rainfall and providing supplementary water during critical stages of crop growth. The two-pond cascade arrangement could offer several practical advantages.
The initiative assumes significance as climate variability and irregular rainfall increasingly complicate agricultural planning in dryland regions. Rather than allowing intense rainfall to go unutilised, scientifically designed storage structures can help convert short-duration rainfall events into a resource for agriculture.