Using Rainwater to Supply Agricultural Water to Fields… RDA’s Non-Powered Technology Cuts Water Shortages by Up to 57%

At the demonstration site in Hapcheon, South Gyeongsang Province, the daily average water shortage, which had reached 98.3㎥, fell to 41.3㎥. The maximum number of consecutive days of water shortage, meaning the period during which drought continued without interruption, was also shortened from 18~21 days to 13~16 days. These figures came from the Hapcheon demonstration site, where there was no electricity, no groundwater well, and no stream of water that could be drawn in and used. There was no power source bringing in the water. Rainwater, the difference in elevation of the terrain, and the pressure generated by the water itself were all there was.

This is the story of the “integrated non-powered agricultural water supply technology” whose development was led by Yu Seok-cheol, a researcher at the Upland Farming Machinery Division of the National Institute of Agricultural Sciences under the Rural Development Administration. With this technology, Yu received the Minister’s Award on September 2 at the “Korea Disaster Safety R&D Awards” hosted by the Ministry of the Interior and Safety. The award has been presented annually since 2019 by the ministry to recognize R&D achievements in disaster safety by universities and research institutes nationwide, and this year 8 people were selected after institutional recommendations and presentation evaluations. 

“An award I received as a representative thanks to the joint research team”

Yu first credited the research team in his remarks on receiving the award. He said, “I did not do this alone; it was thanks to the joint research team,” adding, “Gyeongsang National University, Soonchunhyang University, and the National Institute of Agricultural Sciences carried out the project together, and because the researchers worked so hard, I ended up receiving the award as their representative.” He continued, “Although I applied after being recommended by the National Institute of Agricultural Sciences, I had doubts about whether I could win the award,” adding, “Because I had not expected it, I felt even happier after the judging results were announced.”

The research that led to the award was a joint project conducted from 2023 to 2025, but Yu has spent far longer working on rainwater research. Since 2013, he has steadily continued research using rainwater. He explained the background, saying, “Until now, we had been distributing storage containers for farms in plains to use, but there were limitations in that it is difficult to use wells and groundwater in mid-mountainous areas or highlands,” and “We began this research to develop a technology that can be used without electricity.”

As sudden droughts that develop rapidly over a short period increase due to climate change, the risk of water shortages in upland crop cultivation areas has become constant. In particular, in mid-mountainous and highland cultivation areas, developing wells is difficult and supplying electricity is also challenging, making it hard to apply existing methods of securing alternative water sources such as sewage reuse or groundwater wells. In effect, these areas are blind spots in securing alternative agricultural water.

Collection-pretreatment-storage-transfer, four steps that produce agricultural water without electricity

The developed technology is an integrated system in which the four stages of “collection-pretreatment-storage-transfer” automatically circulate without a power supply. The key is to capture rainfall runoff, which does not seep into the ground when it rains and instead flows away along the surface, and hold it as agricultural water rather than letting it run off.

Asked how it works, Yu explained by following the path of the water. A small runoff channel refers to a small waterway through which water flows along mountain slopes when it rains. He said, “In mid-mountainous areas, we use the small runoff channels where water flows when it rains, connect piping to a collection device, and the water that passes through enters a 5-ton main water tank,” adding, “Large debris is filtered out by the collection device, but smaller material is filtered by a hydrocyclone filter that we developed ourselves.” He continued, “When the main water tank is full, the overflowing water passes through the filter once more and moves on to the next water tank, and the system is designed so that it can reach individual farms and even village units.”

According to the research team, the separation efficiency of the hydrocyclone, which uses centrifugal force to separate soil and foreign matter, is up to 96%, and the maximum collection capacity of the collection device is 8.4㎥ per hour.

The method for sending stored water to fields differs depending on the terrain. Yu explained, “We divide the transfer method between highlands and lowlands; for lowlands, we use the elevation difference so the water flows naturally by gravity, and for highlands we lift it with a hydraulic ram pump.” A hydraulic ram pump is a device that pushes water to a higher place using the pressure generated when flowing water stops, and the non-powered maximum lift of the pump developed by the research team is 12m. That is roughly the height of a four-story building.

At this point, surpassing the limits of commercial products is considered a technical achievement. Yu said, “When we used a commercial hydraulic ram pump, there were problems such as large amounts of water being consumed and high losses due to leaks,” adding, “We supplemented that part by developing the waste check valve, a core component, ourselves, and we have even completed the patent application.”

The research team has filed a total of 4 patents for this technology. They are “Monitoring and Control System for Upland Crop Irrigation”(10-2025-0182493), “Rainfall Runoff Collection and Water Treatment Device, and Method for Treating Rainfall Runoff Using the Same”(10-2025-0046790), “Non-Powered Upland Field Irrigation System”(10-2025-0117299), and “Non-Powered Agricultural Water Supply System Using Rainfall Runoff”(10-2025-0166502). 

Jangsu and Hapcheon, separately verified in two places with different conditions

The research team conducted on-site demonstrations from April 2023 to November 2025 at two locations with different climate and terrain conditions: Jangsu County in Jeonbuk Special Self-Governing Province and Hapcheon County in South Gyeongsang Province. There was a reason for choosing the two sites.

Yu explained, “We decided to try it in places with different topographical and climatic conditions,” adding, “Jangsu is a mid-mountainous area where runoff flows constantly even when it does not rain, while Hapcheon is an area where rainwater can be collected only when it rains.” He continued, “We carried out the demonstration by dividing the sites into a place where water always flows and an area where rainwater gathers, and both places were areas short of water.”

As a result of the demonstrations at the two sites, the daily average water shortage decreased by up to 57%. In Hapcheon County, the water shortage fell from 98.3㎥ per day to 41.3㎥. The maximum number of consecutive days of water shortage was reduced from 18~21 days to 13~16 days, and the integrated system produced an average of 27㎥ per day on its own, supplying irrigation water stably. Even in future climate verification applying SSP2-4.5 and SSP5-8.5 among 18 global climate models (GCMs) and shared socioeconomic pathway (SSP) scenarios, the effect of reducing water shortages was continuously confirmed.

The quality of the stored water also met all agricultural water standards. An analysis of treated water at the demonstration site in Daegok-ri, Janggye-myeon, Jangsu County showed pH 7.87, EC 0.001dS/m, TOC 5.832㎎/L, SS 26.8㎎/L, T-N 0.9㎎/L, and T-P 0.0㎎/L, with all 6 items within the standards. 

Yu explained that the response from farmers was also not bad. He said, “When we demonstrated it in Hapcheon last year, the response from farmers was good,” adding, “We received the assessment that using this technology would make it possible to secure water even in mid-mountainous areas and highlands.” 

A monitoring system that battled moisture in water tanks

The development process was not entirely smooth. Surprisingly, the most difficult part was not the devices that collect and send water, but the monitoring system that allows farmers to check how much water they can use.

Yu said, “We developed an app that allows farmers to check how much water is in the water tank and how much they can use, but during the demonstration, the ultrasonic water level gauge we used lost precision as moisture built up inside the water tank,” adding, “That part became a problem.”

The solution was to change the method of measuring the water level itself. Instead of a non-contact method, the team chose a device that reads the water level by water pressure while submerged. Yu explained, “By switching from an ultrasonic water level gauge to a pressure-type water level gauge, the water level measurement problem was solved,” adding, “This allowed the app-based rainfall runoff monitoring system to operate smoothly.”

Securing durability with field deployment in mind was also a challenge. Yu said, “As we applied and demonstrated it in the field, the durability of the collection device and hydrocyclone became key,” adding, “Because there were issues where it could be damaged or difficult to maintain when distributed, we conducted research with a focus on reducing maintenance costs compared with ordinary equipment so that farmers and field users can maintain and repair it easily.” 

Initial investment cost of 8.7 million won…cheaper than a well

In terms of economic feasibility, which is key to expanding distribution, the system was also assessed as more advantageous than groundwater wells. The initial investment cost of the integrated non-powered system, including 5 five-ton water tanks, is 8.7 million won, 37.4% less than the 13.9 million won cost of a solar-powered groundwater well system. Annual operation and maintenance costs are also 750,000 won, which is 25% lower than the well method (1 million won). The operating costs consist of 500,000 won for water tank cleaning, 150,000 won for replacing consumables such as pipes, valves, joints, and hydraulic ram pump parts, and 100,000 won for outsourcing water quality analysis.

Yu said, “When we evaluated the economics, the facility installation cost was in the 8 million won range, whereas installing a groundwater well costs around 14 million won,” adding, “We believe our technology is more economical than groundwater wells, and that is why we expect expanded distribution.” 

Goal of reflecting it in a 2027 project…also for livestock, landscaping, and firefighting water

The technology is already moving into the policy stage. In December 2025, the research team made a policy proposal to the Ministry of Agriculture, Food and Rural Affairs, requesting that it be included among the support targets for the “Water Development Project in Preparation for Drought.” Yu said, “It is currently being promoted, and we are trying to commercialize it with 2027 as the target,” adding, “Local governments are also contacting us, saying they are curious about this technology.” He continued, “When we spoke again with the agriculture ministry, they said it could be reflected if there is demand from local governments,” adding, “We believe it can be reflected if requests from local governments continue, so we are pushing ahead continuously.”

The plan is also to expand the fields of application. Yu said, “We believe it can be fully used not only in agriculture but also in livestock farming and landscaping, and we plan to expand it to fields outside agriculture.” He also mentioned the possibility of using it for emergency water supply in disaster response, especially as firefighting water. He said, “Because stored water can be used in urgent situations such as fires simply by connecting a hose, I think that part is also fully possible.” Regarding overseas application, he also said, “I believe it can be sufficiently integrated.”

Because the structure allows water tanks to be increased step by step, the supply scale can also be expanded. Yu explained, “Since it is a method of installing water tanks in stages, it can supply enough water for most rural villages.”

The center of gravity for follow-up research is shifting from technology development to dissemination. Yu said, “We have been conducting rainwater research for a long time, and I think we have secured advanced technology,” adding, “What matters is how much we expand and disseminate this technology.” He also cited the fact that Lee Seung-don, Administrator of the Rural Development Administration, has emphasized technology dissemination. Yu said, “As the administrator also emphasizes dissemination, for follow-up research we plan to pursue demonstration research aimed at expanding dissemination and the designation of this as new-technology agricultural machinery.” Expansion into a hybrid method linked with small-scale groundwater in preparation for extreme drought is also under consideration. 

From greenhouse disaster resistance to rainwater, and then to agricultural machinery safety

Yu joined the Disaster Prevention Engineering Division of the Agricultural Engineering Department at the National Institute of Agricultural Sciences through open recruitment in October 2013. His research trajectory runs through disaster and safety issues in agricultural fields. Since 2016, he has conducted research on the safety of disaster-resistant facilities for greenhouses in the horticultural and specialty crop fields at the Disaster Prevention Engineering Division, and as his laboratory was incorporated into the Upland Farming Machinery Division last year, he shifted his focus to research centered on production infrastructure safety. He is currently also conducting research in the field of agricultural machinery safety. This research analyzes the actual use of agricultural machinery using GPS data, and at a pilot complex in Baeksan-myeon, Gimje City, Jeonbuk Special Self-Governing Province, GPS terminals are attached to tractors, rice transplanters, and combines to analyze the level of work optimization. Yu explained, “In the farm work outsourcing conducted by the Baeksan Agricultural Cooperative, we attach terminals to combines and other machines and analyze the workload using GPS data.”

Asked what he would like to say to farmers struggling with drought, Yu returned once again to the field. He said, “Climate change is becoming so severe that farming is getting more difficult by the day,” adding, “In this situation, we will strive to create technologies that are useful in the field so that our research can help ease the difficulties of farmers, even if only a little.”