In July 2024, the strong Typhoon Gaemi ravaged Taiwan, with unprecedented force, triggering a record 20 consecutive hazardous rainfalls and national emergency alerts within two days. Flooding occurred in the Central and Southern Taiwan. Fortunately, when the alerts sounded, the self-precaution community against flood volunteers from Yunlin, Chiayi, and Tainan demonstrated exceptional capabilities in evacuating residents, particularly high-risk groups, and proactively provided food and necessary assistance. One of the key drivers in nurturing this group of volunteers was Professor Jet-Chau Wen, a distinguished professor at the Department of Safety Health and Environmental Engineering at the National Yunlin University of Science and Technology, who has been counseling communities for many years and promoting the concept of non-engineering disaster prevention.

A sense of mission for reducing land subsidence speed in Yunlin and Changhua by 60%

“The true value of hydraulic engineering lies in addressing practical needs; it must be applied to people's livelihoods, agriculture, or industry. For this reason, I’ve always believed that hydraulic engineering is an applied science.” This pithy statement by Professor Wen reveals the key motivation and sense of mission that led to his receiving the 7th National Award for Distinguished Contribution to Industry-Academia Cooperation.

Over the past decade, Professor Wen has carried out 54 industry-academia cooperation projects, with total funding exceeding NT$173 million. Most of these projects were in collaboration with the Water Resources Agency, Ministry of Economic Affairs, addressing urgent issues in Yunlin and Chiayi, particularly the challenges of land subsidence. He proudly states, “Since 1997, when I began teaching at the National Yunlin University of Science and Technology, I’ve been committed to land subsidence prevention and management. I personally led students on field surveys to Yunlin and Changhua, and promoted land subsidence prevention and groundwater recharge along the High-Speed Rail line. Despite initial skepticism, the results proved that my research was on the right track.”

The Taiwan High-Speed Rail (THSR) was launched in 2007, but in 2006, Professor Wen had already noticed the severity of land subsidence near THSR stations. After consulting with the water resources authorities, he proposed a short-term solution: the shutting down of public deep wells within three kilometers of the THSR route. These wells, ranging from 75 to 100 meters deep, were in areas where soil water pressure was decreasing most significantly. Despite initial doubts, after closing 98 wells from 2007 to 2008, the rate of land subsidence dropped sharply from 12.5cm/year to 7cm, and thus dispelled skepticism.

“While land subsidence was alleviated, closing wells was impractical, especially given the high demand for agricultural irrigation using groundwater. Thus, a medium-term plan was proposed: increase groundwater recharge to balance the extraction rate.” Professor Wen recalls that they initially attempted to manufacture a dam within the watercourse to slow water flow and improve groundwater infiltration. However, the project was halted due to flooding risks and high costs. Still firmly believing in groundwater recharge, he proposed the innovative concept of using “water coverage” to “plant water in the soil.”

Professor Wen’s team modified their approach by deepening specific areas during river desilting to better retain water and increase infiltration. He says, “The results were astonishing! In the first year, the recharge volume was equivalent to 28% of the Hushan Reservoir’s capacity. Even during the severe drought of 2021, this method ensured agricultural irrigation. And by watering riverbeds, we reduced dust stirred up by the northeast monsoon.”

Reflecting on his beginnings, Professor Wen says with emotion, “Over a decade ago, during field surveys, I deeply felt people’s struggles. It motivated me to find a way to help them.” Today, the rate of land subsidence in Yunlin and Changhua has decreased from 12.5cm/year to 4–5cm. His perseverance and efforts have earned him the residents’ gratitude and trust.

Innovating out of necessity: the multilevel concentric well pipe

When asked about his continuous innovation, Professor Wen laughs and says, “Innovation often stems from real needs and urgent problems to solve.” For instance, advanced foreign groundwater monitoring systems cost hundreds of thousands of dollars, a heavy burden for the research team, so they developed their own systems, significantly reducing costs while meeting local research needs.

Professor Wen’s independently developed and patented system, the multilevel concentric well pipe, won the 20th National Innovation Award. This innovative groundwater monitoring device was created to vertically monitor groundwater recharge.

“At the time, some questioned the effectiveness of our recharge process, asking difficult questions like, ‘How much infiltration is actually occurring?’ and, ‘How does the infiltrated water move through the subsurface?’ Traditional observation wells could only accurately measure average water depth, not precise vertical water table changes. Advanced foreign monitoring technology could do it, but it was too expensive. As a result, we drew inspiration from CT scanning to ‘scan’ the hidden soil and subsurface water layer structures,” Professor Wen explains.

He elaborates that, similar to how doctors use CT scans to create 3D images of internal organs, the team applied a comparable concept to develop technology that generated 3D images of subsurface layers. Although scanning the vast scope of soil in one go is impossible, they achieved their goal in two steps.

First, the multilevel concentric well pipe was designed as a large one-piece pipe internally separated into several independent channels. Each channel could have well screens installed at different depths to simultaneously monitor and collect groundwater data and samples. This design avoided the limitations of traditional “single-hole single-pipe” systems that could not provide multi-depth measurements simultaneously and “single-hole multi-pipe” setups that were prone to tangled and deformed pipes. It also significantly reduced installation costs, geological disruption, and carbon emissions compared to traditional observation wells, making it an environmentally friendly product.

The second step was installing the device in five groundwater wells within a defined area. Using the mathematical principle that three points determine a plane, the team mapped the distribution and structure of the underground aquifer, akin to conducting a CT scan of the subsurface layers, to generate detailed 3D images.

Professor Wen reveals, “I’m developing a second-generation device, and our partner manufacturers have already begun designing the molds. I hope this will enhance the competitiveness of Taiwan’s well-drilling industry. Additionally, I’ve overcome the domestic technical barriers to measuring water flow in the unsaturated zone and also developed a device capable of measuring water content up to 30 meters below the surface. In the future, I’ll apply for a patent to showcase Taiwan’s exemplary technology to the world.”

How should Taiwan handle extreme rainfall and frequent flooding?

Reflecting on his past, Professor Wen recalls how, as a college junior, he stood beside an irrigation canal and witnessed firsthand how water flow patterns change with volume and speed. The theories from his textbooks instantly came to life, sparking his deep interest in hydraulic engineering. During his doctoral studies in the United States, he learned about El Niño and La Niña, embedding the concept of sustainability in his mind. After returning home, whether promoting soil and water conservation or disaster prevention projects, he always prioritized sustainability.

In recent years, Professor Wen’s team has been actively developing innovative water pollution treatments, particularly using agricultural waste like fruit peels and seeds as bio-adsorbents. They have combined these with magnetic materials and advanced oxidation techniques to tackle water pollution challenges. He believes, “Adsorbent materials are the future of water treatment. Our goal is to make them reusable, recover the adsorbed pollutants for reuse, and integrate them into the industrial chain—not only reducing waste but also promoting a circular economy.”

Additionally, in response to the global issue of flooding caused by extreme rainfall, Professor Wen has proposed five recommendations according to the situation of Taiwan: (1) Strengthen soil and water conservation, (2) enhance smart water resource management, particularly by promoting rainwater collection and reusable systems, (3) upgrade disaster prevention infrastructure, (4) promote community participatory education while establishing the golden principle of disaster response, which is “self-rescue: mutual aid: public assistance = 7:2:1,” and (5) improve policy and regulatory support.

He emphasizes that only by implementing these five measures will Taiwan be able to effectively address climate change and enhance overall disaster resilience. Raising public awareness and self-reliance in disaster response is essential to reducing disaster damage.

Principle of cultivating talent: theory and practice on an equal footing

Professor Wen sincerely states, “I have always believed that the value of knowledge lies not only in innovating but also in passing it down. Over the years, I’ve particularly focused on nurturing young scholars by passing on the experiences and techniques I’ve accumulated. I firmly believe that only by passing it on to the next generation can we ensure the continued advancement of disaster prevention technology research.”

He emphasizes that soil and water conservation and disaster prevention technology are expert fields that balance theory and practice. “On top of a solid foundational knowledge, practical experience must be accumulated, and new techniques should be continually learned. The most important thing is to keep doing the hard work—that will take you far.”