Between September 14–18, Budapest hosted the 53rd World Congress of the International Association of Hydrogeologists (IAH), where experts discussed the future of groundwater, water scarcity, adaptation to climate change, and opportunities for sustainable water management. Some 856 professionals from over 70 countries arrived in Budapest for the event.
At the opening ceremony, Anita Orbán (Minister of Foreign Affairs), Lénárd Darázs (Rector of ELTE), Mihály Pósfai (President of the Hungarian Academy of Sciences), Balázs Horváth (Deputy State Secretary), Judit Mádlné Szőnyi (Vice-Rector of ELTE and Chair of the IAH 2026 Scientific Committee), and Teodóra Szőcs (President of IAH) all gave speeches. Abou Amani, Director of UNESCO’s Water Science Division, welcomed participants in a video message. The chief organizer of the Congress was Anita Erőss, a researcher at ELTE.
Groundwater is invisible from the surface—but its significance is increasingly apparent. Droughts, water scarcity, changing precipitation patterns, and growing water demand worldwide are shining a spotlight on those underground water resources essential for drinking water, agriculture, ecosystems, and energy production.
These questions were at the center of the IAH 53rd World Congress, with the main theme “Groundwater – A Key Multi-Resource”, highlighting groundwater as a crucial, multifaceted resource. One of the world’s most significant hydrogeology professional events returned to Hungary after half a century. Researchers, engineers, water professionals, policymakers, industry representatives, and international organizations all met at the congress.
“Groundwater has perhaps never been as important as it is today. Raising awareness of hydrogeology is more crucial than ever before. Groundwater is invisible, and too often remains out of sight even beyond the expert community,” said Anita Erőss, chief organizer of the congress. She emphasized that hydrogeologists’ mission isn’t only to expand scientific knowledge, but also to communicate it in ways that inform, engage, and inspire society.
Where Science Meets Decision-Making
At the opening, Anita Orbán, Minister of Foreign Affairs, spoke about the strategic importance of groundwater. “Groundwater is especially important for Hungary because nearly 95 percent of drinking water supplies are drawn from underground sources,” she said. She stressed that protecting groundwater resources is growing in importance due to droughts, population, agricultural and industrial water demand, and pollution risks, highlighting the indispensable expertise of hydrogeologists in securing water safety.
“The scientific community also plays a vital role: it draws policymakers’ attention to issues, contributes to data-driven decision-making, pioneers innovative solutions, and shares knowledge and experience around the world,” she said.
Mihály Pósfai, President of the Hungarian Academy of Sciences, noted that water availability, quality and unequal distribution are now major scientific and social challenges. He recalled a professor from the 1980s saying that the most important task for future geologists would be finding water—back then, this seemed unlikely since Hungary was considered water-rich. After this summer’s drought, however, the prediction looks very different. The congress underscored the increasingly important ties between science, education, policy and practical water management.
Balázs Horváth, Deputy State Secretary for Water Affairs at the Ministry for the Living Environment, spoke about the importance of groundwater and the challenges of domestic water retention. He described groundwater as “one of our most valuable and least visible natural resources,” and emphasized that climate change is exerting ever-greater pressure on water reserves. As he explained, Hungary is developing a new water retention concept and action plan focused on nature-based solutions and keeping water in the landscape. “Water must remain in the landscape as long as possible, and we must use it more efficiently,” he said.
Lénárd Darázs, Rector of ELTE, spoke about the growing importance of sustainability and water issues. He emphasized that understanding water-related problems accurately and identifying responsible solutions must be grounded in science. He also highlighted the need for a multifaceted approach to water questions.
Participants at the congress discussed current research findings and practical experiences related to groundwater in more than thirty sections and numerous plenary talks. Topics included climate change and water resources, aridification, groundwater replenishment and monitoring, the integrated management of surface and groundwater, pollution assessment, geothermal energy, and the application of new digital and AI-based methods.
Hungarian Hydrogeological Tradition and International Cooperation
The Budapest congress was also a significant event for the international recognition of Hungarian hydrogeology. The IAH World Congress last visited Hungary in 1976, so after fifty years, the event returned to the country.
Teodóra Szőcs, President of the International Association of Hydrogeologists (IAH), noted that the Budapest congress is a special occasion in IAH’s history: since the Hungarian national chapter was founded in 2006, organizing a world congress in Hungary has been a longstanding goal. She called attention to groundwater’s role in water, food, and energy security, and also discussed IAH initiatives related to the 2026 UN World Water Conference.
Judit Mádlné Szőnyi, Vice-Rector of ELTE and Chair of the IAH 2026 Scientific Committee, commemorated her former mentor, world-renowned hydrogeologist József Tóth, who passed away in Edmonton in the summer of 2026. She said the researcher, considered one of the defining hydrogeologists of the twentieth century, fundamentally transformed scientific thinking about groundwater flows with his revolutionary theory. József Tóth supported Hungarian hydrogeology for over three decades, contributed to the strengthening of the domestic hydrogeological school, and played a key role in connecting Hungarian hydrogeologists with the international professional community. Mádlné Szőnyi Judit emphasized that his legacy lives on in research, education, and water management. As part of the tribute, the audience listened to Professor József Tóth’s video message, recorded in 2025 for the participants of this year’s conference. video message.
Researchers and students from the ELTE Faculty of Science, Tóth József and Erzsébet Hydrogeology Professorship played a prominent role in organizing the conference, serving on the scientific committee, and overseeing its implementation. The ELTE Faculty of Science hosted the conference courses and the board meeting. Faculty members and students presented their research findings through numerous oral presentations and posters.
In addition to serving as a meeting place for the IAH professional community, the conference also provided an opportunity to strengthen international cooperation. Groundwater systems extend across national borders, and their management therefore requires international scientific collaboration and knowledge sharing.
One of the key outcomes of the IAH 2026 World Congress was the Budapest Declaration on Groundwater, which highlights the role of groundwater in global water policy.
This initiative is particularly timely ahead of the United Nations Water Conference, which will be held in Abu Dhabi in December.
"We are proud that Budapest can be associated with international water policy not only as the host city of the 53rd IAH World Congress, but also as the city whose name is given to this important message," said Anita Erőss, the congress's chief organizer.
The organization of the World Congress was made possible with the support of numerous sponsors and partners, including the ELTE Excellence Fund and the NKFIH Mecenatúra grant programme. Project No. MEC_SZ 157097 is being implemented with funding from the MEC_SZ_26 grant programme, supported by the National Research, Development and Innovation Fund of the Ministry of Culture and Innovation.
A Kolodko Miniature Statue and the "Olympic Torch"
In connection with Hungary hosting the world's leading professional event dedicated to groundwater, the Hungarian National Chapter of the IAH and the Tóth József and Erzsébet Hydrogeology Professorship Foundation wanted to create a lasting memorial. As part of this initiative, they proposed the creation of a new memorial to Vilmos Zsigmondy that would also appeal to the general public.
The renowned guerrilla sculptor Mihály Kolodko, famous for his miniature statues found throughout Budapest, was commissioned to bring the idea to life. The result is a Kolodko miniature statue depicting Vilmos Zsigmondy, which commemorates both one of the pioneers of Hungarian hydrogeology and Budapest's extraordinary groundwater resources, whose exploration Zsigmondy played a key role in advancing.
A QR code located next to the statue also gives it an educational purpose, allowing visitors to learn about the creation of the statue, Zsigmondy himself, and the little-known world of groundwater.
On the occasion of the Budapest conference, however, a second version of the Kolodko miniature statue was also created specifically for professionals, in addition to the one accessible to the general public. This travelling statue will accompany the Hungarian hydrogeological community to professional meetings from now on.
Another interesting tradition is that hydrogeology world congresses have their own so-called "Olympic torch": a water bottle into which each host country pours a water sample during the congress. For the Budapest congress, this water sample was collected from the well drilled by Vilmos Zsigmondy in Heroes’ Square.