The dissertation follows an article-based PhD structure, where the summary text contextualizes and synthesizes the three articles of my PhD dissertation. These articles cover the scientific approach and results of separate project-based work carried out along the Tisza River in recent years. I have been involved in these projects as a project leader and analyst. At the Tisza River, the development of flood-peak polders (in line with the Further Development of the Vásárhelyi Plan Program – or VTT according to the Hungarian acronym) was a significant initiative in terms of flood management and rural development in the period 2000-2020, but the assessment of its results from a policy implementation perspective is not unanimous. The aim of the thesis is, among other things, to describe the scientific context of these partly successful (flood management) and partially unsuccessful (rural development, land-use change) results. I believe that without a coherent interpretation, no further progress can be expected in the related policy field, although the reasons for the partial failure will be key issues in the implementation of any climate policy goal requiring territorial adaptation. For this interpretation, I address the development process of the Tisza flood-peak polders through the perspective of Spatial Flood Risk Management (SFRM), an emerging approach. The thesis reflects on the issues that gave rise to it, its characteristics, and why and how it can be used to support the implementation of flood risk management projects that require the involvement of private land. This is one stream of the work. Another source of added value of the PhD thesis is that it contributes to understanding the impact of technological development on the potential conducting economic analyses. Technical advances in flood-risk mapping have now made it possible to apply a reliable cost-benefit- and, consequently, a provider-beneficiary approach to the organization of flood defense from a spatial perspective, which includes the value of flood risk reduction among the benefits. Moreover, the flood-risk modification potential of these spots (sites) can also be expressed, depending on assumptions about land use. This new situation will allow more effective solutions to flood-risk reduction to be developed. This can be exploited by making a cross-sectoral comparison of public and private impacts and their relationship to land use alternatives in a monetizable form. The dissertation explores these potentials based on the experience gained from the flood-peak polder development process of the Tisza River. The second part consists of the articles that provide the background for the synthesis and the summary of the work. The first paper, Reducing flood risk by effective use of flood-peak polders: A case study of the Tisza River (Ungvári & Kis, 2022b), presents the methodological development and results of a flood-risk calculation-based economic support system for the management of the Tisza River flood-peak polders. The second, Combining Flood Risk Mitigation and Carbon Sequestration to Optimize Sustainable Land Management Schemes: Experiences from the Middle-Section of Hungary's Tisza River (Ungvári, 2022), presents the results of cost-benefit analyses that support the multi-criteria utilization of land suitable for flood-risk mitigation. The third article, Social, economic, and legal aspects of polder implementation for flood risk management in Poland and Hungary (Warachowska et al., 2023), compares the regulatory approaches underlying the operation of flood-peak polders on the Tisza River and the Warta River in Poland.
