Hydro-meteorological risks are a growing issue for societies, economies and environments around the world. An effective, sustainable response to such risks and their future uncertainty requires a paradigm shift in our research and practical efforts. In this respect, Nature-Based Solutions (NBSs) offer the potential to achieve a more effective and flexible response to hydro-meteorological risks while also enhancing human well-being and biodiversity. The present paper describes a new methodology that incorporates stakeholders’ preferences into a multi-criteria analysis framework, as part of a tool for selecting risk mitigation measures. The methodology has been applied to Tamnava river basin in Serbia and Nangang river basin in Taiwan within the EC-funded RECONECT project. The results highlight the importance of involving stakeholders in the early stages of projects in order to achieve successful implementation of NBSs. The methodology can assist decision-makers in formulating desirable benefits and co-benefits and can enable a systematic and transparent NBSs planning process.

The 2022 European drought has underscored critical deficiencies in European water management. This paper explores these shortcomings and suggests a way forward for European drought risk management. In particular, we focus on four key aspects: the increasing drought risk, its spatial and temporal impacts, current management approaches, and how these differ across Europe. We base our findings on a continent-wide survey of water managers involved in responding to the 2022 drought. The survey collected 481 responses from 30 European countries and contained 19 questions on perceived sectorial impacts and the drought risk management practices implemented by the respondents' organizations. Information from the survey was supported with climate-related data on drought severity as quantified by the Standardised Precipitation Evapotranspiration Index, to offer a comprehensive overview of how extreme historical droughts are managed across Europe. Our findings reveal a consensus on the growing risk of drought, driven by droughts' rising frequency and intensity. While the 2022 event affected most of the continent, our findings show significant regional disparities in management capacity. In many countries – particularly those with agriculture-dominated economies – drought responses remain short-term and reactive, often leading to potentially maladaptive practices. Despite these challenges, we also observe a positive shift, with organizations showing increased awareness and preparedness. Hence, the lessons learnt from the 2022 event may provide an ideal opportunity to mainstream European-wide drought risk management. To seize this opportunity, we advocate for a European Drought Directive, to harmonize and enforce risk management policies across the continent. This directive should promote a systemic, integrated, and long-term risk management perspective. It should also set clear guidelines at the national and sub-national level, and for cross-boundary drought collaboration. This study and its companion paper, “From Crisis to Capacity: Institutional Preparedness and Response During the 2022 European Drought”, result from work carried out by the Drought in the Anthropocene network, an initiative of the International Association of Hydrological Sciences (IAHS).

Mitigation of adverse effects of global warming relies on accurate flow projections under climate change. These projections usually focus on changes in hydrological signatures, such as 100-year floods, which are estimated through statistical analyses of simulated flows under baseline and future conditions. However, models used for these simulations are traditionally calibrated to reproduce entire flow series, rather than statistics of hydrological signatures. Here, we consider this dichotomy by testing whether performance indicators (e.g. Nash-Sutcliffe coefficient) are informative about model ability to reproduce distributions and trends in the signatures. Results of streamflow simulations in 50 high-latitude catchments with the 3DNet-Catch model show that high model performances according to traditional indicators do not provide assurance that distributions or trends in hydrological signatures are well reproduced. We therefore suggest that performance in reproducing distributions and trends in hydrological signatures should be included in the process of model selection for climate change impact studies.

Floods cause considerable damages worldwide and mitigation of their adverse effects through effective protection measures is needed. Along with the commonly applied “grey” infrastructure, “green” measures that can offer additional benefits, such as ecosystem services, are increasingly being considered lately. While the recent research tendencies are focused on the effectiveness and the value of green measures in urban areas, this paper presents a comprehensive financial evaluation of green and grey flood mitigation scenarios for a smaller rural watershed. A micro-scale damage model that builds on the hydrodynamic modeling of hazard, detailed asset identification, and damage assessment is presented and applied for evaluation of benefits from various flood mitigation measures in the Tamnava watershed in Serbia. Four scenarios are considered: (1) existing flood protection system; (2) green scenario involving new detention basins; (3) grey infrastructure enhancement by rising of the existing levees and diverting flood discharges; and (4) green-grey scenario that combines scenarios (2) and (3). The benefits (loss reduction) are the greatest with the green scenario and marginally higher with the combined green-grey scenario. The results suggest that for small rural watersheds, a holistic, integrative approach that includes both types of infrastructure can provide the most effective flood risk mitigation.