Monitoring the qualitative status of freshwaters is an important goal of the international community, as stated in the Sustainable Development Goal (SDGs) indicator 6.3.2 on good ambient water quality. Monitoring data are, however, lacking in many countries, allegedly because of capacity challenges of less-developed countries. So far, however, the relationship between human development and capacity challenges for water quality monitoring have not been analysed systematically. This hinders the implementation of fine-tuned capacity development programmes for water quality monitoring. Against this background, this study takes a global perspective in analysing the link between human development and the capacity challenges countries face in their national water quality monitoring programmes. The analysis is based on the latest data on the human development index and an international online survey amongst experts from science and practice. Results provide evidence of a negative relationship between human development and the capacity challenges to meet SDG 6.3.2 monitoring requirements. This negative relationship increases along the course of the monitoring process, from defining the enabling environment, choosing parameters for the collection of field data, to the analytics and analysis of five commonly used parameters (DO, EC, pH, TP and TN). Our assessment can be used to help practitioners improve technical capacity development activities and to identify and target investment in capacity development for monitoring.

Attempts to monitor the quality of freshwater resources on a global scale unveil huge data lacks. Involving citizens in data collection has potential to resolve this lack of water quality data. However, it is widely unclear which factors drive the success of citizen science activities. Based on a systematic literature review of 56 peer-reviewed research articles, we identify three sets of factors for successful citizen science projects in water quality monitoring: (i) attributes of citizens (knowledge and experience in collecting data, awareness of environmental problems, motivation, and socio-economic background of citizens), (ii) attributes of institutions (motivation, type of organization, consistent and adequate funding), and (iii) the interactions between citizens and institutions (supporting structure, communication and feedback). These three sets of factors enable a systematic analysis and design of citizen science projects in the future.

Governance for complex problem solving has been increasingly discussed in environmental sustainability research. Above all, researchers continuously observe that sustainability problems are complex or “wicked”, and suggest participatory models to address these problems in practice. In order to add to this debate, this study suggests a more differentiated theoretical approach to define governance for complex environmental problem solving than in previous studies. The approach consists of two vital steps: First, we operationalize complexity and define management strategies for solving environmental sustainability problems based on findings from psychology research. Second, we identify governance strategies that facilitate these management strategies. Linking those strategies suggests that the role of diverse institutions, actors, and interactions differs for five key dimensions of complexity: goals, variables, dynamics, interconnections, and informational uncertainty. The results strengthen systematic analyses of environmental sustainability problems in both theory and practice.

The nitrogen pollution of freshwater heavily affects social–ecological systems. To reduce negative effects, research calls for an integrated approach, including a coherent and diverse set of governance instruments. Thus far, however, the effects of (non-)integration have been blurry. Taking Germany as an example, this study sheds light on the actual complexity of the problem along five dimensions of complexity (goals, variables, dynamics, interconnections, and uncertainties). It also sheds light on related governance instruments (rules, information, and economic incentives) and their impacts on problem-solving (implementation of specific measures). Analyses include expert interviews on complexity, European water and agricultural policies, and official data on the planning and implementation of measures to reduce nitrogen concentrations. Results show Germany’s path of sustaining a complex problem by using a non-coherent and low diversity governance approach, avoiding rigorous rules, and barely using economic instruments to deal with nitrogen surpluses. A stronger integration of water and agricultural policies, as well as a better use of economic instruments, are suggested to enhance water quality in the future.

The nexus concept has considerably matured during the past decade. Numerous literature reviews have significantly contributed to taking stock of the advancements in knowledge and tool development to improve science-policy support on highly connected and interdependent resources. However, literature reviews often focus on specific sector-based nexus concepts (such as water-energy-food nexus) and analyses (such as environmental assessment, technical tools, or the management and policy dimension). Therefore, a comprehensive understanding of the actual nexus and the resources it builds upon still needs to be improved. This paper aims to test the validity of the nexus construct for research and practice. Based on a systematic review of reviews, including 62 nexus-related review papers and subsequent consultation of some sixty nexus experts, we suggest a robust but flexible approach to advancing the Resource Nexus for research and practice. In doing so, the knowledge provided by nexus research may provide more substantial support to decision-makers when designing and implementing policies for the sustainable management of environmental resources.

Governance has become a cornerstone in addressing complex linkages between multiple resources such as water, energy, and food. However, contributions of governance research in interdisciplinary research projects are either lacking or highly controversial. Drawing on Integrated Water Resources Management-related experiences of German research projects in emerging and developing countries, we demonstrate how to strengthen NEXUS-related governance analyses: There has to be a stronger focus on the analyses of existing and useful governance strategies as well as of conditions for governance transitions; governance analyses should refer to different types of problems, instead of only focusing on single cases and abstract analyses; and answers must be based on a more elaborate practice of inter- and transdisciplinary research. These suggestions should be implemented on the level of single researchers, but should also require incentives on an institutional level.