Unconventional water resources: Global opportunities and challenges.

Water is of central importance for reaching the Sustainable Development Goals (SDGs) of the United Nations. With predictions of dire global water scarcity, attention is turning to resources that are considered to be unconventional, and hence called Unconventional Water Resources (UWRs). These are considered as supplementary water resources that need specialized processes to be used as water supply. The literature encompasses a vast number of studies on various UWRs and their usefulness in certain environmental and/or socio-economic contexts. However, a recent, all-encompassing article that brings the collective knowledge on UWRs together is missing. Considering the increasing importance of UWRs in the global push for water security, the current study intends to offer a nuanced understanding of the existing research on UWRs by summarizing the key concepts in the literature. The number of articles published on UWRs have increased significantly over time, particularly in the past ten years. And while most publications were authored from researchers based in the USA or China, other countries such as India, Iran, Australia, and Spain have also featured prominently. Here, twelve general types of UWRs were used to assess their global distribution, showing that climatic conditions are the main driver for the application of certain UWRs. For example, the use of iceberg water obviously necessitates access to icebergs, which are taken largely from arctic regions. Overall, the literature review demonstrated that, even though UWRs provide promising possibilities for overcoming water scarcity, current knowledge is patchy and points towards UWRs being, for the most part, limited in scope and applicability due to geographic, climatic, economic, and political constraints. Future studies focusing on improved documentation and demonstration of the quantitative and socio-economic potential of various UWRs could help in strengthening the case for some, if not all, UWRs as avenues for the sustainable provision of water.

Success factors for citizen science projects in water quality 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.

Capacity challenges in water quality monitoring: understanding the role of human development.

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.

Attribute value extraction mechanism of Constructed Wetlands information.

Constructed Wetlands (CWs) are a nature-based solution for the treatment of wastewater. The CWetlands - the Constructed Wetlands Knowledge Platform - intends to help understand how CWs can support achieving the Sustainable Development Goals. The platform is based on more than 100 attributes of CWs including criteria for design criteria, operation, efficiency, climate and other geographical factors. This study aims at developing an attribute value extraction mechanism tool in R to extract meaningful information from peer-reviewed journal articles in a reliable and fast way. •The tool focuses on the extraction of eighteen different extractable attributes gathered in 4 classes, which describe the main characteristics of CW systems.•The process contains 4 sub-processes: 1-2) the papers are accessed and pre-processed, 3) the attributes are extracted by two data mining techniques: Keyword Match and Web Scrap, and 4) the values are exported to a database.•For the development and testing of the tool, 13 articles were used. The tool achieved a mean success rate of 79% in 30 min; less compared with the 480 min needed with a manual approach. In further versions, the tool is expected to obtain a higher success rate in all attributes.

Learning from integrated management approaches to implement the Nexus.

In the 1990s, the emergence of Integrated Management Approaches to water, land and waste established a widely accepted understanding on integration of environmental systems. Nexus Approaches try to often build on these. This paper assesses i) the intended goals and features of three Integrated Management Approaches (Integrated Natural Resources Management - INRM, Integrated Water Resources Management - IWRM and Integrated Solid Waste Management - ISWM) and two Nexus Approaches (Water-Energy-Food (WEF) Nexus and Water-Soil-Waste (WSW) Nexus), and ii) how target systems and their integration are viewed in each of the Integrated Management Approaches. From this we assess commonalities and some lessons-learned for the Nexus. The method is based on a systematic literature review and a document analysis. From 1652 articles 52 peer reviewed papers were analysed. The results show that in terms of goals the Nexus Approaches are very similar to Integrated Management Approaches with the addition of clearly wanting to address governance and policy aspects e.g. in the WEF Nexus. Nexus Approaches try to move away from a single-resource centric view (e.g. WSW Nexus) and intend to go beyond resources towards sectors (e.g. WEF Nexus). It cannot be confirmed, that integration is clearly addressed in the analysed Integrated Management Approaches and what integration means is hardly defined. To provide some clarity for Nexus Approaches we propose a concept to describe integration by using "categories of integration" and the term "aspect" which includes systems, subsystems and other aspects alike.