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.