The increasing incidence of droughts and heavy rainfall events is exacerbating conflicts between human and environmental demands for water. However, through providing multiple water-related ecosystem services and benefits simultaneously, Natural/Small Water Retention Measures (NSWRM) can mitigate such competing claims. Thus, they also contribute to the achievement of various Sustainable Development Goals and environmental targets set out in water- and agriculture-related policies of the European Union. In particular, NSWRM provide for the sound management of watersheds, which can significantly contribute to improved water quality and availability—as well as improving the resilience of agriculture and society. This paper demonstrates how NSWRM fit into the framework of ecosystem-based concepts, including Natural Water Retention Measures (NWRM), Green Infrastructure (GI), Sustainable Land Management (SLM), Ecosystem-based Adaptation (EbA), and Nature-based Solutions (NbS). NSWRM, as a distinct concept, bring added value to the other concepts by focussing on easy-to-implement, modestly sized, localised technical solutions to problems associated with water management, sediment, and nutrient loss. Through experience under the EU Horizon 2020 project OPTAIN (“OPtimal strategies to retAIN and re-use water and nutrients in small agricultural catchments across different soil-climatic regions in Europe”), we show what NSWRM are, how they are linked to each of the ecosystem-based concepts, and how they can help add value to these concepts. Fourteen case studies are drawn upon from diverse countries across Europe. As a result of this analysis, we present the potential for the application of NSWRM in the context of these concepts, while helping to identify planning tools, the expertise required, and potential funding mechanisms.