The beam origin concept is used to describe the mechanisms governing the ecological condition of running waters. It is based on the positive influence of sections in very good condition on sections in less good condition. The idea was first introduced in 2008 by the German Council for Land Stewardship to reach the goals defined in the Water Framework Directive of the European Union. Background In order to force politics to take more responsibility in acting against ecological, economic and social problems related to water, the European Union implemented the Water Framework Directive. For each river basin district member, the states had to develop, implement and monitor measures to reach its prescribed goals. As a tool to accomplish this goal, so-called river basin management plans were required. The implementation is an individual matter for the member states and must be reported regularly. In Germany, the German Council for Land Stewardship worked on a project financially supported by the North Rhine-Westphalia State Agency for Nature, Environment and Consumer Protection and Lennart-Bernadotte-Stiftung, in order to investigate how, in the sense of a beam effect, water biocoenoses in restricted areas can be developed and decoupled from a complete structural improvement in the area concerned. The applicability of stepping stones was thereby to be examined for the beam effect of interventions on running waters, as a parallel to wildlife corridors. Concept The main driver of the concept is the beam effect, which indicates the influence of sections in very good ecological condition on sections in less good or rather poor condition with respect to their ecological status. There are two categories of beam effects which are biotic and abiotic. The biotic beam effect relies on the migration or drift of typical aquatic organisms; the abiotic beam effect refers to the transport of positive environmental conditions from one directed downstream. In general, the beam effect is not tied to the flow direction of the running water and can occur both upstream and downstream. In contrast, negative long-distance and vicinity effects cause the opposite effect to the positive beam effect, thus deteriorate the ecological condition of running waters. For instance, negative biotic effects are migration or drift of atypical aquatic organisms, that might have a negative effect on domestic species in their habitats; carry-over of fine sediments, material load or temperature influences are examples of negative abiotic effects on the ecological condition. Another negative effect is