Efforts to assess farmer participation in irrigation management have often focused on differences between "large-scale" and "small-scale" systems. It is more instructive to think in terms of the structure of an irrigation system using the number of levels of operation and organization to delineate patterns of agency and farmer activity in irrigation management. "Levels" within an irrigation system are socio-technical in that they can be defined both physically and organizationally. Recognizing that "levels" in irrigation systems can be understood both in organizational terms and in operational terms is important, and achieving a correspondence between the social and technical sets of activities is crucial for satisfactory system performance. Efforts to improve irrigation management often focus on farmers in their organizational and operational activities at the lowest level, along the channel serving their fields. In some assessments of water management, water waste is blamed on farmers who are themselves the "victims" of poor management at higher levels.