Cross-basin water transfers raise the cost of supply significantly and can have a substantial environmental impact (see e.g. Barcelo, 2009). Several cross-basin water transfers exist and fall under central government competence. Users play an important role, mostly through user associations, as their representatives (the users' assembly) directly participate in some management tasks and elect members of RBA decision-making boards, contributing a third of their members. In most RBAs, consumptive users, especially from the irrigation sector, dominate the users’ representation, reflecting their large weight in consumptive water use.