This section will examine each of these reform drivers in turn. Concerns about scarcity can be fuelled by increasing demand or shifts in water availability, or due to degraded quality, or climatic shifts. In particular, droughts can provide a salient, visible event to trigger action (see Box 4.1). Efforts to secure adequate water for ecosystems can be driven by new legislation, such as the EU Water Framework Directive, or visible environmental deterioration, such as rivers running dry. In some cases, reforms have sought to address issues that have arisen from previous allocation reforms. The cases of Alberta, Canada, Australia, Chile, Israel, England and Wales, and South Africa provide insight on this theme.