A drought trigger is the specific value of a drought indicator that ACTIVATES a management response. For example, a drought trigger could be a reservoir decreasing below 50% of its storage capacity. In a drought contingency plan, trigger levels can be varied to alter the SENSITIVITY of the response and the effectiveness of the plan. Defining drought triggers can be difficult. Trigger levels change over time, that is, an APPROPRIATE trigger level for a particular system may change dramatically if that system has an increase in available infrastructure or if water demands change dramatically. Urban water triggers are often quite different from agriculture drought triggers, as the urban infrastructure can often MITIGATE the impacts of short-term droughts.

A drought trigger is the specific value of a drought indicator that activates a management response. For example, a drought trigger could be a reservoir decreasing below 50% of its storage capacity. In a drought contingency plan, trigger levels can be varied to alter the sensitivity of the response and the effectiveness of the plan. Defining drought triggers can be difficult. Trigger levels change over time, that is, an appropriate trigger level for a particular system may change dramatically if that system has an increase in available infrastructure or if water demands change dramatically. Urban water triggers are often quite different from agriculture drought triggers, as the urban infrastructure can often mitigate the impacts of short-term droughts.