When forces of nature combine to become destructive and have potential to damage the environment and endanger communities.

A number of dwellings per hectare. Data required to calculate this measure can be obtained from Australian Bureau of Statistics 2011 Census QuickStats and community profiles.

Quality of life of a population. This can be measured by objective indicators, for example, life expectancy, educational attainment and income, or by subjective measures of how people perceive the quality of their life, as revealed by surveys of happiness.

A method of analysing complex interactions between an environment and people, which is able to integrate environmental with attitudinal, demographic, social, economic, technological and political factors. Systems thinking seeks to understand the whole rather than its parts, and see patterns of change over time rather than just as a snapshot in time. The drivers–pressures–state–impact–response (DPSIR) model used in the Australian State of the Environment report (SoE 2011) is an example of a human–environment system. Systems can be extended to include elements, for example, values and beliefs.

Systems of water movement on, above and below the surface of the earth.