The pressures discussed previously influence the state and trends of inland water environments in multiple ways, and the pressure–state interactions are further affected in many areas of the country by our management responses. Climate and land use largely control much of the state of both surface-water and groundwater resources, and these are further modified by water resources infrastructure and operational management. Pests and invasive species then interact with the groundwater and surface-water hydrological regimes to influence the state of inland water environments.

Australia’s surface-water and groundwater conditions have varied considerably during the past 5 years, largely in response to the varying climatic conditions mentioned previously. In 2012, after the strong 2010–12 La Niña event, many regions of the country had experienced recent high streamflows and floods, groundwater levels were stable or rising, and Australia’s aggregated water storage holdings were around or above 80 per cent of capacity. After the millennium drought, this wetting of the country was welcome, with positive responses for water quality and ecological processes. More recently, with the pressures of historically warm years and significant regional drying, the condition of our inland water environments has been more varied.

Four condition assessments of Australia’s inland waters are provided in this report, considering the state and trends of:

• inland water flows and levels
• groundwater resources—a new assessment for 2016
• inland water quality, focusing primarily on surface water
• ecological processes and species populations.

The 2011 state and trends assessments were based, to a greater degree, on analyses undertaken specifically for SoE 2011, including a highly detailed site-based report for water quality. For 2016, the assessments are based on publicly available data and information, including state-based SoE assessments, and specific national or regional assessments, such as for the Great Barrier Reef catchments, the Lake Eyre Basin and the Murray–Darling Basin.

One of the challenges of assessing states and trends is determining the baseline against which the assessment is made. For this report, SoE 2011 provides the baseline, although there is some uncertainty about the methods that were used to reach a particular grade. The Wentworth Group of Concerned Scientists has been leading work since 2008 to provide more comprehensive and uniform baselines and assessments of environmental condition (see information on environmental economic accounting in the Drivers report). Under the National Plan for Environmental Information, the Bureau of Meteorology published a Guide to environmental accounting in Australia (BoM 2013b), which describes water accounts and their purpose, the risks and issues to be considered in accounts, and pathways for implementing accounts. Additionally, the Australian Bureau of Statistics has published annual economic-focused environmental accounts since 2014. Such approaches  offer future opportunities, including aligning data with current assessment methodologies and increasing the use of readily available monitoring data.