Climate change impacts on our water resources

Water resources in NSW are essential for urban water supply. As populations grow in NSW’s major cities, more water is needed to support them. 

In regional NSW, water is also a major part of many livelihoods, and the success of agricultural businesses and jobs can depend on the amount of available freshwater. 

NSW freshwater sources are also valued for tourism, recreation and cultural activities. 

NSW ecosystems depend on freshwater to some degree. Surface water supports aquatic plants and animals, as well as habitats and species in surrounding floodplains. Water movement that better represents natural flow patterns is needed to keep these ecosystems healthy. 

Groundwater can support entire ecosystems. Natural springs, for example, support a range of plants and animals in arid parts of NSW. 

Agriculture is one of Australia’s largest industries and uses the most water of any Australian industry. Without long-term access to freshwater, Australia’s agriculture industry would decline, affecting the economy, jobs and food production. 

NSW’s tourism industry also relies strongly on healthy ecosystems to attract tourists. Changes to our water resources can damage tourism businesses. This was seen in 2008, with an estimated loss of $70 million in the River Murray region due to the decline in visitor numbers during drought. 

Climate change is likely to reduce the amount of surface water available in NSW. Warming temperatures and changing climate patterns are projected to: 

• increase evaporation from water bodies and evapotranspiration from plants
• change the influence of key climate drivers such as east coast lows, the El Niño Southern Oscillation, the Indian Ocean Dipole, the Interdecadal Pacific Oscillation and the Southern Annular Mode. Changes to these drivers will affect the frequency and magnitude of rainfall events over NSW. 

People access groundwater using bores, some plants can access groundwater when their roots meet the water-table underground, and some ecosystems access groundwater when the water-table reaches the surface through springs or seeps up through riverbeds. 

Groundwater is replenished as rainfall seeps into the ground (a process called groundwater recharge). The processes for recharge include direct infiltration from rainfall onto the land surface and infiltration from surface water.  

Both of these processes are expected to be affected by climate change. In some cases, groundwater recharge may be reduced, for example, in a scenario where rainfall decreases. However, in areas that currently receive high rainfall, recharge may increase because of changes in the frequency and intensity of rainfall events. Groundwater resources can also be affected by sea level rise, which can contaminate fresh groundwater with saltwater, and cause waterlogged soil from increased groundwater levels.  

More research is required to determine how recharge events will be impacted by climate change and how our groundwater supplies will be affected. 

Poor water quality has far-reaching impacts on people, communities, wildlife, industries and the economy. 

Climate change is causing changes to our weather and oceans. These changes may reduce the quality of NSW water resources: 

• sea level rise pushes saltwater further up coastal waterways, degrading freshwater habitats
• bushfires reduce water quality through ash, sediments and contaminants that enter waterways
• extreme storms and rainfall events can erode soils and wash them into waterways, carrying sediment and contaminants, and reducing water quality
• warmer waters in storage facilities, such as dams, can increase the risk of bacterial or algal growth
• drought conditions increase the concentration of naturally occurring salts in waterways through evaporation and decrease the frequency of high flow events, which flush out salts. 

These impacts can make water resources unsuitable for human water supplies and agriculture, and damage freshwater ecosystems.