11.4.1.3 Water quality

In Australia, there is a 50% chance by 2020 of the average salinity of the lower Murray River exceeding the 800 EC threshold set for desirable drinking and irrigation water (MDBMC, 1999). There are no integrated assessments of the impacts of climate change on runoff quantity and quality, salt interception and revegetation policies, and water pricing and trading policies. Eutrophication is a major water-quality problem (Davis, 1997; SOE, 2001). Toxic algal blooms are likely to become more frequent and to last longer due to climate change. They can pose a threat to human health, for both recreation and consumptive water use, and can kill fish and livestock (Falconer, 1997). Simple, resource-neutral, adaptive management strategies, such as flushing flows, can substantially reduce their occurrence and duration in nutrient-rich, thermally stratified water bodies (Viney et al., 2003).

In New Zealand, lowland waterways in agricultural catchments are in a relatively poor state and these streams are under pressure from land-use intensification and increasing water abstraction demands (Larned et al., 2004). There is no literature on impacts of climate change on water quality in New Zealand.