Issue: Habitat scale influences - Water Quality (for surface and groundwater) - Salinity
This is an issue under the Inland waters theme of the Data Reporting System.
While some inland waters are naturally brackish or saline, reductions in the area of perennial and native vegetation in catchments have altered the surface and ground water hydrology, increased ground water recharge and increased salt movement to rivers and streams. High salinity can have toxic effects on aquatic plants and animals and indirect impacts by contributing to the loss of habitat and food species. Most freshwater biota are adversely affected by long-term increases in salinity.
Dryland salinity and/or irrigation induced salinity has increased the instream salinity of many river systems.
Wetlands are particularly susceptible to the affects of salinity. Lowland or floodplain wetlands are affected by salinisation through river regulation, irrigation-induced groundwater rises, increased extractions from the river, floodplain disposal of saline drainage water, groundwater rises due to land clearing (and associated dryland salinity) and seawater intrusion. These threats differ significantly from those in upstream wetlands, where the major cause of salinisation is the evaporation of saline inflow water.
Complex interactions between climate, flow variability, hydrology and salt stores, groundwater residence times and changing river management practices, make it difficult to predict changes.
- IW-20 Exceedance of salinity water quality triggers
Number of exceedences of water quality triggers for salinity is a direct measure of this pressure.
- CO-68 Examples of sea surge and seawater intrusion events
Examples of sea water intrusion events may shed light on salination of surface and ground water in coastal areas and wetlands.