Salt Management: The Australian Experience
Salinity is the accumulation of soluble salts (predominantly NaCl) in soil and water, usually over an extended period of time. For most people the term has negative connotations, associated as it is with long-term land and water degradation. Problems arise when increasing salt concentrations negatively affect soil and water quality, plant growth, agriculture, the built environment and biodiversity. Salinisation is both the process and outcome of salt accumulation. The former occurs naturally in conjunction with landscape and soil formation. Salt may come from a number of sources including wind-borne salt from the ocean, salts dissolved in rainwater, marine sediments and weathering of the earth’s crust. Although the salt content of rainfall is low, rainfall can be the primary source of salt in some areas (Department of Environment and Resource Management QLD 2011). Salinity rarely occurs in isolation from other natural resource problems such as decreasing soil and water quality, erosion and loss of native vegetation. For example, water coming from areas affected by dryland, irrigation or urban salinity can flow into creeks and rivers causing salinity levels to rise. This reduces water quality, affecting the health of plants and animals and reducing farm income. Poor water quality may also have an impact on town water supply, with social and economic impacts for both rural and urban dwellers in the form of rising council rates and taxes.