Understanding the variability of salinity in landscapes of the Upper Lachlan: Models for NSW

Landholder questions answered:

What should I look for if I think I may have salinity on my property?

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Start with visual changes. Allan pointed to bare areas or white precipitates, changes in plant species or paddock colour, barley grass, spike rush, tree decline and waterlogging. These indicators are not the end of the diagnosis, so follow them with soil or water testing to understand the scale of the salinity.

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Can I test water in a dam or flowing creek for salinity?

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Yes. Allan recommended using a small electrical conductivity (EC) meter to test streams and other water sources. Monitoring water can help show how salty it is and, when repeated over time, can add to your understanding of how the property and catchment are behaving.

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Where does the salt come from?

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Salt is naturally present in Australian landscapes. Sources discussed in the webinar included salt delivered through aerosols and dust, salt held within geological materials and salt mobilised through water movement. The key issue is not simply whether salt exists, but how water moves through the landscape and mobilises stored salt.

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Why are some nearby landscapes much saltier than others?

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The webinar emphasised that geology, soil, landform and regolith control the movement and storage of water and salt. Even broadly similar geology can behave differently where soils, weathering depth or landform change. This is why HGL mapping combines several landscape factors rather than relying on one layer alone.

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What is a Hydrogeological Landscape (HGL)?

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An HGL is a way of grouping areas with similar landscape “plumbing”. It brings together geology, soils, landform, regolith and climate to help explain salinity processes, identify hazards and guide where different management actions are most appropriate.

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How was salt managed naturally before European settlement?

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Allan explained that salt was already part of the natural landscape. Under native vegetation there was a dynamic balance between rainfall, evaporation and plant water use. Clearing and agricultural land-use change can increase groundwater recharge, allowing more water to move through salt stores and mobilise salt into soils, discharge areas and streams.

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Is funding still available to help producers manage salinity?

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Allan said there is now very little funding dedicated specifically to salinity compared with earlier programs. However, salinity outcomes can still be supported through programs focused on soils, riparian vegetation, grazing management and related land-management work. Funding availability changes, so check current opportunities with Local Land Services and relevant NSW programs rather than assuming a dedicated salinity stream exists.

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How could climate and land-use change affect salinity?

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Allan described land use and climate as intrinsically linked to salinity. He noted increases in salinity in some NSW cropping landscapes following land-use change and wet periods, and said changing rainfall patterns and high-intensity rainfall can create different regional and local effects. For longer-term planning, the discussion emphasised understanding the whole landscape system and considering resilient vegetation mixes and future interception needs.

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What management actions can help?

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There is no single salinity treatment for every site. Examples discussed included perennial pastures, grazing management, salt-tolerant pasture systems, maintaining or improving native vegetation, interception and riparian planting, and adjusting management to the particular recharge, discharge and landscape setting. The HGL approach is intended to help put the right action in the right part of the landscape.

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Are there actions that can make salinity worse?

Yes. In the example discussed for an upland closed-basin landscape, Allan cautioned against actions that increase infiltration or hold more water in the system, including deep ripping in that setting and some dam construction. The key point is site specificity: understand the landscape plumbing before applying a treatment.