Salinity Province 40, Hamilton

Dryland salinity in the large Hamilton Salinity Province is associated with local to regional scale Groundwater Flow Systems in a volcanic landscape. Local Groundwater Flow Systems feed discharge at the edges of eruption points, such as Mt Napier, but on the broader volcanic plains that make up the majority of the province, shallow watertables, seasonal waterlogging and salinity occur due to poorly developed drainage and clay rich basalt soils. Primary salinity is associated with wetlands and drainage lines in the pre-agricultural landscape, and secondary salinity is found at the margins of this primary salinity and where high watertables occur in landscape depressions and drainage lines.

Management options are limited due to the primary nature of much of the waterlogging and salinity found, and need to focus on ‘living-with-salt’ for farming land, where sympathetic grazing management is required to protect site adapted plants and soil structure to maximise productive potential and limit degradation.