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Abstract
Although dryland farming and grazing have been practiced for over 130 years in
the 17,000 ha Simmons Creek catchment without surface salinity problems, the area has been
identified as a significant source of salt seepage to Billabong Creek in the NSW Murray
catchment. Groundwater movement and salinity levels are spatially heterogenous at Simmons
Creek. Groundwater of the upper catchment is relatively fresh and seemingly unconnected
with the highly saline groundwater of the lower catchment. However, fresh surface water does
flow from the upper to the lower catchment. This spatial diversity provokes the question of
where high-water-use forest habitats might be placed to achieve different combinations of
environmental services (greater water yield, lower stream salinity and greater biodiversity) at
least cost. Agro-forestry and or carbon sequestration benefits are not considered here. This
paper presents methods and preliminary calculations of land use changes for least-cost
delivery of these environmental service targets.