Wetland degradation in the Upper South East of South Australia is an urgent
management concern. Scant recent environmental data is available for the r
egion and long-term monitoring data is lacking. Usually a palaeoecological
analysis is able to reveal environmental change in the medium- to long-term
past. However, the region is not conducive to palaeoecological investigati
on due to a fluctuating upper groundwater aquifer and alkaline soils which
have destroyed most microfossils. It was found that the diatom assemblage w
as preserved in the wetlands of the region for the period of European settl
ement. Analysis of the diatom assemblage enabled production of an inferred
salinity curve. In combination with a small amount of historical informatio
n that was available, the salinity trend for the wetlands, for the period o
f European agricultural activities, was identified. It was found that, whil
e groundwater salinity has been increasing, the wetland areas have experien
ced a freshening of surface water. This is due to an increase of throughflo
w of surface water, a result of constructed drainage systems flushing salts
from the wetlands. Despite the freshening of wetlands they continue to deg
rade due to the changed hydrology, an impact of the drainage structures.