Farm dams can provide a reliable and important source of water for farmers. However, there is increasing concern about the impact that they may have on the quality and quantity of downstream water supplies.

The Heytesbury area was cleared of native vegetation shortly after the Second World War. Since then, water quality in Curdies River and its sub-catchments has fallen. Explanation is sought in reference to history of land use, climate, irrigation practice and the steady increase in the number of farm dams emplaced. Over this time period, distinctive changes in the stream regimes and nutrient load of water draining to the coastal lagoons further south have been recorded.

In the search for explanations, a time-series record of land cover is used to document the nature of the intensification of land use. The relative significance of various land use systems and their farm-by-farm exploitation can be identified from this time-series land cover record.

It is argued that local variation in topography, lithology and soils results in a range of responses/vulnerabilities to land use changes, thus defining the need to use location-specific guidelines when educating land users about sustainable land management practices.