Excessive growth of the benthic alga Cladophora aff. albida in the Peel-Harvey estuarine system has
coincided with greatly increased inputs of phosphorus from rivers over the last 20-25 years. At present,
about 90%, of phosphorus input is derived from rural coastal plain catchments, where use of superphosphate
increased fourfold over the period 1945-1975.
The present export of phosphorus from these catchments was found to be positively correlated with rates
of superphosphate application, dairy farming, and presence of alluvial clay soils, and negatively correlated
with beef farming. Reduction of phosphorus input to the estuary from the coastal plain, therefore, could be
achieved by reducing or modifying the present use of superphosphate, and reducing runoff from dairy farms
into waterways.