SS4.13 Water Quality of Lakes, Rivers and Coastal Zones
Date: Thursday, June 13, 2002
Time: 10:15:00 AM
Location: Carson B
 
BukaveckasPA, University of Louisville, Louisville, USA, pabuka01@athena.louisville.edu
Hamilton, D, P, University of Western Australia, Crawley, Australia, hamilton@cwr.uwa.edu.au
 
MASS BALANCE OF C, N, P IN AN URBAN EXTUARY: THE SWAN-CANNING ESTUARY, WESTERN AUSTRALIA.
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The Swan-Canning Estuary in Western Australia has been important to the establishment and growth of the city of Perth and is an integral part of regional tourism and fisheries. During the past century, extensive land clearing in the Swan Coastal Plain has resulted in the replacement of remnant vegetation with agricultural crops. The estuary has experienced substantial changes in runoff and inputs of salt, nutrients and sediments. To better understand the sources and fate of nutrients in the estuary, we used a mass balance approach to quantify nutrient loading from tributaries, nutrient export to the ocean and retention within the estuary. TN budgets suggests that the estuary was in equilibrium with respect to inputs and outputs during 1999 but acted as a net sink in 2000. The estuary acted as a net source of TP and DOC since tributary inputs were small in comparison to losses through tidal exchange. Estimates of TP and DOC generation within the estuary were fairly robust to assumptions about tidal exchange and suggest that sediment P-release and autochthonous DOC production may be important internal sources.