Integrating research and management for an urban estuarine system: the Swan–Canning Estuary, Western Australia

✍ Scribed by David P. Hamilton; Jeffrey V. Turner

• Book ID: 102264508
• Publisher: John Wiley and Sons
• Year: 2001
• Tongue: English
• Weight: 39 KB
• Volume: 15
• Category: Article
• ISSN: 0885-6087
• DOI: 10.1002/hyp.299

✦ Synopsis

Expansion of human populations along coastal land margins and changes in land use of watersheds are having major impacts on water quality of estuarine ecosystems around the world. Nowhere are these impacts more profound than in Australia, where extreme climatic variability, clearing of remnant vegetation for agriculture and relatively dense human populations in temperate coastal land margins have led to great modifications to the hydrology and ecology of many estuary and river systems (Harris, 1995). These changes also pertain to the Swan-Canning Estuary, in the south-west of Western Australia, where major changes in land use and water allocation have occurred since the first European settlement of the Swan River Colony in 1829 (Riggert, 1978).

The papers presented in this special issue of Hydrological Processes summarize the research of projects that were mostly initiated in the mid-1990s. At this time there was growing recognition by the scientific community, government and the general public, that the ecological health of the Swan-Canning Estuary was deteriorating and that urgent steps had to be taken to slow and reverse the decline. The convergence of increasing community concern, and awareness and knowledge of environmental health issues, prompted action to be taken to improve the health of the Swan-Canning Estuary system.

The most visible signs of the decline in system health were the apparently increasing severity and frequency of nuisance algal blooms in the Swan and Canning Rivers. Phytoplankton production in the Swan-Canning Estuary is closely linked to the supply of nitrogen, the limiting nutrient over the most productive summer months (Thompson and Hosja, 1996). Periodic events symptomatic of estuary eutrophication, including fish kills, cyanobacterial blooms (Hamilton, 2000), red tides (Hamilton et al., 1999) and accumulation of organic matter in the bottom sediments of deep holes (Douglas et al., 1997), are clear signs that there are significant environmental health problems in the estuary.

It was recognized at the outset of the projects reported in this issue that there was little scientific knowledge available on the Swan-Canning Estuary system, and thus environmental managers charged with responding to community demands had limited information upon which to base their management decisions.