"Who hears the rippling of rivers will not utterly despair of anything." - Henry David Thoreau
The Swan and Canning rivers flow through the heart of metropolitan Perth.
The Swan River (Derbal Yerrigan) is 72 kilometres long and the Canning River (Djarlgarra or Dyarlgarro) is 110 kilometres long. Together, these two rivers and their tributaries drain a catchment area of 2,090 square kilometres.
The lower reaches of the Swan and Canning rivers form an estuary created by geological conditions more than 10,000 years ago.
The Swan River was mostly brackish before settlers removed the Fremantle bar in the late 1800s and dredged the large flood delta nearby.
The Swan and Canning rivers are now a permanently open estuary that changes from fresh/brackish conditions in winter and spring, to salty conditions during summer and autumn.
The Swan and Canning Rivers are under threat from development pressure, climate change, dredging and a range of other sources.
The declining ecological health of the river can be seen in the problems with the water quality, which include nurtrient and organic loading, algal blooms, low oxygen levels and contaminants from urban, farming and industrial drainage.
Evidence of the stress the ecological system is under can be seen in recent fish kills, changes in aquatic communities, dolphin deaths and the loss of habitat for plants and animals.
Foreshore degradation is also on ongoing problem, with the negative impact of boat wash, foreshore erosion, loss of shoreline vegetation and damage to trees.
The constant pressure from development is also a continuing threat.
The Greens (WA) want: