Descending down the slippery track
Dodging ruts and boulders
Careful not to get too close
To sheer drops on the shoulders
And in the valley far below
Gleaming like a jewell
The ancient home of catfish
The famous Cobbler’s Pool
But the pool is still and fishless
And ringed with dying trees
And the smell of rotting algae
Is fetid on the breeze
Few of the hundreds of kayakers participating in the Avon Descent in August each year would be aware of the poor health of the river. It is still spectacularly beautiful when it is swollen with winter rain and cascades through the magnificent Avon Valley. Few would realise as they pitch their tents at the Cobbler’s Pool camping ground that there are no longer any fish in the pool. The catfish that thrived in the pool for millions of years before the coming of the Aborigines and for 50,000 years since are long gone and the Avon is as dead as the Dodo.
I stand on the banks of Cobbler's Pool under a dying Flooded Gum and look wistfully at the stagnant green water scummed with blue-green algae. It is a hot summer’s day but you would have to be desperate to dive into that toxic brew. Can this be the same clean fresh pool teeming with catfish that sustained Aboriginal people for millennia? Is this the same pool that provided clean freshwater for the boilers of the steam engines as the steam trains made their way down the Avon last century? A more fundamental question is can we bring it back to life? Now that it has descended as far it can, can we help it to ascend? The answer to that one is possibly, but no time soon.
The problem with the Avon is dry-land salinity. The death of the Avon and many other wheat-belt rivers is a consequence of over-clearing for wheat farming. Excessive removal of native vegetation has increased rates of rainwater infiltration into the soil causing ground-water levels to rise and bringing salt to the surface. Much of this ends up in the river system. The once fresh Avon now has a salinity of about half seawater. The mussels, insect larvae, worms and crustaceans that once supported the food chain are gone along with the cobblers and the many other species of fish that once inhabited the river. The irony is that much of the excessive clearing that has killed the Avon has not occurred anywhere near the Avon. Once again it demonstrates the connectedness of things and the unpredictability of consequences.
