What has caused freshwater to be such a problem in australia

There are several reasons why ecosystems in Australia have been extensively altered, many wetlands have been degraded and freshwater can be a problem in Australia:
- pollution - Intensive agriculture is affecting Australia's coasts and oceans
- deforestation (cutting of forests)
- agriculture clearing
- overfishing  - the ecosystem is damaged
- illegal fishing
- infrastructure development

Answerstratovolcanoes///near or in the ring of fire;

Answermost of the time it would be ground into fine sediment,and sometimes they are carried away from the original location;