West Australian: The health of the Swan and Canning rivers has no chance of improving unless pollution entering the waterway is cut by almost half in the next seven years, a report for the Swan River Trust has warned. The draft Swan Canning Water Quality Improvement Plan said the system was under “enormous pressure” and could handle only about half of the 251 tonnes of nitrogen and 26 tonnes of phosphorous it took in annually. It said the Avon River, which was outside the scope of the plan, …