The main cause of the river’s chronic poor health can be traced to a cocktail of environmental pollutants entering the river system from a range of industrial, agricultural and urban sources. These pollutants’ impact is exacerbated by climate change as we receive less rain in the catchments to flush the nutrients out to sea, and higher temperatures aid algal growth.

Over the past five years, toxic algal blooms in the Swan have dramatically increased. During this time, the river has had to be kept on ‘life support’ during summer months by the artificial pumping of oxygen into the water. Summer fish-kills have also become common, with thousands of fish killed directly by toxic algae, or indirectly due to the loss of oxygen caused by the breakdown of algae in the water column.

Fertilising our river to death

The main source of nutrient pollution entering the river is phosphorous and nitrogen-based fertiliser products used in farming and urban environments. When applied to the sandy soils of the Swan Coastal Plain, these nutrients dissolve readily and are transported through groundwater and surface flows into the river.

Attempts have been made for years to reduce the impacts of these fertilisers through educating farmers and gardeners, developing nutrient-stripping basins and undertaking drain engineering works to intercept pollutants. Despite this, the Swan Canning Water Quality Improvement Plan recently released by the Swan River Trust noted that nutrients entering the Swan River at present are roughly double maximum levels that would be required for the river health to be restored. Rather than learning from history, the plan proposes more of the same treatments that have failed to solve the nutrient pollution problem in the past.

Because it is impossible to trace where the nutrients are coming from as the sources are diffuse, it has always been considered impossible to use pollution control regulations that work for point-source pollutants to control nutrients.

Wasted nutrients

One way to look at the nutrient pollution problem is to consider it as a waste management issue. Nutrients that are not used by garden plants or agricultural crops and pastures are a wasted resource. Just as with other waste problems, the most effective way to deal with this problem may be to place the responsibility on the producer, in this case the fertiliser industry.

We know that alternative, slow-release fertilisers can have the same, if not greater, results in promoting plant growth without the pollution, however at present the fertiliser industry has a vested interest in selling polluting products. The more nutrients that are wasted from farms and gardens as polluted runoff, the more fertiliser that has to be applied, keeping the fertiliser industry in business.

Trials of river-friendly fertilisers in the past (notably in the Peel– Harvey catchment) have failed due to farmers rejecting the products based on cost. However, fertiliser producers have conceded that they could make river-friendly fertiliser products more cheaply if there was a bigger market with guaranteed volumes of production.

Fertiliser Action Plan

The Fertiliser Action Plan was developed under the previous State Government based on the understanding of the wasted nutrients from fertilisers polluting our river and the need to treat it as a waste management problem. This would have seen the phase-out of polluting fertiliser products on the Swan Coastal Plain by 2011 and would have placed responsibility back on the fertiliser industry for the problems caused by its products (polluter pays). At the same time, it would have created a large enough market for cost-effective river-friendly products to be produced. This would have allowed farmers to continue farming without losing income or polluting the environment.

Unfortunately the current Environment Minister has not implemented the Fertiliser Action Plan, instead choosing to rely on continued voluntary approaches by the fertiliser industry combined with expensive end-of-pipe engineering treatments and nutrient interventions that have not worked in the past.

It is unlikely that these plans will produce the necessary reduction in nutrient pollution to save the river from further collapse. Disappointingly, the Minister’s preferred approach does nothing to make the fertiliser industry accountable for the damage done by its products, instead leaving a dying river and a large bill for taxpayer-funded temporary solutions that do not tackle the source of the problem.