Nutrient enrichment of the Harvey Estuary has been caused by the clearing of native vegetation in the policy area and by land uses that result in nutrients, especially phosphorus, leaching into waterways in the policy area and then flowing into the Estuary. This stimulates excessive algal growth and leads to environmental deterioration.
In 1989 the Peel Inlet and Harvey Estuary System Management Strategy Stage 2 (the Strategy) was approved for implementation by the Minister for the Environment. The Strategy was developed to manage the massive algal growth in the Peel-Harvey Estuarine System caused by an increase in nutrients. The Strategies main actions were the construction of the Dawesville Channel and the implementation of a Catchment management Plan to limit the amount of phosphorus entering the estuaries from the river and drainage systems. The Peel Harvey EPP was gazetted in 1992 as a legislative framework to allow for catchment management initiatives in the policy area.
The purpose of this EPP is:
- to set out environmental quality objectives for the Estuary which if achieved will rehabilitate the Estuary and protect the Estuary from further degradation; and
- to outline the means by which the environmental quality objectives for the Estuary are to be achieved and maintained.
The Peel Inlet and Harvey Estuary System Management Strategy: Progress and Compliance by the Proponents with the Environmental Conditions set by the Minister for the Environment in 1989, 1991 and 1993 (Bulletin 1087) found the Dawesville Channel (constructed in 1994) to have been successful in improving water quality in the main body of the Peel Inlet and Harvey Estuary. However, water quality and environmental problems remained in the rivers, and in areas such as the Serpentine Lakes. The second part of the Strategy, that of catchment management to “cap” the phosphorus input to the waterways, remained an aspect of the management package that still required significant action.
As a result, in 2008, the EPA and the Australian Government prepared a Water Quality Improvement Plan that took the findings of seven supporting projects and recommended a combination of management measures to reduce phosphorus load to the Estuary from land uses within the coastal sections of the three catchments - the Serpentine, Murray and Harvey - draining to the Peel-Harvey Estuary.