The Peel-Harvey Estuary is the largest and most complex estuarine system in the South West, with an area of 134 square kilometres. It forms a key part of the Peel-Yalgorup wetland system – a wetland of international importance under the Ramsar Convention. The wetland system is important for waterbirds and waders, and regularly supports more than 20 000 birds. It also supports the regional fishing economy and is used extensively for recreational purposes, particularly boating, fishing and crabbing.
The Peel-Harvey Estuary has a long history of water quality problems. Since European settlement, drainage throughout the catchment has been heavily modified and has increased the amount of nutrients entering the rivers and estuary. The first of many mass fish mortalities in the estuary occurred in 1907 and was attributed to the increased input of silt due to drainage modifications.
The estuary suffered ecological collapse in the 1970s-80s due to excessive nutrient loads being transported from the catchment via the rivers and drains. Extensive and persistent blooms of toxic microalgae in the Harvey Estuary and macroalgal blooms in the Peel Inlet destroyed the ecological health of the estuary and seriously constrained recreational use and economic activities such as fishing and tourism.
Part of the state government’s solution to these problems was to increase marine exchange in the estuary by constructing the Dawesville Channel in 1994. This improved the water quality in the main estuary basins through increased ocean water exchange. Recent signs of poor water quality in some parts of the estuary are directing us to catchment actions that will ensure nutrient pollution is minimised.