Concern about the potential collapse of the estuarine system led to a range of research projects to identify the cause of algal blooms and possible engineering or ecological solutions.
In the early 1980s, an idea was developed to cut a channel through the sandhills at Dawesville to create an artificial connection between the estuary and the ocean. This channel would increase the flushing of nutrients to the sea and increase the salinity of the estuarine water to a point beyond the tolerance of the potentially toxic phytoplankton species Nodularia.
While this option was considered, dredging work was done on the Mandurah channel aimed at improving the flushing of nutrients to the sea.
Work was also undertaken to change the way landholders used fertilisers. This included the development of techniques for soil testing, changing the time of fertiliser application and development of less soluble fertilisers.
Harvesting and removal of weed from the estuary continued.
The Dawesville Channel was eventually built and opened in 1994. It is two kilometres long, 200 metres wide and about 6.5 metres deep at its ocean entrance.
The channel has had the desired impact in terms of improving marine water exchange and tidal flushing, resulting in improved water quality in the estuary itself. However water quality problems, fish kills and algal blooms continue to be experienced in the estuarine reaches of the river tributaries. The increase in tidal exchange has also brought about changes in fringing vegetation composition and in some areas further riverbank or foreshore erosion.