Dawesville Channel

The channel alleviated a serious environmental problem, by allowing seawater from the Indian Ocean to move in and out of the estuarine system using the daily tidal movements, preventing the build-up of algae.

The ability of the system to support the natural flora and fauna had become seriously degraded, and the smell of rotting algae, particularly during the summer months, had caused increasing complaints from residents.

During the late nineteenth century, landowners and governments undertook major drainage works to remove the excess water and free up land for livestock and pastures.

Since then, over 100 years of development of the low-lying sand plain depleted the moisture-holding capacity of the soil, so that any rainfall falling in the region quickly dissipated into the drains.

In the early 1970s, several industries within the lower catchment, including a large piggery and sheep holding paddocks increased the amount of nutrients entering the river system.

In the meantime, the region surrounding the estuaries, particularly the coastal strip south of Mandurah, was undergoing major population growth.

[citation needed] For over twenty years, government and agricultural industry groups battled with the problem, largely unsuccessfully.

The channel is spanned by the four-lane Port Bouvard Bridge, used by approximately 40,000 vehicles per day,[6] which is part of the Old Coast Road between Perth and the southern coastal townships.