Warren River (Western Australia)
Warren River is in the South West region of Western Australia. It drains a catchment that includes the towns of Manjimup and Pemberton. The river is about 137 km long, drains about 4,350 square kilometres, and has an average discharge of 291 gigalitres per year.
The river was named by Governor James Stirling, likely after Admiral Sir John Borlase Warren. It was first noted in 1831 by Lieutenant William Preston during a coastal survey; after his boat wrecked near Green Point, Preston and his crew walked along the coast from Albany to Fremantle. The first European settler along the Warren was Edward Reveley Brockman, who in 1862 set up Warren House on the riverbank.
Where it starts and ends: The Warren rises in Tone State Forest, west of Strachan, about 30 km southeast of Manjimup. From the confluence of the Tone and Perup Rivers near Murtinup, it flows about 137 km southwest, crossing the South Western Highway and passing through Warren State Forest, Greater Hawke and D’Entrecasteaux National Parks and the Dombakup Nature Reserve, finally reaching the Southern Ocean near Coolyarbup.
The river flows through woodlands and forests and is the second largest by flow in the Busselton-Walpole region. Its main tributaries are the Perup, Yerraminnup, Wilgarup and Tone rivers, and the Quinninup, Lefroy and Dombakup brooks.
Water quality: Before clearing land for farming, salinity was about 120–350 mg/L (fresh water is under 500 mg/L). Clearing in the 1920s–1960s raised salinity, and the Warren catchment was declared a clearing control catchment in 1978. Since then, revegetation—especially in the Perup and Tone sub-catchments—has reduced the salt load entering the river by about 60%. Clearing is now about 35%. The lower Warren near the mouth is slightly brackish, with an average salinity around 990 mg/L (1993–2002). Dombakup Brook remains fresh (<440 mg/L).
This page was last edited on 2 February 2026, at 20:41 (CET).