St John Brook babbles through the conservation park, providing the ideal environment for several species of native fish, including western minnow, night fish, western pygmy perch and Swan River goby. However they are threatened by the introduced rainbow trout that prey upon these small native fish.
Swamp peppermints fringe the brook. You will also find open forest with marri, river banksia, monah and peppermint. Further up on the hilltops there is jarrah.
Birdlife is abundant in the park, with many small birds in the desne shelter afforded by the riparian vegetation and red-tailed black cockatoos in the jarrah trees. At least 38 bird species live in the park, along with six reptiles, four amphibians, four native fish and 11 mammals.
A timber mill was established on the banks of ST John Brook in 1910. Prized jarrah timber was transported by rail. Today, the Timberline Trail follows where the track once was.
Prior to European settlement, Nyoongars probably followed St John Brook at the end of summer as they moved from the coastal lowlands to the open woodlands inland.
St John Brook Conservation Park is a short drive from Nannup, along an unsealed road.
You can swim at Workmans Pool and Barrabup Pool. Beware of submerged logs and rocks.
Walking and cycling
The Timberline Trail passes through Workmans Pool and Barrabup Pool.
Drive-in camping is available at Barrabup Pool and Workmans Pool. Walk-in camping is available at the Sleeper Hewer’s Camp, about three kilometres north of Barrabup Pool along the Timberline Trail. The camp has three tent sites and a hut that sleeps four to six people. Bring your own fuel stove. These camp sits are generator free.