The Kalgan River head waters are located in the Stirling Ranges National Park and eventually discharges into the Oyster Harbour. The main channel is approximately 100 kilometres long.

The average annual rainfall in the lower of the catchment is 1100mm while the upper of the catchment receives significantly less rainfall. The River flows all year round.

The majority of the Kalgan River catchment consists of Jarrah, Marri and Wandoo woodlands. Since European settlement approximately 66% of the catchment has been cleared for agriculture but the upper catchment has remained relatively vegetated.

The River was sampled between February 2006 and December 2007.

Night Fish, Western Pygmy Perch and fresh water crayfish Cherax crassimanus were all recorded in the Creek. Pictures of these can be viewed in the gallery.

The sites that were sampled on the Kalgan River were in B grade condition and were slightly degraded. No other sites were assessed for foreshore condition.

All sites on the Kalgan River were saline with conductivity readings between 25.7 - 29.0 mS/cm. The Takenup Creek is was brackish (6.8mS/cm) and Naiper Creek, Chilgiup Brook, Little Creek and Churchlane Creek were all fresh.

All sites across the catchment recorded a neutral pH.

KAL-K1, KAL-K3, KAL-K8 and KALK9 al recorded high or very high levels of turbidity. KAL-K2 recorded moderate levels of turbidity and all other sites recorded low levels.

Only the Kalgan River was sampled for nutrients. KAL01 and KAL02 recorded low levels of total phosphorus and moderate levels of total nitrogen, while KAL03 recorded high levels of both TP and TN.