|Gardner River at a glance|
|Average annual catchment rainfall:||1350 millimetres|
|River length:||35 kilometres|
|Extent of tidal influence:||Five kilometres|
|River health:||no significant pollution|
Water temperature probably ranges from 10°C. or less in winter to 24°C. in summer. Summer recordings show the surface water at 24°C., with deep water temperature decreasing gradually to 20.5°C. at three metres.
Total phosphorus readings range from 0.01 to 0.08 mg/litre. Part of the upper catchment is cleared, mainly for cattle grazing, but the greater part remains uncleared.
Estuaries and Coastal Lagoons of South Western Australia. Broke Inlet and other estuaries of the Shire of Manjimup. Environmental Protection Authority; Perth, Western Australia. Estuarine Studies Series Number 6: September 1989