Stream Characteristics of Kedron Brook

Healthy streams

Healthy streams have the following characteristics

• Channel complexity
• Natural biodiversity
• Terrestrial
• Aquatic vertebrates 
• Macro-invertebrates
• Riparian vegetation 
• Open – grassy
• Forest 
• Water quality
• Dissolved oxygen 
• Nutrient balance 
• Level of toxic substances
• Continuity
   

Overview of Kedron Brook stream structure

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Water quality in Kedron Brook

The biodiversity of aquatic organisms declines with declining water quality. The quality of water in Kedron Brook is reported as being in fair, rather than good, condition. The lower water quality was recorded in the Ferny Grove reaches and improved as the stream flows through the Mitchelton reaches (BCC State of the Environment Report, 2001). There has only been limited systematic measurement of water quality along Kedron Brook.

The Australian Catholic University, previously sited at Mitchelton, used to carry out a Waterwatch component in their pre-service primary teacher course. Part of this unit involved testing at two sites along Kedron Brook for Benthic Macroinvertebrates and physical and chemical water tests. Studies showed water quality to be within acceptable limits but could be improved.

Water quality is dependant upon the water flow that varies between the years and with the seasons. It also is affected by the distance downstream from the relatively pristene sources in Brisbane Forest Park . Small levels of urban and industrial wastes have more significant effects upon water quality when there is insufficient rainfall to assist dilution of their concentration. The droughts of a couple of years ago have been replaced by a sequence of vigourous floods. The violent flows of stormwater in recent rainly seasons caused much disturbance of creek banks and generated a high solids load due to bank erosion in the fast flowing sections.

It is understood from anecdotal reports that the water quality in the Kedron Brook catchment, though generally acceptable, still needs to be improved. Although native fish generally cope with the uneven competition from exotic imports, the variety and number of natives are usually lower in proportion in the numbers of fish sampled. More recent waterwatch surveys (2005-2009) have been carried out under the name of Fish Snapshots. The results of these surveys will be added to this website in due course.