EcoH plots

Spring 2008	Autumn 2009

Previous Year Spring 2007 Autumn 2008

Change over time

Legend
		Fish indicator
		Physical/Chemical indicator
		Nutrient Cycling indicator
		Ecosystem Processes indicator
		Invertebrates indicator

A description of the indicators and methods used can be downloaded as a PDF file.

Indices

Legend

The charts show the distribution of the site scores for the catchment in a box and whisker plot. The image to the right shows the meaning of the different elements in the chart.

The number behind the charts is the number of sites with valid data. It can be less than the total number of sites in the catchment if some data could not be collected.

A description of the indicators and methods used can be downloaded as a PDF file.

Summary

One site was assessed in the Mid Brisbane reporting area, which was awarded a 2009 Report Card grade of ‘C+’, lower than its 2008 grade of ‘B’. The river was generally in fair condition. Substantial declines in the Nutrient Cycling and Ecosystem Processes indicators offset an increase in the Fish indicator resulting in a decline in grade.

The five highest scoring indices for the Mid Brisbane reporting area during 2008‑09 were pH (Annual Reporting Area Index Score = 1.00), DO (1.00), Number of Taxa (1.00), PET (1.00) and O/E₅₀ (1.00). The three lowest scoring indices for the area were δ¹⁵N (0.53), SIGNAL (0.64) and GPP (0.79). The one site assessed within the Mid Brisbane reporting area yielded a very good annual score of 0.84.

It should be noted that the regulation of river flow within the adjacent section of the river (Wivenhoe Dam to Mount Crosby Weir) may have artificially increased ecological condition estimates. While the majority of the Brisbane River once dried to a series of pools, the mid-section of the river now has a continuous flow of water from Wivenhoe Dam to feed the Brisbane water supply originating from the impounded waters of Mount Crosby Weir.

Abbreviations glossary

Site scores

The scores range from 0.0 (worst) to 1.0 (best). A dash ('-') indicates that sufficient data was not available.

Flowchart for calculation of summary statistics based on site scores

Map

Click to open PDF version of the map.

Facts

• Total area: 552km²
• Stream network length: 1,135km
• Local Councils: Brisbane City Council, Somerset Regional Council, Ipswich City Council, Moreton Bay Regional Council
• Dominant land uses: native bush, grazing, managed forests, intensive agriculture, rural residential
• Catchment extends from the Wivenhoe dam wall to Mt Crosby weir
• Flow in this part of the river is regulated, depending on releases from Wivenhoe Dam
• Inputs of nutrients, sediments and other pollutants from Lockyer Creek pose the biggest threat to the Mid Brisbane River
• Brisbane Forest Park takes up a significant part of the northern and eastern areas of the catchment
• The Mid Brisbane River features some of the more intact regional riparian corridors in SEQ

Fish

Fish species identified in Mid Brisbane streams