The Coomera estuary received “B-” grade in the 2009 Report Card, a slight drop in ecosystem health from the previous year (“B”).  This reduction was due mainly to increases in nutrient concentrations (53% and 39% compliance with QWQ guidelines for TN and TP, respectively for 2008/2009 compared with 100% and 70%, respectively the previous year).  There were also increases in phytoplankton abundance in the lower and middle reaches of the system.  However, turbidity remained low, and DO high throughout the estuary and were within QWQ guidelines.

Overall, only 34% of the total Coomera estuarine riparian zone contains unmodified habitat and this low proportion of natural habitat limits the BHR for the system and impacts on its Report Card grade.  Much of the unmodified habitat is restricted to the northern bank in the lower reaches where the estuary runs through a National Park.  By contrast, much of the southern bank is heavily modified with high density urban land uses predominating.

Abbreviations glossary | Indicators and methods

ECOSYSTEM HEALTH INDEX (EHI)

The EHI is a measure of the proportion of a reporting zone that complied with the water quality objectives for key indicators monitored as part of the Ecosystem Health Monitoring Program. The water quality objectives are defined in the South East Queensland Regional Water Quality Management Strategy (2001).

• EHI 1 = 100% of area complies with the environmental objectives.
• EHI 0 = 0% of the area complies with the environmental objectives.

BIOLOGICAL HEALTH RATING (BHR)

The Partnership's Scientific Expert Panel has endorsed a change to the BHR in 2006-07 which increase the BHR from 20% to 30% of the Report Card Grade.

The reason for the change is the implementation of the Riparian Assessment Program (RAP) which will comprise 15% of the total grade (half of the BHR). The other BHR indicators will make up the last 15%

The data from the riparian assessment is available as PDF document.