The Broadwater received a “C-” for the 2009 Report Card, indicating a deterioration in ecosystem health from the previous year (“B”).  Generally the Broadwater has good water quality but for this reporting period there were increases in the sewage nitrogen signal (δ¹⁵N) and nutrient concentrations.  The enhanced nutrient (TN, TP) levels were mostly concentrated towards the northern zone of the Broadwater with the maximum concentrations monitored during April 2009 when the region experienced high rainfall.  The Broadwater was fully compliant with QWQ guidelines for Chl-a (phytoplankton abundance) and DO during 2008/2009.

The Report Card grade for the Broadwater was also slightly impacted by a small reduction in the BHR for the system caused by a small reduction in the depth range of seagrass (Zostera muelleri) found within this zone.

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 BHR forms 20% of the the Report Card Grade. The values in this sheets are calculated using the original method used since 2002-03 and is presented for comparison.