June 2025: Chemical, Water Quality and Macroinvertebrate Analysis

Alison Loxton
Jul 28
2 min read

Hi everyone

Please find attached the WQM results for the month of June 2025.

June was saltwater sampling month, plus Waterhen Lake. the results were a little variable however it is great to report that water flows and levels, after a tumultuous wet season, have somewhat returned to normal.

In respect of the results please find that following observations:

Waterhen Lake recorded pH levels varying from slightly acidic to alkaline; as there was no outflow this would have been due to prevailing winds pushing water into areas where there were pockets of higher and lower pH. There was no obvious sign of small fish activity and there were only a couple of pelicans. Even the carp so obvious a couple of years ago appear to have vanished.
The Oxidation Reduction Potential (ORP) at the Coomera weir was higher than normal at 498mV. This is great because ORP, simply stated, is the ability of water to break down impurities, although it should be noted that to be really effective the ORP should exceed 600mV. When you look at other results for ORP you can see that the water quality at Santa Barbara was in poor shape at the time of sampling. On a different day, the reading would normally be significantly higher.
Dissolved Oxygen (D.O) levels were good which is expected in colder weather, primarily due to colder water retaining more oxygen than warmer water. The danger level for D.O is if levels fall below 4, at which level fish and other animals suffer and can die.
In terms of chemical analyses, the weir returned a higher than normal reading for Phosphorous which would most likely be due to agricultural activity upstream, and the Koala Town Road result was higher than normal, most likely due to the increased development upstream along Yaun Creek.
Chemical analyses from Waterhen Lake were quite variable, with the stagnant outflow next to the Oxenford - Tamborine Road proving to be highest in Phosphorous, no doubt due to accumulation by wind blowing nutrients to the outflow.

We are now only a couple of weeks out from our next planting at Regatta Waters Park. You are invited to participate in that planting on Saturday 9^th August 2025, commencing at 8am. Our plantings are always productive and lots of fun and this time round we will be able to access the sheltered table in Graywillow Park in which to serve morning tea.

Looking forward to the pleasure of your company.

Kind regards

Steven Gill