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September 2025: Chemical, Water Quality and Macroinvertebrate Analysis
- Alison Loxton
- Nov 2
- 2 min read
Hi everyone
I trust you are all well.
Attached are the Water Quality Monitoring results for the month of September, 2025.
The following is commentary on the results and their interpretation:
The pH of most of the streams was less than the neutral reading of 7; normally lower pH is often an indicator of poor water flow and possible pollution. As the phosphate and ammonia nitrate levels were generally within the normal range, it could possibly be some other form of pollution our testing does not reflect
The overall ammonia nitrogen readings were most pleasing, reflecting good control of both septic tanks and reticulated sewerage
Reactive phosphate readings were a little higher than normal, possibly reflecting reduced flow and greater evaporation which concentrates pollutants
Guanaba Creek remains the benchmark of a healthy stream across our catchment, testimony to the level of environmental conscience across the local businesses and residents
We currently need significant rainfall to assist in stream flow, and supply of nutrients, and food for such animals as platypus and water birds.
At the recent sampling of Waterhen Lake, it was evident that the usual number of the four species of egret using the refuge island as a breeding colony was way less than normal. Their numbers are slowly building and will perhaps be sustained by the numbers of herring present below the Coomera River Weir.
I believe that herring numbers are directly linked to salinity: at this month’s (October) sampling the salinity was 25 parts per thousand which is quite high. Recently whilst visiting the weir there were a number of mangrove jack and trevally being caught, both of these species being herring predators.
I am fortunate to have faithful and loyal people to assist in sampling activities – young Helen and Ross, and Brian, are all thanked for their voluntary hours and for their sustained interest and support.
Kindest regards to you all.
Steven Gill
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