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April 2023: Water Quality and Macroinvertebrate analysis
- Alison Loxton
- May 16, 2023
- 2 min read
Hi everyone.
Attached are the sampling results for the month of April 2023. It is great that we were able to recommence the chemical sampling when the chemical reagents arrived about mid-April, earlier than expected.
Some sampling had already been undertaken by that time, so some samples are without accompanying chemical analyses.
Many thanks to Helen, Ross, and Brian for their sustained interest and for assisting the sampling effort.
In respect of the sampling the following observations are offered:
The estuarine reaches of the Coomera River are as saline as I can remember, due to the lack of rain; this in turn has encouraged many fish in recent months to penetrate the river up to and beyond the weir on a spring tide
The chemical analyses were interesting in that, given the lack of rainfall, the levels weren’t higher. Higher readings generally are caused when stream’s flow slows down, allowing chemicals to settle rather than being washed downstream.
The ammonia nitrogen results were less than expected too, potentially meaning that septic tank maintenance has been effective and stock waste has been reduced. This could also be due to an absence of heavy rainfall to wash the waste into the waterways.
In the Macroinvertebrate results, the SIGNAL scores are generally less than last year’s for the same period. Attention is drawn to two waterways where no result was recorded due to there being no flow at the time of sampling. When the water stops flowing the macroinvertebrates burrow deeper into the substrate seeking moisture. To harvest them means damage to the stream bed habitat and to the animals living in it. These days I prefer to wait until there is sufficient flow then sample with minimal damage to the stream bed. In the future you may see results recorded outside the normal sampling schedule when significant rain fall does occur, and I am able to sample responsibly.
Kind regards
Steven Gill
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