Te Hōnonga a Iwi Youth Leader Alicia Stowers has to be a scientist and a detective as part of her role monitoring water quality in the portion of Alexander Stream that runs through the Rosedale restoration site.
Once a month, Alicia conducts chemical testing in the stream at three different sites, looking for any changes that might indicate a cause for concern.
Generally, the test results are consistent, with very little fluctuation.
“This is not surprising as it does take a long time to see improvements in water quality. If there was a sudden change in a result due to a certain pollutant, the testing would pick up on that.”
In March this year, the concentration of dissolved oxygen in the water dropped to 3mg/l, from a normal level of 6-8mg/l.
This can be caused by warmer temperatures and shallow water in the testing areas, promoting more algae growth, but the result was worrying.
Dissolved oxygen is one of the most critical indicators of water quality as it defines the amount of oxygen available to organisms in the area.
With the help of Amy Sadler and Rhiannon Leddra from Whitebait Connection, Alicia did some follow-up testing using more accurate equipment. This crack team then investigated further upstream, detecting sewage odour in an area close to the nearby water treatment plant, which could also have been responsible for decreased dissolved oxygen.
Watercare was notified and asked to investigate the manholes in and around Alexandra Stream.
Subsequent testing has indicated that stream health levels are back to normal, Alicia says.
In addition to testing for dissolved oxygen, Alicia monitors ammonia levels, which indicate the presence of sewage, nitrates, which can be caused by several factors but mostly come from runoff from fertilised soil, and phosphates. High levels of phosphates can cause dramatic growth in aquatic plants and algae, which can contribute to low dissolved oxygen levels.
She also examines water clarity: good clarity can indicate low levels of erosion and pollutants. Clearer water means more light for plants to photosynthesise and helps fish find food and reproduce.
Whitebait Connection also helps with eDNA water testing once a year and carrying out a bio aquatic diversity analysis twice a year in the stream.
“All of these tests together help to determine the health of the stream. I’m super grateful to have worked with Amy and Rhiannon and to have them share their expertise with me.”
Alicia is a Year 13 student at Kristin School and has been involved with Te Hōnonga a Iwi for almost two years. “I saw a notice on our school’s student forum that was looking for students to help with water quality testing. I was interested in the science element of it and also in helping the local environment so I thought it would be a really good opportunity to be involved in.”
She is also part of Kristin’s Roots and Shoots Waste Team, which manages the school’s composting system and promotes good waste disposal management.
Next year she plans to study engineering at university. “I want to be able to create sustainable solutions to problems so, combined with my interest in STEM subjects, I thought engineering would be a good fit for me.”
Te Hōnonga a Iwi project co-ordinator Nicky Shave says Alicia has done an incredible job of taking leadership of water quality testing at the restoration. “We are gaining a good picture of the stream’s health and how it’s impacted by the work the community is doing over time in the catchment.”
Alicia is hoping to train up the next Water Quality Youth Leader before she goes to university – anyone interested in that role can contact Nicky on hello@restoringrosedalepark.org.nz.
The team also is hoping to encourage local businesses to fund real-time water quality monitoring technology and an underwater video to further improve the data available.
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