New Plymouth Boys High School 2011
Water quality in two central New Plymouth locations was the focus of scientific attention for nine Year 11 students from New Plymouth Boys’ High School in 2011. The team spent five sessions with 60 Springs educator Nathan Hills learning about water quality in the Huatoki River and stream that drains Pukekura Park's main lake.
Park waterways are a big topic throughout New Zealand – with Pukekura Park being no exception. The park has some water quality problems, especially in summer when the water temperature can be high, dissolved oxygen levels very low and water flow is almost non-existent.
The class got busy conducting a variety of tests including pH, water temperature, conductivity and water clarity. One result that alarmed the students was the high water temperature of the Pukekura Stream, which reached 19.9 degrees Celsius (2.9 degrees warmer than the Huatoki River). Temperatures exceeding 20 degrees are known to cause considerable stress to some fish (e.g. Brown trout) and are not survivable for sensitive invertebrates.
An MCI (Macroinvertebrate Community Index) was another test the students conducted and this involved the sampling of miniature creatures (invertebrates) in the water. Each invertebrate has its own sensitivity score, which in turn can be used to give an overall water-quality score for the waterway. Their results seem to suggest that Pukekura Stream had moderate-poor water quality. However, the students concluded that their sample size was too small to be representative. The Taranaki Regional Council recommends that at least 10 different species be collected for it to be representative sample of life in a stream. Rain on the day prior to the sampling was also identified as having a possible effect on the results as it may have flushed invertebrates downstream.
The research done with 60 Springs is forming part of the students’ studies towards their Maths and Science Unit Standards.
New Plymouth Boys High School 2010
A group of a dozen Year 11 students investigated the abundance and diversity of fish between the spring-fed Pukekura Stream (just below Lily Lake) and the Huatoki River. After first familiarising themselves with the scientific equipment and sampling techniques they headed out into the field.
The students set up fish traps in both waterways and caught a lot more fish in the Huatoki River than in the Pukekura Stream. The species included a giant kokopu, red fined bully, banded kokopu and an eel. The students caught no fish in Pukekura Stream traps but they did see goldfish and an eel. Pukekura Park is known to have fish access issues due to its manmade structures.