James Magee, Engineer
Morphum Environmental recently undertook a large water quality monitoring and sampling programme in Onehunga for the New Zealand Transport Agency (NZTA). The programme involved the installation of continuous turbidity, conductivity, temperature and pH monitoring equipment at five stormwater manholes located across Onehunga. At regular intervals, site visits were undertaken to collect data from each of the sites as well as to calibrate the equipment.
At one of the sites, an automatic multi-bottle sampling device, telemetry system and data logger were installed, which detected when a rain event was occurring and automatically initiated the sampling device. Following this, the equipment generated an email notification alerting Morphum Environmental’s monitoring team that samples were ready for collection. The deployment of the data logger in combination with telemetry at this site also meant that the collected data could be viewed online in real time. This allowed for the opportunity to visually compare different data sets as a rain event occurred; for example, the relationship between the water depth and conductivity (see image).
The data collected from the programme is being used to inform the design of treatment systems for the NZTA’s East West Link project, as well as the environmental assessments to support resource consent applications and notice of requirements. The East West Link project will provide a new link on the north side of the Mangere Inlet between State Highway 20 in Onehunga and State Highway 1 in Mount Wellington.