As a part of the Mei Te Vai Ki Te Vai project, coastal engineers from the University of New South Wales have been working to gather data on nearshore ocean currents, and mixing processes in the ocean off Rarotonga. This work will help us to evaluate the feasibility of an ocean outfall for treated wastewater – one of the two options we’re considering for wastewater disposal.
The work involved dye tracing and current profiling at four locations along the coast. The team dropped dye at each location, and measured the movement of the dye for between 30 minutes and one hour. They also used acoustic measurements to help profile currents at each location, and to understand how the currents vary at different depths.
The data on currents and mixing processes will help us to understand the potential mixing and movement of wastewater from an ocean outfall, and support the development of an outfall with the least possible environmental impact.
Alongside ocean disposal, we are also evaluating and preparing information on land-based wastewater disposal, to enable Government to consider both options before deciding on a preferred method.