Embankment Trial Undertaken In Otiake River Bed
For immediate release: Monday, 9 February 2004
EMBANKMENT TRIAL UNDERTAKEN IN OTIAKE RIVER BED
An embankment trial using gravel that could be used to build the proposed Project Aqua canal has been completed in the Otiake River bed.
This trial is part of the geotechnical programme, which aims to improve the understanding of the geology of the lower Waitaki Valley.
Project Aqua is a proposed canal-based hydro-electric scheme in the Waitaki Valley near Oamaru. It would generate enough renewable electricity to power the equivalent of about 375,000 households in an average rainfall year and 250,000 households in a very dry year such as occurred in 1992 (a 1 in 20 year event).
The trial is an integral part of investigations to see if Project Aqua is viable.
"Building gravel embankments is not as simple as piling up mounds of gravel. Engineering practice requires detailed geotechnical data on how the gravels compact and how they behave in slopes," says Alan Seay, spokesperson for Meridian Energy.
The field test was performed using fan gravels from the Otiake River bed. The trial site was near Grants Road on the planned alignment of the proposed canal. It was around 1.5km upstream from the proposed location of power station 1.
"The information we get from the trial will be used for the detailed design of Project Aqua and will help with cost estimates for the proposed scheme. It will also assist with confirmation of the conceptual design including the location of power stations and the canal," says Alan Seay.
Project Aqua must be commercially viable and environmentally sustainable to proceed. It must cost less than other forms of generation (between 4.5c and 5c per kilowatt-hour). A major potential benefit of Project Aqua is that it could enable irrigation in the Waitaki district.