Southern Lakes

The client

Contact Energy is one of New Zealand’s leading power companies, and our relationship with them goes back to the 1990s. Recently, they sought our expertise again for the hydrographic survey of two lake and riverbeds to continue effective hydroelectric operations.

The challenge

PDF cross-section plots, survey reports and digital data for lake bed sedimentation monitoring assessments were necessary for consent compliance, analysis and siltation volume monitoring for Contact’s assets.

This project’s success required a mobile surveying operation on a boat to cover the Lake Roxburgh and Kawarau Gorge surveys (35km+ and 20km+ respectively). With variable water depth (0 to over 40m deep) and over 100 cross sections surveyed, each section required precise measurements and reliable data. The narrow gorges and limited cellphone reception provided for challenging survey conditions.

The solution

Some topographical surveys needed to be undertaken by foot due to remote access. But having invested heavily in high precision GNSS (Global Navigation Satellite System) equipment and infrastructure, we were able to ensure the reliability of our gear on-site. We were also able to deploy our equipment on Contact Energy’s boat to complete the surveys. From power to reception, telemetry communication and using portable electronic surveying equipment, we remained totally self-sufficient throughout the survey – all while surveying in remote locations on a boat.

Paired with the processing techniques we’ve refined over decades, we could also efficiently collate, store and present all 100+ cross-sections in PDF plots and digital data formats.

As a result, our ability to provide alternative surveying solutions, software packages and deliverables has enabled another cost-effective result for a longstanding client.