Our Projects (USL)

As the sea levels are rising around the main Island of Tuvalu , Funafuti International Airport runway has been affected by the undermining sea currents creating washouts and tomos beneath the runway’s surface.

Underground Service Locators (USL), in conjunction with GHD, were commissioned to complete a comprehensive ground penetrating radar (GPR) scan to determine areas of interest requiring immediate repairs. The scan covered about 109km in walking distance, which was completed by two USL Utilities Locators over three days.

The urgency of this project was crucial. The runway is the lifeline for the island – Every week, just two flights arrive and depart from Tuvalu, so safety of the runway is important in keeping those connections with the surrounding islands. Rapidly-rising sea levels also pose a real threat to the future existence of this small island nation.

Challenge 

The major challenge was that the Airport’s base station, which provides a satellite connection, was damaged and out of order. This meant that the satellite connection was needed for the team to provide data captured from surveying and scanning the runway using ground penetrating radar (GPR). 

Our team only learnt about the problem a week before departure, so they needed to come up with a back-up solution to be able to provide accurate GPR scanning and location data for the client. The pressure was certainly on as it was a long way back if they didn’t get it right first time around, not to mention the financial implications for the Downer business.  

Other challenges included the logistics of shipping the required equipment (including a state-of-the-art 30 array antenna GPR) to the remote island, as well as working in extreme heat conditions.

Solution 

With quick thinking, USL GIS Team Lead, Chris Blazkow, managed to find a solution which came in the form of handheld surveying equipment (Trimble TRX) for marine correction services. 

The team also had two additional back-up options if this wasn’t successful, including a Lecia GPS surveying tool, and analogue measurements they could use.  Testing on both of the digital methods was tight and stressful as the were simulating test data which needed to be online and accurate for an island that was 3318 km away from New Zealand (via Fiji).  

After a long journey, upon arriving in Tuvalu from Auckland, the team immediately unpacked their equipment and headed to the runway to set up and see if they could get signal and achieve the accuracy required to complete the project.

Outcomes

The Trimble solution worked and was far the best option of the three. Apart from delays due to weather, the USL team completed Downer’s largest ever single scan with results over and above their client’s needs.

The client was having issues with one of their holding reservoirs at the wastewater treatment plant in Morrinsville.

They recognised that there was a leak but were unsure of how and where the leak was coming from. The leak was causing deformation and problems to the concrete slab at the base of the reservoir.

Challenge

Because the team were working around wastewater, full safety measures and sanitary precautions had to be taken, including full PPE (full suits and facemasks. The reservoir had to be emptied and washed down before the team could complete their scan and al equipment had to be washed thoroughly after its use in the reservoir to avoid any contamination.

Solution 

Using  Stream DP, the latest ground penetrating radar technology for 3D mapping, the team scanned the concrete slab. After processing the data, the USL team were able to find two stormwater lines running through the pad and the void that had formed around them, caused by the leaking pipes. 

Outcomes

The USL team provided the client with their findings. This allowed them to identify the problem and get the issue fixed – preventing further corrosion to the concrete base.