Data collected will help KiwiRail identify areas that most need stabilising and know ahead of time which sections are more at risk of tumbling down and cutting off or damaging the rail line.
Any slope will have an expected natural amount of movement as it soaks up moisture then dries out. With WSP’s system, if the threshold of what is considered normal is breached, the sensors will send an alert.
Timelapse footage will be taken every 15 minutes, letting KiwiRail track what the slope movement looks like over time. Photos can be taken on demand - in a heavy weather or active slip event – helping KiwiRail make up-to-the-minute operational decisions.
With its sensors, the system can pick up the smallest of slope changes. It’s precise to a 0.2-degree angle. Data from the monitoring system can be viewed in an online dashboard, visible to KiwiRail and WSP.
Mike says the value of this kind of always-on, real-time slope monitoring comes from the stream of data giving long-term averages of movement. Including observed weather data provides even greater insights.
“Instead of being the ambulance at the bottom of the cliff saying, ‘your slope has moved 2mm,’ we can say ‘there's been heavy rain, which means your soil moisture will have increased and there's a higher likelihood of needing to prepare for next steps with possible slope failure’. By using seasonal weather forecasts, we can identify periods in the calendar when these kinds of risks are higher.”
WSP has spent the past few years honing its slope monitoring system with other clients, including Transpower and Waka Kotahi. With climate change expected to result in more frequent extreme rainfall events, heightening the risk of landslide in some parts of the country, this kind of smart slope monitoring is set to become more important than ever.