Linking piezometers to computers a first in Canada
District manager calls water monitoring system "brilliant."
By JUSTIN BEDDALL Staff Reporter
Jan 12 2006

Rain, rain, go away.

Last year’s deadly landslide along the Blueridge escarpment has made the current nearly month-long spell of heavy winter rainfall a grave concern to residents living along the top of the slope — and those who dwell beneath.

Fortunately, with just a few mouse clicks, Jozsef Dioszeghy can monitor the ground water elevation levels on the Blueridge escarpment — and keep an eye on potentially risky levels of slope saturation.

The District’s director of environment, parks and engineering services can also check the actual rainfall quantity for the day with another gauge — right down to the minute.

“I can tell you what it is from midnight until now, this moment,” he explained.

Shortly after last January’s tragic landslide that killed Eliza Kuttner and seriously injured her husband, Michael, the District of North Vancouver installed seven piezometers along the top of the slope to measure ground water levels and pressure. At the time, it was necessary for District personnel to read the sensors manually, but now they have been linked electronically to allow for remote viewing in real time.

“I can click on my computer, sign in, and see the ground-water elevations of any or all of those seven piezometers,” Dioszeghy explained. “We also monitor the battery condition in the data controllers so that we don’t run dry. We can monitor the ambient air temperature as well.”

Dioszeghy said the District has been using the new remote-viewing technology for the past three months.
“It’s a brilliant system, I have to say. Basically all these piezometers are wired up to a data collector on site. And between the data collector and a computer there is a wireless connection established that means that periodically or in real time we can download the information collected by the data collectors on the computer. The computer basically processes the information and virtually from any computer you can have real-time access to that information collected.”

As part of the District’s new slope stability and monitoring process, the municipality has an agreement with BGC Engineering, a Vancouver-based geotech company that set up the system jointly with RST Instruments, also a local company, to monitor groundwater levels and rainfall along the Blueridge escarpment. BGC, an applied earth sciences company, has experience in landslide hazard monitoring.

“It is set up in such a way that should we get close to a threshold that are pre-established, the system would automatically issue an alert to BGC staff; they would get in touch say with Environment Canada and find out what the short-term forecast is, particularly for rainfall events. And if the need is there basically there is a call-out procedure, and we know about it and we would do the necessary steps.”

Dioszeghy said the District’s geotechnical engineers have studied climatic conditions leading to known landslide events that have occurred in North Vancouver District over the last 30-plus years.

“They looked for the similarities in the climatic patterns leading up to landslides,” he said.

Based on historical information and site-specific information related to soil conditions thresholds have been established so they can predict with a fairly high degree of accuracy the conditions in the past when landslides occurred.

“Basically we can forecast by monitoring a few things,” he said.

Dioszeghy said the piezometer technology isn’t that new, its probably been around for decades, but the application for these purposes is, to his understanding, the first in Canada.

In the months following the landslide last January the District installed piezometers in the immediate vicinity of the slide area. Now, as part of the current embankment-wide study process, the municipality will be installing and additional 20 piezometers across the embankment.

North Vancouver District has also established a precautionary evacuation procedure.