Engineers learntyphoon lessonsLocal | Stella Wong 22 Jul 2019
New surveying technologies to inspect marine infrastructures like seawalls and breakwaters have been put in play by the Civil Engineering and Development Department to better prepare the SAR against typhoons and extreme weather.
They have been installed aboard surveying vessels, and include an Integrated Multibeam Echo Sounder & Laser Scanner System that can visualize data captured in real time above and below surface.
The echo sounder transmits sound pulses underwater to measure the shape of any object, while the laser scanner system measures the terrain above sea level.
By combining the data, a 3D model of marine infrastructures can be worked out to determine if there are any defects.
An Imaging Sonar System can also gather images for underwater inspections.
Its remote-controlled rotatable 2D sonar view can produce high-resolution images to identify damaged structures.
Land surveyor Tim Cheuk Yuet-wai said the system works in zero visibility.
After Typhoon Mangkhut in September, the department conducted emergency repairs and strengthening work on a 50-meter long collapsed seawall at the Sai Kung Sewage Treatment Works.
This included the erection of a wave wall 1.5m in height.
A 600m wave wall is also going up along Tseung Kwan O Waterfront Park after it was devastated by Mangkhut.
For long-term measures, the department has commissioned a study to review low-lying coastal and windy locations.