The Civil Engineering & Development Department’s Geotechnical Engineering Office is exploring the use of drones for aerial seed sowing on landslide scars to speedily restore the natural appearance in those areas.

Plant seeds are put in a seeder which can be operated by remote control. The drone then flies over the landslide scar to spread the seeds.

Some of the seeds are wrapped in soil mixed with bio-charcoal to help plants grow in dry soil.

The office said using drones to sow seeds will be more cost-effective than the traditional method, where access and working platforms for material transport and planting works need to be constructed.

The technology is being tested at slopes in Shek Kong, Ta Shek Wu and at Fan Kam Road. If proven effective after the three-year trial, it will be adopted in other districts to improve the natural terrain.

At a media briefing on slope safety today, the department reminded residents to be vigilant as urbanisation, slope degradation and extreme weather have increased the risk of landslide.

There were 214 reported landslides in 2020, which is more than the 131 cases in 2019, but lower than the annual average of 300 reported landslides over the past 25 years.