The Tung Chung New Town Extension (TCNTE) is the first trial project for the development of a smart low-carbon community on Lantau Island, adopting city concepts that are smart, green and adaptable to climate change. Right from the design and construction stages, the TCNTE project has incorporated the concept of sustainable development, including the creation of Eco-shorelines in the Tung Chung East Extension area. This time, I have invited a colleague from the Civil Engineering and Development Department (CEDD) to tell us about the “Mangrove Planting Scheme”. He will also take us to the trial Eco-shoreline in Tung Chung for a visit to show us how biodiversity can be enhanced by planting mangroves and placing bio-blocks.

First Eco-shoreline in Hong Kong

Making use of the opportunities brought by the TCNTE, the Sustainable Lantau Office (SLO) of the CEDD will construct in the Tung Chung East Extension area an approximately 4.9-km-long waterfront promenade, including the first Eco-shoreline in Hong Kong with a total length of about 3.8 km, with a view to enhancing biodiversity by mimicking the ecological habitat of natural inter-tidal zones.

Mangrove Planting Scheme

Recently, the project team launched a 4-month Mangrove Planting Scheme, inviting primary school students in Tung Chung to plant mangrove seedlings. During the first workshop, participating students learnt about conservation with Eco-shorelines and mangroves, designed their own pots and planted mangrove seedlings called Kandelia obovata in them. They also learnt some mangrove tree planting techniques. Upon completion of the scheme, the mangrove seedlings planted by participants will be transplanted to the Eco-shoreline in Tung Chung. The primary school students say that they are very happy to have participated in the activity. Apart from having the opportunity to learn more about mangrove trees and related works, they are excited that they got to plant the mangrove trees themselves and take part in building the Tung Chung community.

Promoting the idea of community co-building

Marine Conservation Officer (Lantau) of the Sustainable Lantau Office of the CEDD, Mr WO King-tai, says that the scheme aims at promoting sustainable development and co-building the community. By organising a series of workshops and visits, the project team hopes that participants can learn more about mangroves, biodiversity and related works projects. Most importantly, the team hopes to build and beautify the community together with residents so that they will have a stronger sense of belonging to the TCNTE.

Three types of Eco-shorelines

The Tung Chung East Extension area is also the first Government public works project to adopt Eco-shorelines. The project team will create different types of Eco-shorelines, including Mangrove Eco-shoreline, Rocky Eco-shoreline and Vertical Eco-shoreline, based on factors such as geographical environment and tidal flow to replace the man-made concrete seawalls built in the past. For example, a Mangrove Eco-shoreline will be created at locations less susceptible to sea waves, and bio-blocks will be provided at locations more exposed to sea waves.

New residents found at the site of the trial Eco-shoreline in Tung Chung

In order to optimise the design of Eco-shorelines, the project team has set up a trial Eco-shoreline in Tung Chung. Recently, quite a number of “new residents”, such as mudskippers, fiddler crabs (e.g. Uca acuta) and gastropods (e.g. Lunella coronata granulata), have been found at the site. Mr WO King-tai says that the site has been set up for more than two years and the mangrove trees planted have been growing satisfactorily, forming a good marine intertidal habitat. As mangroves can add greenery to the environment and block waves from hitting or eroding the coast, they have very high ecological value. Mangrove Eco-shoreline can serve as the habitat for various marine species, and the fallen leaves and other debris of the mangroves can become food for numerous invertebrates and fish.

Bio-blocks mimicking intertidal zones

With uneven and rather rough surfaces that can retain sea water when tides are low, bio-blocks of various heights line the Rocky Eco-shoreline. Since these bio-blocks can lower temperature and provide suitable habitats for marine species, species in the inter-tidal zones can easily attach themselves to the blocks for growth and reproduction. Mr WO King-tai says that marine species have been attracted to the Rocky Eco-shoreline and made it their home. Also, marine species are also increasingly abundant in the area.

Eco-tiles have also been placed along the Vertical Eco-shoreline. As species of smaller sizes can attach themselves to the cavities on the eco-tiles for growth, biodiversity can be enhanced.

The TCNTE is a main project for the development of North Lantau. I am pleased to learn that reclamation works are making good progress. Apart from housing and commercial development, conservation of the existing natural ecology and sustainable development are also important to the SLO. During the process, we put great emphasis on public participation and have invited stakeholders from various sectors and the general public to participate. I hope the project will be completed soon so that the public can appreciate the hard work of the project team.