Greening works contribute to the improvement of air quality in addition to the aesthetic of an area. They are essential to the protection, rehabilitation and enhancement of our landscape and ecological environment, which helps create sustainable environmental outcomes. Apart from fulfilling the functional requirements of the development projects, the Civil Engineering and Development Department (CEDD) has been actively promoting greening through a wide range of initiatives, including (1) development and implementation of the Greening Master Plans (GMPs) and other greening initiatives; (2) greening works associated with infrastructure projects; (3) greening works associated with the Landslip Prevention and Mitigation works; (4) greening works for quarry rehabilitation; (5) soil erosion control planting on natural hill slopes; and (6) tree risk assessment and management.
Some of the plant species commonly recommended in the Greening Master Plans
Development and Implementation of Greening Master Plans and Other Greening Initiatives
A Greening Master Plan (GMP) seeks to define comprehensively the greening framework of an area by studying its characteristics and particular needs, and providing a guide to the planning, design and implementation of greening works. To ensure high-level commitment to the GMPs, each GMP is approved by the Greening Master Plan Committee chaired by the Director of Civil Engineering and Development, and endorsed by the Steering Committee on Greening, Landscape and Tree Management chaired by the Permanent Secretary for Development (Works).
We promote public participation in the GMP formulation process and adopt the "Enhanced Partnering Approach" whereby each relevant District Council forms a District Participation Group (DPG) to partner with us in reviewing the contents of the GMPs and to advise us on the greening of the districts. The successful implementation of greening measures is made through expertise and coordination of multiple disciplines, including landscape architecture, town planning, civil and traffic engineering and even public relations. We organise community planting ceremonies and school talks and invite local residents to participate in our planting activities. We believe that public participation not only enables us to tap into valuable local knowledge but also creates a sense of ownership of the GMPs in the community. We have received very encouraging responses and appreciation of our works from the public.
Following the successful completion in 2011 of the GMPs for the urban areas, we commenced the greening works in the GMPs for Sha Tin, Sai Kung, Tuen Mun and Yuen Long in 2014, and completed them in 2017. We have planted about 4,000 trees and 2.6 million shrubs in the four aforementioned districts. We are planning for the implementation of GMPs for New Territories in Tsuen Wan, Kwai Tsing, Islands, Tai Po and North District.
Here are photos of some of the completed greening works in urban areas and the New Territories:
Landscape Improvement Works in Ngong Ping
The Sustainable Lantau Blueprint announced in June 2017 by the Government dedicated part of Lantau Island to be used for conservation with sustainable leisure and recreational purposes. In view of the cool climate, good transport connectivity as well as the synergy with the existing tourist attractions in Ngong Ping, we have planted around 400 cherry trees and native spring-flowering trees in Ngong Ping for visitors' enjoyment during the blossoming season.
We commenced the landscape improvement works in Ngong Ping in January 2018 and completed the works in mid 2018. We held a planting ceremony in January 2018 to give impetus to the landscape improvement works.
Trial Schemes for "Rain Garden" and "Vegetation Diversity"
To celebrate the 20th Anniversary of the establishment of the HKSAR, DEVB launched a "City Dress-up" Programme to enhance the city's appearance and also to augment the liveability of Hong Kong. This includes a trial scheme to transform an existing traffic island at Wylie Road into a "Rain Garden". Rain Garden helps our city to absorb more rainwater. It is designed with layers of different soil particle sizes that allow more rainwater to infiltrate into the garden. In carrying out the planting design, we have carefully selected plants that can filter out some of the pollutants in the rainwater, thus reducing pollution to our waterways and harbour. The plants can also adapt to both wet and dry conditions, and require little maintenance. CEDD, in collaboration with DSD, completed the construction works for the trial scheme of Rain Garden in February 2018 and the plants will blossom during growing season.
Another trial scheme is enhancing an existing planter at Tung Chung Eastern Interchange with a main focus on promotion of "Vegetation Diversity". For the planting design, a more diverse plant palette with emphasis on native species were selected to enhance biodiversity. We completed the landscape works in December 2017 and the plants are in good conditions. We will closely monitor the effectiveness of the trial schemes.
Greening Works Associated with Infrastructure Projects
We provide essential infrastructure to the public with the prime purpose of fulfilling the community's growing need for enhanced safety, well-being and quality of living. To this end, most of our infrastructure projects include the provision of extensive planting schemes serving as landscape / ecological enhancement and impact mitigation measures. Such greening works involve planting in a variety of settings like roadsides, footbridges and flyovers, podiums, slopes, river channels and promenades.
Some of the major infrastructure projects with extensive planting schemes included Development at Anderson Road and Kai Tak development – Stage 3A and Stage 4 infrastructure works at north apron area of Kai Tak Airport. In 2017, approximately 320,000 plants were planted.
Greening Works Associated with Landslip Prevention and Mitigation Works
When implementing the slope works under the Landslip Prevention and Mitigation Programme, we pay attention not only to the stability of the slopes but also to their appearance and ecological sustainability. To minimise the visual impact, landscape treatments are provided to all upgraded man-made slopes and engineering works on natural terrain. In pursuit of a naturalistic and environmentally conforming appearance for the upgraded slopes and engineering works on natural terrain, we provide vegetation cover wherever practicable and use hard surface cover only as the last resort on slope stability grounds and as emergency repairs. On average, we plant about 300 000 plants each year in connection with our landslip prevention and mitigation works, and over 90% of the plants are native species.
We published GEO Publication No. 1/2011 – Technical Guidelines on Landscape Treatment for Slopes to promulgate the best landscape treatment practice on slopes, natural terrain mitigation works and landslide repair works.
In order to establish robust, cost-effective, and eco-friendly vegetation covers on slopes, we pursue various research initiatives to improve the slope greening technology. Ongoing research initiatives include the following:
- Performance Assessment of Planter Holes for Slope Works
- Performance Assessment of Proprietary Greening Techniques on Slopes with Hard Facing
- Review of Hydroseeding Specification for Slope Works
- Study of Health Conditions of Trees and Undergrowth on Upgraded Fill Slopes
Based on the research results, we will publish guidelines on good practices of landscape treatment for slope works.
Greening Works for Quarry Rehabilitation
The plan to rehabilitate quarries was formulated in 1989 as an outcome of the Metroplan Landscape Strategy for Urban Fringe and Coastal Areas, which identified quarries as areas of degraded landscape requiring rehabilitation. The rehabilitation works typically involve major recontouring and extensive planting. Upon completion of the quarry rehabilitation works, attractive greened areas will be formed for a variety of uses beneficial to the community.
Under an innovative scheme developed by the Government and the quarrying industry, we completed the rehabilitation works at Lamma Quarry in end 2002, Shek O Quarry in early 2011 and Anderson Road Quarry in mid 2017 and are managing the existing quarry rehabilitation contract at Lam Tei. In the course of quarry rehabilitation, slopes are revegetated extensively with suitable vegetation with a long-term objective of creating anticipated climax vegetation communities that will blend ecologically and aesthetically with the surrounding natural vegetation and providing favourable habitats for wildlife. In 2017, we planted about 800 plants in connection with our quarry rehabilitation projects.
Soil Erosion Control Planting on Natural Hill Slopes
The programme to control soil erosion on natural hill slopes through re-vegetation stems was formulated according to the Metroplan Landscape Strategy for Urban Fringe and Coastal Areas, which identified eroded hill slopes in the urban fringe as areas of degraded landscape requiring rehabilitation. Under the soil erosion control planting programme, we establish primary vegetation covers on the eroded or erosion-prone natural hill slopes on unleased or unallocated land outside country park. The objectives are to control soil erosion and improve the ecological and landscape value of the degraded land. The planting and establishment of about 77,000 number of plants in Tuen Mun Trail and Lam Tin Black Hill were completed from 2016 to 2017.
Tree Risk Assessment and Management
To ensure public safety and for sustainable development and tree care, we conducted the annual tree risk assessment and management exercise for approximately 25,000 trees according to the guidelines promulgated by the Tree Management Office in early 2017 prior to onset of the rainy season. The tasks include conduction of tree inspections, tree risk assessments, appropriate mitigation tree works and the related tree audits.
In the planting schemes, we adopt a mixture of plant species, which includes fast-growing pioneer species to arrest any further soil erosion and native species wherever practicable to allow enhancement of biodiversity. We also continue to exchange knowledge and experience with other government departments to further enhance our effective greening works for different soil erosion situations.
Management of Construction Waste
The composition of construction waste varies, depending on the nature of the construction works. In general, about 90% of it is inert construction materials, also known as public fill, which is suitable for reuse in reclamation and earth filling works, or recycle for use in other construction works. The remaining non-inert construction waste, subject to recovery of reusable/ recyclable items, is disposed of in landfills.
In 2017, our local construction activities generated about 17.9 million tonnes of public fill, 4.6 million tonnes of which were reused and the remaining 13.3 million tonnes were stockpiled temporarily in the fill banks for reuse in the future. As at December 2017, we stockpiled about 18.2 million tonnes of public fill in the 2 temporary fill banks located in Tseung Kwan O Area 137 and Tuen Mun Area 38.
In managing this huge volume of construction waste, our objective is to promote the reduction, reuse and recycling of public fill and to prevent public fill from being disposed of in landfills, which are designed primarily for putrescible waste. Specific measures include:
- Avoiding and minimising construction waste generation at sources through better planning, design and construction management
- Implementing Construction Waste Disposal Charging Scheme to provide an economic incentive for waste producers to reduce construction waste that requires disposal
- Processing/recycling public fill
- Setting up sorting facilities to facilitate the reuse of inert materials
- Establishing temporary fill banks to stockpile surplus public fill temporarily to facilitate later reuse
- Setting up barging facilities for collection of surplus public fill and delivery to the fill banks
- Reusing surplus public fill in Mainland/local reclamation projects
To ensure proper disposal of public fill arising from local construction activities, we are operating the temporary fill banks and construction waste sorting facilities at Tseung Kwan O and Tuen Mun and the barging facilities at Chai Wan and Mui Wo.
Reuse of Surplus Public Fill in the Mainland
Since the reclamation projects in Hong Kong are unable to absorb all the public fill generated by local construction, excavation, renovation, demolition and road works, we are currently relying on two fill banks for temporary storage of public fill. Notwithstanding different management measures taken to reduce fill generation at source and to promote its reuse and recycling, we still face the problem of surplus public fill.
To tackle the problem, we continue to explore opportunities to reuse our surplus public fill in Mainland. We signed a Cooperation Agreement with the State Oceanic Administration (SOA) in March 2004. It provides a foundation for delivery of our public fill in Mainland waters. We further reached an agreement with the South China Sea Branch of the State Oceanic Administration (SOA(SCSB)) in June 2005 on the implementation details, including the material specifications, delivery requirements, inspection and control measures, to ensure that the use of public fill in the Mainland's reclamation projects will not cause any environmental problems.
In January 2006, SOA(SCSB) designated a trial reclamation site in Guang Hoi Wan (廣海灣) of Taishan (台山) to receive public fill from Hong Kong. Contracts were subsequently awarded for the cross-boundary delivery of surplus public fill to the reclamation site concerned. The delivery of public fill to Taishan commenced in July 2007 and about 119 million tonnes of public fill have been delivered up to May 2018.
The scheme demonstrates that the delivery of surplus public fill to the Mainland for reuse is an environmentally sound and mutually beneficial arrangement. This arrangement helps alleviate our pressure in accommodating surplus public fill and enables beneficial reuse of our public fill in the Mainland. In the absence of the scheme, the fill banks would have already been filled up and any surplus public fill would have to be disposed of in landfills, of which the capacity is fast depleting.
The Government promulgated the Sustainable Lantau Blueprint (Blueprint) in June 2017, with "Development in the North; Conservation for the South" adopted as its overarching principle. The major economic and housing developments are planned in North Lantau and the East Lantau Metropolis (ELM), while Northeast Lantau will be developed into a node for leisure, entertainment and tourism. The predominant part of Lantau, in particular South Lantau, will be for conservation, leisure, cultural and eco-tourism purposes.
On conservation, we are conducting an ecological study to review the existing ecological information of South Lantau and explore appropriate conservation measures. We have also set up expert group (e.g. "Expert Group on Ecological Conservation of Pui O, Shui Hau and Tai O") for respective specific topics with a view to achieving concrete results through discussion and consolidation of experts' views. Apart from encouraging non-profit making organisations' participation in conservation projects by leveraging the funding resources, we strive to promote conservation in Lantau through community activities (e.g. ecological guided tours, workshops, roving exhibitions, etc.).
On sustainable recreation and leisure, we commenced the mountain bike trail network works in South Lantau. For better enjoyment of the natural resources in Lantau by the public and visitors, we are preparing to take forward the other projects, such as upgrading the hiking trail facilities in Lantau and the existing volley ball court at Silvermine Bay Beach in Mui Wo.