The Landscaping of Man-made Slopes

Department: Landscape Architecture
Active Dates: March 2010 – November 2016

Project Title: The Landscaping of Man-made Slopes

Project team:
P-I: Matthew Pryor, HKU
Dr. Billy Hau
Allan Watkins, Halcrow China Limited
Prof. Charles W. W. Ng, HKUST
Chen Yu Xiao, M.Phil Student, HKU

Project funding:

  • Applied Research Funding, GEO Publication No. 1/2011 – Technical Guidelines on Landscape Treatment for Slopes, Geotechnical Engineering Office, Civil Engineering and Development Department (P-I; M. Pryor).
  • Collaborative Research Fund. Green Slope Engineering and Live Capillary Barrier for Man-made Fill Slopes and Landfill Capillary Barriers in Hong Kong. (P-I: Prof CWW Ng, HKUST, 9 Co-I’s, from HKU, HKUST and CUHK) (2012-16).



The visual appearance of hard surface covers used on many of Hong Kong’s 70,000 registered man-made slopes, has caused public concern over the last 20 years.  The aim of this applied research study is to address this by identifying and defining alternative, visually appropriate, ecologically relevant and resilient green slope covers for soil and rock cut slopes, embankments and retaining walls in Hong Kong, and establishing best practice in their landscape treatment.  The study continues and updates earlier research studies (1998-2000), and maintains its unique collaboration between landscape, ecological and geotechnical engineering expertise. The original research in this study comprises the detailed analysis of international case studies and best practice publications (in the USA, Europe and Australia), a critical literature review of scientific papers relating to planting on slopes and the influence of tree and shrubs on soil mechanics, an extensive review of archival records of the construction and maintenance records of, and the field assessment of (N>200) selected slopes to determine the efficacy of both hard and soft (planted) landscape treatments. 


Pryor, M. and Chen, Y.X.  Landfill after use: planning for acceptance.  In Proceedings of 15th International Waste Management and Landfill Symposium.  International Waste Working Group, Sardinia. Italy. October 2015

Pryor M., Hau C.H. and Watkins A. GEO Publication 1/2011 – Technical Guidelines on Landscape Treatment for Slopes. (‘Blue Book’ technical publication series) Geotechnical Engineering Office (GEO) of Civil Engineering and Development Department, HKSAR Government, Hong Kong, 2011, 220.

Conference papers and presentations:

  • Pryor, M. The challenge of planting trees on slopes in Hong Kong.  In Proceedings of  7th Annual International Arboriculture Summit – Hong Kong. (21 November 2014)
  • Pryor, M. Seminar on Landscape Treatment for Slopes, Lecture Theatre, Hong Kong Central Library. Development Bureau, The Government of the Hong Kong SAR, (17 August 2012).
  • Pryor M.R., Hau C.H. and Watkins A. Promulgation of GEO 1/2011 – Technical Guidelines on Landscape Treatment for Slopes, in:
    • Joint Professional Institutes Technical Seminar. HKILA, HKIA, HKIP HKIS, (2012)
    • Technical Seminar for Practicing Geotechnical Engineers. HKIE, GEO-CEDD, (2012)
    • Seminar on Landscape Treatment for Slopes. Development Bureau, HKSAR, (2012).
  • Specialist Technical Judge for Best Slope Feature Award, 5th Anniversary of the Landslip Prevention and Mitigation Programme. Geotechnical Engineering Office, CEDD. 2015.


Anticipated Outputs:

  • Pryor, M., Ng C.W.W., Hau C.H. et al Reliability-based preliminary guideline for the design, construction and management of live cover systems that are self-regenerative and sustainable for both man-made fill slopes and landfill covers. (end 2016)
  • Academic paper with Chen, Y.X. Perceived and actual impacts of landfill operations and the mitigation of planned after-uses (2017)
  • PhD Thesis Chen Yu Xiao. The restoration of SENT Landfill and its possible after-uses (end 2018) 



GEO Publication 1/2011 – Technical Guidelines on Landscape Treatment for Slopes “is the document that has had the most significant positive impact on Hong Kong Landscape in the last 30 years.”

Citation from judging panel at HKILA Design Awards 2012


  • Pryor M.R., Hau C.H. and Watkins A., GEO Publication 1/2011, Merit Award – Landscape Planning & Research, Hong Kong Institute of Landscape Architects, Design Awards 2012.


Enlarge Photo: Proposed Liver Cover Section for LandfillsEnlarge Photo: Slope restoration at SENT Landfill (Ph.1)Enlarge Photo: The Landscaping of Man-made Slopes 3Enlarge Photo: The Landscaping of Man-made Slopes 4Enlarge Photo: The Landscaping of Man-made Slopes 5