TO LANDSCAPETREATMENT OF SLOPESAND RETAINING WALLS

LLLLLAAAAAYMAN'S GUIDEYMAN'S GUIDEYMAN'S GUIDEYMAN'S GUIDEYMAN'S GUIDE

Geotechnical Engineering OfficeCivil Engineering Department

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This Layman’s Guide, intended for the use of the general public,provides general guidance on landscape treatment for man-madeslopes and retaining walls.

It is Government’s policy to make slopes look as natural aspossible. We have committed to landscape every existing slopeupgraded under the Landslip Preventive Measures Programme andevery newly-formed Government slope. With this commitment andeffort, we believe that our living environment will be greener andmore harmonious.

With the experience gained from providing landscape treatmentto Government slopes, we have prepared this document with theassistance of Urbis Limited. We hope that it will help and encourageprivate slope and retaining wall owners to provide landscapetreatment to their slopes and walls when planning maintenance orupgrading works.

For more detailed guidance, the reader may refer to GEOPublication No. 1/2000 “Technical Guidelines on LandscapeTreatment and Bio-engineering for Man-made Slopes and RetainingWalls” published by the Geotechnical Engineering Office of the CivilEngineering Department.

R.K.S. ChanHead, Geotechnical Engineering Office

July 2002

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ContentsContentsContentsContentsContents

Foreword

Contents

Why Do We Need Landscape Works on Slopes and Retaining Walls?

"Before" and "After" Look of a Landscaped Slope

Examples of Soft Landscape Treatments

Examples of Hard Landscape Treatments

Seven Landscape Design Objectives

Some Tips for Landscaping Slopes

Tip 1 - Preserve trees in your community

Tip 2 - Create planting opportunities

Tip 3 - Provide Ornamental planting

Are Landscape Works Costly?

Are Landscape Works Difficult to Maintain?

Seven Things to Remember

Assistance

Selected Publications Related to Slopes

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BEFOREBEFOREBEFOREBEFOREBEFORE

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Examples ofExamples ofExamples ofExamples ofExamples of Soft Landsca Soft Landsca Soft Landsca Soft Landsca Soft Landscape Tpe Tpe Tpe Tpe Trrrrreaeaeaeaeatmentstmentstmentstmentstments

Ornamental plantingof shrubs andherbaceous plants atthe toe of a slopewith ferns coveringthe slope face

Well maintainedmature trees and

ornamentalshrubs on a slope

Climbers on aretaining wall withpalm trees anddecorative shrubsin a planting stripimmediately infront

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Examples ofExamples ofExamples ofExamples ofExamples of Har Har Har Har Hard Landscad Landscad Landscad Landscad Landscape Tpe Tpe Tpe Tpe Trrrrreaeaeaeaeatmentstmentstmentstmentstments

Artificial rock and stonefacing used to decorate alarge-scale retaining wall

Artificial rock used to blend asteep slope into thesurrounding natural landscape

Decorative designs onthe face of a retainingwall enhanced by trees andshrubs in a toe planter

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SeSeSeSeSevvvvven Landscaen Landscaen Landscaen Landscaen Landscape Design Objectivpe Design Objectivpe Design Objectivpe Design Objectivpe Design Objectiveseseseses

Fit with surrounding landscape/natural topography

Where possible,the creation or

restoration offeatures should

respond to thebroad variations

in surroundinglandform and

vegetation.

Limit impacts on the natural environment1

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Where possible,as much existingvegetation on andaround the featureshould be retained.

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Achieve naturalness

The fewer the number of different engineering orlandscape techniques used on a feature, the morelikely it is to look coherent.

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4 Maintain simplicity

Solutions involving natural materials (rock andvegetation) are almost always visually preferable tothose using artificial ones.

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Where artificial or built elements are used, effortsshould be made to blend the built elements into theirsurroundings in order to create harmony betweenthe artificial and natural landscape.

Vegetation on features helps to eliminate green-house gases and can provide ecological habitats andsources of food for insects and birds.

5 Mitigate visual impact

6 Contribute to environmentalsustainability

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ii. Proportion and scale

Planting at the toe and top of a retaining wall and fillslope successfully creates a unified appearance to thewhole slope.

7 Aesthetically pleasingThe landscape design of features should conform to generalprinciples of good aesthetic design.

i. Unity and coherence

The buttresses with masonry facing are suitably sizedand dispositioned in relation to the retaining wall withribbed finish to create a sense of proportion.

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This design solution employs a variety of techniques ina co-ordinated manner, resulting in a compositionhaving both pattern and texture.

Ribbed finish and plain concrete create a scene with bothrhythm and complexity.

iii. Pattern and texture

iv. Rhythm and complexity