Landscape Design of ABC Water Features and Rooftop Greenery in Public Housing Projects

7/27/2019 Landscape Design of ABC Water Features and Rooftop Greenery in Public Housing Projects

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Landscape Design of ABC Water Features and

Rooftop Greenery in Public Housing Projects

29 Feb 2012

HDB Architectural Consultants Sharing Session 2012

Speaker: Dr MA, Cheng Yi LydiaHDB/DPD/LU


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Introduction

Objectives

To clarify the design intentions:

ABC Waters Design: Environmental benefit; visual enhancement;

public awareness & acceptance of a sustainable living

environment

Rooftop Greenery: Elevated landscape space for activities(passive / active); environmental benefit; pleasant view

To share some design tips:

Design principles for good practice and some learning points of

past experiences will be discussed.

To brief on HDBs desirable designs:

Good examples will be presented to highlight general design

considerations and requirements for desirable proposals.


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Introduction

Suitable Types of ABC Waters Design- Landscape Soak-away

- Enhanced Soak-away

- Vegetated Swale

- Bio-retention Swale

- Bio-retention Basin

- Design Tips

Rooftop Greenery in HDB Estates

Case Studies

Presentation Outline


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Image Source: Google Images

Landscape Soak-away

Image Source: PUBs Engineering Procedures for ABC

Waters Design Feature

Characteristics:

Landscaped area with good soil

hydraulic conductivity to allow

infiltration e.g. topsoil not over-

compacted

Subsoil drain and surface overflowto be provided when advised

Photo taken by Lydia Ma


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Enhanced Soak-away

Characteristics:

A designated landscaped basin withsand and/or turf to keep runoff for

infiltration and create temporary

pond after storm events.

Underground water retention tank

and overflow discharge are required.

Higher soil hydraulic conductivity is

preferred and water detention depth

must be controlled. Image Source: HDB; Photo taken by Lydia Ma


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Vegetated Swale

Photo taken by Lydia Ma

Image & Picture Source: Google Images

Characteristics:

A strip of land with shallow

depression and gentle gradient

to convey surface runoff

Soil media is generally porous to

allow infiltration

Subsoil drain is only necessary

when the longitudinal slope is

less than 1%


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Characteristics:

A strip of land with depressionand gentle longitudinal gradient to

allow water conveyance

Subsoil pipe, layers of filtration

media, surface overflow discharge

and planting are required Choice of plant material and

filtration/planting media are crucial

design elements

Bio-retention Swale

Picture Source: PUBs Engineering Procedures for ABC Waters Design Feature & ABC Workshops

Image Source: Google Images


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Bio-retention Basin

Characteristics:

A flexible bio-retention systemwith various size and form

Technical design details are

close to bio-retention swale

Storm-water treatment capacity

is greaterImage & Picture Source: PUBs ABC Waters Design Guidelines 2011


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Design Tips

Keys for Successful Design:

To determine the suitable types ofABC designs:

- the catchment area & expected runoff

- the pollutant level & expected treatment

To understand the technical

challenges:- the water conveyance means & capacity

- the inflow speed & volumes and overflow

capacity

- the flow path & invert levels etc

To take care of design details:

- the treatment for level changes

- the design for inflow energy dissipation /

coarse sediment deposition

- the safety and maintenance concerns


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Introduction

Suitable Types of ABC Waters Design

Rooftop Greenery in HDB Estates- Suitable System for Accessible Rooftop Gardens

- Design Challenges for Stand-alone Car Park

- Design Tips

Case Studies



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Suitable System for Accessible Rooftop Gardens

Design Considerations:

Facilities Provision Technical Requirements Maintenance Concerns

- Access/Entrance

- Circulation

- Lighting

- Seating

- Others

- Fire Safety Regulations

- Natural Ventilation

- BFA

- Durability

- Irrigation Need

- Pruning Frequency

System Recommended:

Planter with 300mm highPlanter with

300-500mm high

Planter with

500-800mm high

Planter with

1-1.2m high

- Allow to plant most types of

shrubs

- Exempt from occupant load

calculation if densely planted

with shrub

- Occupant load base on 1.5

sqm/person if no dense planting

- Allow to plant small size

tree & large shrub

- Exempt from occupant

load calculation if densely

planted with shrub

- Occupant load base on

1.5 sqm/person if no

dense planting

- Allow to plant small

to medium size tree

- Exempt from

occupant load

calculation

- Allow to plant

large tree

- Exempt from

occupant load

calculation


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Design Challenges for Stand-alone Car Park

The Call for a Smart Design Approach:

To cope with limited paved area due to occupant load restr iction:- Effective circulation plan with small pocket spaces

- Innovative design with different planter high

To overcome limited structure strength and facility provision:

- Design according to the potential structure strength for higher planter

- Use simple design finishes and details for cost-effective outcome- Provide flexible design layout for easy conversion/upgrading in future

Photo taken by LA Ms HOO Xin Yu


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Design Tips

Keys for Desirable Design:

To make use of the periphery drain:- the maintenance path com gutter

could be widen to 1 m to serve as

informal footpath

- To incorporate high planter:

- high planter could be shallow planterfor wheelchair users

- the use of high planter could gain more

occupant load for paved area

To locate tree planter upon

columns:

- tap on existing structure strength to

avoid structure reinforcement

To reserve space for potential use:

- future community gardening space- potential picnic or exercise corners


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Introduction

Suitable Types of ABC Waters Design

Rooftop Greenery in HDB Estates

Case Studies- Greenwood Sanctuary @ Admarity

- Balam Estate Rain Garden

- Bioretention Swale @ Dawson

- Punggol Ridges

- MSCP Rooftop Greenery @ Bukit Batok



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All case studies will be further elaborated and

compiled in HDB Landscape Design Manual, which will

be published in 2nd or 3rd Q 2012.

PUBs ABC Waters Professionals Course will be

conducted every year with 4 Core Modules and 5

Elective Modules. (Participants who complete all four

modules plus any two elective modules would be

eligible to be registered as an ABC WatersProfessional).

After Briefing Notes


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Thank You

Landscape Design of ABC Water Features and Rooftop Greenery in Public Housing Projects

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