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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
Presentation Outline
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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
Presentation Outline
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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