south australian
Planning Policy Library
03
Assessment and
Design Notes
The purpose of this technical information sheet is to assist development assessment
officers and development designers with interpreting selected Development Plan policies
and terms. This technical information sheet could be read in conjunction with the Planning
Guide: South Australian Planning Policy Library Terminology List (DPLG, 2011).
How to use net residential site density
The new zone modules introduce a strategic policy regarding net residential site density.
In some cases this policy has replaced traditional land division and site area policies.
To determine if an application meets the minimum density requirements, follow the steps
below:
Step 1: Divide 10,000 (number of square metres in a hectare) by the site area.
Step 2: Multiply this number by the number of proposed dwellings for the site.
This will provide the proposed net residential site density.
For example:
Step 1: 10,000m2 / 700m2 (site area) = 14.29
Step 2: 14.29 x 7 (proposed number of dwellings) = 100du/ha.
The proposal would therefore meet the desired density of 100 dwelling units per
hectare.
South Australian Planning Policy Library
Technical Information Sheet 3 – Assessment and Design Notes
Release: September 2011
Technical Information Sheet 03
Introduction and purpose
If the site area is known but you want to work out the minimum number of dwellings you can
fit onto the site to accord with the minimum density, follow the steps below:
Step 1: Divide the minimum net density required in the zone by 10,000 (number of square
metres in a hectare).
Step 2: Divide this number (maximum area per dwelling to achieve the minimum density) by
the site area.
For example:
Step 1: 10,000m2 / 80 (minimum net density per hectare) = 125
Step 2: 700m2 / 125 = 5.6 dwellings
Since the policy requires that a minimum density be met, the above figure should be
rounded up to 6, so that 6 dwellings should be built on a site area of 700m2 where the
minimum net density is 80 dwelling units per hectare.
The above policy concerns net density which is appropriate for assessing individual
development applications. Gross density is often referred to when considering a large area
strategically. Gross density calculations include road areas, open space and the like. Further
information and examples of density in existing developments can be found in Understanding
Residential Densities: A Pictorial Handbook of Adelaide Examples (DPLG, 2006).
Building envelopes
A number of the mixed use zones include policies that effectively establish a building
envelope within which development can occur. The envelope is made up of height and
setback provisions. The envelope provides the outer limits of the allowable built form
therefore providing flexibility in design. For example, a building can be set back further
than the minimum and be built lower than the maximum building height. A design might
include sections of the building that are set back one distance and others that are set at the
numeric maximum.
Interface height provisions
The Urban Corridor Zone includes maximum building height requirements. However,
in addition to these requirements there are interface building height provisions and
overshadowing policies that consider the impact of building height on the adjoining zone
(rather than internal to the zone).
The overshadowing policies require an applicant to build within an envelope provided by a
30o plane measured from 3 metres above the southern zone boundary.
The interface height policy addresses building massing at the interface with an adjoining
zone. This policy introduces a height within a 45 degree plane measured from the zone
boundary.
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South Australian Planning Policy Library
Technical Information Sheet 3 – Assessment and Design Notes
Release: September 2011
Protecting development from wind tunnelling
Why is this important?
Areas with taller buildings can produce a range of unwanted wind effects. These need to be
considered and carefully managed.
Taller buildings invariably create challenging wind conditions at street level, including down
drafts and wind tunnel effects. Measures to reduce the impact of these effects should be
considered.
Policy provided in the Medium and High Rise Development (4 or More Storeys) general
module applies to all buildings over 21 metres high (5 or more storeys) and other
development where the planning authority requires wind effects to be considered.
Windy conditions can cause discomfort and danger to pedestrians and down drafts from
buildings can inhibit the growth of street trees. Conversely, moderate breezes that reach
the streets can enhance pedestrian comfort and disperse vehicle emissions and airconditioning plant exhausts.
The shape, location and height of buildings should be designed to satisfy wind criteria for
public safety and comfort at ground level and not inhibit the growth of street trees. The
useability of open terraces on buildings also depends on comfortable conditions being
achieved.
In assessing an application for a multi-storey building, the assessing officer and authority
should ensure that new developments satisfy any nominated wind standards and maintain
comfortable conditions for pedestrians/cyclists and the structural integrity of the built form,
while not inhibiting the growth of street trees.
There are a number of design features that can be incorporated into a building to ameliorate
existing adverse wind conditions.
Building design may also need to minimise adverse wind effects on recreation facilities and
open spaces within developments.
South Australian Planning Policy Library
Technical Information Sheet 3 – Assessment and Design Notes
Release: September 2011
03
Technical Information Sheet 03
Design considerations
To ensure useability and comfort, development may also need to minimise the impact of
wind on balconies by utilising partially recessed sun screens, pergolas and shutters.
On tall buildings, balconies may be recessed to reduce wind impacts. Where high winds
prevent other solutions, development is to provide operable screens and, where possible,
balconies can be recessed.
Where there are significant concerns about wind tunnelling, a wind effects report may be
prepared by a suitably qualified engineer to be submitted with a development application.
Design suggestion 1:
Use stepped building forms and articulation of the building mass to reduce wind turbulence
at ground level.
Design suggestion 2:
Provide protection for pedestrians in public and private spaces from wind down drafts
where a building is taller than the surrounding development.
Source: Victorian Department of Planning and Community Development High Density Residential Development Guidelines.
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South Australian Planning Policy Library
Technical Information Sheet 3 – Assessment and Design Notes
Release: September 2011
Public realm
The creation of high quality streetscapes and public space is crucial for achieving the positive
health and lifestyle outcomes of higher density development envisaged by The 30-Year Plan
for Greater Adelaide through mixed use zones and Transit Oriented Developments (TODs).
This may be realised by providing effectively integrated public spaces and community
areas which can become social hubs for the community. There will also be a greater
need for residents to have access to public space within walking distance (500 metres),
especially natural landscaped open space, as there is likely to be less private open space
provided within higher density developments.
Key elements of the private realm which planning policy and desired character statements
should guide include:
• setbacks
• heights
• orientation to street
• mass
• fencing
• vehicle parking.
Other Relevant Guides
South Australian Planning Policy Library Terminology List (DPLG, 2011)
www.sa.gov.au/planning/planningpolicies
Design for water sensitive development and public spaces
The policy library contains policies that support the application of water sensitive design
principles in urban areas, including for stormwater management in accordance with The
30-Year Plan for Greater Adelaide’s strategies and targets to achieve more sustainable
development. These policies are located in the general section in the Natural Resources
module and so are applicable to all areas and forms of development.
The desired character statements for the new zone modules refer to water sensitive urban
design (WSUD) systems for the harvesting, treatment, storage and reuse of stormwater.
The Water Sensitive Urban Design Technical Manual for the Greater Adelaide Region
(December 2010). The manual describes the principles of WSUD and provides a ‘WSUD
toolkit’, that is a range of WSUD techniques suitable for application in the Greater Adelaide
region. These measures can be applied for different types and scale of development as well
as in public areas and open space.
South Australian Planning Policy Library
Technical Information Sheet 3 – Assessment and Design Notes
Release: September 2011
05
Technical Information Sheet 03
Understanding Residential Densities: A Pictorial Handbook of Adelaide Examples
(DPLG, 2006)
Research and experience demonstrates that WSUD measures can be designed for all
different types and scale of development including inner city areas where limited space is
available. The manual includes a process and checklists for applying WSUD principles to
urban areas, whether in a greenfield, infill or retrofit context (see chapter 3 of the manual,
’Designing a WSUD Strategy for Your Development‘).
Examples of the WSUD measures detailed in the manual include the following:
• demand management
• bioretention systems for streetscapes
• rainwater tanks
• swales and buffer strips
• rain gardens, green roofs and
infiltration systems
• sedimentation basins
• pervious pavements
• urban water harvesting and reuse
• constructed wetlands
• wastewater management
• siphonic roofwater systems.
• gross pollutant traps
(Please note that this list is not intended to be exhaustive nor to apply in all situations.)
WSUD systems may be vegetative or engineered but the manual encourages an integrated
systems approach (a ‘treatment train’) that incorporates a range of complementary design
measures to address specific urban water management objectives as well as local
conditions (such as soil type, topography and climate). The manual’s design guidelines are
tailored to conditions in Greater Adelaide and include, for example, designing more storage
into vegetative WSUD systems to ensure their survival during the region’s long hot summers.
Siphonic roofwater systems offer opportunities to harvest and store roofwater from multistorey buildings and large structures (such as a sports stadium) thereby enabling its reuse
on-site or in nearby public spaces and greenways. This offers opportunities to support the
achievement of desired future character objectives for water sensitive design in Transit
Oriented Developments (TODs) and other areas of higher density.
Other Relevant Guides
The Water Sensitive Urban Design Technical Manual for the Greater Adelaide Region
(December 2010)
For further information
Policy Reform Team
[email protected]
Strategic Policy Division
Phone (08) 8204 8281
Department of Planning and Local Government
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South Australian Planning Policy Library
Technical Information Sheet 3 – Assessment and Design Notes
Release: September 2011