Download PART 6.4: DEVELOPMENT ENGINEERING This Part of the CDCP

PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
PART 6.4:
DEVELOPMENT ENGINEERING
This Part of the CDCP provides a common set of
engineering design, construction and management
principles, which when implemented properly, will
ensure a high standard of engineering design for all
development in Canterbury. This Part applies to all
development, including building work and subdivision,
and is designed to ensure that the quality of
Canterbury’s infrastructure and assets is consistent
with the future needs the community. The engineering
requirements in this document cover the following
areas:
their retention and protection can be incorporated into
the design of the engineering infrastructure.
The CDCP is intended to prevent or reduce the impact
of increased development, through integrated design
and the use of on-site detention of storm water.
OBJECTIVES FOR DEVELOPMENT ENGINEERING
O1. Infrastructure design and
appropriate to each site.
Site engineering requirements,

Pedestrian access,

Vehicular access,

Stormwater,

Submission requirements,

Flood management,
6.4.1

Final certification.
i.
ABOUT DEVELOPMENT ENGINEERING
O3. Possible
engineering constraints to the
development are considered at the first stage of
the design of the development.
O4. Public infrastructure managed by Canterbury City
Council is not compromised by development.
i.
In the urban environment, stormwater drainage is
rapidly changing with new challenges being
encountered due to the ever changing climate and
environment, and it is becoming ever more important
to monitor the usage of stormwater and rainwater
responsibly and economically.
Design conflicts can be identified at an early stage in
the processes involved in preparing engineering plans,
and through intelligent use of driveways, parking areas
and landscaping, costs can actually be reduced. Trees
represent an important asset to the community, but
could affect the layout or design of a development, and
Submission requirements
When submitting a development application, the
information in Table 6.4.1 (following page) is
required, according to the type of development:
6.4.2
The engineering infrastructure provided with
development is often in the public domain, on land
that is owned and managed by Council, or will affect
Council’s engineering assets (that could already be on
public or private land). Council, therefore, must ensure
that all engineering infrastructure that is provided with
development meets appropriate standards and will be
complementary to its public infrastructure.
With urbanisation comes the transformation of
landscape, pervious areas of grass and vegetation into
impervious surfaces such as roofs, concrete and paving.
Such transformation results in less water being used by
vegetation or naturally infiltrating into the ground and
leads to an increase in the amount of stormwater
runoff.
is
O2. Quality engineering works are produced for all
developments.

This Part will apply when assessing development
applications and construction certificate applications
where engineering work is required.
construction
Pre-lodgement requirements
The applicant must satisfy the pre-lodgement
requirements, as specified in the checklist in Table
6.4.1. In terms of engineering requirements, the
applicant must obtain the following prior to the
submission of the development application, with
the exceptions listed in Table 6.4.1. Failure to do
so will prevent the lodgement of the development
application:


Street alignment levels,
Tree report, both internal and external.
Street Alignment Levels
ii.
The street alignment levels are critical in the
design of the development and incorporation of
this information at the initial design phase could
reduce the likelihood of redesign at a later stage.
Tree Report
iii. The tree report will provide information on the
likely development conditions to be set in regard
to trees, both within the property and adjacent to
the property, in the road reserve. Consideration of
the trees at the initial design could again prevent
redesign at a latter stage.
CANTERBURY DEVELOPMENT CONTROL PLAN 2012
P6.4-1
PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
Pre-lodgement
Requirements
Drainage
Plan
Traffic
Traffic
Plan
Management
Control
Plan
Traffic
Generation
Report
Traffic
Manoeuvrability
Report
Street
Alignment
Levels
Tree
Report
No
No
No
No
No
No
No
Extension
to
Single dwelling
Yes, if new
street access
is proposed
Yes
Yes
No
No
No
No
Yes, if new
street access
is proposed
Yes
Yes
Single dwelling
No,
unless
requested.
No,
unless
requested.
No,
unless
requested.
No,
requested.
Yes
Yes
Yes
No,
unless
requested.
No,
unless
requested.
No,
unless
requested.
Yes
Yes
Yes
Yes
No,
unless
requested.
Yes
If 10 or more
dwellings
proposed.
Yes
Industrial
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Commercial and
Retail
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Tourist facility
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Aged Care
Yes
Yes
Yes
Yes
Yes
Yes
DA
Multi-unit
housing
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No,
unless
requested.
Yes
Yes
Yes
Yes
Yes
Yes
No,
unless
requested.
No,
unless
requested.
No,
unless
requested.
No,
requested.
Transport links
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Open Space
Yes
Yes
Yes
No,
unless
requested.
No,
unless
requested.
No,
unless
requested.
No,
requested.
Internal change
of
existing
premise
Dual Occupancy
Townhouse/
Villa
Child Care Centre
Heritage
site
Listed
Table 6.4.1
6.4.3
i.
ii.
unless
unless
Submission requirements by development type
Off-site engineering requirements
Design the development to utilise and integrate
with the existing infrastructure, and minimise any
potential adverse effects on community assets –
unless an applicant is required to undertake
infrastructure improvement works adjacent to the
property that may alter the existing level or
location of the infrastructure.
Consult with Council engineers prior to DA
submission to ascertain the possible improvement
to infrastructure required for the development.
This is advice only, as the final determination of
works required will be conditioned as part of the
development application process.
iii. Take into account the following in the design of
proposed development:

unless
Finished road and footway levels,

Location of proposed vehicular access with
respect to drainage structures/infrastructure,
traffic facilities, street trees, signs, power
poles, utilities and other infrastructure.
Council approval required to do work
iv. In addition to any development consent, approval
is also required from Council for any work that:

Is external to the development site,

Impacts on land that is under the ownership,
care and control of Council, such as foot
paths, public reserves, drainage easements
and drainage reserves,

Impacts on Council's roads and related
infrastructure, street trees and stormwater
system.
Such works could include kerb and gutter
reconstruction, footpath reconstruction, vehicular
crossing construction, trunk drainage installation
and drainage pit construction.
CANTERBURY DEVELOPMENT CONTROL PLAN 2012
P6.4-2
PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
v.
These works must be constructed in accordance
with Council’s specifications and requirements.
Work Permit (WP)
vii. A work permit issued by Council, is required in
accordance with Section 138 of the Roads Act 1993
and Section 68 of the Local Government Act 1993,
or any works carried out by a developer on
Council’s road reserve, within public land, or on
Council’s assets including stormwater pipes and
pits.
viii. The applicant must apply to Council for a WP to be
assessed subject to appropriate fees and charges.
It is very important for applicants to apply for a WP
as early as possible at the construction certificate
stage to seek Council’s approval.
ix. Where construction of new Council infrastructure,
excavation for vehicular crossing and/or works for
utilities including stormwater, water, sewer, gas,
electricity, communication network cables, occurs
adjacent to or within the road reserve, the work
must be carried out in accordance with an
approved Council WP.
x.
Utility installations must be carried out in
accordance with, and to the satisfaction of, the
relevant utility authorisation. The restoration of
Council’s assets must be carried out to Council’s
satisfaction following installation:
Note: for any other works in the road reserve not related to a
development, a WP for road openings or vehicular crossing
must be obtained subject to appropriate fees and charges.
Traffic Management Plan (TMP) and Traffic Control
Plan (TCP)
xi. Submit a TMP for any development where the site
work will interrupt or have a significant impact on
road and footway activities on a regular basis – the
plan is to assess the impacts on traffic flow,
cyclists, pedestrians, local residents, businesses,
parking stations, schools, hospitals, public
transport and emergency services:
Note: The TMP is often included in a construction
management plan, which provides details of how the
construction activities related to a development will integrate
with the daily operation of the road network.
xii. Submit a TMP and/or certified TCP for any work
within Council road reserve, and involving
temporary partial road closure and/or closure of
the footway:
Note: The TCP is a plan that is intended to ensure the safety
of road users and road workers at the work zone area. The
TCP specifies the signs, devices and illumination to be used to
warn, instruct and guide road users in the safe negotiation of
work sites on road reserves and provide a safe working
environment.
xv. The TCP must be prepared in accordance with the
state road authority’s guidelines “Traffic Control at
Work Sites” and AS 1742.3 “Traffic Control Devices
for Works on Roads”, including proposed timelines
of the above matters.
Road Occupation Licence (ROL)
xiii. An application for lane closure and/or partial road
closure on regional roads, RTA State Roads, and
within 100m of a traffic facility, must be submitted
to the state roads authority for issue of a (ROL) traffic facilities include traffic signals, roundabouts,
speed humps, kerb islands, refuge islands,
pedestrian signals, pedestrian crossings.
Submit documents
xiv. Submit a copy of TMP, TCP and any ROL prior to
issue of a WP.
6.4.4
Off-site engineering details
Footpath and vehicular crossing levels
i.
It is a pre-lodgement requirement that street
alignment levels be obtained from Council prior to
lodgement of the DA. See Table 6.4.11 and Section
6.5.2 (ii).
ii.
These levels must be incorporated into the design
of the proposed footpath/vehicular crossing for
the site. Site levels at the street boundary must be
compatible with footpath and driveway levels.
iii. The consideration of the street alignment levels is
particularly important at the initial design stage as
the level at the street alignment could determine
critical design elements in relation to floor levels,
internal pavements, car parks, basement levels,
landscaping and stormwater drainage systems.
iv. A fee is payable for street alignment levels as per
Council’s Annual Fees and Charges.
Road, kerb and gutter and footpath design
v.
The development may be conditioned to include
the reconstruction of the kerb and gutter, and or
footpath paving along the frontage of the site.
vi. The applicant shall arrange for a practicing Civil
Engineer with suitable experience to prepare the
design in accordance with this document, NatSpec
and
Council’s
Standard
Drawings
and
specifications. See appendices for Council’s
standard construction details.
vii. The design shall be drawn to a scale of either 1:100
or 1:200 scale drawing on A1 sheets.
viii. Long-sections of works shall be drawn at a 10x
exaggerated vertical scale.
ix. The design shall indicate the following:

Existing and proposed road,
CANTERBURY DEVELOPMENT CONTROL PLAN 2012
P6.4-2
PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
x.

Existing and proposed kerb and gutter,

Existing and proposed footpath and boundary
levels,

Location of all services,

Location of existing and proposed drainage
structures.
The design shall be submitted to and approved by
Council prior to the release of the construction
certificate.
xi. The construction shall be undertaken in
accordance with NatSpec and Council specification
and the work certified by a qualified engineer on
completion. A Works As Executed Plan shall be
provided to Council. Failure to certify the works or
provide a Works As Executed Plan may prevent
progress of the application.
Street trees
xii. Street trees represent an important asset of the
street landscape and consideration must be given
to the location of the street tree in relation to the
proposed layout of the development - to ensure
this it is a pre-lodgement requirement that a tree
report be obtained from Council prior to the
lodgement of the DA. See Table 6.4.1 and 6.4.2
(iii). This report will provide information as to the
likely conditions that would be placed on the
street tree, both during and post construction.
xiii. Council has a Street Tree Management Plan, which
may require certain species to be retained, and
accordingly proposed developments must
incorporate these protected species into the final
design. The report will specify clearances of
proposed vehicular crossings and footpaths to
existing street trees. These clearances shall be
complied with in the proposed design of the
development. Council’s requirements in relation to
the street tree may affect the internal design of
the development as a whole, from layout, accesses
and landscaping.
xiv. The consideration of this information in the initial
design process could prevent expensive redesign
should the street trees not be considered at the
early stages of the development process. During
both construction and on completion of the
development every effort must be made to protect
the street trees from damage, by the installation of
suitable protection during construction and to
adherence to appropriate clearances of the final
development.
xv. Removal of street trees will only be approved in
accordance with Councils Tree Preservation Order.
Applicants may be required to replace any
removed trees with other suitable tree(s), as
approved. All costs being borne by the applicants
for the replacement of any removed trees.
Stormwater drainage
xvi. A development may require the installation of
street trunk drainage where the conditions set for
alternative stormwater disposal in Section 6.4.11
Disposal of Property Runoff cannot be met.
xvii. Extension of the Council trunk drainage system will
be required where the proposed drainage system
from the development cannot connect to the kerb
and gutter within 15m of the site or the discharge
is in excess of 55 l/s. In this case the applicant will
be required to extend the Council system to the
site. The applicant shall arrange for a practicing
Civil Engineer with suitable experience to prepare
the drainage design in accordance with this
document and AS/NZS 3500.3 Plumbing and
Drainage – Part 3.
xviii.
The drainage plan shall be submitted to
Council for approval and shall provide the
following information.

Plan at 1:200,

Long-section at 1:200H, 1:20V,

Plan and long-section of all services to be
crossed, including proposed drainage line,

Flow-rates and grades of all pipes,

Invert, natural surface level at a minimum of
10m intervals.
xix. The construction works shall be undertaken in
accordance
with
NatSpec
and
Council
specifications and the work certified by a qualified
engineer on completion.
6.4.5
i.
ii.
On-site engineering requirements
The on-site engineering requirements for
development may involve several engineering
disciplines, including:

Drainage/Hydraulic Engineering,

Traffic/Transport Engineering.
Design development to utilise and integrate with
the existing infrastructure and minimise any
potential adverse effects on community assets:
iii. When designing take account of the following:

Road and footpath levels,

Location of proposed vehicular access with
respect to drainage structures, traffic facilities,
street trees, signs, power poles and other
infrastructure,

Existing drainage infrastructure,

Overland flow path of stormwater,

Traffic requirements
development.
of
the
CANTERBURY DEVELOPMENT CONTROL PLAN 2012
proposed
P6.4-3
PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
Traffic Generation Report (TGR)
iv. For any development where the site work will
interrupt or have a significant impact on road and
footway activities on a regular basis, submit a
Traffic Generation Report to Council. See Table
6.4.1 to determine if a TGR is required for the
proposed development.
v.
Undertake the TGR in accordance with the state
roads authority and best practice guidelines with
an objective to assess the impacts the proposed
development will have on traffic flow, cyclists,
pedestrians, and local residents, businesses,
parking facilities, schools, hospitals, public
transport and emergency services.
Traffic Manoeuvrability Report (TMR)
vi. In any development vehicles may be required to
execute specific turning movements to access
garages, car spaces and visitor car parks – a report
may be required describing and illustrating how
the site is accessed from the road reserve as well
as how specific locations within the site are also
accessed. See Table 6.4.1 to determine if a TMR is
required for the proposed development.
vii. Undertake the TMR in accordance with Australian
Standard AS 2890.1, to illustrate the turning paths
into and within the development through the use
of AustROADS documentation or computer
generated turning paths (using software packages
such as AutoTurn). Adopt design vehicles that are
appropriate for the proposed development.
viii. Unless stipulated otherwise in AS 2890.1, for
domestic circumstances, adopt the B85 vehicle for
assessment purposes. Notwithstanding, the AS
shall specify the type of vehicle to be considered
for respective development types.
ix. For commercial and industrial development the
size of the vehicle illustrated for accessing the site
will be taken as the maximum proposed for the
site, and may be conditioned as such. However,
the size of vehicles permitted may be reduced
through the approval process.
Vehicular access, internal footpath and driveway
levels
x.
Undertake the design of the proposed vehicular
access and internal pavements must with
consideration to the street alignment levels.
xi. As described in Table 6.4.1 and section 6.4.2 (ii),
the development application can’t be lodged
without the prior application, payment and
adoption of the street alignment levels - having
obtained the street alignment levels from Council
evidence must be provided on the plans that these
levels have be adopted in the design of the
development, including designs of the internal
pavement, car parks, landscaping and stormwater
drainage.
xii. Show the proposed level of internal pavements on
development
application
plans,
indicating
direction of fall to establish appropriate surface
drainage and overland flow paths - the design and
construction of the internal pavements shall be in
accordance with NatSpec and the relevant
Australian Standards.
xiii. An application fee is applicable for the design,
preparation of specifications, and for the
inspections of the proposed vehicular crossing and
if approved, the applicant must provide a concrete
vehicular crossing across the full width of Council’s
footway.
xiv. Construct the vehicular crossing in accordance
with plans, design levels and specifications issued
by Council. Where a basement is proposed as part
of the development, adequate manoeuvring area
must be provided to allow vehicles exiting the site
in a forward direction, reversing onto public roads
is prohibited.
6.4.6 On-site engineering details
Location and width of vehicular access
i.
The location and width of vehicular crossings is
important in ensuring minimal conflict with
existing infrastructure:
ii.
Where the proposed vehicular crossing in the road
reserve is in conflict with existing utilities and civil
infrastructure, any cost incurred in adjusting
/removing/reinstating such structures will be
borne by the applicant.
iii. Position vehicular crossings so as to avoid conflict
with existing street trees. The Tree Report will
specify the required clearance from the tree to
proposed vehicular crossings - (a separate
application for tree removal will be required for
Council’s assessment where the location of the
proposed vehicular crossing will affect the existing
trees.
iv. Vehicular crossings, which do not comply with
RMS guidelines, or those located in positions that
require special assessment/consideration, will
need specific approval from Council’s Traffic
Committee.
v.
When determining the position and width of
vehicular crossings, consider adequate sight
distances for vehicles exiting driveways - in
particular, provide clear sight lines to ensure
adequate visibility between vehicles on the
driveway and pedestrians within the property and
on the footpath – (sight line information is
available section 6.8 Vehicle access and car
parking).
CANTERBURY DEVELOPMENT CONTROL PLAN 2012
P6.4-4
PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
Dual driveway access
vi. Do not propose a second driveway or horseshoe
driveway, as Council’s current policy will not
support such a proposal unless:

The proposal will not affect on-street parking
demand,

The area of paving within the property is
minimised,

There is sufficient landscaping being provided
to compensate for the additional paved area,

The proposal has merit on road safety
grounds.
Internal Driveway Profile
vii. Design the vehicular driveway profile within
private property to prevent vehicles from scraping
and so that it will satisfy the requirements set out
in AS 2890.1 with the following grade
requirements:

The maximum allowable grade is 25%,

Transition grades for changes in grade in
excess of 12.5%,

Driveways with a grade in excess of 15% are
constructed with a non-slip finish.
viii. Provide a long-section of basement driveway
accesses, drawn to the current scale described in
AS 2890.1. Draw the long-section from a minimum
of 3m inside the basement, along the driveway to
the road shoulder, approximately 2.5m from the
lip of the gutter. It is the designer’s responsibility
to confirm access along the most difficult route
into the basement. The long-section shall be
confirmed using the AS 2890 B85 templates. This
plan shall be provided at DA submission for Council
approval.
ix. Consider adequate sight distances for vehicles
exiting driveways and provide clear sight lines.
Note: The consideration of basement levels is a critical
assessment point for a development. Non-compliance with
this element could have adverse effects on the entire design
process.
xii. A practicing civil engineer with suitable experience
is to prepare the drainage plan in accordance with
the CDCP and AS/NZS 3500.3 Plumbing and
Drainage – Part 3.
xiii. Involve the drainage engineer in the site layout
and initial concept design and integrate the
drainage system with the design of the
development (to avoid costly problems that may
arise later on).
xiv. Design the drainage system to collect and convey
stormwater runoff from the site and into receiving
systems with minimal nuisance, danger or damage
to the site, adjoining properties or Council’s
property.
xv. Address all the issues outlined in Table 6.4.2, the
Drainage Requirement checklist below, and the
OSD design checklist shown in Appendix A.
Note: In particular, sites that fall to the rear may have
difficulty in discharging stormwater runoff to the street
frontage the applicant will be required to negotiate a
drainage easement through a neighbouring property to
discharge their stormwater or use the discharge alternatives
in section 6.4.8.
Note: The designer is responsible for preparing adequate
hydraulic plans to address any issues that may emerge with a
particular site, as the DCP is not intended to cover all possible
situations.
6.4.7
Drainage
Stormwater drainage requirements
i.
Highlight any potential overland flow path
throughout the development and the necessary
measures taken to minimize the impact on the
development, adjoining properties, Council’s
stormwater system and any other authority’s
drainage system.
ii.
Stormwater system is to be gravity fed, however;
there are some provisions made allowing
alternative methods to be used for single
dwellings, only where gravity system can not be
provided (See Table 6.4.2 in Appendix H).
Stormwater drainage
iii. Generally, approval of stormwater system to drain
against the natural fall of the land will not be
granted. Any proposed development on a site that
slopes away from the street frontage will require a
drainage
easement
through
downstream
properties, if one does not exist already. It is the
applicant’s responsibility to confirm that a
drainage easement can be obtained prior to
lodging the development application.
xi. Provide a detailed stormwater drainage plan
(required with most development such as all new
development, additions and alterations) to
illustrate how stormwater runoff from the site will
be managed.
Note: In some cases where the development is proposed on
unusual and difficult sites for drainage, the use of
combination drainage methods might be considered,
however; it is up to the applicant to present the necessary
details and calculations to demonstrate that the proposed
system is the most feasible one for Council’s consideration.
Internal Trees
ix
Removal of trees will only be approved in
accordance with Councils Tree Preservation Order
(refer to Part 6.7).
xi. Applicants may be required to replace any
removed trees with other suitable tree(s).
CANTERBURY DEVELOPMENT CONTROL PLAN 2012
P6.4-5
PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
Drainage plan requirements
iv. Provide a block plan of the property drawn to a
scale of 1:100 showing the storm water service.
Reduced scale plots of plans may be accepted (that
is, A1 size reduced to A3) where the plans are
produced using AUTOCAD and are legible at that
scale:
v.
Show the following clearly on the stormwater
plans:

North point

Street and site details


Contours s of site and road to AHD
Existing services within the site and in front
of the site on the nature strip
Roof plan of proposed and existing
buildings
Downpipes location and connection into
the system
Pipe sizes and grades indicated along all
pipes
All pit sizes, grate levels, invert levels, inlet
& outlet pipe levels indicated adjacent to all
proposed and existing pits
Levels of all retaining walls throughout the
site
Finished floor levels of both existing and
proposed
Finished surface levels of courtyards,
driveways pathways and detention basin
1.2 m high pool type fence barrier around
detention basin where the ponding depths
are greater than or equal to 500mm
Detailed
cross-section
through
the
detention basin and the control pit
Overland flow paths clearly indicated
The detention basin clearly defined
Permissible site discharge PSD
Site Storage requirement SSR
Detailed working volume calculations of the
SSR
Detailed orifice diameter calculation.















6.4.8
Property drainage
Roof drainage
i.
Roof drainage systems are designed in respect to
potential monetary loss, property damage
(including contents of buildings) and injury to
persons due to overtopping. The design of roof
drainage system shall be carried out in accordance
with the Australian Standard AS/NZS 3500.3:2003.
Surface runoff
ii.
All surface runoff, regardless of type of surface
(pervious - grassed and landscaped - or impervious
- concreted or paved) must be appropriately
collected into suitable drainage components (pits,
grated drains and floor waste) and connected into
a piped network. The design of surface drainage
systems shall be in accordance with AS/NZS
3500.3.
Piped drainage system
iii. Incorporate a piped drainage system and an OSD
storage system where applicable. The provision of
OSD will be a major component of the stormwater
system design, and accordingly, the design of the
OSD system and Council's requirements for that
design are detailed in Section 6.4.10.
iv. Design the piped drainage system to cater for 1 in
20 year ARI storm rainfalls based on the IntensityFrequency-Duration tables and coefficients
provided in Appendix B.
v.
In addition to the 20 year ARI event, design the
piped drainage system to ensure that any potential
overflows generated from system blockage, or
overloads in storm events with an ARI of 100 years,
do not present a hazard to people or cause
significant damage to property (surface runoff or
overland flow paths must be indicated on the
design plans).
vi. Pipes that are laid within a public roadway, or
which drain public areas such as a road or public
park, are to have a minimum diameter of 375mm.
vii. Piped systems shall meet the minimum pipe
diameter, cover and gradient criteria specified in
AS/NZS 3500.3:2003. Such systems shall be
arranged so that any potential overflows will not
pond against or enter into buildings.
Basement pump system
viii. Pump out systems for basements are permitted
2
when the system is limited to the driveway– 50m
maximum allowable driveway area draining to a
pump system:
Ix. Design any basement pump system in accordance
with AS/NZS 3500.3 and as follows:




Grade the basement car parking area to fall to
the sump and pump system,
Limit the contributing catchment area to the
pump out system to the basement access
ramps only - all other surface flows are
diverted away from the basement,
Design the two pumps to work in tandem to
ensure that both pumps receive equal usage
and neither pump remains continuously idle,
Design the pump out pit to have sufficient
volume for a 100 year ARI rainfall event for
two hours duration so that a minimum volume
of water can be retained in the sump when
the pumps are in the off position,
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PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER

x.
3
could not be created. (see Table 6.4.1) Applicants
must provide relevant documentation to
demonstrate to Council why an alternative
drainage method (such as a pump system) should
be considered.
Minimum pump-out pit size 3m .
Submit engineering details and manufacturers
specifications for the pumps, switching system and
sump for approval prior to the issuing of the
construction certificate.
xii. Indicate clearly the sequence and order of
operation of the system, and associated alarm and
light signal warning, on the plans.
Multiple unit dwellings
v.
Sub-soil drainage system
xiii. Design and construct subsoil drainage systems in
accordance with Section 6 in AS/NZS 3500.3.
xiv. Do not connect subsoil drains directly to kerb and
gutter - they must first be connected to a pit –
connect to a gravity fed system stormwater is
disposed of in a manner that will not have an
adverse impact upon adjacent properties.
xv. Where proposed development will have
substructures (such as a basement) in areas
adjacent to a watercourse, or where a high water
table is anticipated, tank/seal the substructure
from underground water.
6.4.9 On-site detention (OSD) requirements by type of
development
Single dwelling and dual occupancy development
i.
ii.
iii.
Provide OSD with all detached dwellings (including
alterations and additions), and all dual
occupancies, regardless of whether the site slopes
toward the street of away from it, where the
proposed impervious area is greater than or equal
to 70% of the total site area (impervious area
includes roof, concrete driveways, concrete paths,
paved and hard surface areas and swimming
pools).
OSD is not required when the proposed
impervious area is less than 70% of the site; in this
case the drainage system can be designed, without
OSD, using gravity fed pipes and a silt arrestor pit,
before the stormwater is discharged into the
receiving system.
Submit an OSD checklist (Appendix A) with the
development application.
Note: Driveways constructed with gravel, grasscrete or
pervious pavers are considered to be impervious for drainage
calculation purposes. Courtyards and pathways paved with
pervious pavers will be considered to be 25% impervious.
Provide OSD with all development consisting of
multiple dwellings (where three units or more are
proposed), regardless of the impervious area
before and after the development, and regardless
of whether the site falls toward or to the street.
vi. Create a drainage easement if one does not exist
already,
through
respective
downstream
properties where the site falls away from the
street, only gravity fed system will be supported.
Commercial and industrial
vii. Provide OSD with all new commercial
development
and
other
non-residential
development and sporting facilities, such as
institutes, tennis courts net ball courts and car
parks/major driveways, regardless of the existing
impervious area on site and regardless of the slope
of the site:
viii. Create a drainage easement if one does not exist
already,
through
respective
downstream
properties - where the site falls away from the
street, only gravity fed system will be supported.
ix. Where additions/alteration are proposed on sites
with an existing impervious area equal to 70% or
more, a maximum of 5% of additional impervious
area will be permitted before OSD is required
(hence the maximum impervious area in this
instance is 75%):
x.
Collect stormwater from roofed and large paved
areas within the property in a system of gutters,
pits, grated drains and pipe lines, and then
discharged into the street gutter or stormwater
system approved by Council:
xi. Where discharge of stormwater to the street
gutter, common drainage lines, other authority’s
drainage system or Council stormwater system is
not possible, and an easement through
downstream property could not be established by
way of negotiation, Council may consider the use
of alternative drainage methods such as charged
line or absorption system subject to certain
conditions (Refer to 6.4.15).
iv. Where a dual occupancy development is proposed
on a site sloping away from the street frontage,
and a gravity pipe system to the street can’t be
used, provide a drainage easement through
downstream property. There are no provisions for
alternative drainage methods similar to the single
dwelling provisions when a drainage easement
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PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
6.4.10
On-site detention system details

Depth of ponding not to exceed 150mm under
design conditions,

Transverse paving slopes within storages not
less than 1:50,

Where the storage is located in commonly
used areas where ponding would cause
inconvenience, provide part of the storage
required in an area that will not cause a
nuisance.
On-site detention systems have four main elements

Temporary storage
This may consist of an open surface area above
ground to allow ponding of stormwater or a closed
tank installed underground. It is designed to
temporarily contain the excess volume of
stormwater that is unable to pass through the
discharge control during intense rainfall
conditions.

Discharge control pit
This is the means of limiting the flow from the site.
This may consist of a limited orifice (design outlet
diameter) or other means of reducing the flow of
stormwater from the site.

iii. Use the following criteria for OSD systems located
in underground tanks:

Fix the hydraulic control for the storage,
usually an orifice plate on an outlet pipe,
firmly in place to prevent removal or
tampering,

Grade floor of tanks at a minimum slope of
1:140, towards the outlet, to minimise
ponding and depositing of debris,

Provide an inspection/access opening above
the location of the outlet with dimensions at
least 600mm x 600mm or 600mm Ø for
storages up to 800mm deep; and 600mm x
900mm for deeper storages. Ensure there will
be no impediment to the removal of debris
through this opening and inspection will be
possible without residents or owners having
to remove heavy access covers,

When storages are not sufficiently deep to
work in (less than 1.5m), provide access at
intervals of approximately 10m to allow the
system to be flushed to the storage outlet,
and adequate access at the outlet,

Provide a sump (with the base level set below
that of the main storage) at the outlet point to
collect debris. Where a discharge control pit is
included in the storage, this also contains a
sump set at a minimum of 1.5 times the
diameter of the orifice of the outlet below the
centre of the orifice. Equip sumps with
adequate weepholes to drain out to the
surrounding soil - they shall be founded on a
compacted granular base,

Underground storage tanks must be
constructed of concrete or rendered
brickwork or other approved materials in
accordance with AS/NZS 3500.3 - VERSITANK
MODUALS will not be permitted,

In addition to the required design storage a
20% buffer storage for pump out OSD is to be
provided.
Overflow structure (Weir)
An overflow weir or emergency outlet is to be
provided from the temporary storage basin, it is
designed to cater for extreme storm events (1 in
100 year event) and when system failure occurs, it
should safely direct overflows away from the site
or adjoining properties and into the street system.

Below ground systems
Maintenance
Regular maintenance of on-site detention system
is required in order to keep them in a functioning
manner. Maintenance includes clearing of
accumulated debris from screens and removal of
sediment from the base of the pit or tank. It is the
responsibility of the owner of the property to carry
out periodic maintenance.
Aboveground systems
i.
ii.
Use the following criteria in for OSD systems in
landscaped areas:

Minimum slope for surfaces draining to an
outlet 1:5 (2%) and absolute minimum slope
1:100 (1%),

Maximum ponding depth
conditions is 300mm,

Increase required storage volumes in
landscape areas by 20% to allow for
vegetation growth,

Provide subsoil drains around outlets to
prevent the ground from becoming saturated
during prolonged wet weather,

Minimum freeboard required above the top
water level is 300 mm for a habitable room
and 100mm for a garage,

Brick and mortar is the only material to used
where retaining walls are used along the
perimeter of the basin.
under
design
Use the following criteria for OSD systems Indriveway and car park storages:
All systems
iv. In addition to the above use the following criteria
for all OSD systems:
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

Provide for the harmless escape of overflows
in the event that an outlet becomes blocked
and the storage is completely filled. Any
ponding of water resulting from a blockage
shall occur at a visible location, so that the
fault can be noticed and corrected,
Permissible site discharge (PSD)
Ponding and overflow levels shall not be less
than 300mm below any habitable floor levels
of building and not less than 150mm below
non-habitable floor level.
x.
Note: Ensuring that peak flow-rates, at any point within the
receiving downstream drainage system, do not increase as a
result of the development, during storms, is achieved by
providing sufficient storage (OSD) on sites.
Location
v.
Locate the OSD system at the lowest point of the
site, with all paved areas and pipes draining into it
- the use of driveways, parking areas and/or
landscaped areas for an above ground OSD system
is encouraged.
vi. Do not position an OSD system in overland flow
paths that convey the local catchment flows
through the site - typically a drainage easement
through a site would attract overland flow path for
the local catchment.
ix. The permissible site discharge (PSD) is limited to
150 litres per second per hectare for a 1 in 10 ARI
year storm event.
Site storage requirements (SSR)
A stage-storage routing model is the preferred
method of calculating the required storage
volume.
xi. Methods that assume a constant discharge, such
as the Mass Curve Analysis, require a factor to be
applied to the constant discharge to determine the
detention volumes - the adjustment factor for
aboveground storage is 0.75 and for belowground
storage is 0.6.
xii. Ensure a minimum of 75% of the entire site area
will drain through the storage area and that all the
roof area, and as much of the paved area as
possible, will drain through the detention system.
xiii. Incorporate provision for on-site storage resulting
from a storm with an ARI of:


vii. Locate storages in common areas in multiple unit
development.
Design methodology
Note: The main and most important factor in determining the
magnitude and hydraulic capacity for any stormwater system
is design flow; this is derived from rainfall statistics using a
rainfall-runoff model (Appendix B) for rainfall Intensity in the
Canterbury area.
6.4.11
Q = C I A /3600
Where:
Q = design flow of stormwater (L/s)
C = runoff coefficient (see Appendix 7.2)
I = design rainfall intensity (mm/h, see Appendix A)
2
A = catchment area (m )
Disposal of runoff from property
i.
Discharge stormwater runoff to kerb and gutter,
street drainage, pipe in an easement, pipe in an
inter-allotment drainage system, Transport Roads
and Maritime Services system and Sydney Water
channel or river.
ii.
Dispose stormwater runoff by an in ground gravity
system. Elevated pipelines are not favoured
although pipelines contained within buildings or
low-level garden beds may be considered.
Calculating peak flow rates
viii. Use Council’s standard method below for relatively
2
small catchments (< 7500m ), and for larger sites
use the Rational Formula from Australian/New
Zealand Standard Plumbing and Drainage Part 3:
Stormwater Drainage AS/NZS 3500:
10 years where overland flow paths are not
through private property. Design and provide
a weir to direct the 100 year discharge to the
street drainage system,
100 years where overland paths are through
private property and/or known flooding
problems occur.
iii. Do not fill the land excessively (that is, ≥ 150mm),
in order to get an in ground pipeline to drain to the
street, rather than obtain an easement for the
disposal of stormwater (Refer Appendix C for
methods that are satisfactory to drain various
types of development.
Connection to kerb and gutter
iv. Discharge stormwater runoff directly into the kerb
and gutter at a point no greater than 15m
downstream from the boundary of the developed
lot.
v.
Maximum allowable single point discharge to
Council's kerb and gutter is 55 l/sec, or the PSD,
whichever is the lesser.
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PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
vi. If more than one outlet is required, separate them
by a minimum of 500mm, however; the total
discharge shall remain at 55 l/s or the PSD.
vii. Stormwater conduits laid in the footpath area
should be sewer grade PVC or galvanised steel (i.e.
RHS) and not greater than 100mm in height - the
pipe or conduit is to discharge into the kerb and
gutter at an angle of 45 degrees to the flow in the
gutter.
Control of seepage
viii. Where increased seepage is anticipated, or
becomes evident as a result of site or building
works, and this seepage is likely to have an adverse
impact on adjoining properties or Council managed
land, adequate subsoil drainage is to be provided
and connected to the piped drainage system.
Subsoil drains are not to be installed below the
water table. Should the water table be
encountered within the depth of the excavation
the structure is to be tanked and sealed.
Connection to Council’s street pipe system or interallotment drainage system
ix. Make the connection into the top third of Council's
pipe and at an angle of 45 degrees to the flow in
the pipe – no pipe protrusion is permitted into
Council's pipeline.
x.
All work is to be carried out to the satisfaction of
Council - products used for the joints shall be in
accordance with AS/NZS3500.3: 2003.
xv. Council will permit connection directly to its
stormwater pit or pipe providing the outlet invert
level from the property is at or above the top of
kerb level at the connection point.
xvi. Outlet pipes less than Ø150mm can be connected
directly to a council pipe. Outlet pipes Ø225mm or
greater will require the construction of a standard
council pit at the point of connection:
Charged line
xvii. Charged lines will be only be permitted for
proposed additions/alterations, outbuildings and
single dwellings.
xviii. For a new detached dwelling, where rainwater
tanks are included, the pipes are completely
sealed, from the tank overflow to the point of
discharge.
Note: Typically a charged system will only work for the roof of
buildings.
xix. Use the following criteria for charged lines:

Will only be permitted if there are no drainage
problems downstream in the catchment
where the drainage is being directed.

A full hydraulic analysis of the system
including a hydraulic grade line and
calculations MUST be submitted with the
Development Application.

Adequate height within the system must be
provided (minimum of 0.9 m) between the
roof gutter and the higher of the top of the
kerb OR the overflow level from the rainwater
tank.

All gutters and pipes in the system MUST be
designed for a 1 in 50 year ARI storm event (1
in 100 years for box gutters) without
overflowing.

All pipes and downpipes are to be sealed to a
minimum of 0.5 m above the top water level
within the system. The system shall be
pressure tested prior to backfilling.

There must be a gravity flow across the
footpath from an isolating pit within the
property boundary into the kerb. If the
footpath falls towards the property; then the
pipeline must remain sealed to the kerb
outlet, with a sealed cleaning eye installed
within the property boundary.

All services within the footpath must be
identified and located prior to submitting the
plans and the details must be shown on the
plans.

A flash point must be provided at the lowest
point of the system within an inspection pit
(350 x 350 min) with a sump for cleaning.
xi. Arrange for Council to inspect the connection prior
to the sealing of the joint.
Connection to Sydney Water Corporation drainage
system
xii. Provide documentation that Sydney Water
Corporation has approved the proposed
connection into the channel before Council
approves the hydraulic details.
Disposal to natural watercourse
xiii. Provide documentation that the relevant authority
has approved the proposed connection into the
watercourse before Council approves the hydraulic
details.
Note: Rivers within the city area are under the control of the
Department of the Sydney Water Corporation. The applicant
will have to identify the responsible authority and satisfy the
requirements of the authority.
Submerged outlet
xiv. For drainage proposals that require connection
directly to Council’s stormwater pit or drainage
pipe, the designer is to consider the effects of a
drowned outlet.
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P6.4-10
PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
There must be a minimum of 1 m long pipe
from the last downpipe to the inspection pit.
The connection to the pit is to have a sealed
screw cap to allow for periodic cleaning, the
cap shall have a 5 mm dribble hole to allow for
a slow release of trapped water. The pit shall
be appropriately located within the property
so that runoff or surcharge during
maintenance will not affect downstream or
adjoining properties (see Figure 1).

Gutter guards MUST be installed on all gutters
to minimize debris from entering the system.
ii.
Use the following criteria in the design and
construction of an absorption system:

The absorption pit is to be designed to cater
for all surface runoff generated from the
impervious areas for the 1 in 50 year ARI
storm event,

A detailed design and supporting calculations,
prepared
by
suitably
qualified
and
experienced engineer must be submitted with
the development application,

A geotechnical report in support of the above
design and an assessment of the infiltration
(absorption rate) of the soil profile must be
submitted with the development application,

The absorption rate in litres/square
metre/second must be determined with a
recognised falling head or constant head test.
The test shall be repeated until there is less
than 5% difference in results. Full details of all
test results are to be submitted with the
development application. At least one test
hole at each proposed pit location is to be
drilled to a minimum depth of 1.5 m below
surface level,

When calculating storage volume allow for
20% voids in the base aggregate. The standard
pipes network shall not be considered as
storage volume,

The absorption system shall be installed as far
as practicable from downstream property
boundaries (minimum 5.0m) and a minimum
3.0 m from any buildings. The system should
not be placed under any paved surfaces and
must be at least 1.0m from pavements subject
to vehicular traffic,

A silt arrestor pit shall be constructed
immediately upstream of the underground
absorption system,

On-site absorption will not permitted in areas
where the nominal absorption rate is less than
2
0.01 l/m /sec and there is clearly identified
soil salinity problem.
Pump-out system
xx. Council may consider the use of pump-out system
as a last option, for sites slopping away from the
street, in the event that a drainage easement can’t
be created or the use of an alternative drainage
method (such as charged line or absorption
system) is determined to be unachievable:
xxi. Council’s discretionary approval of a pump out
system is based on the following criteria:


The maximum pump rate must be limited to
PSD 150 litres/second/hectare,

Dual submersible pumps must be provided
with all connections and configuration
complying with Section 9 of AS/NZS 3500.3,

The underground storage tanks must be
constructed using pre-cast or cast in situ
reinforced concrete subject to structural
engineers design,

The required storage volume shall be designed
entirely underground,

The underground pump system must be
located at the lowest part of the site,

Design storage volumes for the pump system
must comply with Table 6.4.2,

A positive covenant must be created and
registered over the pump system to ensure
long-term maintenance.
6.4.12
i.
Applicants
must
provide
easement
documentation and relevant information
regarding alternative drainage methods to
demonstrate why these methods can’t be
installed,
Absorption systems
Absorption system may be permitted for paved
areas (such as driveway, pathway and hard
surfaces) associated with additions/alterations,
outbuildings and single dwellings only.
Note: Most of Canterbury consists of clay subsoil and the
absorption (rubble pit) system is generally ineffective.
Therefore, it is the least preferred drainage method.
Methods of sizing absorption pits
viii. Apply a reduction factor to the Nominal
Absorption Rate (ARN) determined in the above
geotechnical report to cater for clogging of filters,
variability of soils and likelihood of multiple storms
in accordance with the following.
Nominal Absorption Rate (ARN)
Reduction Factor (FR)
0.1 ≥ ARN ≤ 1.0
0.75
ARN < 0.1
0.50
Then ARD = ARN * FR where ARD = design absorption rate.
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PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
Storage method with average rainfall intensity
Inlet pit locations
iv. Determine a preliminary pit dimension and
proceed through a process of trial and error:
iii. Position inlet pits, or grated drains, systematically
at locations within the developed site to capture
the majority of surface runoffs, while also fitting
neatly into the layout of the site stormwater
system.
Base area (BA) = width * length
v.
Calculate the rate of discharge to the sand using
ARD * BA in litres/second, then calculate the
required storage for a number of storms by
calculating the difference between the generated
runoff volumes and the absorption volumes.
Compare the required storage to the available
storage in the proposed system. Where the
available storage is greater than the required
storage for all time steps the proposed system is
feasible.
Note: It is suggested that the designer create a spreadsheet
so multiple sizes and configurations can be readily tested
(refer to Appendix F).
6.4.13
Rainwater tanks
Rainwater tanks and the use of stored rainwater for
non-potable uses (such as watering gardens, washing,
flushing of toilets) is encouraged, and a minimum size
of rainwater tank is required for all new residential
development as part of BASIX certificate requirements.
i.
Where OSD, or absorption, are part of the
proposed stormwater system, up to 25% of the
required volume for the above systems can be
offset into a rainwater tank.
Note. If water in rainwater tanks is intended for human
consumption, the tank should be maintained to ensure that
the water is fit for human consumption-see the Rainwater
Tanks brochure produced by NSW Health and the publication
titled Guidance on the use of rainwater tanks, Water Series
No 3, 1998, published by the National Environmental Health
Forum. For more information about rainwater tanks and
other water-wise options, visit www.sydneywater.com.au
6.4.14
Surface pits
Depth (mm)
Minimum Pit Size (mm)
< 300
300 x 300
300 - 600
450 x 450
600 - 1200
900 x 600
> 1200
900 x 900
iv. Size on-grade pits, or grated drains that are
located on sloping surfaces, or in channels or
gutters, to intercept a large proportion of the flow
- place so that any bypass flows, under minor
storm event conditions, will not cause a nuisance
and so that widths of such concentrated flow is
negotiable by pedestrians.
v.
Inlet pits in locations subject to potential mosquito
borne disease (dengue fever) shall be designed
without a sump and be self-draining.
Note: Care should be taken by positioning and specifying
details (e.g. type of product) of grated pits in areas subject to
pedestrian or vehicular traffic to avoid possible damage to
pits and danger to pedestrians.
Note: Site stormwater drains should be laid in straight lines:


To avoid conflict with other services, and
To minimize overall length and number of changes in
direction.
Silt arrestor pits
vi. Install an approved silt arrestor pit at the lowest
part of any developed site to eliminate
contamination (generally silt, oil, or both) from
stormwater runoff prior to discharge into the
stormwater drainage network - in the case of car
wash bays, the silt arrestor shall be also designed
to retain oil.
vii. Locate the arrestor within the subject property
and install upstream of the discharge point
(connection to kerb and gutter or Council
pipeline).
viii. Wherever practicable, grade the area adjacent to a
silt arrestor so as to drain to the silt arrestor.
ix. A silt arrestor may receive the discharge from an
upstream pit or sump, which has been installed to
receive surface water only, provided that the silt
arrestor is of sufficient capacity to receive the
additional discharge.
Table 6.4.5 - Minimum internal dimensions of surface inlet pit
Design of silt arrestor pit
i.
Construct all surface pits in accordance with
AS/NZS 3500.3 6.5.4 with the finished surface level
of the grates consistent with the surrounding
levels - the grates of any stormwater component
must not protrude above ground level.
x.
ii.
Provide step irons in pits deeper than 1200mm.
Determine the capacity of the arrestor from the
estimated peak discharge to the arrestor. Design
and dimension rectangular or square silt arrestors
in accordance with the following table.
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PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
200mm below the invert level of the downstream
pipe – provide minimum of two 50mm weep holes
at the base of the sump.
Nominal
size
of
inlet pipe
(mm)
Minimum
nominal
size
of
outer pipe
(mm)
Width
(mm)
Depth
from
invert
of
outlet
pipe to
base of
pit
(mm)
150
100
600
300
600
150
150
600
300
1000
225
225
700
300
1000
300
300
800
300
1000
450
450
1000
300
1200
600
600
1000
300
1500
Length
(mm)
Table 6.4.6: Minimum internal dimension for silt arrestor pit
xi. Determine the inlet capacity of on grade and sag
inlet pits using equations given in Chapter 14 of
Australian Rainfall & Runoff (1987) - the arrestor
shall be constructed of concrete or other approved
materials.
xii. Locate the invert of any inlet pipe at least 50mm
above the nominal water level in the arrestor
subject to normal flow conditions.
xx. Construct the control pit on an aggregate base
wrapped in geotextile fabric.
xxi. Construct all pits in reinforced concrete - bricks
cement rendered, or precast concrete and plastic
pits will not be permitted.
xxii. Provide large paved areas and driveways falling
towards Council’s footpath with a heavy duty
grated drain across the whole driveway width, the
outlet from the grated drain shall be connected to
the internal drainage system before being
discharged into the receiving system.
6.4.15
i.
Submit details of approval of the drainage
easement with the development application to
demonstrate the consent
of respective
downstream owners.
Note: A genuine attempt to obtain an easement must include
monetary offer of compensation, based on a valuation report
prepared by a registered land valuer.
ii.
If the required drainage easement has not been
obtained provide the following documentation to
demonstrate all avenues have been exhausted:

A land valuation report prepared by a
registered land valuer, with an estimate of the
land value of the easement (excluding
construction/installation cost),

A letter of request from the applicant to
owners of all possible downstream properties,
requesting permission to create a private
drainage easement through their property –
including a concept plan illustrating the
proposed location of the drainage easement,
an offer of compensation (as estimated in the
valuation report) and a commitment to pay all
relevant expenses and reinstate disturbed
areas,

A signed letter of correspondence from the
downstream property owners either accepting
or rejecting the offer.
xiii. Place the outlet pipe at a height of not less than
300mm above the pit base, depending on the
nominal size of the outlet pipe.
xiv. Except where otherwise permitted, provide a
removable cover for the silt arrestor – use heavyduty cast iron or fabricated galvanised steel grates
on all surface inlet pits in areas with vehicular
traffic.
xv. Construct covers with galvanised steel, cast iron or
other approved material that is capable of
withstanding any load likely to be imposed on the
cover - perforated with wholes of not less than 15
mm diameter and spaced at 40mm centres, or use
open bar grill design, or another approved design.
xvi. Use appropriate cover designs and products where
pits are located in high pedestrian traffic areas, or
in playground areas.
xvii. Provide weep-holes at the base of silt arrestor pit either 4 x 20mm diameter hole or 1 x 40mm
diameter hole.
xviii.
Cut all inlet and outlet pipes entering or
exiting a pit flush with the inside wall of the pit.
xix. Provide a sump at the base of all discharge control
pits, to prevent silt and debris from blocking the
orifice or outlet pipe - the sump is a minimum
Drainage easements
Creation of private drainage easements
iii. The applicant will bear all costs associated with the
creation of the drainage easement.
iv. Provide evidence that the easement has been
prepared by a registered surveyor and has been
lodged with the Land and Property Information
Division for registration prior to the issue of a
construction certificate, and that the easement has
been registered prior to issue of an Occupation
Certificate or occupation of the site.
CANTERBURY DEVELOPMENT CONTROL PLAN 2012
P6.4-13
PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
v.
For sites that have existing Council pipelines
through them that are not covered by an
easement, or where an existing pipeline is not
within the easement, Council will require the
creation of an easement in favour of itself, or
relocation of the easement over the existing
pipeline. Relevant documents shall be submitted
with the development application to demonstrate
easement registration with the Land and Property
Information Division of the Department of Lands
has been established.
vi. The minimum easement widths required over
various pipe sizes are shown in the table below.
Pipe Diameter (mm)
Drainage Easement Width
(m)
150 minimum pipe size in
easement
0.9 – 1.0
225
1.0 – 1.2
300
1.2 – 1.5
375 , 450
1.5 – 2.0
525 , 675
2.0 – 2.5
750 , 900
2.5 – 3.0
1050 , 1200
3.0 – 3.5
1350 , 1500
3.5 – 4.0
1650 ,1800
4.0 – 4.5
Floodway
Full width of nominated
floodway
Table 6.4.7: Drainage easement widths for common drainage
lines and council pipelines
Existing private drainage easement
vii. Where it is proposed to discharge collected runoff
into an existing pipeline that passes through an
adjoining lot, or to lay a new pipe within an
existing inter-allotment drainage easement,
submit confirmation from NSW Land and Property
Information to indicate that the subject property
enjoys rights to use the drainage system with the
development application.
Council’s stormwater system and easement
viii. Generally buildings over Council drainage
easements and stormwater infrastructure will not
be permitted. However, subject to the approval of
Council, lightweight structures such as carports
and pergolas may be permitted.
ix. Where the location of the common drainage
pipeline is in conflict with proposed building,
relocate the drainage clear of the building in
accordance with a hydraulic analysis, undertaken
by a practising civil engineer, that demonstrates
the hydraulic capacity of the system is not
compromised due to the relocation.
x.
Where an approval is given for the construction of
a carport or other light structure over a drainage
easement, the structure will be easily
demountable and be removed, at the owner’s
expense, if requested by Council (for any necessary
work within the easement).
Sydney water
xii. Submit written evidence of compliance with
Sydney Water requirements with the development
application.
6.4.16
Overland flow path
Surface overland flow-paths are an integral part of the
drainage system and must be considered at the design
stage of the stormwater system. They are to be
preserved and maintained unobstructed throughout
the developed site and adjoining properties.
xi. Do not obstruct any overland flow path - Council
will enforce the removal of any obstruction to
overland within private properties, and recover
from the owners the coast of carrying out such
work.
xii. Do not obstruct existing runoff, entering the site
from upstream properties or sub-catchments, from
flowing into the subject site, or redirect it so as to
increase the quantity or concentration of surface
runoff entering adjoining properties.
Note: During periods of heavy rainfall it is anticipated that
there will be potential runoff, across boundaries of some
properties, which will enter downstream sites from upstream
properties due to the local contours of the area.
xiii. Consider potential runoff at the design stage and
design so it will not have any adverse impact on
adjoining properties. Overland flow it should not
be obstructed from flowing naturally and causing it
to pond or concentrate along boundaries of
adjoining properties. Suitable channels, open dish
drains, walls or any other measures may be
necessary to accommodate the existing and
potential overland flow paths throughout the
subject site.
xiv. Care must be exercised to ensure that provision of
any of the above remedial measures will not result
in diverting runoff into the OSD system, if this is
unattainable, then the OSD system must be
designed to cater for the additional stormwater
runoff anticipated from upstream catchment
area(s).
xv. Council may require that the design specify the
extent of the overland flow path through the site,
and that the development be located/modified
clear of the overland flow path, or set at an
appropriate freeboard.
CANTERBURY DEVELOPMENT CONTROL PLAN 2012
P6.4-14
PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
6.4.17
i.
Areas subject to possible flooding
OSD is not required on sites affected by the 1 in
100 year flooding.
Note: Council has a record of the flood levels for properties
adjacent to the Cooks River and the Salt Pan Creek. Council
will issue flood levels on written request, subject to a fee.
Flood levels will be issued to Australian Height Datum to the
nearest 100mm. Levels for the 1 in 20 year flood, 1 in 50 year
flood and 1 in 100 year flood can also be provided.
Approximate ground levels can also be given, however; it is
the applicant’s responsibility to engage a surveyor to
determine the actual ground and floor levels.
ii.
ii.
Submit the original of the WAE of the drainage and
OSD to Council, to verify that the constructed
works have been completed in accordance with
the approved design. The plan shall be prepared by
a registered surveyor or an engineer and include
all relevant levels. The WAE shall indicate an as
constructed level adjacent to all design levels,
including pit/tank cross sections, in red ink on the
approved stormwater and OSD drawing.
ii.
Include the following on the WAE, as a minimum:
(Refer to Appendix G – Flood Management & Flood
proofing in order to address all relevant issues prior to
submitting a development application).
i.
ii.
Prior to occupation of the development the Crown
will submit evidence of the compliance of this
condition and the registration of documents with
the Land Titles Office protecting the On-Site
Detention System.
6.4.19
i.
ii.
Do not begin work on the site until the hydraulic
plans have been approved in conjunction with the
construction certificate by the nominated PCA.
Certification
Provide a compliance certificate of the constructed
OSD - the certificate shall be prepared by an
accredited engineer competent in the field of
stormwater drainage design and who inspected

Sufficient levels and dimensions of the
constructed OSD,

Locations, surface levels, invert levels of all
drainage pits/grates/floor waste,

Verification that orifice plate has been
installed, together with its diameter,

Verification that trash screens have been
installed,

Finished floor levels of units and garages,

Weir/OSD overflow level,

Detail of any variations or omissions made
from the approved plans.
6.4.22
i.
Requirements for construction certificate
Submit detailed design calculations and plans with
the construction certificate - to Council or an
accredited certifier (PCA Civil). The drainage design
is to comply with the requirements of the CDCP
and the specific conditions of development
consent.
6.4.20
i.
Crown development
A fully detailed design of the stormwater drainage
system is required with the development
application for Crown Development - a condition
of the development consent will be imposed
requiring the construction of stormwater drainage
system in accordance with the approved drainage
plans.
Works as executed plan (WAE)
i.
All garages or parking areas are to be at least
150mm above the 1 – 100 year flood level.
6.4.18
List any variations on the certificate with the
engineer’s justification as to how these
discrepancies will not affect the performance of
the system or the design parameters.
6.4.21
Council may require a flood study be undertaken
and submitted with the development application,
where flood studies have not previously been
undertaken for areas adjacent to water courses.
iii. Habitable floor levels of all residential and
institutional buildings are to be a minimum of
500mm above the 1 – 100 year flood level.
iii
the OSD, examined the Work-as-Executed plans,
and certifies that the works have been constructed
in accordance with the approved design details.
Before making any changes to the approved design
during the construction the design engineer should
discuss these with Council’s development
engineer. Based on the extent and implications of
the variations the Engineer will either be:

Advised on the spot as to the acceptance or
refusal of the discrepancies, or

Requested to submit amended plans (section
96 modification) and calculations for approval.
6.4.23
i.
Variations during construction
Registration of OSD on title
Any OSD system, location on the land, terms and
conditions must be registered on the title of the
property, prior to occupation of the development,
issue of an occupation certificate or issue of a
subdivision certificate, to ensure the owners are
aware of the system’s design parameters, location
and their obligation to maintain it.
Note: A sample document for the guidance of applicants
setting out the terms and conditions required by Council
regarding the instrument to be registered is shown in
Appendix E.
CANTERBURY DEVELOPMENT CONTROL PLAN 2012
P6.4-15
PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
6.4.24 Flood management
v.
This section applies to development on land potentially
affected by a one in 100 year Flood Standard for Salt
Pan Creek and the Cooks River, as well as sites within
close proximity to this flood plain within Canterbury.
Objectives
O1. Development in flood liable areas is designed and
constructed to withstand the stresses of the
highest probable flood.
O2. Development will not increase the flood hazard or
flood damage to other properties or adversely
affect them in any way during times of flooding.
Flood levels of all habitable rooms should be 0.5m
or more above the standard flood level. A
certificate by a registered practicing surveyor
certifying the level of the completed building will
be required.
vi. Provide a certificate from a qualified practicing
structural or civil engineer stating that the building
is capable of withstanding the likely floodwaters
and impact from debris in those waters without
sustaining structural damage.
Any other development
Note: This Part should be read in conjunction with NSW
Floodplain Development Manual – the development of flood
liable land, 2005.
vii. Developments such as sporting grounds and open
air car parks will be considered on flood liable
land. Any consent for such development will
require certificates from surveyors and engineers
as referred to above.
Controls
Habitable floor space
New residential
viii. Bedrooms, bathrooms, living rooms, study, lounge
rooms, dining rooms, games rooms, kitchens, halls,
garages, offices, laundries, utility rooms,
manufacturing rooms / areas, class rooms, storage
areas.
i.
Submit a survey plan to Council showing the
relative levels to AHD, prepared by a registered
practicing surveyor.
ii.
Flood levels of all habitable rooms should be 0.5m
or more above the standard flood level. A
certificate by a registered practicing surveyor
certifying the level of the completed building will
be required.
iii. Where Council considers flooding could damage a
proposed development, no work should be
commenced until a qualified structural/civil
engineer has submitted a certificate of structural
adequacy with regard to stability as a result of
flooding.
Existing residential
iv. Where additions and alterations to existing
buildings include habitable rooms, a survey plan,
prepared by a registered practicing surveyor and
showing the relative levels of AHD, must be
submitted.
Non-habitable floor space
ix. Decking, sports grounds, car parks.
Note: The above lists are not exhaustive and may include
other forms of accommodation, storage and space use.
Flood levels
x.
Council will issue flood levels on written
request. They will be issued to Australian Height
Datum to the nearest 100mm. Levels can be
provided for the 1 in 20 year flood, 1 in 50 year
flood and 1 in 100 year flood. Approximate ground
levels can also be given but it is the applicant’s
responsibility to engage a surveyor to establish the
actual ground and floor levels.
CANTERBURY DEVELOPMENT CONTROL PLAN 2012
P6.4-16
PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
APPENDICES
FIGURE 1:
Charge line clean out pit
APPENDIX A:
On-site stormwater detention checklist
APPENDIX B:
Intensity - Frequency - Duration Table
APPENDIX C:
Runoff Coefficients for Canterbury
APPENDIX D:
Silt arrestor Pit Details
APPENDIX E:
Restriction Instrument
APPENDIX F:
Absorption Design Calculation
APPENDIX G:
Flood management and flood proofing
APPENDIX H:
Drainage requirement checklist
CANTERBURY DEVELOPMENT CONTROL PLAN 2012
P6.4-17
PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
FIGURE 1:
CANTERBURY DEVELOPMENT CONTROL PLAN 2012
P6.4-18
PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
APPENDIX A
On-Site Stormwater Detention (OSD) Checklist
for Dual Occupancy and Single Dwelling including Additions and Alterations
This form is to be used to determine if OSD will be required for residential developments and must be completed
before the submission of any Application. Please read the reverse side of this form carefully for its applications and
definitions.
Part A. Address and type of proposed development
Lot…………DP……………………………………………………………………………
No…………
Suburb…………………………………………………………………………………….
Street………………………………………………………………………..
Type of development (tick relevant boxes):
□ Dual Occupancy
□ Single Dwelling
□ Extensions
□ Garage, outbuildings and others (specify)…………………………………..........
Part B. Exemption for flood affected areas
Is the subject site located within an established 100 year floodplain and the site also floods in 20 and 50 year storm
events (tick one only):
□ Yes
□ No
If yes, OSD is not required. If no, go to Part C.
Part C. Exemption for minimum allowable size of site impervious area
Refer to the back of this page for definitions and explanations.
2
(a) Site area =…………………………………………………………………………………… (m )
2
(b1) Total existing impervious area =………………………………………............................... (m )
(b2) Total remaining existing impervious area =……………………………………………….. (m2)
(C) Proposed impervious area:
2
(C1) roofed areas =……………………………………………. (m )
2
(C2) paved areas =……………………………………………. (m )
2
(C3) supplementary areas =…………………………………… (m )
2
(d) Total post-development impervious area (b2) + (C1 + C2 + C3) =…………………………. (m )
(e) Total proposed impervious area (C1 + C2 + C3) x 100 / (a) =………………………………..(%)
(f) Existing impervious area percentage (b1) x 100 / (a) =……………………………………… (%)
(g) Post-development impervious area percentage (d) x 100 / (a) =…………………………….. (%)
OSD will not be required if either of the following is satisfied:
□ (g) is less than 70%
□ (f) is greater than 70% and (e) is less than or equal to 5%
Notes:
Developments covered by this form are for dual occupancy, single dwelling including alterations and additions and works that involve
driveways, garage, outbuildings and hardstand areas. Commercial and multiple occupancy developments are not exempt from OSD.
Definitions:
Site Area (a): This is the total area of the site for which the development is proposed for residential development, the
total site area is taken to be the area as shown on the Deposited Plan (DP).
Existing impervious Area (b1): This refers to all of the impervious areas, within the site of the development. prior to
any proposed works. This includes, calculated in plan view, all of the existing roofed areas, paved surfaces, hardstand
areas, garages, outbuildings, etc.
Remaining existing impervious Area (b2): This refers to the existing impervious areas of the site which will not be
removed or demolished as part of the proposed works, but will remain after the proposed works have been carried out.
CANTERBURY DEVELOPMENT CONTROL PLAN 2012
P6.4-19
PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
If a building is to be altered internally, that is, works involving only the removal/demolition of internal non-structural
members/walls within the footprint of the building, then the remaining impervious areas shall be calculated as the total
area of the building. Existing Dwelling
Proposed impervious Area (C): This includes all new impervious areas created as part of the proposed development,
such as; all proposed roofed, paved, supplementary (i.e. In-ground swimming pools), garages, outbuildings and
hardstand areas.
Post-development impervious Area (d): This includes ALL of the impervious areas within the site that are to remain
after the development is completed, that is, the finished works and includes all of the remaining existing and proposed
impervious areas.
C2
New
concrete
crossing
C
b1 &
b1 &
b2
Ubi8
Existing
Garage
C2
C1
C3
CANTERBURY DEVELOPMENT CONTROL PLAN 2012
P6.4-20
PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
APPENDIX B
Rainfall Intensities in Canterbury (mm/h)
Duration
(Minutes)
5
6
7
8
9
10
11
12
13
14
15
16
17
18
20
25
30
35
40
45
50
55
60
45
90
2 hours
3 hours
4 hours
5 hours
6 hours
8 hours
10 hours
12 hours
14 hours
16 hours
18 hours
20 hours
22 hours
24 hours
36 hours
48 hours
60 hours
72 hours
Average Storm Recurrence Interval (years)
1
2
5
10
20
50
100
94
88
83
79
75
72
69
67
64
62
60
58
57
55
52
46.9
42.7
39.3
36.6
34.3
32.3
30.6
29.1
36.6
22.7
19.0
14.7
12.2
10.6
9.43
7.88
6.83
6.08
5.54
5.1
4.75
4.45
4.19
3.97
3.07
2.53
2.16
1.89
199
188
178
169
162
156
150
145
140
136
132
128
125
122
116
105
96
89
83
78
74
70
67
83
52
43.2
33.2
27.5
23.8
21.2
17.6
15.2
13.5
12.3
11.3
10.5
9.87
9.30
8.81
6.81
5.62
4.81
4.21
233
219
208
198
190
183
175
170
165
160
155
151
147
143
137
123
113
105
98
92
88
83
80
98
62
51
39.3
32.6
28.2
25.0
20.7
17.9
15.9
14.5
13.3
12.4
11.6
11.0
10.4
8.03
6.63
5.67
4.96
258
243
231
220
211
203
196
189
183
178
173
168
164
160
152
138
127
117
110
104
98
94
89
78
69
57
44.0
36.4
31.5
27.9
23.1
20.0
17.7
16.2
14.9
13.9
13.0
12.2
11.6
8.96
7.40
6.33
5.54
120
113
107
101
97
93
89
86
83
80
78
75
73
71
68
61
55
51
47.5
44.5
42.0
39.8
37.9
47.5
29.5
24.6
19.0
15.8
13.7
12.2
10.2
8.84
7.87
7.16
6.60
6.14
5.75
5.42
5.14
3.97
3.27
2.80
2.45
155
146
138
131
125
120
116
112
108
104
101
98
96
93
89
80
73
67
61
59
56
53
50
61
39.2
32.7
25.2
20.9
18.1
16.1
13.4
11.6
10.3
9.39
8.65
8.05
7.54
7.11
6.74
5.20
4.29
3.67
3.21
173
163
155
147
141
135
130
126
121
118
114
111
108
105
100
90
83
76
71
67
63
60
57
71
44.7
37.2
28.6
23.7
20.5
18.2
15.1
13.1
11.7
10.6
9.78
9.10
9.53
8.04
7.61
5.88
4.86
4.15
3.63
CANTERBURY DEVELOPMENT CONTROL PLAN 2012
P6.4-21
PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
Polynomial coefficients for Canterbury
The following table has been obtained from the Bureau of Meteorology, reference FiV299O, dated 2nd May 1989 and
refers to the following location 33.925 South, 151,100 East (near Campsie).
List of Coefficients to equations of the form:
In(I) = a + b * (In(T)) + c*(In(T))**2 + d*(In(T))**3 + e*(In(T))**4 + f*(In(T))**5 + g*(In(T))**6
I = Intensity in millimetres per hour
T = Time in hours
ARI
a
b
c
d
e
f
g
1
3.3659
-0.5895
-0.0368
0.00768
0.001088
0.0002073
0.0000324
2
3.6278
-0.5874
-0.0393
0.00747
0.001347
0.0001911
0.0000417
5
3.9054
-0.5829
-0.0462
0.00787
0.001891
0.0002783
0.0000406
10
4.0403
-0.5802
-0.0504
0.0078
0.002316
0.0002836
0.0000526
20
4.1919
-0.5788
-0.0533
0.00821
0.002514
0.0003451
-0.000047
50
4.3626
-0.5761
-0.0568
0.00802
0.002846
0.0003344
0.0000579
100
4.4766
-0.5749
-0.0592
0.00823
0.003037
0.0003675
0.0000579
(years)
* Please note; that the data provided is derived automatically by computer using the nearest grid point to the latitude
and longitude of the location, not the location name. Therefore; because of possible mistake in specifying the latitude
and longitude by the user or in transference to the Bureau computer, it is essential that you check that the location you
require (to the nearest 0.025 degrees) corresponds to the latitude and longitude on the curves and tabulated data
supplied. If there are any discrepancies, please contact the Bureau of Meteorology, Hydrology Branch, Melbourne.
Alternative Rainfall Site Data
The following nine parameters can be applied in the methods provided in Chapter 2 of Australian Rainfall and Runoff
(1987).
2 year I
1 hr : 37.89
I 12 hr : 7.87
I 72 hr : 2.45
50 year I
1 hr : 79.68
I 12 hr : 15.90
I 72 hr : 4.96
Skewness Factor G : 0.00
Short Duration Factors: F2 : 4.29
F50 : 15.85
CANTERBURY DEVELOPMENT CONTROL PLAN 2012
P6.4-22
PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
APPENDIX C
Runoff coefficients for Canterbury (from A.R.&R. Figure 14.13)
ARI
years
Fraction Impervious
0
0.1
0.2
0.
0.4
0.5
0.6
0.7
0.8
0.9
1
1
0.41
0.44
0.47
0.50
0.53
0.57
0.60
0.63
0.66
0.69
0.72
2
0.44
0.47
0.50
0.53
0.57
0.60
0.63
0.67
0.70
0.73
0.77
5
0.49
0.52
0.56
0.60
0.61
0.67
0.71
0.74
0.78
0.82
0.86
10
0.51
0.55
0.59
0.63
0.67
0.71
0.75
0.78
0.82
0.86
0.90
20
0.54
0.58
0.62
0.66
0.70
0.74
0.78
0.82
0.86
0.90
0.95
50
0.59
0.63
0.68
0.72
0.77
0.81
0.86
0.90
0.95
0.99
1.04
100
0.62
0.66
0.71
0.76
0.80
0.85
0.89
0.94
0.99
1.03
1.08
Note: A minimum runoff coefficient of 0.7 should be adopted for design purposes.
CANTERBURY DEVELOPMENT CONTROL PLAN 2012
P6.4-23
PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
APPENDIX D
CANTERBURY DEVELOPMENT CONTROL PLAN 2012
P6.4-24
PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
APPENDIX E
INSTRUMENT SETTING OUT TERMS OF RESTRICTIONS AS TO USER OF LAND
AND POSITIVE COVENANT INTENDED TO BE CREATED
PURSUANT TO SECTION 88B OF THE CONVEYANCING ACT 1919
Lengths are in metres
(Sheet 1 of 3 sheets)
Plan:
Subdivision covered by Council
Clerk's Certificate No.
Full name and address
of proprietors of the land
Paul Citizen and Sharon Citizen
13 Cross Street City
PART 1
Identity of Restriction As To User firstly referred to in the above mentioned plan.
Schedule of Lots Affected
Lot/s Burdened
Lot x
Lot/s, name of Authority Benefited
Canterbury City Council
Identity of Positive Covenant, Easement secondly referred to in the above mentioned plan.
Schedule of Lots Affected
Lot/s Burdened
Lot x
Lot/s, name of Authority Benefited
Canterbury City Council
PART 2
1. Terms of Restriction on Use firstly referred to in the above mentioned plan.
CANTERBURY DEVELOPMENT CONTROL PLAN 2012
P6.4-25
PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
The standard terms of the Restriction On The Use Of Land under Section 88B shall benefit Canterbury City Council or under
Section 88E shall nominate Canterbury City Council the prescribed Authority and shall read as follows:
The Proprietor of the burdened lot(s) shall not:
(a)
Erect, construct or place any building or other structure.
(b)
Make alteration to the ground surface levels, grates, pits, kerbs, tanks, gutters or any other structure
associated with the on-site stormwater detention system. (which expression shall include; all ancillary
gutters, pipes, drains, walls, kerbs, pits, grates, tanks, chambers, pumps, basins and surfaces designed to
temporarily drain stormwater) (hereinafter called "the system").
Within the land so burdened, without the prior written consent of Canterbury City Council.
2. Terms of Public Positive covenant (firstly/secondly/thirdly/fourthly) referred to in the above mentioned plan.
The standard terms of the Positive Covenant under Section 88B shall benefit Canterbury City Council or under Section 88E
shall nominate Canterbury City Council the prescribed Authority and shall read as follows:
1. The proprietors of the lots burdened will in respect to the system described in the
this instrument:
restriction on use referred to in
(a) permit stormwater runoff to be temporarily detained by the system;
(b) keep the system clean and free from all silt, rubbish and debris;
(c) maintain and repair the system so that it functions in a safe and efficient manner;
(d) replace, maintain, repair, alter, and renew the whole or parts of the system within the time and in the manner
specified in a written notice issued by the Council;
(e) carry out the matters referred to in paragraphs (b), (c) and (d) above at the proprietor's expense;
(f) not make any alterations to the system or elements thereof without prior consent in writing of the Council;
(g) permit the Council or its authorised agents from time to time upon giving reasonable notice (but at any time and
without notice in the case of an emergency) to enter and inspect the land for compliance with the requirements of
the covenants set forth herein.
2.
In the event of the registered proprietor failing to comply with the terms of any written notice served in respect of the
matters in clause (i) above, the Council or its authorised agents may enter with all necessary equipment and carry
out any work required by such notice to ensure the safe and efficient operation of the system and recover from the
registered proprietor the cost of carrying out such work, and if necessary, recover the amount due by legal
proceedings (including legal costs and fees) and enter a covenant charge on the lot burdened under section 88F of
the Conveyancing Act 1919. In carrying out any work under this clause, the Council shall take responsible
precautions to ensure that the land is disturbed as little as possible.
3. Comply with the terms of any written notice issued by Council in respect to the requirements of the covenants set forth
herein, within the time stated in the notice.
In these covenants "Council" means Canterbury City Council.
Name of person or authority whose consent is required to release, vary or modify the Restriction as to User and Positive
Covenant referred to in the above mentioned plan.
The Council of the City of Canterbury
CANTERBURY DEVELOPMENT CONTROL PLAN 2012
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PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
Signed in my presence by the said
_________________________
___________________________
Signature of Witness
Signed in my presence by the said
_________________________
___________________________Signature of Witness
CANTERBURY DEVELOPMENT CONTROL PLAN 2012
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PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
APPENDIX F
ABSORPTION DESIGN CALCULATION
SITE DETAILS
Address
2
Site Area (m )
2
Impervious Area (m )
Nominal Absorption Rate (ARN)
Reduction Factor (FR)
Design Details
2
2
Design Impervious Area (DA)
area ……..m x 1.2 = ………..m (DA)
Design Absorption Rate (ARN)
ARN …. l/m /sec x FR ….. = ….. l/m /sec (ARD)
Base Area of Absorption Pit (BA)
Width …. m x Length …. m = … m (BA)
2
2
2
Required Absorption System Volume Calculation for 50 Year ARI Storm
Time
T
Rainfall
Intensity
Runoff
I
R
=I
DA/3600
min
mm/hr
l/s
5
233
6
219
7
208
8
198
9
190
10
183
11
175
12
170
13
165
14
160
15
155
20
137
25
123
30
113
45
92
60
80
90
62
120
51
x
Runoff Volume
Infiltration Vol
RV = R x T x 60/1000
IV = BA x ARD x T x
60/1000
m
3
Maximum required Absorption System Volume
m
3
Required
Absorption Volume
RV – IV
m
3
m
3
CANTERBURY DEVELOPMENT CONTROL PLAN 2012
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PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
APPENDIX G
Construction standards for development in flood liable areas
Electrical and Mechanical Materials
(a)
Main Power Supply
Subject to the approval of Energy Australia the incoming
main commercial service equipment, including all metering
equipment should be located above the DFL. The dwelling
must be able to be easily disconnected from the main power
supply.
(b)
Wiring
All wiring, power outlets, switches, etc., should, to the
maximum extent possible, be located above the DFL. All
electrical wiring installed below the DFL should be suitable
for continuous submergence in water and should contain no
fibrous components. Only submersible-type splices should
be used below the DFL. All conduits located below the DFL
should be installed so that they will be self-draining if subject
to flooding.
(c)
Equipment
All equipment installed below or partially below the DFL
should be capable of disconnection by a single plug and
socket assembly.
(d)
Heating & Air Conditioning
Heating and air conditioning systems should, to the
maximum extent possible, be installed in areas and spaces of
the house above the DFL. When this is not feasible every
precaution should be taken to minimise the damage caused
by submersion according to the following guidelines.
Fuel
Heating systems using gas or oil as a fuel should have a
manually operated valve located in the fuel supply line to
enable fuel cut-off.
Installation
The heating equipment and fuel storage tanks should be
mounted on and securely anchored to a foundation pad of
sufficient mass to overcome buoyancy and prevent
movement that could damage the fuel supply line. All
storage tanks should be vented to an elevation of 600
millimetres above the DFL.
Ducting
All ductwork located below the DFL should be provided with
openings for drainage and cleaning. Self draining may be
achieved by constructing the ductwork on a suitable grade.
Where ductwork must pass through a water-tight wall or
floor below the DFL the ductwork should be protected by a
closure assembly operated from above DFL
CANTERBURY DEVELOPMENT CONTROL PLAN 2012
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PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
Construction Materials
Construction materials are graded into the following four classes according to resistance to flood waters:
Most Suitable
The materials or products which are relatively unaffected by submersion
and unmitigated flood exposure and are the best available for the
particular application.
Minor Effects
Where the “most suitable” materials or products are unavailable or
economic considerations prohibit their use, these materials or products
are considered the next best choice to minimise the damage caused by
flooding.
Marked Effects
As for “2 preference” but considered to be more liable to damage under
flood conditions.
To Be Avoided
The materials or products listed here are seriously affected by
floodwaters and in general have to be replaced if submerged.
nd
Buildings should be constructed using the “most suitable” materials. See Table 1 attached to this Plan. Second and
third preference materials will only be considered where circumstances warrant it.
COMPONENT
Flooring and sub-floor
structure.
ORDER OF PREFERENCE
MOST SUITABLE
SECOND PREFERENCE
THIRD PREFERENCE
TO BE AVOIDED



Timber floor (T&G
boarding,
marine
plywood with ends
only epoxy sealed
on
joints
and
provision of side
clearance for board
swelling.

Timber floor close
to ground with
surrounding base.

Timber flooring with
ceilings or soffit
linings.

Timber flooring with
seal on top only.
Asphalt tiles with
asphaltic adhesive.

Asphalt tiles (A).

Carpeting,
gluedown type or fixed
with smooth-edge
or jute felts.
Concrete slab-onground monolithic
construction.
Note: Clay filling is
not
permitted
beneath
slab-onground
construction, which
could be inundated.
Floor covering.
Wall Structure (up to
the DFL).

Suspension
reinforced concrete
slab.

Clay tile.

Concrete, precast or
in situ.

Timber floor (T&G
boarding,
marine
plywood) full epoxy
sealed, on joints.
Cement/bituminous
formed-in-place.


Cement/latex
formed-in place.

Rubber tiles, with
chemical-set
adhesive.

Concrete tiles.

Epoxy,
place.
formed-in-


Mastic
flooring
formed-in-place.

Terrazzo.

Rubber sheets with
chemical-set
adhesives.

Vinyl tiles
chemical-set
adhesive.

Silicone
floors
formed-in-place.

Vinyl tiles, asphaltic
adhesives.

Vinyl sheets with
chemical-set
adhesive.

Loose rugs.

Ceramic tiles with
acid and alkaliresistant grout.

Two
skins
of
brickwork
or
blockwork
with

Solid
brickwork,
blockwork,
reinforced, concrete
Loose fit nylon or
acrylic carpet with
closed cell rubber
underlay.
Ceramic tiles (A).
Chipboard (particle
board).
with

Brick or blockwork
veneer construction
with
inspection

Cork, Linoleum, PVA
emulsion cement,
rubber sheets or
tiles (A), vinyl sheets
or tiles (A).

Vinyl sheets or tiles
coated on cork or
wood backings fibre
matting (sea-grass
matting).

Inaccessible
cavities.
CANTERBURY DEVELOPMENT CONTROL PLAN 2012
P6.4-30
PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
COMPONENT
ORDER OF PREFERENCE
MOST SUITABLE
SECOND PREFERENCE
or mass concrete.
Roofing structure (for
situations where DFL is
above the ceiling).
Doors.
Reinforced concrete
construction.

Galvanised
metal
construction.


Wall and ceiling linings.
inspection
openings.


Solid panel with
water
proof
adhesives.
Flush door with
marine ply filled
with closed cell
foam.
Painted
metal
construction.

Aluminium
galvanised
frame.

Compressed cement
or plaster board.

THIRD PREFERENCE


Flush panel or single
panel with marine
ply wood and water
proof adhesive.

T&G lined door,
framed ledged and
braced.

Painted steel.

Timber frame fully
epoxy sealed before
assembly.

Brick, common.

Plastic wall tiles.
or
steel
Brick, face or glazed
in
waterproof
mortar.
Timber trusses with
galvanised fittings.
Inaccessible
flat
roof construction.

Ungalvanised
steelwork eg lintels,
arch bay tie rods,
beams etc.

Unsecured
tiles.

Hollow core ply with
PVA adhesive and
honeycomb paper
core.
roof

Fly-wire doors.

Standard
frame.

Chipboard exterior
grade.

Chipboard.

Fibreboard panels.
Hardboard exterior
grade.

Minerar fibreboard.

Paperboard.

Plaster-board,
gypsum plaster.

Wall
coverings
(paper, burlap cloth
types).
timber

Wood, solid or
exterior
grade
plywood
fully
sealed.
Wood, solid (boards
or
trim)
with
allowance
for
swelling.

Wood,
plywood
exterior grade.

Fibrous
board.
plaster

Wood,
standard
plywood
strawboard.

Bat
or
types.
blanket

Open
types.

Timber with PVA
glues mild steel
fittings.
Concrete block.
Steel
waterproof
applications.

Stone, natural solid
or
veneer,
waterproof grout.

Glass blocks.

Glass.

Plastic sheeting or
wall
with
waterproof
adhesive.
Insulation.

Foam or closed cell
types.

Reflective
insulation.
Windows.

Aluminium frame
with stainless steel
or brass rollers.

Epoxy sealed timber
waterproof
glues
with stainless steel
or brass fittings.

Galvanised
painted steel.
Removable
hinges.

Rubber mouldings &
trim.


Traditional timber
roof construction.
window


with
or
Large
openings.
Metals, non ferrous.

Brass, nylon
stainless steel.


Concrete.

openings.


Nails, bolts, hinges and
fittings.

TO BE AVOIDED
cell
fibre
or

Mild steel.
pin
CANTERBURY DEVELOPMENT CONTROL PLAN 2012
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PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
Appendix 6.4G: Table 1: Flood management and flood proofing
Definitions
Flood
Relatively high stream flow that overtops the natural or
artificial banks in any part of a stream or river.
Flood Standard
The flood selected for planning purposes based on flood
behaviour and associated flood risk taking into account social,
economic and ecological considerations.
Floodway
The area where the main flood waters pass when floods occur
often resulting in hazardous situations because of the depth
and speed of the floodwater.
Flood Storage
Those parts of the flood plain that are important for the
temporary storage of floodwaters.
Flood Fringe
Land outside the flood ways which may be flooded infrequently
and where development will normally be approved subject to
flood proofing measures.
AHD
Australian Height Datum – a common national plane of level
corresponding approximately to mean sea level.
Survey Plan
A plan prepared by a surveyor registered with the Surveyors
Act 1929, showing the boundaries and location of a property,
plus any existing or proposed building or other improvements
together with existing levels to AHD.
Designated Floor Level
(DFL) The minimum floor level acceptable to Council when
giving consent to an application for development. It will
normally be 0.5m above the Standard Flood Level for habitable
rooms.
Habitable Room
Means a room, compartment or enclosed area that is designed,
constructed, capable of being used or adapted for activities
normally associated with domestic living, such as a bedroom,
living room, lounge room, television room, kitchen, dining
room, study, playroom and the like.
Freeboard
The height of the Designated Floor Level above the Flood
Standard to allow for wave action and local hydraulic effects.
Flood Liable Land
Land that would be inundated as a result of the Standard Flood.
CANTERBURY DEVELOPMENT CONTROL PLAN 2012
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PART 6.4 GENERAL CONTROLS - DEVELOPMENT ENGINEERING FLOOD AND STORMWATER
Type of development
Property falls
to
Street
OSD
required
Charged
line
Absorption
system
N/A
N/A
Pump
system
N/A
Yes
(1)
Rear
away
from street
Yes
(1)
Yes
(6)
Yes
(6)
No
(2)
Street/rear
Yes
(1),(3)
Yes
(6)
Yes
(6)
No
(2)
Dual occupancy
Street
Yes
(1)
No
No
Dual occupancy
Rear
Yes
(1)
No
No
Townhouse/villa
Street
Yes
No
Townhouse/villa
Rear
Yes
Single dwelling
Single dwelling
Adds/Alts
Outbuilding
Residential
building
flat
Residential
building
flat
Commercial/Industrial
(4)
Street
Rear
(4)
Street
Comments
No
No
(2)
No
No
(5)
No
No
No
(5)
Yes
No
No
No
(5)
Yes
No
No
No
Yes
No
No
No
(1) OSD must be provided if postdeveloped impervious area is greater
than or equal to 70% of the site area
(Refer section 6.4.10)
(2) Drain site by gravity pipe using
stormwater
easement
via
downstream property, pump system
may be considered where easement
is rejected AND all supporting
(documents*)
are
provided
accordingly. For single dwellings only,
a pump system is permissible where
alternative methods (charged and
absorption) are not viable
(3) Proposed development that does
not increase existing impervious area
shall be connected to existing
drainage system however; OSD must
be provided where the existing
impervious area is equal to 70% or
more and the proposed additions /
alterations are more than 5% of the
site area
(4) Gravity pipe system using a
stormwater
easement
via
downstream property is the only
method accepted
Commercial/Industrial
Rear
(4)
Yes
No
No
No
(5) For basement driveway only with
2
maximum area of 50m , can drain
into a pump system, pump wet well
to have a capacity for 1 hour storm
2
(that is, 50m will require a pit with
3000 litres capacity)
(6) Both charged and absorption
system are permissible providing they
comply with section 6.4.14
Table 6.4.2
Drainage requirement checklist for proposed development in Canterbury
Notes for Table 6.4.2 impervious area includes all buildings and paved areas (roof, driveway, car parking space and swimming pool,
(see Appendix A.)
Supporting documents include the following:
1.
A land valuation prepared by a registered land valuer to estimate the value of the easement only (excluding
construction/installation cost).
2.
A signed letter of request from the applicant to all possible downstream properties requesting their permission to create a
stormwater easement through their property (the amount estimated in the valuation report must be disclosed in the letter as an
offer of compensation,) and that all relevant expenses to construct and reinstate any disturbed areas is at the cost of the
applicant.
3.
A signed letter of correspondence from the downstream property owner(s), either accepting or rejecting the request
CANTERBURY DEVELOPMENT CONTROL PLAN 2012
P6.4-33