Book 3 | Case Studies - WSUD

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Water Sensitive Urban Design 

Book 3 | Case Studies

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Book 3 | Case Studies 

Table of Contents 

1 | Introduction 4 

2 | WSUD in the Planning Phase: Renwick 5 

2.1 WSUD Objectives 6 

2.2 Constraints to WSUD 7 

2.3 Opportunities for WSUD 8 

2.4 Integration of WSUD into the development 9 

2.4.1 Water quality and flow management 9 

2.4.2 Stream rehabilitation 10 

2.4.3 Urban and open space design requirements 11 

2.5 WSUD outcomes 12 

2.6 Conclusions 12 

3 | WSUD in the Implementation Phase: The Ponds 13 





3.4.1 Water conservation 15 

3.4.2 Pollution control 16 

3.4.3 Flow management 16 

3.4.4 Stream rehabilitation 17 

3.4.5 Construction in a saline environment 17 

3.5 WSUD Outcomes 19 


4 | WSUD in the Implementation Phase: Prince Henry 20 




4.3.1 Water conservation and reuse 22 

4.3.2 Water quality treatment 22 



4.5.1 Water quality treatment 26 


5 | Operation and Maintenance of WSUD treatment measures: Victoria Park 28 




5.3.1 Overcoming site constraints 30 


5.4.1 Water quality 31 

5.4.2 Water quantity 31 


5.5 WSUD Implementation and Maintenance 32 

5.5.1 Establishment 32 

5.5.2 Maintenance - bioretention swales 33 



Book 3 | CASE STUDIES 3


1 | Introduction 

The four case 

studies illustrate 

how WSUD can 

be integrated into 

different stages of 

land development. 

4 Book 3 | CASE STUDIES 

This document (Book 3 of 4 in Landcom’s 

Water Sensitive Urban Design (WSUD) 

Strategy box set) presents four case 

studies which demonstrate the application 

of WSUD in a range of Landcom projects. 

Projects were selected to represent 

conditions that are typical of the extent of 

developments undertaken by Landcom, 

including greenfield and urban renewal 

developments, inner city and fringe areas. 

The four case studies illustrate how WSUD 

can be integrated into different stages of 

land development – from planning through 

to implementation, as well as providing an 

understanding of the ongoing operation 

and maintenance of WSUD elements. The 

case studies include: 

•• 

The planning phase – Renwick WSUD 

strategy for a greenfields development 

to address stringent water quality 

requirements for developments within 

the Sydney Catchment Authority (SCA) 

area. 

•• 

The implementation phase – The Ponds. 

A site-specific WSUD strategy is being 

implemented in an environment with 

a high salinity hazard. The outcomes 

of this carefully planned development 

include attractive and functional 

landscaping features that have 

contributed to the high desirability of 

the lots and the consequent good sales 

records. 

•• 

The implementation phase – Prince 

Henry. An urban renewal project that 

looks to water management and its 

relationship with surrounding landuses, 

in this case a golf course. Elements of the 

strategy include stormwater treatment, 

harvesting and reuse through both the 

golf course and the development as 

well as greywater reuse. 

•• 

The operation and maintenance 

phase – Victoria Park. This case study 

documents how working with the natural 

site topography and environment can 

lead to well built stormwater treatment 

devices that will provide years of service, 

and with landscape requirements no 

different to most urban green spaces. 

Each case study identifies WSUD targets, 

the natural environmental constraints and 

opportunities that informed the WSUD 

strategy for each site, how the strategy 

targets were met, and the lessons learnt 

through the WSUD Strategy. The case 

studies provide examples of WSUD 

elements with preliminary sizing of 

elements presented. They represent a 

conceptual design of opportunities and 

do not represent detailed designs.


2 | WSUD in the Planning Phase - Renwick 

BONG BONG ROAD 

GREAT 

SOUTHERN RAILWAY 

Western Drainage Chanel 

SW Minor Watercourse 

Main Waterway 

INKERMAN ROAD 

Billabong 

and Floodplain 

SW external 

catchment 49ha 

TC1 


SE Minor Watercourse 

TC2 

TC1 external 


TC2 external 


Legend 

External Catchment Boundary 

Renwick Development Boundary 

Minor Watercourse 

Major Watercourse 

Riparian Corridor 

Figure 1 - Waterways within Renwick 

The Renwick WSUD Strategy reflects the 

successful integration of social, cultural, 

environmental and economic objectives. 

This case study demonstrates the 

planning stage of the 116 hectares (ha) 

Renwick development in Mittagong, 

120 kilometres south west of Sydney. 

The development will provide up to 600 

dwellings, in a range of lot sizes including 

cottages, traditional houses and semi 

rural / half acre and acre blocks. 

The lands that form the Renwick 

development property have been 

extensively cleared and used for 

agricultural purposes. A number of 

streams flow through the Renwick site, 

illustrated in Figure 1. 



Table 1 | WSUD targets for Renwick to reflect NorBE 

Objective 

Water Conservation 

Performance Measure and Target 

(a) Combination of water efficiency and reuse options – 40% reduction 

on base case. 

(a) 65% reduction in the mean annual load of Total Nitrogen (TN). 

Pollution Control 

Flow Management 

(b) 84% reduction in the mean annual load of Total Phosphorus (TP). 

(c) 91% reduction in the mean annual load of Total Suspended Solids 

(TSS). 

Post-development storm discharges = pre-development storm 

discharges for the 1.5 year ARI event 

The WSUD 

strategy forms a 

core component 

of the Renwick 

masterplan. 

2.1 WSUD Objectives 

The site is located within Sydney’s 

water supply catchment, and any runoff 

from the site drains via the Nattai River 

into Warragamba Dam and Sydney’s 

potable water supply. Under SEPP 58 

the development must meet the SCA‘s 

Neutral or Beneficial Effect (NorBE) Test. 

This requirement translates into WSUD 

objectives which are more stringent than 

the conventional Landcom requirements 

as outlined in Book 1, Table 1. 

Demonstration of neutral or beneficial 

effect (NORBE) of stormwater quality 

is achieved by comparing the pollutant 

concentration characteristics of postdevelopment 

scenarios against that for 

pre-development conditions. 

A cumulative probability function relates 

the probability at which contaminant 

concentrations fall below a reference level. 

A modelling approach is used to simulate 

existing catchment conditions and derive 

the cumulative probabilities for daily 

pollutant concentrations under existing 

and post-development conditions. 

Table 1 lists the resulting reductions in 

pollutant loads by attaining Neutral or 

Beneficial Effect outcomes as stipulated 

by the Sydney Catchment Authority. 

These targets are more stringent than 

conventional WSUD targets and may be 

regarded as stretch targets applicable 

only to sensitive environments. 

The WSUD Strategy has been developed 

to address: 

•• 

Stormwater treatment to protect 

the quality of the water entering the 

Warragamba Catchment, 

•• 

Flooding impacts to prevent detrimental 

impacts on receiving ecosystems 

•• 

Potable water conservation to address 

water scarcity. 

A comprehensive stream rehabilitation 

plan has been developed as part of the 

WSUD strategy. This is to improve the 

condition of the degraded and unstable 

streams on site, caused by changes to 

hydrology and water quality that result 

from urban development. The stream 

rehabilitation will improve the landscape 

and amenity value of the riparian corridor 

for the local community. 

The WSUD strategy forms a core 

component of the Renwick masterplan. 

The masterplan brings together social, 

cultural, environmental and economic 

objectives and aims to meet best practice 

in these disciplines. The masterplan also 

aims to preserve the area’s ‘community 

feel’, character and rural setting. The 

character of the area stems from the 

development of significant gardens and 

the landscape in the European tradition in 

response to the cool temperate climate of 

the Southern Highlands. 

6 Book 3 | CASE STUDIES


Renwick site 

2.2 Constraints to WSUD 

The poor ecological and geomorphological 

condition of the existing streams 

and the desire for a public open space 

of high value creates both difficult 

constraints and excellent opportunities 

for WSUD and stream rehabilitation. 

Constraints for the development are: 

•• 

Renwick is located within a Sydney 

drinking water supply catchment and 

the development must demonstrate 

that it will have a neutral or beneficial 

effect on the quality of the runoff from 

the site. This requires Renwick to have 

a comprehensive stormwater treatment 

strategy beyond that typically employed 

on Landcom sites. 

•• 

Rainwater tanks reduce the volume of 

stormwater that requires treatment. 

However, because rainwater tanks 

would reduce the volume of stormwater 

run-off to the drinking water supply 

catchment, tanks will not be used. This 

will place a greater demand on the space 

required for stormwater treatment and 

flow attenuation measures. 

•• 

The site has a badly degraded stream 

that flows through the site. The stream 

channel is highly unstable, rapidly 

eroding and requires considerable 

reshaping work. This stream must be 

restored as part of the development. 

•• 

Three external catchments upstream 

drain to Renwick and flood attenuation 

controls must be provided for flows 

from these catchments, increasing the 

demand for space for flood detention 

basins. 

•• 

Most of the land surrounding the 

streams is now populated by pasture 

grasses, weedy shrubs and trees. These 

weeds have been declared noxious 

weeds and the site managers have a 

legal obligation to suppress or destroy 

these plants. 

•• 

Sites of Aboriginal and European 

cultural heritage occur alongside the 

riparian corridor, impinging on the 

space available for riparian restoration 

and WSUD elements. 

•• 

Activity in Renwick is focussed on the 

centre of the site. Consequently, the 

bulk of public open space, parkland, and 

community facilities are also located 

in this area and these require some 

stream realignment to accommodate 

the desired landform. 



Renwick site 

2.3 Opportunities 

for WSUD 

Landscaping will be 

used to engage the 

community to make 

maximum use of 

this area. 

•• 

Large areas of open space have been 

set aside within Renwick (approximately 

25% of the site) to maintain the sense 

of open space that characterises 

the area. The position of the open 

space and riparian corridor along 

the centre of the development area 

gives an opportunity for the riparian 

corridor to define the character of 

the public open space, and to create 

natural habitat through the heart of an 

urban area. Thus WSUD and stream 

rehabilitation will be incorporated into 

the landscaping works that give the 

village its defining character. 

•• 

Landscaping will be used to engage 

the community to make maximum use 

of this area. A stream corridor that is 

well used and valued by residents will 

be better maintained and protected 

through passive surveillance. 

•• 

Urban development at Renwick will 

increase runoff to the downstream 

waterways. Therefore, stream works to 

stabilise the channel will also reshape 

the channel to accommodate these 

extra flows. 

•• 

The stream rehabilitation work will 

stabilise the channel and protect the 

urban infrastructure from erosion and 

flooding. 

•• 

Modifications associated with the 

stream works will be used to create 

more diverse in-stream habitats than 

occur within the site at present. 



Analysis showed 

that the best 

treatment method 

was a combined 

wetland and 

bioretention 

system. 

2.4 Integration of WSUD 

into the development 

2.4.1 Water quality and flow 

management 

In development of the WSUD strategy, 

modelling was undertaken using the 

Model for Urban Stormwater Improvement 

Conceptualisation (MUSIC), to assess 

compliance with the Neutral or Beneficial 

Effect (NorBE) requirements for water 

quality. The pollution concentrations were 

translated to the pollution load reduction 

targets for total suspended solids, 

total phosphorous and total nitrogen. 

Analysis showed that the best treatment 

method was a combined wetland and 

bioretention system. A treatment element 

corresponding to approximately 3% of the 

contributing impervious urban / road area 

was required. These treatment devices 

will remove pollutants to the SCA’s 

requirements for NorBE, prior to release 

to the stream. 

The water quality treatment areas will 

be located within the riparian buffer 

zone, between the development and the 

riparian corridor. In some areas of the 

development vegetated swales along 

low-density roads with wide reserves will 

be used to improve water quality. The 

raingardens will be planted with native 

grasses and ephemeral wetland species 

adapted to the intended inundation 

regime. The plants used are indigenous to 

the Southern Highlands Shale Woodlands 

species assemblage, thus ensuring 

ecological continuity between the riparian 

zone and the stormwater treatment 

devices. 

To reduce the impact of increased frequent 

flows from increased runoff volumes from 

urban catchments, discharges from the 

urban areas corresponding to the 1.5 year 

ARI flow will be attenuated to protect the 

downstream waterway from erosion. The 

location of detention areas are still to 

be determined and will be incorporated 

within the floodplain. 

A plan showing the location of proposed 

treatment measures is presented in 

Figure 2. 



GREAT 

SOUTHERN RAILWAY 

INKERMAN ROAD 



Legend 

WSUD Elements 

Renwick Development Boundary 

Minor Watercourse 

Major Watercourse 

Riparian Corridor 

Figure 2 - WSUD treatment elements 

The stream 

rehabilitation 

strategy developed 

for Renwick’s 

waterways was 

designed to 

complement the 

WSUD and urban 

requirements of 

the site. 

2.4.2 Stream rehabilitation 

The stream rehabilitation strategy 

developed for Renwick’s waterways was 

designed to complement the WSUD 

and urban requirements of the site. The 

objectives were: 

•• 

Stabilisation of stream bed and 

banks to facilitate and promote the 

natural development of in-stream 

geomorphological processes. The 

stream works will create a dynamic 

stability where the natural stream 

forming processes of erosion and 

sediment deposition can take place 

within the confines of the channel but 

will not change dimensions during 

engineering timeframes, or damage 

nearby roads and housing infrastructure 

•• 

Retention of valuable stream physical 

and hydraulic habitats where they exist, 

and creation of habitats where streams 

are degraded and habitat is poor or 

absent. 

•• 

Revegetation of stream channels and 

marginal riparian zones with species 

indigenous to the area and appropriate 

to the hydraulic habitats created. 

•• 

Making the riparian corridor accessible 

to the public through the adjoining 

public open space, so that the corridor 

can also become a source of community 

identity and a focal point for recreation, 

and consequently highly valued by the 

community. 

Such work is more intensive than the work 

most commonly done in streams, but the 

outcome of diverse, healthy functioning 

streams will add substantial value to the 

community that will be created in the 

urban development surrounding this 

riparian corridor. 



Renwick will reflect the distinct nature of the Southern Highlands 

Stream rehabilitation will complement WSUD 

objectives at Renwick 

The riparian 

corridors have 

been designed 

to accommodate 

or facilitate these 

activities without 

compromising the 

function and form 

of the stream. 

2.4.3 Urban and open space design 

requirements 

The riparian corridor will become an 

important component of public open 

space for the community and will be 

subject to a diversity of uses, such as: 

•• 

The aboriginal heritage conservation 

areas 

•• 

The Village Green adjacent to the 

riparian corridor will provide a focal 

point for community activity and 

recreation. A meander in the stream 

will be realigned to complement the 

Village Green parkland. 

•• 

Informal access to the stream and in 

formal stream crossings (sandstone 

boulder riffle zones) will be built within 

the core riparian zone. Three public 

roads and several pedestrian paths will 

cross the stream. 

•• 

Appropriate passive recreation 

activities such as pedestrian and cycle 

paths, and areas for play, relaxation and 

gathering will be located alongside and 

within riparian corridor buffer zone. 

The riparian corridors have been 

designed to accommodate or facilitate 

these activities without compromising 

the function and form of the stream. It is 

envisaged that by providing good public 

access to the riparian zone the community 

will gain an appreciation of the natural 

values of the streams and riparian 

corridors and a sense of ownership of 

these important natural resources. 



Integration of water into a semi rural landscape | Bridgewater, South Camden 

The key to 

the successful 

integration of the 

various aspects of 

the site was the 

incorporation of 

WSUD early in the 

planning process. 

2.5 WSUD outcomes 

The outcomes of the WSUD strategy, 

supported by the riparian rehabilitation 

works are: 

•• 

Meet SCA requirements for NorBE. 

•• 

Low maintenance requirements. A 

well vegetated stream whose natural 

habitat evolves and matures requiring 

only minimal maintenance and remains 

resistant to weed infestation. 

•• 

Preservation of the heritage values of 

the site. 

•• 

A naturally functioning stream system 

where stream forming processes of 

erosion and sediment deposition 

can take place within the confines 

of the channel that will not change 

dimensions during engineering 

timeframes, or damage nearby roads 

and housing infrastructure. 

•• 

An ecologically diverse and healthy 

stream containing a diversity of 

physical, hydraulic and biological 

habitats, and supporting a diversity 

of vegetation representative of the 

Southern Highlands Shale Woodland 

plant community. 

•• 

Integration with urban design and 

engaging the community in a public 

space that fosters activity, appreciation 

and learning about natural systems, 

social interaction and recreation. 

2.6 Conclusions 

The WSUD strategy developed for 

Renwick illustrates how WSUD can be 

integrated into the masterplan and 

complements a range of site needs. 

The key to the successful integration 

of the various aspects of the site was 

the incorporation of WSUD early in the 

planning process. The master planning 

process identified many of the constraints 

and opportunities that the site presented. 

In Renwick Village, the public open 

space that surrounded the waterway 

was required to serve multiple functions, 

many of which were complementary. 

Careful planning allowed many facilities 

to be co-located and designed in such a 

way so as to complement each other. In 

this way the raingardens for water quality 

treatment could act as a buffer for the 

riparian corridor, while enhancing the 

experience of people using cycle ways or 

foot paths and recreation areas. Similarly, 

the restored waterway will provide a 

connection with nature in the public open 

space, while also providing ecological 

habitat and attenuating flows from the 

urban development. WSUD is most 

efficient if site-specific strategies can 

be developed that respond to the local 

environment. Such synergistic outcomes 

can only result by identifying the WSUD 

requirements early in the master planning 

process. 



3 | WSUD in the Implementation Phase - The Ponds 

Figure 3 - Aerial photograph of The Ponds in the 

Blacktown LGA, Sydney. The approximate 

development site boundary is indicated 

by the dotted line. Note the extensive 

erosion associated with the creek 

channel. 

The Ponds 

illustrates how 

Landcom has 

applied WSUD to a 

large development 

currently under 

construction in an 

environment with a 

high salinity hazard. 

The Ponds case study relates to the 

implementation phase of WSUD. The 

Ponds illustrates how Landcom has 

applied WSUD to a large development 

currently under construction in an 

environment with a high salinity hazard. 

The carefully planned development 

has overcome many constraints to 

construction and created attractive and 

functional landscaping that has led to 

positive environmental and economic 

outcomes. 

The Ponds is in Sydney’s North-West, 

between Quakers Hill and Rouse Hill in 

the Blacktown LGA. Second Ponds Creek 

is the main watercourse of the site and the 

development extends along both sides of 

the creek. The site consists of 320 ha of 

land, on which 3,200 lots will be built over 

10 years. A large portion (80 ha) of the site 

will be set aside for parklands and public 

open space. Most of the public open 

space occurs along the stream corridor. 

The area was cleared for grazing in the 

mid-1800s, and aerial photos show that 

by 1947 approximately 5 ha of the stream 

was affected by salt. Groundwater near 

the creek is highly saline and groundwater 

levels probably rose in the early 1900s in 

response to the clearing of the catchment. 

Extensive erosion had occurred along the 

creek, probably caused by saline scalds 

and exacerbated by disturbance from 

grazing livestock (Figure 3). 




Stormwater management at The Ponds 

is directed at two principal management 

objectives: 

•• 

The treatment of stormwater runoff 

to ensure the loads of stormwater 

pollutants discharged to Second Ponds 

Creek and downstream receiving 

waters do not adversely impact on the 

ecological health of these waterways. 

•• 

Protecting the ecosystem health and 

channel form stability of Second Ponds 

Creek 

The Landcom WSUD targets were 

adopted for the site as summarised in 

Table 2. 

Table 2 | WSUD targets for The Ponds 

Objective 




on base case. 



Flow Management 



(TSS). 

Post-development storm discharges = pre-development storm 

discharges for the 1.5 year ARI event 


Groundwater near the creek is saline and 

lies as little as 1m below the soil surface 

in low-lying areas. The saline soils and 

groundwater can cause environmental 

problems and damage to urban 

infrastructure in the following ways: 

•• 

The water quality of streams can be 

detrimentally affected if salts from 

saline groundwater and soils leach into 

the waterway. 

•• 

If saline soils are exposed they become 

highly erosive and dispersible and 

support very little vegetation. 

•• 

A rising groundwater table may kill 

plants if the water table reaches the 

root zone, leaving the surface soil 

unprotected and susceptible to further 

erosion. 

•• 

Salts that come into contact with urban 

infrastructure may cause the breakdown 

of cement and bricks, and promote 

the rusting of steel. Consequently all 

earthworks near the creek must not 

disturb the saline subsoil and must 

treat any exposed subsoil, and must not 

cause an increase in the height of the 

groundwater table. 

To avoid impacting or exacerbating the 

effects of salinity, the stormwater treatment 

measures used must be those that do not 

rely on infiltration of stormwater into the 

ground, where percolating stormwater 

may mobilise salts or raise the water table. 

It was not appropriate to use stormwater 

treatment wetlands in many locations. 

Too little water was available to sustain 

stormwater wetlands because of the high 

rates of evaporation in the region and the 

small size of the urban catchments. 


The Ponds Boulevard 


Masterplan 

To Hambledon Road 

Ridgeline Drive 

To Hambledon Road 

Schofields Road 

Seconds Ponds Creek 

The Ponds Boulevard 

John Palmer 

Primary School 

YOU ARE 

HERE 

Riverbank Drive 

Proposed 

Primary School 

Proposed 

Council Park 

Fyfe Road 

Stanhope Parkway 

Conrad Road 

Belbourne Road 

Fyfe Road 

Keirle Road 

To Windsor Road 

To Sunnyholt Road 

Please note that the above masterplan is an artist’s impression and is to be used as a guide only. Whilst every care is taken to ensure that this plan is 

correct, it is indicative only and subject to change without notice. Purchasers must rely on their own enquires and the Contract for Sale. 

LAN0282_MasterPlan_brochure_V2.indd 3-4 

Figure 4 - Masterplan of The Ponds development showing the 

proximity of development to Second Ponds Creek 

28/10/08 12:24:28 PM 

3.3 Opportunities for WSUD 

Large areas within the developments 

have been devoted to public open space, 

providing adequate area for stormwater 

treatment measures as shown in the 

masterplan and urban layout (Figure 4). 

Due to the elongated nature of the site 

along the creek, many urban catchments 

were small, and the corresponding 

area required for stormwater treatment 

devices was small. Stormwater treatment 

measures could be located along the edge 

of the watercourse making the connection 

to the stream relatively simple. 

Second Ponds Creek is highly degraded 

and required substantial reshaping and 

rehabilitation works, making it easier to 

incorporate the connection between 

stormwater treatment devices and the 

stream. 



WSUD elements have been designed to 

meet the current best practice objectives 

in pollutant load reduction and flow 

targets set by Landcom (Table 2). 

3.4.1 Water conservation 

The water conservation targets have been 

met by the supply of reclaimed wastewater 

from the Rouse Hill Recycled Water Plant. 

The reclaimed water is used for toilets and 

irrigation and equates to a BASIX score of 

approximately 50 for houses within The 

Ponds. 



Figure 5 - A street tree 

bioretention system 

Figure 6 - A vegetated swale designed to convey runoff to Second Ponds Creek. Road runoff 

from all small flows is directed towards the filter media, where pollutants are removed. 

3.4.2 Pollution control 

Stormwater pollution control is achieved 

by using a combination of bioretention 

systems (Figure 5) and vegetated swales 

(Figure 6). Swales convey runoff and are 

effective in removing particulate pollutants 

from stormwater, while bioretention 

systems are effective for removing 

dissolved pollutants. Bioretention systems 

have been configured as small systems to 

support street trees and treat road runoff, 

and as large basins that treat runoff from 

many lots (Figure 7). The bioretention 

basins have been located in the public 

open space alongside Second Ponds 

Creek. 

Stormwater treatment wetlands were 

unsuitable for this site. It is difficult to 

maintain a permanent wetland water 

body in many locations at The Ponds due 

to the small catchment sizes and high 

evaporation rates. Bioretention systems 

were also preferred to wetlands as water 

treatment devices because the presence 

of water in bioretention systems is 

ephemeral – the ephemerality decreases 

the risk that stormwater will infiltrate into 

the ground and mobilise the salts in the 

subsoil layers. The hydraulic conductivity 

of the sandy loam bioretention filter media 

is significantly higher than the surrounding 

soils. Therefore the flow path of infiltrated 

stormwater in the bioretention system 

is well defined and exfiltration to the 

surrounding soils minimised. To avoid any 

impacts of infiltrating water on the water 

table of Second Ponds Creek, the bases 

of the bioretention systems will be lined 

to eliminate any likelihood of groundwater 

recharge by stormwater infiltration. 

3.4.3 Flow management 

To stabilise and protect the channel form 

of Second Ponds Creek, flood retarding 

basins were constructed to attenuate 

frequent small flood events to the intensity 

of pre-development floods. To make the 

most efficiently use of the flood detention 

areas, bioretention systems have been 

incorporated into the floor of these basins 

thus combining both flow and pollution 

control in the same device (Figure 7). 



Figure 7 - A flood retarding basin that incorporates a 

bioretention system on the floor of the basin 

Figure 8 - Revegetation of Seconds Ponds Creek has been very 

successful. Good growth and plant survival has created a 

stable channel form. 

3.4.4 Stream rehabilitation 

Second Ponds Creek was extensively 

rehabilitated prior to the development 

of the urban areas (Figure 8). The 

stream rehabilitation works were 

directed at elimination of exposure of 

the B-horizon soil layer and rehabilitation 

of the geomorphic form of the existing 

watercourse. Natural stream templates 

in the area were used as a guide to how 

vegetation can stabilise and mitigate bank 

erosion. The landscape strategy for the 

rehabilitation of Second Ponds Creek was 

guided by these features. Key features 

of the proposed waterway rehabilitation 

works include: 

•• 

The construction of regular rock bars to 

stabilise the bed profile of the creek. 

•• 

The provision of a low flow channel with 

sufficient capacity to convey flows up 

to the 3-month Average Recurrence 

Interval (ARI) event. 

•• 

The provision of a vegetated 

watercourse (mid-flow channel) with 

sufficient capacity to convey flows up to 

the 2 year ARI event. 

•• 

The formation of flatter bank slopes 

with adequate coverage of A-Horizon 

soil layer. 

•• 

The planting of the mid-flow channel 

with appropriate vegetation with 

sufficient density to enable adequate 

bank erosion protection in addition 

to its habitat and other riparian zone 

function attributes. 

3.4.5 Construction in a saline 

environment 

WSUD at The Ponds required a very 

site-specific solution. One of the keys 

to successful WSUD in a salinity hazard 

area was involving the geo-technical 

specialists in the planning stages. A 

thorough site investigation identified the 

site hazards and formed the basis of the 

salinity management plan for the site. The 

salinity management plan was updated 

as required as new information became 

available and as the project progressed. 

Geotechnical specialists supervised the 

earthworks to ensure that the salinity 

hazard was managed at all times. This 

well informed approach ensured that 

contractors could cost work realistically 

and the earthworks were successful and 

stable. The result was good plant growth 

throughout the riparian corridor and a 

durable, well-functioning riparian zone. 



Figure 9 - A flood retarding basin that incorporates a bioretention system on the floor of the basin. The 

basin will be properly vegetated when earthworks in the catchment are completed 

To ensure that bioretention systems 

function properly it is important to 

exclude the effects of salinity in order to 

promote good plant growth, and good 

plant growth is important to providing 

good water quality treatment. 

Some ornamental ponds have been built 

throughout the development to improve 

the amenity of the public open spaces. 

Since it was important to avoid exposure 

of sodic subsoils, and to prevent 

stormwater from interacting with the 

subsoils or saline groundwater, the basins 

for the ornamental ponds were lined with 

suitable non-sodic soils taken from other 

areas of the site. The soil liner used was 

suitably impermeable so that water from 

these ponds did not infiltrate into the 

subsurface soils below. The soil layer also 

acted to cap any sodic subsoils that may 

have been exposed during earthworks 

so that these areas could be stabilised 

and vegetated and thus protected from 

weathering and erosion. 

Bioretention systems are susceptible 

to clogging and require protection 

from sediment. Since high sediment 

loads are generated from developing 

catchments, the construction of the 

bioretention systems will not be fully 

completed until the construction work 

of the roads, infrastructure and housing 

lots has been finished. All of the 

earthworks for the bioretention systems 

have been completed, the media is in 

place and grasses have grown across the 

filter media surface. The batters will be 

planted to enhance the visual amenity 

of the bioretention systems. Once the 

earthworks in each of the bioretention 

system catchments have been 

completed, the sediment that has built up 

on the bioretention media surface will be 

removed and the media will be properly 

vegetated (Figure 9). 



Proposed water quality treatment within the public domain | The Ponds 

The parks and 

green spaces 

throughout the site 

were constructed 

and established 

early to make the 

development 

attractive to buyers. 

3.5 WSUD Outcomes 

The focus on the waterway at the centre of 

the community has provided the impetus 

for extensive rehabilitation of Second 

Ponds Creek, and WSUD was incorporated 

to protect the ecosystem health of the 

creek. The parks and green spaces 

throughout the site were constructed and 

established early to make the development 

more attractive. The riparian corridor was 

densely vegetated to quickly stabilise 

the channel form and create a visible 

vegetated corridor throughout the site. 

The revegetation of the stream has been 

very successful and most of the planting 

has survived and grown well. As a result, 

not only was the channel form protected 

but the landscaping for the site was visible 

to buyers when the lots were released for 

sale. Having well-developed landscape 

features has contributed to the higher 

desirability of the lots for sale, which was 

reflected in good sales records for The 

Ponds. 


The development at The Ponds is an 

example of WSUD being successfully and 

consistently applied over a large area. 

This was made effective by adapting the 

WSUD strategy to the site constraints 

and accommodating the salinity hazard, 

the topography, and accounting for high 

evaporation rates and relatively small 

catchment sizes. The success of this 

strategy was facilitated by the integration 

of stormwater treatment systems within 

the public open space. The location 

of stormwater treatment systems was 

complementary with the landscape 

theme that highlighted the presence 

of the stream through the centre of the 

development. The bioretention systems 

and swales will sustain and protect the 

ecological health of Second Ponds Creek, 

thereby adding to the value of the stream 

and the associated green spaces that 

attract residents to the area. 



4 | WSUD in the Implementation Phase - Prince Henry 

Bioswale integrated into public space | Prince Henry 

Prince Henry is a 

medium density 

development with 

approximately 

900 dwellings to 

be provided on 

the 34 hectare 

developable area. 

The Prince Henry development at Little 

Bay is a residential development in the 

eastern suburbs of Sydney. The total site 

area is approximately 84 hectares of which 

34 hectares is being redeveloped into a 

mix of residential and community uses. 

The remainder of the site is occupied 

by the Coast Golf Course and Eastern 

Suburbs Banksia Scrub conservation area. 

Prince Henry is a medium density 

development with approximately 900 

dwellings to be provided on the 34 hectare 

developable area. The dwellings include: 

•• 

Apartment buildings, from 2 to 6 stories 

high, which provide 641 dwellings 

•• 

120 single dwellings including detached 

dwellings, courtyard houses and 

terraces. 

•• 

114 apartments for over 55’s 

•• 

A 119-person aged care facility 

There are also a number of community 

buildings, including a community centre, 

chapel and small scale commercial and 

retail space. 

The site is of Aboriginal and European 

heritage significance. The development 

was formerly the site of the first public 

hospital administered by the government 

and contains significant heritage items, 

including 19 buildings which are listed on 

the NSW State Heritage Register. The site 

also comprises remnant bushland of state 

and national significance, a geological 

site, wetlands, ponds, a creek and Little 

Bay beach. 

Importantly for the WSUD strategy, the site 

has an existing golf course downstream 

of the development. The golf course 

currently uses one main storage pond and 

another secondary pond to irrigate the 

golf course when there is sufficient water 

available. The golf course is currently 

undergoing an expansion of its irrigation 

system whereby its irrigation demand will 

double. 




The WSUD objectives for the site 

were developed during the 

Masterplanning process in 2003 and 

are outlined in Table 3. 

These targets were complemented by the 

following objectives: 

•• 

Promotion of stormwater reuse to 

reduce the demand on potable water 

supply 

•• 

Ensure that no existing stormwater 

reuse is disadvantaged because of the 

development 

•• 

Restoration of the riparian zones and 

creek lines of two waterways on site, 

identified as the Central and Southern 

Watercourses. 

•• 

Use less water for landscaping through 

careful design and selection of plants 

and irrigation methods suitable to the 

soil type and location 

Table 3 | Landcom’s WSUD Targets for Prince Henry 

Objective 




on base case. 





(TSS). 

Heritage, flora 

and fauna, and 

the surrounding 

land uses were the 

most important 

constraints on the 

development. 


There are a number of significant 

constraints for the re-development of 

Prince Henry Hospital in general and 

a number of minor constraints on the 

WSUD strategy. Heritage, flora and 

fauna, and the surrounding land uses 

were the most important constraints on 

the development. The heritage status of 

the channel in the Southern Watercourse 

in particular dictates that the Southern 

Watercourse could not be restored to a 

natural waterway as in the original WSUD 

strategy. The heritage road infrastructure 

has had important implications for the 

location and the design of the storage 

ponds. 

The site also has important bushland, 

archaeological remains and an important 

geological site. The bushland includes 

a significant stand of Eastern Suburbs 

Banksia Scrub, an endangered ecological 

community. The archaeological remains 

on the site include both Aboriginal 

and European uses. These constraints 

have had important implications for the 

location and design of the stormwater 

quality treatment devices. 

The existing and surrounding land 

use is also a significant constraint on 

the development. A buffer is required 

between the golf course and the 

residential development for safety 

reasons. The existing waterways and their 

riparian zones are currently situated on the 

golf course and have therefore provided 

significant constraints on the waterway 

restoration and riparian zones. 

The site’s significant heritage value 

creates a unique opportunity to blend 

WSUD elements within a heritage garden 

context. The material selection and 

design, species selection and landscaping 

design can conform to the heritage 

requirements. 



Wetland | Prince Henry 

4.3 Opportunities for WSUD 

A better outcome 

for the catchment 

could be achieved 

by maximising 

the harvesting 

of stormwater 

runoff from the 

development into 

the existing golf 

course storage. 

The WSUD strategy for the site has three 

major components, namely: 

•• 

Water quality treatment 

•• 

Water conservation and reuse strategy 

•• 

Riparian restoration 

The key focus in the WSUD strategy for the 

site was to ensure that for optimal WSUD 

outcomes a whole of catchment approach 

was undertaken. 

4.3.1 Water conservation and reuse 

The second component of the WSUD 

strategy was a water conservation and 

reuse strategy. The reuse strategy was 

developed around stormwater harvesting 

and reuse. 

The original strategy recommended that 

the most optimal water conservation 

outcomes for the catchment as a whole. 

The additional demand of the open 

space watering in the development was 

small (21 megalitres(ML)/yr) compared 

to the demand of the golf course (125 

ML/yr). Water balance modelling for the 

development and the golf course showed 

that large scale harvesting of rainwater 

or stormwater within the development 

would reduce the effectiveness of 

existing stormwater reuse at the golf 

course. Only minor decreases in potable 

water consumption would occur overall, 

as the savings in potable water for the 

development would be offset by the 

increased potable water usage by the 

golf course. Thus rainwater tanks for 

the development were not an optimal 

investment in infrastructure. 

A better outcome for the catchment 

could be achieved by maximising the 

harvesting of stormwater runoff from the 

development into the existing golf course 

storages, where it would improve the 

effectiveness of the existing reuse system. 

This would mean avoiding rainwater tanks 

within the development, and utilising the 

existing storages and infrastructure that 

had been developed by the golf course 

4.3.2 Water quality treatment 

To meet the objective of best practice 

stormwater treatment a water quality 

treatment strategy was developed for the 

site. The water quality treatment strategy 

included a treatment train to ensure that 

any stormwater discharging from the 

development site met the best practice 

objectives. 



Bioswale | Prince Henry 

The stormwater treatment train was 

developed to meet the suspended 

solids, phosphorus and nitrogen load 

reduction targets, as well as reductions 

in heavy metals, hydrocarbons and gross 

pollutants. The treatment train included: 

•• 

Sediment Control Pits on individual 

properties. The development is located 

on sandy soils which are susceptible 

to high shock loads of wind blown 

sediment and erosion by surface water 

runoff. The sediment control pits are 

effectively small sediment basins and 

are an important first barrier in reducing 

the loads of coarse sediment from the 

private lots. 

•• 

Gross Pollutant Traps installed at the 

inlet to the bioretention systems to 

prevent the deposition of litter into 

these systems. 

•• 

Buffer strips which separate the 

impervious surfaces and the drainage 

system. The buffer strips filter sediments 

and coarse pollutants entrained in the 

runoff. Buffer strips are also useful in 

providing a detention role to reduce 

peak flows of small stormwater events. 

•• 

Bioretention Systems incorporated into 

the public open space areas, including 

parks and the buffer zone between 

the golf course and the development. 

Stormwater is treated via infiltration 

though soil media in the base of these 

bioretention systems and conveyed 

downstream via perforated pipes. 

High flows are retarded within each of 

these systems as a result of the surface 

storages provided in these systems. 

•• 

Heavily vegetated swale system to 

convey the water from the development 

to the golf course. This swale system 

would also involve restoration of the 

waterways and the original concept 

included replacement of the current 

open brick channel in the Southern 

Watercourse with a naturalised 

waterway to improve the waterway’s 

ecological and aesthetic value. 



Figure 10 - Swale bioretention system 

Figure 11 - Bioretention basin including detention storage 



During the Development Application 

(DA) and Construction phases of the 

development various modifications to the 

WSUD strategy were made. The changes 

to the strategy occurred to meet the needs 

and requirements of Landcom, Council, the 

project design team, State Government 

Departments, and the golf course. 

A number of relatively minor modifications 

were made to the designs of the stormwater 

quality strategy. These changes included: 

•• 

Provision of additional bioretention 

systems due to the changes in the 

development land uses and provision 

of additional single dwellings. 

•• 

Modifications to the bioretention 

system in the northwest of the site 

to provide for stormwater storage 

detention. This meant that the 

bioretention system was much deeper 

than originally intended and changes 

to the batter slopes and shape of the 

bioretention were required. 

•• 

Minor modifications of the bioretention 

shape and format to conform with the 

competing needs of the buffer zone 

between the development and the golf 

course. 

Some images of completed bioretention 

systems are shown in Figures 10 and 11. 

The full intent of the stormwater quality 

strategy has been incorporated into the 

development during its implementation, 

despite the minor modifications. 

This is not the case with the stormwater 

harvesting and reuse strategy. The original 

strategy has been modified substantially 

and in the process the full intent of the 

strategy has not been met. Council 

were unable to waive their mandatory 

rainwater tank policy for single dwellings, 

but exempted apartment dwellings from 

mandatory rainwater harvesting. 

Furthermore the original strategy outlined 

sharing of the increased stormwater 

resource between the development 

and the golf course as the optimal 

water conservation outcome. However 

in negotiations between Council and 

Landcom it was agreed that the public 

open space at the development required 

its own separate high reliability storage 

pond. This would be built on the golf 

course and integrated into the golf course 

design as an added playing feature of 

the course. The Prince Henry dedicated 



Golf course stormwater storage | Prince Henry 

storage pond would be upstream of 

the main storage pond of the Coast 

Golf Course. This meant that the golf 

course would have reduced stormwater 

flows to its storage ponds. While the 

additional storage increased the amount 

of stormwater that could be harvested, 

the harvested stormwater would not be 

used optimally between the two users 

as water would not be shared between 

the two users. Finally as compensation 

to the golf course Landcom agreed to 

construct an additional storage pond for 

the golf course. This storage pond had 

minimal catchment and was constructed 

based on observational evidence from 

the golf course maintenance staff that it 

was at the interception point for shallow 

groundwater flows. The success of this 

storage pond will depend predominantly 

on its use as an offline storage to pump 

water from the main storage pond after 

rainfall events. 

The Central Watercourse restoration 

has been completed in keeping with the 

original intent of the WSUD strategy. 

Rock weirs were used in the channel and 

riparian plantings were established on the 

banks. 

The Southern Watercourse restoration 

has been significantly modified from 

the original design intent. The bricklined 

drainage channel is considered to 

have significant heritage value due to 

its visibility, condition and age. Thus the 

waterway could not be naturalised. 




WSUD was also 

incorporated into 

the design of open 

spaces. 

4.5.1 Water quality treatment 

Water quality treatment including gross 

pollutant traps, bioretention systems and 

buffer strips was modelled in MUSIC. The 

modelling showed that the WSUD strategy 

will meet the pollutant load reduction 

targets of 80% of total suspended solids, 

45% of total phosphorus and 45% of 

total nitrogen for the three watercourses 

draining to the east towards the golf 

course and Little Bay. A small area which 

drains to the west will have treatment that 

meets phosphorus and nitrogen targets 

but suspended solids reduction will only 

be around 65%. 


The dwellings within the development will 

achieve a minimum of 40% reduction in 

mains water use compared to a benchmark 

dwelling in the same area. The reduction 

for apartment buildings with more than 

30 apartments will achieve a minimum of 

60% reduction in mains water use. These 

reductions will be achieved through the 

use of demand management measures 

and water reuse. 

The demand management measures for 

all dwellings include: 

•• 

Water efficient 3-star fittings for 

showers and taps, and 6/3L dual flush 

toilets. 

•• 

Eco-packages for new residents where 

information and discounts will be 

offered on the purchase of efficient 

appliances such as washing machines 

and dishwashers. 

•• 

Water efficient and drought tolerant 

species for 50% of the soft landscape 

areas 

In addition, all single dwellings will have 

rainwater tanks - 2kL rainwater tanks for 

smaller dwellings and 3kL tanks for larger 

dwellings – the stored rainwater used 

for toilet flushing and private landscape 

irrigation. 

As rainwater harvesting was not part 

of the WSUD strategy for multi-unit 

buildings, multi-unit buildings with more 

than 30 apartments (i.e. 10 buildings 

with 472 apartments in total) incorporate 

greywater treatment within the building. 

The greywater will be used for toilet 

flushing, private landscape irrigation and 

car wash bays. 

WSUD was also incorporated into the 

design of open spaces. There are three 

major parks within the development, all 

of which will receive 95% of their water 

demands from harvested stormwater. The 

open space will also incorporate the best 

designs in irrigation technology including 

automatic irrigation systems, with in built 

rain and wind gauges to control irrigation 

timing. The open space will also have 

drip irrigation in the garden beds and 

for the trees. Turf within the parks will be 

irrigated by pop up sprinklers. The parks 

also reduce their demand by having areas 

of native plantings within the landscaped 

areas. The ability to use drought tolerant 

species has been limited by the need for 

the landscape to reflect the European 

heritage of the buildings with high water 

use plantings, including large areas of turf 

around heritage buildings and the central 

park. 



Prince Henry Hospital WSUD Opportunities 

Integration of WSUD measures into 

public open space 

Proposed bioretention systems can 

be incorporated in public open space 

in the proposed development, which 

includes three major parks 

Council rainwater tank policy 

The local Council’s rainwater tank 

policy requires all new dwellings to 

include rainwater tanks. This will be 

applied to proposed single dwellings 

Neighbouring golf course 

The neighbouring golf course uses 

significant amounts of water for 

irrigation. Stormwater storage for the 

site will still be located on the golf 

course, where it will be a feature 

Chifley 

Little Bay 

Anzac Pde 

Little Bay 

Total Developable Area 

34.43 HA 

The Coast 

Golf Course 

St Michaels 

Golf Course 

Irrigation strategy 

Three parks which require irrigation will 

utilise treated stormwater. Wind and 

rain gauges will be used to control an 

automated irrigation system so that the 

use of water is optimised. Low-water use 

species will be used where appropriate 

Sandy soils 

The coastal location 

means that sediment 

loads tend to be high. 

Sediment control pits 

on individual properties 

will address this issue 

Water efficiency in 

dwellings 

Residents will be 

encouraged to use 

efficient appliances and 

efficient fittings will be 

installed 

Waterway 

rehabilitation 

Existing modified 

channels on the site 

will be restored as far 

as possible to achieve 

higher ecosystem 

values 

Source - Google Earth 



5 | Operation and Maintenance of WSUD 

treatment measures - Victoria Park 

Figure 12 - Aerial photograph of Victoria Park site in Zetland, Sydney. 

The site boundary is indicated by the dotted line. Image: Waltcorp 

The site was 

formerly known as 

Waterloo swamp, 

which by 1908 had 

been drained and 

converted into a 

race track. 

This case study reports on the operation 

and maintenance of the WSUD treatment 

measures at Victoria Park that have been in 

place for over eight years. It highlights the 

innovative approach taken to overcome 

many of the site constraints, and the 

longevity of the treatment devices. 

Victoria Park represents one of the earliest 

and most durable applications of WSUD 

in Sydney. The Victoria Park development 

is in Zetland, 4 km southeast of the Sydney 

CBD (Figure 12). The total site area is 25.2 

ha. Approximately 1800 dwellings will be 

built consisting of 92% apartments and 8% 

terrace housing for a population of 3000 

residents. Public open space occupies 

15% or 3.7 ha of the site, commercial, retail 

and community uses occupy 4.3 ha. 

The site was formerly known as Waterloo 

swamp, which by 1908 had been drained 

and converted into a race track. After 

World War II the racetrack became an 

industrial site and was used for a car 

manufacturing plant for the British motor 

Co. From 1974 to 1997 it was then used as 

a naval supply centre. 



Victoria Park 


To reduce dependency on potable water 

supplies, opportunities were identified for 

water conservation and re-use. The WSUD 

strategy for the site also aimed to protect 

the downstream ecosystems by: 

•• 

Removing pollutants from urban runoff 

and, 

•• 

Controlling the flow of water running 

off the site. 

As the site was planned prior to the 

establishment of Landcom’s WSUD 

strategy, specific targets were not 

established for the site. 


This low-lying inner-city site had many 

constraints to development: 

•• 

The redevelopment of this former 

industrial site required extensive land 

remediation. 

•• 

The developable area was tightly 

constrained by existing property 

boundaries and infrastructure. 

•• 

The groundwater aquifer is also quite 

shallow sitting only 1 – 2.8 m below the 

ground surface. The aquifer itself is 

complex, made up of permeable strata 

separated by impermeable layers of 

peat. 

•• 

The large areas of site set aside for 

public open space required a reliable 

source of irrigation water to be 

maintained as green spaces. 

•• 

Flood control is difficult in flat sites 

because pipes on flat grades need to 

be larger to accommodate the same 

volume as smaller pipes on steeper 

grades. Victoria Park site already 

receives runoff from Kensington 

upstream and to accommodate extra 

urban runoff from the Victoria Park site 

in stormwater drainage would need to 

be upgraded. 

•• 

The Victoria Park site was also 

required to detain large flows from the 

surrounding catchments making some 

of the site flood prone. 



Figure 13 - Bioretention swales have been buillt in the road 

median strip to remove pollutants from urban 

runoff 

5.3 Opportunities 

for WSUD 

Figure 14 - Water is directed to the bioretention 

swale from an inverted road camber and 

through kerb cuts 

Space for water 

conveyance swales 

was made available 

along the forefront 

of the residential 

towers on the site. 

Although development of the site is 

constrained in many aspects, the location 

of Victoria Park in a low landscape position 

surrounded by high density development 

also offers many opportunities: 

•• 

Flood prone areas are unsuitable for 

buildings, but the available space was 

used for the multiple purposes of water 

conveyance, water treatment, and flood 

detention. 

•• 

Flood prone areas also suitable for use 

as public open space, as well watered, 

flat open spaces provide ideal locations 

for urban parks. 

•• 

Harvesting water is easier for sites 

located in low-lying areas of catchments 

and was desirable that this potential be 

realised. Water harvesting can be used 

to meet the irrigation requirements of 

the surrounding public open space. 

•• 

Although the shallow aquifer constrains 

building through areas of the site, this 

aquifer provides both a source of water 

for the site as bore water, and as a 

storage facility that can be harnessed 

through groundwater aquifer storage 

and recovery. 

5.3.1 Overcoming site constraints 

The constraints imposed by the undersized 

stormwater infrastructure were overcome 

by conveying water along the ground 

surface. Space for water conveyance 

swales was made available along the 

forefront of the residential towers on the 

site. Tall buildings require a wider set back 

from the road to create the symmetry of 

space that makes aesthetic urban and 

landscape design. Bioretention swales 

were built on these open spaces and used 

to convey stormwater run-off. 



Figure 15 - Joynton Park: Treated urban runoff from the 

bioretention swales is reused in the water stairs 

Figure 16 - Public open spaces also function 

as flood detention basins 

The groundwater 

aquifer is 

replenished with 

stormwater run-off 

from the detention 

basins. 



5.4.1 Water quality 

Bioretention swales were built into the 

central median strips of the east-west 

roads (Figure 13). The camber of the 

road was graded towards the central 

median strip rather than towards the road 

image, to direct water to the bioretention 

swale (Figure 14). Pollutants in road 

runoff removed as water flows through 

bioretention swales and the filter media. 

Perforated pipes collect treated water 

and discharge it to a water storage tank. 

This water is used in two substantial water 

features in Joynton Park - the water stairs 

(Figure 15). 


Irrigation of the public open spaces is 

sourced from the groundwater aquifer 

(Figure 17). The groundwater aquifer is in 

turn replenished with stormwater run-off 

from the detention basins. The vegetation 

used in the constructed wetlands and 

bioretention swales have been selected 

for drought and flood tolerance and 

require no irrigation. 

5.4.2 Water quantity 

To slow the rate of runoff from the site, 

and to encourage water infiltration to 

replenish the groundwater aquifer - the 

public open spaces within the site also 

function as stormwater detention basins 

(Figure 16). Overland flow is resulting 

from major storm events in excess of the 

one in 20 year annual recurrence interval 

(ARI) are conveyed by the road surfaces. 

To facilitate this, the roads throughout the 

site were carefully graded to direct runoff 

appropriately and to avoid ponding. 

Figure 17 - All water for irrigation is sourced from 

the groundwater aquifer below the 

surface 



Figure 18 - Tufted species maintain their biomass through vigorous vegetative growth 

5.5 WSUD Implementation 

and Maintenance 

The bioretention 

swales have 

functioned as 

designed through 

all rainfall events for 

several years. 

5.5.1 Establishment 

The establishment vegetation in the 

bioretention swales was very successful. 

The following vegetation was planted: 

•• 

Eucalyptus citriodora (Lemon-scented 

Gum Tree), 

•• 

Isolepis nodosa (Nobby Club-rush, a 

tufted species of sedge) 

•• 

Lomandra longifolia (Matrush, a tufted 

species of sedge) 

•• 

Poa spp. (Tussock Grass) 

There was very little mortality during the 

establishment phase for all grasses and 

sedges. There was no mortality of the 

trees. Plants were irrigated throughout 

their establishment. The death of some 

grasses was associated with the failure of 

the irrigation system that coincided with 

a six-week hot, dry spell. After six years 

the vegetation is now considered to be 

self-sufficient for water requirements. 

The biomass of the tufted species is 

maintained through vegetative regrowth 

(Figure 18). The trees of the bioretention 

swales have grown as tall or taller than the 

nearby street trees of the same species, 

and appear to be an equally good health 

(Figure 19). Water stress on the plant 

is partially relieved by maintaining an 

adequate surface mulch of bark chips to 

retain soil moisture (visible in Figure 14). 

The bioretention swales have functioned 

as designed through all rainfall events for 

several years. The media has retained 

its permeability and continues to allow 

water to drain through the bioretention 

swales appropriately. There have been no 

instances of water remaining ponded for 

longer than the design period (less than 

24 hours). The swale plants have survived 

all the wet periods, usually responding to 

the wet conditions with a flush of growth. 

The woodchip mulch of the swales has 

also been stable; there were no instances 

of the mulch migrating from the swales to 

the street during periods of high rainfall 

(Figure 20). 

The experience at Victoria Park has 

demonstrated that WSUD elements can 

be built with few ongoing maintenance 

requirements, and can be maintained at 

a cost that is comparable to many public 

landscapes. 



Figure 19 - The trees of the bioretention 

swales (left) have grown as tall 

as the street trees (right) and 

are in good health 

Figure 20 - The woodchip mulch is stable 

even during ponding from 

urban runoff 

The cost of 

maintaining the 

WSUD features 

is comparable 

to landscaping 

costs for standard 

landscape features 

such as swales and 

street trees. 

5.2.2 Maintenance 

bioretention swales 

Maintenance of the trees in the 

bioretention swales involves the practices 

normal for street trees; branches are 

trimmed and leaves and bark must be 

swept. Leaves and bark generated by the 

swale trees is put back into the swale to 

act as mulch. The grasses and sedges 

are periodically trimmed. These plants 

die back during dry periods and the dead 

material is removed to reduce the risk that 

may pose as a fire hazard. 

The maintenance of the vegetated 

WSUD features has been integrated into 

the landscape maintenance program 

for all of the public open spaces of the 

Victoria Park site. The cost of maintaining 

the WSUD features is comparable to 

landscaping costs for standard landscape 

features such as swales and street trees. 

The maintenance does not require any 

specialised equipment. 

Initially, the contractors were concerned 

about maintaining swales in the 

high-density urban environment. Their 

concerns centred on the accumulation of 

litter and the possibility of needle stick 

injuries from unseen debris hidden in 

the tussocks of the grasses and sedges. 

Fortunately these concerns have not been 

realised. Very little litter has accumulated 

in the swales and no needles have 

been found yet. The low maintenance 

requirements of the swales is attributed 

to: 

•• 

The use of hardy plant species 

appropriate to the growth environment, 

resulting in good vegetation growth 

(Figure 18) 

•• 

The high value that the residents place 

on the bioretention swales, resulting in 

lower litter loads and few instances of 

plants disturbances and trampling 



Figure 21 - The water stairs reuse harvested stormwater 

The Victoria Park 

development 

dispels fears 

that bioretention 

systems may 

create onerous 

maintenance 

obligations for the 

land manager. 


Only small volumes of water have been 

available for reuse. The stormwater from 

the swales is captured and stored for reuse 

in the water stairs - two prominent features 

of Joynton Park (Figure 21). However, a 

high proportion of runoff is held within the 

filter media and evaporated or transpired 

by the vegetation. Consequently, treated 

stormwater only becomes available for 

reuse after sustained rain or large rainfall 

events. 


WSUD is best created by forming site 

specific solutions that respond to the 

local environment. WSUD at Victoria 

Park was achieved by working around 

the site constraints and making the 

most of the opportunities that the site 

presented. The development illustrates 

that by working with the site topography 

and environment, well built bioretention 

swales can filter urban runoff and help 

protect downstream aquatic ecosystems 

in addition to creating green spaces of 

long-lasting amenity. The success of 

these swales was due to the selection 

of appropriate hardy plants and the 

creation of landscape elements highly 

valued by the residents. The Victoria 

Park development dispels fears that 

bioretention systems may create onerous 

maintenance obligations for the land 

manager. 




Level 2, 330 Church Street 

Parramatta NSW 2150 

PO Box 237 Parramatta NSW 2124 

DX 28448 Parramatta 

Telephone 61 2 9841 8600 

Facsimile 61 2 9841 8688 

Printed May 2009 on recycled paper.

Book 3 | Case Studies - WSUD

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