CSIRO LAND and WATER. Characterisation of the Perth North-East Corridor Study Area

Transcription

1 CSIRO LAND and WATER Characterisation of the Perth North-East Corridor Study Area CSIRO Urban Water Program S.M. Cuddy, S. Maheepala, V.G. Mitchell and R.J. Shipton Consultancy Report CSIRO Land and Water, Canberra Laboratory June 2000

2 Characterisation of the Perth North-East Corridor Study Area CSIRO Urban Water Program S.M. Cuddy 1, S. Maheepala 2, V.G. Mitchell 2 and R.J. Shipton 2 Publication Details CSIRO Land and Water Consultancy Report June 2000 CSIRO Land and Water Canberra Laboratory GPO Box 1666 Canberra ACT Australia Publication Enquiries Publications Officer CSIRO Land and Water Canberra Laboratory GPO Box 1666 Canberra ACT 2601 ph: (02) publications@cbr.clw.csiro.au 1 CSIRO Land and Water, Canberra 2 CSIRO Building, Construction and Engineering, Highett, Melbourne

3 CSIRO Urban Water Program This report is one of the outcomes of the feasibility stage of the CSIRO s Urban Water Program. The Urban Water Program is a multi-divisional project, sponsored by CSIRO s Executive, involving the Divisions of Building, Construction and Engineering, Land and Water and Molecular Science. The vision for the Urban Water Program is in the face of economic, social and climatic change, enable Australia s urban water systems to improve services to the community and improve economic performance while achieving ecological sustainability. This report stands alone, but information included within it has been used within the wider Urban Water Program. Readers wishing to obtain more information about the Urban Water Program could contact Andrew Speers on or at andrew.speers@dbce.csiro.au. The Urban Water Program website can be visited at CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page i

4 ACKNOWLEDGMENTS AUTHORS The four authors were the principal data gatherers and interpreters for the characterisation described in this report. Grace Mitchell, Shiroma Maheepala and Bob Shipton collected much of the primary data. Grace and Shiroma described the estates and clusters and carried out the enormous amount of processing required to derive water usage descriptions for those clusters. Bob pulled together all the population projection and flow data. Susan Cuddy performed the GIS work to provide land use and population distribution and predictions and digitised the potable, waste and storm water infrastructures. Shiroma derived the abstracted views of the water supply infrastructure for modelling through GIS processing. Susan Cuddy prepared the first draft of this report, based on internal working papers written by the authors to document their data preparation during the Urban Water Program feasibility study. DATA AND MODEL PROVIDERS All agencies that were approached to provide data, or assist with data collection and interpretation, were co-operative and extremely helpful. We thank them for their contribution and good will. In particular, Water Corporation Western Australia, Ministry for Planning Western Australia, Water and Rivers Commission, Agriculture Western Australia and the Bureau of Meteorology contributed significant resources to preparing the data used in the project. CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page ii

5 Acknowledgments Table of Contents Authors... ii Data and Model Providers... ii Introduction 1 Background... 1 Report Coverage... 1 Format of Report... 1 Companion Reports... 2 Physical Description 3 Estates... 4 Climate... 5 Topography... 6 Soils... 6 Hydrology... 7 Wetlands... 8 Population... 8 Year 199x... 8 Year Land Use... 9 Data Sources... 9 Year 199x... 9 Year Characterisation of Physical Description 11 Spatial Disaggregation...11 Estates, Clusters and Unit Blocks Nodes Topography...11 Elevation Depth to Groundwater Surface Material Soils...12 Land Use Profiles...12 Water Systems 17 Potable Water...17 Data Sources Water Sources Pipes Pumping Stations Waste Water...19 Data Sources Waste Water Treatment Pipes...20 Pumping Stations Storm Water...21 Data Sources Year 199x Year Characterisation of Water Systems 23 Potable Water...23 Water Supply...23 ii CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page iii

6 Pipes...23 Logical Network...24 Physical Network...24 References 26 Source UWP Working Papers...27 Appendix 1 - Summaries of Estate and Cluster Compositions 28 Appendix 2 - GIS References and Processing 34 List of Tables Table 1, Estates of the study area... 5 Table 2, Average temperature and rainfall in Perth and the study area... 5 Table 3, Climate Statistics for elevated CO 2 series, compared to current... 6 Table 4, Soil types in the Estates... 7 Table 5, Populations within estates for Years 199x and Table 6, Main land use categories... 9 Table 7, Land uses (in ha) in Estates for Year 199x Table 8, Land use areas (ha) within Estates for Year Table 9, Final Land Use Classification used for Modelling Table 10, Cluster Identification Number for Year 199x Table 11, Cluster Identification Number for Year Table 12, (Demand) Node Identification for Year 199x Table 13, Changes to (Demand) Node Identification for Year Table 14, Material Type assigned to proposed wastewater pipes...20 Table 15, Stormwater Pipes - Dimensions, Total Length and Average Year of Installation Table 16, Potable Water Pipe Types...24 Table 18, Summary of estate and cluster composition for Year 199x...28 Table 19, Summary of estate and cluster composition for Year List of Figures Figure 1, Location map of study area... 3 Figure 2, Topographic map of study area... 4 Figure 3, Map of study area estates... 5 Figure 4, Rainfall and evaporation sequences for elevated CO 2 series... 6 Figure 5, Map of main streams in the study area... 8 Figure 6, Map of potable water network Figure 7, Map of waste water network Figure 8, Map of storm water network Figure 9, Schematic diagram of the potable water supply system...23 Figure 10, Water Supply Physical Network in Bullsbrook Estate...24 Figure 11, Water Supply Physical Network in Vines, Ellenbrook, Upper Swan and Henley Brook Estates...25 Figure 12, Water Supply Physical Network in Herne Hill, West Swan, Middle Swan, Caversham, Midland and Guilford Estates...25 CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page iv

7 INTRODUCTION BACKGROUND The purpose of the Urban Water Program was to identify and analyse alternative configurations for the delivery and distribution of water within an urban environment. A case study approach was adopted to provide a framework for describing these configurations and to provide data for the models used to analyse the configurations. These models required a sufficient description of the study area to model the hydrology and hydraulics of the urban water system and infrastructure at both local and regional scales. REPORT COVERAGE The purpose of this report is to describe the data used and its characterisation for modelling. A great deal of other data were collected to describe the technologies and costings of the infrastructure, the characterisation of urban water flows and usage, and the water quality modelling. While much of these data were used by the models, they are described elsewhere. This report concentrates on the physical characterisation of the study area, and the layouts of the infrastructure and describes: spatial disaggregation (into estates) topography climate soils hydrology population land use potable water supply infrastructure waste water infrastructure storm water infrastructure. The study area has been characterised for two time periods. The 'base case', referred to as Year 199x, describes the 'current' state of the study area. Note that the notion of 'current' reflects a range of collection periods for the data, from the 1980s (paper maps of the stormwater infrastructure) to The 'Year 2020' is a hypothetical state of the study area and combines data on future land use zoning, population trends, and infrastructure upgrade proposals. The reader must appreciate that an accurate characterisation of the study area was not required for the project. Rather the purpose of the study area was to provide a realistic case study for exploring alternative urban water systems scenarios. FORMAT OF REPORT The report has four major sections: physical description of the study area characterisation of the study area for modelling description of the water systems, and characterisation of the water systems for modelling. The first section gives a broad overview of the physical and urban characteristics of the study area. The following section then describes how these characteristics were mapped for the modelling work. The layout and materials for the water systems are described in the third section. The fourth section describes the abstraction of the potable water system. While the modelling framework implemented is capable of dealing CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page 1

8 with an integrated network of potable, storm and waste water systems, only the potable system was characterised for modelling within the feasibility study. COMPANION REPORTS This report is one of six technical reports supporting the final report which describes the modelling work carried out within the feasibility phase of the CSIRO Urban Water Program. The full suite of reports is as follows: Final Report on the Application and Refinement of Assessment Tools for the CSIRO Urban Water Program Feasibility Study (Zoppou et al. 2000) Integrated Water Resource Model - Methodology, Implementation and Application (Maheepala et al. 2000a) Tool for Assessing Water Systems (TAWS) - Methodology (Maheepala et al. 2000b) Tool for Assessing Water Systems (TAWS) - Design, Implementation and Data Specification (Maheepala et al. 2000c) The Scenario Manager - Functionality and Implementation (Coleman et al. 2000) Contaminant Balance component of UVQ Model - Technical Specification (Farley 2000). Reports directly relevant to this report, which are available through other UWP contracts, are: Urban Water Balance Modelling (Mitchell and Maheepala 1999) Input Data for Water Balance Modelling. (Mitchell 1999) Hydrometeorological and Population Data for the Study Area (Shipton 1999). CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page 2

9 PHYSICAL DESCRIPTION The criteria set for selecting the study area were (Speers, 1998): a catchment containing developed areas and potential for greenfields development less than 100,000 equivalent population a single sewage catchment. Figure 1, Location map of study area Study area Perth A study area of about 422 square kilometres was selected in the North-East Corridor of the metropolitan region of Perth, Western Australia (see Figure 1). The study area is situated within the Shires of Swan and Mundaring and stretches from Guilford and Midland in the south to the Metropolitan Region Scheme boundary in the north. The southern boundary of the study area is about 15 kilometres from the centre of Perth and the northern boundary is about 40 kilometres. The main localities included in the study area are Midland, Guilford, Swan Valley, Ellenbrook and Bullsbrook. Figure 2 shows the topographic details of the study area. About one-third is covered with urban and rural developments, with the remainder under State forests, natural reserves and grasslands. In 1996, the study area supported approximately 39,000 persons according to census data. A regional sewage treatment plant with ocean disposal serves the majority of the current urban development. Two local sewage treatment plants with on-site disposal serve about 10% of the urban population. CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page 3

10 Figure 2, Topographic map of study area ESTATES For modelling purposes (water balance, contaminant balance and water related infrastructure), the study area was divided into 11 sub-areas or estates (see Figure 3 and Table 1). In general, estates represent the main localities in the study area. CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page 4

11 Table 1, Estates of the study area Vines Ellenbrook Henley Brook West Swan Caversham Bullsbrook Herne Hill Middle Swan Upper Swan Name ID Area (sq kms) Bullsbrook Upper Swan 2 59 Vines 3 14 Ellenbrook 4 30 Henley Brook 5 17 Herne Hill 6 17 West Swan 7 14 Middle Swan 8 23 Caversham 9 14 Midland Guilford 11 3 Total 422 Guilford Midland Figure 3, Map of study area estates CLIMATE The climate in the study area is Mediterranean, with hot dry summers and mild wet winters. The average temperatures and rainfall of Perth, Upper Swan and Bullsbrook are given in Table 2. Table 2, Average temperature and rainfall in Perth and the study area Perth Study Area Upper Swan Bullsbrook Av. Daily Max Temp Av. Daily Min Temp Av. Rainfall (mm) (Source: North-East Corridor Structure Plan, Dept of Planning and Urban Development, 1994) While there is a small change in climate across the study area, only one set of historical climate data was prepared for the project. This set was based on rainfall and evaporation data for the period February 1975 to April 1992 from Belmont rain gauge (station 9021) at Perth Airport (located 3km south of the southwestern corner of the study area. These historical data were used to build elevated CO 2 climate sequences (provided by Bates and Viney, CSIRO Land and Water, Perth). The elevated series were 100 year series, of which the first 20 years were used to model the implications of changes in climate on infrastructure. CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page 5

12 Table 3, Climate Statistics for elevated CO 2 series, compared to current Climate Series Statistic CO 2 x 1 CO 2 x 2 CO 2 x 3 Min Daily Rainfall (mm) Max Daily Rainfall (mm) Average Daily Rainfall (mm) Total Rainfall for 20 years (mm) 14,545 15,680 15,846 17,881 Average Yearly Rainfall (mm) Min Daily PET (mm) Max Daily PET (mm) Average Daily PET (mm) Figure 4, Rainfall and evaporation sequences for elevated CO 2 series TOPOGRAPHY The main topographical features in the study area are the large sand dunes in Ellenbrook, the State Forest, the Swan River running through the centre of the study area and the Darling Scarp to the east. The sand dunes in Ellenbrook and the State Forest are approximately 45 to 75 metres above the sea level. The land within the areas of Bullsbrook, Henley Brook, West Swan and Caversham is about 10 to 45 metres above sea level. SOILS The soil types in the estates are listed in Table 4 and include: Southern River: grey sandplain with low dunes and many intervening swamps; iron and humus podsol clays and peat. CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page 6

13 Yanga: poorly drained plain with grey sandy benches and intervening swamp; also areas of bog iron ore, marl or solonetzic soils. Beermullah: poorly drained sandplain; saline and solonetzic soils, bog iron ore and shallow sands over bog iron ore. Guilford: flat plain with medium textured deposits; yellow duplex soils. Swan: alluvial terraces with red earths and duplex soils. Forrestfield: latterised foothills of the Darling Scarp dominated by gravelly and sandy soils. Darling Scarp: steep slopes with red and yellow earths and rock outcrops. Table 4, Soil types in the Estates Estates Soil Types Bullsbrook Yanga, Beermullah, Forrestfield, Darling Scarp Upper Swan Swan, Guilford, Forrestfield, Darling Scarp Ellenbrook, Vines Yanga Henley Brook, West Swan, Caversham Swan, Southern River Herne Hill Guilford Middle Swan, Midland, Guilford Swan, Guilford Source: North East Corridor Structure Plan, Dept of Planning and Urban Development, 1994 HYDROLOGY The main watercourses in the study area are the Swan River, Helena River, Avon River, Woorooloo Brook, Jane Brook, Susannah Brook and Ellen Brook. The Swan River runs through the centre of the study area. Helena River forms part of the southern boundary and is not modelled within the study area. Figure 5 shows the main watercourses with the Swan River highlighted. At the confluence of the Avon River and Woorooloo Brook, the Avon River becomes the Swan River. CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page 7

14 Figure 5, Map of main streams in the study area Despite the moderate to high rainfall over the northern half on the Swan plain, run-off is quite sparse (Bestow, 1976). This is due to the highly permeable soils that underlie most of the Swan plain, generating little surface runoff from pervious areas. Few streams having their source on the plain and all major rivers (Avon River, Woorooloo Brook, Susannah Brook, Jane Brook, and Helena River) rise in the Darling Range or further east (Bestow, 1976). Ellen Brook is the largest of the few streams which originate on the coastal plain (Allen, 1981). Ellen Brook is generally dry in summer months, with a mean annual flow of 38 megalitres, receiving some runoff from the Darling Range and partly spring fed from groundwater in the sands to the west (Bestow, 1976; Allen, 1981). Flows are highly episodic with storm events producing large changes in rates of flow (Sharma et. al. 1995). Predicted inflows to the study area under elevated atmospheric CO 2 conditions, required for storm flow modelling, were modelled by Evans and Schreider (1999) for Brockman River, Avon River, Susannah Brook and Jane Brook. Inflows from Ellen Brook were not modelled as historical flow data were not available during the life of the project. Wetlands There are 71 ha of wetlands in the study area, concentrated in Ellenbrook and Upper Swan Estates. Some of those in Ellenbrook are on the resort's golf course and parklands, and may be man-made. There are natural wetlands associated with Gnangara Mound. POPULATION Year 199x Census data showed that population in the study area in 1996 was about 39,000 persons. Single houses accounted for about 89% of all dwellings. These dwellings accommodated about 93% of the population at an occupancy rate of 2.9 persons per dwelling (North East Corridor Structure Plan, 1994). About 1% of the dwellings in the study area were medium density houses with the rest being caravans. About 5.3% of the population lived in caravans at an occupancy rate of 1.8 persons per caravan (North East Corridor Structure Plan, 1994). Year 2020 Year 2020 projected populations were based on Shipton (1999). Table 5, Populations within estates for Years 199x and 2020 Name 199x Scenario 2020 Scenario X times 2020: 199x Bullsbrook 2,626 4, Upper Swan 1,661 2, Vines 986 1, Ellenbrook , Henley Brook , Herne Hill 1,544 7,890 5 West Swan 1,154 11, Middle Swan 8,915 15, Caversham 1,969 6, Midland 17,142 27, Guilford 1,743 3, Total Population 38, , CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page 8

15 LAND USE Data Sources The land use distribution was derived from processing of digital data (see details in Appendix 2). Waterways were an additional land use created for the project by buffering major rivers and streams within the study area. These buffers have no legitimacy and were created to provide the opportunity for modelling of externalities (ref Young's work in the UWP). A land use classification was defined by aggregating mapping classifications provided by State agencies to suit the needs of the models. These land use classes are listed in Table 6. When defining different land uses, ie residential (urp), industrial (gli) and commercial (cb), different water consumption patterns of each of these components were taken into account. Table 6, Main land use categories Land use category Code Description Urban residential (permanent) urp Houses, flats, boarding houses, units, retirement villages Urban residential (temporary) urt* Caravan parks and camping grounds Rural residential rr Dwellings on land used for rural activities Commercial business cb Retail & professional offices, shops, cinemas, hotels/motels, airports, service stations, function centres Commercial horticulture ch Market gardens, vineyards, orchards, plant farms, nurseries, etc. General light industry gli Low water users (rural industry, noxious industry, waste disposal) General heavy industry ghi* High water users (generally metered monthly) (mining of ores, stone, gravel, etc.,) Institutions ins* Comm/State/Local Government & civic offices, utilities, hospitals, churches, prisons, schools, health centres, aged care centres, museums, public art galleries, zoos Parks & gardens p&g Parkland, botanic gardens, recreation grounds, sports arenas, public & private clubs with or without recreation areas, golf courses, public open space Rural open space ros Natural open grassland, forests, rural road reserves, rubbish disposal, nature reserves, National parks, State forests Roads and parking r&p* Roads and parking areas Waterways ww Waterways (buffered drainage lines) (* these categories were not retained as separate classes in the final classification - see Table 9) Year 199x Area of land use classes in each estate for Year 199x are listed in Table 7. Current land use is largely rural and covered with either natural grassland, reserves, State Forests, rural residential hobby farms or intensive horticultural land uses. The horticultural land uses are in the Swan valley between Great Northern Highway and West Swan Road. A small proportion of the study area is urban and covered with urban residences, parks and gardens, industries or commercial premises. Information on number of occupied dwellings, and commercial and industrial premises in the study area in 1997 were extracted from the database of Ministry for Planning, Western Australia. CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page 9

16 Table 7, Land uses (in ha) in Estates for Year 199x Estate Areas of land uses in hectares urp rr cb gli p&g ch ros ww Total Bullsbrook ,822 2,224 20,554 Upper Swan 0 1, , ,925 Vines ,380 Ellenbrook , ,998 Henley Brook , ,685 Herne Hill ,676 West Swan , ,434 Middle Swan ,330 Caversham ,426 Midland , ,518 Guildford urp rr cb gli p&g ch ros ww Total Total 929 3, ,165 29,519 4,616 42,236 Percentage 2% 8% 1% 1% 2% 5% 70% 11% Year 2020 The Year 2020 mapping was derived from digital maps of predicted land use provided by NEC Planning Authority. Major changes from 199x were:! The loss of commercial horticulture in the estates of Henley Brook and West Swan.! Large increases in urban residential, generally at the expense of rural open space, and in Middle Swan, Midland, and Guilford, at the expense of rural residential areas.! Increases in rural residential in all but three estates (listed above) at the expense of rural open space.! Increase in commercial business primarily due to growth in the Bullsbrook estate.! Increase in general light industry primarily due to growth in the Bullsbrook and Upper Swan estates. The Year2020 predicted distribution of land uses within Estates is given in Table 8. Table 8, Land use areas (ha) within Estates for Year 2020 Estate Areas of land uses in hectares urp rr cb gli p&g ch ros ww Total Bullsbrook ,873 2,224 20,554 Upper Swan 0 2, , ,925 Vines ,380 Ellenbrook , ,998 Henley Brook ,685 Herne Hill ,676 West Swan ,434 Middle Swan , ,330 Caversham ,426 Midland , ,518 Guildford urp rr cb gli p&g ch ros ww Total Total 2,831 5,756 1, ,790 24,265 4,658 42,236 Percentage 7% 14% 3% 2% 2% 4% 57% 11% CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page 10

17 CHARACTERISATION OF PHYSICAL DESCRIPTION Both the UVQ and the TAWS models used for the project represent the water supply, waste and storm water systems, as well as precipitation and evapotranspiration, and divide the urban area into different land uses. The land use classifications and mappings described in the previous section were thus most appropriate for the modelling work. For the purposes of the following discussion, the UVQ model was applied at cluster scale, and the TAWS model at estate scale. SPATIAL DISAGGREGATION Estates, Clusters and Unit Blocks Estates were introduced in the physical description section. These are further broken down into clusters. An estate comprises a number of clusters. A logical network can be defined which states the spatial relationships between clusters and the flows of supply, storm water, and waste water through each estate, from cluster to cluster. A cluster comprises a number of unit blocks as well as roads and public open space, representing a neighbourhood or suburb. To simplify the modelling process, each land use within an estate was designed as a cluster, allowing the unit blocks within a cluster to be lumped together into a gargantuan unit block demanding water according to the pattern of the relevant land use. Therefore, an urban area (or an estate) containing a mix of land use was represented as a number of separate clusters. Each spatial scale (unit block, cluster, and estate) was separated into pervious and impervious surfaces. Impervious surfaces were further separated into roof, road, and paved portions. As a result, the conceptualisation of the urban water system applied to each spatial scale. A water balance was conducted for each unit block and cluster contained in the study area, as well as the estate as a whole. Nodes The TAWS model represents water uses and sources as sets of nodes. The water supply flow paths between source and demand nodes are represented by a set of links. In particular, water uses are known as demand nodes and water sources are known as source nodes. The clusters mapping of land uses was suitable for node mapping, though not identical. Cluster to node relationships are described in the following section on Population and Land Use. TOPOGRAPHY Many physical and topographical attributes were required for the modelling. Enough rigour was incorporated into the description of these data to ensure that the model setup and predictions were sensible. Elevation A rough 10m contour map was prepared to assist with describing elevation of pipes. However, the elevation attributes assigned to each pipe are very rough and have not been checked with the local authority. Depth to Groundwater While groundwater across the study area varies from about 0 to 5 metres, it was held constant at 5m for the purposes of modelling. This was considered more appropriate than assigning incorrect data and ensured that differences in this attribute did not influence model results. CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page 11

18 Surface Material The description of infrastructure layers required knowledge of the type of surface over the pipe. To simplify the urban water balance modelling and the calculations of life cycle costing for the infrastructure, it was assumed that surface area over the physical infrastructure was simply covered with grass. Hence, in the data files, this attribute was held constant at 'UNDER LAWN' for all pipes. SOILS For similar reasons to those outlined above, the whole study area was assumed to consist of sandy soil. LAND USE PROFILES Population and land use were used to develop land use profiles, using the following characteristics: land use population total area of cluster total area of road total area of public open space total area of unit blocks number of unit blocks in cluster average area of a unit block (garden, roof and pavement) average unit block occupancy average area of a unit block garden average area of a unit block roof average area of unit block pavement source of potable water. 199x profiles were based on extensive data collection and analysis from the study area and elsewhere in urban Australia, using the following assumptions: Land use assignment! The urban residential (temporary) (urt) land use category can be incorporated into the urban residential (permanent) (urp) land use category! The institutions (ins) land use category can be combined into the commercial business (cb) land use category! The roads and parking (r&p) land use category can be incorporated into the urban residential (permanent) (urp), rural residential (rr), commercial business (cb), commercial horticulture (ch), general light industry (gli), and rural open space (ros) land use categories! The average size of the urban residential (permanent) (urp) unit blocks in the Midland estate is 780 m2 (equal to the Perth average (MWA, 1985))! The urban residential (permanent) (urp) land use in West Swan can be reassigned to rural residential (rr) as the average unit block size is equal to 1.5 hectares! Only 30% of the combined total of the urban residential (permanent) (urp) and rural residential (rr) land use areas in the Midland Estate is actual rural residential (rr) land use Road area assignment! 10% of the urban residential (permanent) (urp) land use in a cluster is road area (Stewardson et al, 1994; Mitchell, 1998)! 5% of the rural residential (rr) land use in a cluster is road area, equivalent to half of that of the urban residential (permanent) (urp) land use category! 10% of the commercial business (cb) land use in a cluster is road area, equivalent to that of the urban residential (permanent) (urp) land use category CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page 12

19 ! 2% of the commercial horticulture (ch) land use in a cluster is road area! 5% of the general light industry (gli) land use in a cluster is road area, equivalent to half of that of the urban residential (permanent) (urp) land use category! 2% of the rural open space (ros) land use in a cluster is road area Roof area assignment! 20% of the urban residential (permanent) (urp) unit block in a cluster is roof area (WAWA, 1987), except in the Vines and Ellenbrook estates which are 15% and 40% respectively! The rural residential (rr) unit block roof size is 250 m2! 40% of the commercial business (cb) unit block in a cluster is roof area (WAWA, 1987)! The commercial horticulture (ch) unit block roof size is 300 m2! 30% of the general light industry (gli) unit block in a cluster is roof area (WAWA, 1987) Paved area assignment! 45% of the general light industry (gli) unit block in a cluster is paved area! 5% of the urban residential (permanent) (urp) unit block in a cluster is paved area! The rural residential (rr) unit block paved area is 60 m2! 40% of the commercial business (cb) unit block in a cluster is paved area (WAWA, 1987)! The commercial horticulture (ch) unit block paved area is 60 m2 Water use assignment! 70% of the urban residential (permanent) (urp) unit block garden is irrigated (MWA, 1985) Occupancy rate assignment! Commercial business (cb) is assigned an occupancy rate of 3 to reflect its water demand! General light industry (gli) is assigned an occupancy rate of 10 to reflect its water demand! The occupancy rate for urban residential (permanent) (urp), rural residential (rr), and commercial horticultural (ch) unit blocks within an estate are equal. These assumptions resulted in a smaller set of land uses than was described in Table 6 as follows: Table 9, Final Land Use Classification used for Modelling Land Use Urban residential Rural residential Commercial business General light industry Parks and gardens Commercial horticulture Roads and open spaces Waterways Land Use Code urp rr cb gli p&g ch ros ww For modelling purposes, and for ease of identification, each cluster was assigned a unique number in order from upstream to down stream within estate, e.g. the waterway land use cluster drains into the waterway (ww) land use of the next estate. These differed for Year 199x and 2020 and are listed in Table 10 and Table 11. Note that differences in land uses are highlighted in Table 11 and demand node identifications listed in Table 13. CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page 13

20 Table 10, Cluster Identification Number for Year 199x Estate Land Use urp rr cb gli p&g ch ros ww Bullsbrook Upper Swan Vines Ellenbrook Henley Brook Herne Hill West Swan Middle Swan Caversham Midland Guilford urp rr cb gli p&g ch ros ww Due to the urban development that is used to create the Year 2020 land use pattern, three Year 199x clusters have their land use reassigned. Cluster 9 in the Upper Swan estate has been converted from commercial business (cb) to general light industry (gli), while Cluster 28 in the Henley Brook estate and cluster 40 in the West Swan estate has been converted from commercial horticulture (ch) to urban residential (urp). Table 11, Cluster Identification Number for Year 2020 Estate Land Use urp rr cb gli p&g ch ros ww Bullsbrook Upper Swan Vines Ellenbrook Henley Brook Herne Hill West Swan Middle Swan Caversham Midland Guilford urp rr cb gli p&g ch ros ww For each cluster the following properties are described: road area public open space total unit block area number of unit blocks average unit block occupancy area of unit block area of unit block garden area of unit block roof area of unit block pavement potable water source. CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page 14

21 These details are provided in Table 17 and Table 18 in Appendix 1 - Summaries of Estate and Cluster Compositions. Year 2020 cluster descriptions were developed from the 199x descriptions by matching predicted land use areas with 199x block size and occupancy rates to give populations and number of unit blocks within each cluster. While not realistic, this was sufficient for the purpose, which was simply to provide a more urbanised description of the study area. These clusters were mapped to TAWS nodes, modified to accommodate the following: Urban residential clusters were mapped to two demand nodes: urban residential indoor (urpi) and urban residential garden (outdoor) (urpg), so that possibility of supplying different quality water to outdoor water use can be explored. Residences in rural residential and commercial horticulture land uses utilised groundwater for their outdoor water use. While supply of groundwater to these land uses was not modelled, nodes were described so that groundwater supply could be explored at a later stage. Rural open space and waterways clusters were not mapped to demand nodes as they were not water uses. Table 12, (Demand) Node Identification for Year 199x Estate Cluster Demand Node (Identification Code) Demand Node Supply Source Bullsbrook 1 Urban residential indoor 1BB_urpi Greenmount & Yokine 1 Urban residential garden (outdoor) 1BB_urpg Greenmount & Yokine 2 Rural residential indoor 2BB_rri Greenmount & Yokine 2 Rural residential garden (outdoor) 2BB_rrg Groundwater 3 Commercial business 3BB_cb Greenmount & Yokine 4 General light industry 4BB_gli Greenmount & Yokine 5 Parks and gardens 5BB_p&g Greenmount & Yokine Upper Swan 8 Rural residential indoor 8US_rri Greenmount & Yokine 9 Commercial business 9US_cb Greenmount & Yokine 10 Parks and gardens 10US_p&g Greenmount & Yokine 12 Commercial horticulture indoor 12US_chi Greenmount & Yokine 12 Commercial horticulture garden (outdoor) 12US_chg Groundwater Vines 14 Urban residential indoor 14V_urpi Wanneroo 14 Urban residential garden (outdoor) 14V_urg Wanneroo 15 Rural residential indoor 15V_rri Wanneroo 15 Rural residential garden (outdoor) 15V_rrg Groundwater 16 Commercial business 16V_cb Wanneroo 18 Parks and gardens 18V_p&g Wanneroo Ellenbrook 20 Urban residential indoor 20EB_uri Wanneroo 20 Urban residential garden (outdoor) 20EB_urpg Wanneroo 21 Rural residential indoor 21EB_rri Wanneroo 21 Rural residential garden (outdoor) 21EB_rrg Groundwater 22 Commercial business 22EB_cb Wanneroo 24 Commercial horticulture indoor 24EB_chi Greenmount 24 Commercial horticulture garden (outdoor) 24EB_chg Groundwater Henley Brook 26 Rural residential indoor 26HB_rri Greenmount & Yokine 26 Rural residential garden (outdoor) 26HH_rrg Groundwater 28 Commercial horticulture indoor 28HB_chi Greenmount & Yokine 28 Commercial horticulture garden (outdoor) 28HB_chg Groundwater Herne Hill 30 Urban residential indoor 30HH_urpi Greenmount & Yokine 30 Urban residential garden (outdoor) 30HH_urpg Greenmount & Yokine 31 Rural residential indoor 31HH_rri Greenmount & Yokine 31 Rural residential garden (outdoor) 31HH_rrg Groundwater CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page 15

22 Estate Cluster Demand Node (Identification Code) Demand Node Supply Source 32 Commercial business 32HH_cb Greenmount & Yokine 33 Parks and gardens 33HH_p&g Greenmount & Yokine 35 Commercial horticulture indoor 35HH_chi Greenmount & Yokine 35 Commercial horticulture garden (outdoor) 35HH_chg Groundwater West Swan 37 Rural residential indoor 37WS_rri Greenmount & Yokine 37 Rural residential garden (outdoor) 37WS_rrg Groundwater 38 Commercial business 38WS_cb Greenmount & Yokine 40 Commercial horticulture indoor 40WS_chi Greenmount & Yokine 40 Commercial horticulture garden (outdoor) 40WS_chg Groundwater Middle Swan 42 Urban residential indoor 42MS_urpi Greenmount & Yokine 42 Urban residential garden (outdoor) 42MS_urpg Greenmount & Yokine 43 Rural residential indoor 43MS_rri Greenmount & Yokine 43 Rural residential garden (outdoor) 43MS_rrg Groundwater 44 Commercial horticulture indoor 44MS_chi Greenmount & Yokine 44 Commercial horticulture garden (outdoor) 44MS_chg Groundwater 45 General light industry 45MS_gli Greenmount & Yokine 46 Parks and gardens 46MS_p&g Greenmount & Yokine 48 Commercial business 48MS_cb Greenmount & Yokine Caversham 50 Urban residential indoor 50C_urpi Greenmount & Yokine 50 Urban residential garden (outdoor) 50C_urpg Greenmount & Yokine 51 Rural residential indoor 51C_rri Greenmount & Yokine 51 Rural residential garden (outdoor) 51C_rrg Groundwater 52 Commercial business 52C_cb Greenmount & Yokine 53 General light industry 53C_gli Greenmount & Yokine 54 Parks and gardens 54C_p&g Greenmount & Yokine 55 Commercial horticulture indoor 55C_chi Greenmount & Yokine 55 Commercial horticulture garden (outdoor) 55C_chg Groundwater Midland 59 Rural residential indoor 59M_rri Greenmount & Yokine 59 Rural residential garden (outdoor) 59M_rrg Groundwater 60 Commercial business 60M_cb Greenmount & Yokine 61 General light industry 61M_gli Greenmount & Yokine 62 Parks and gardens 62M_p&g Greenmount & Yokine 63 Urban residential indoor 63M_urpi Greenmount & Yokine 63 Urban residential garden (outdoor) 63M_urpg Greenmount & Yokine Guilford 65 Urban residential indoor 65G_urpi Greenmount & Yokine 65 Urban residential garden (outdoor) 65G_urpg Greenmount & Yokine 66 Rural residential indoor 66G_rri Greenmount & Yokine 66 Rural residential garden (outdoor) 66G_rrg Groundwater 67 Commercial business 67G_cb Greenmount & Yokine 68 General light industry 68G_gli Greenmount & Yokine 69 Parks and gardens 69G_p&g Greenmount & Yokine Table 13, Changes to (Demand) Node Identification for Year 2020 Estate Cluster Demand Node (Identification Code) Demand Node Supply Source Upper Swan 9 General light industry 9US_gli Greenmount & Yokine Henley Brook 28 Urban residential indoor 28HB_urpi Greenmount & Yokine Henley Brook 28 Urban residential garden (outdoor) 28HB_urpg Greenmount & Yokine West Swan 40 Urban residential indoor 40WS_urpi Greenmount & Yokine West Swan 40 Urban residential garden (outdoor) 40WS_urpg Greenmount & Yokine CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page 16

23 WATER SYSTEMS The study area is serviced by a traditional water infrastructure, with sewerage systems servicing the urban area and the rural areas being mainly on septic. Waste water and drainage systems are totally separate. POTABLE WATER Data Sources The Water Corporation, Western Australia, provided digital data of the potable water supply network. Data included both existing pipe layout and extensions to the existing network to meet demand in However, attributes of individual pipes such as pipe sizes, material type, construction year, etc. were not included in the data base of digitised maps, rather pipe sizes and material type were provided as visual objects as a layer of data on the digitised map. Hence, the potable water supply network was derived from digital data of the pipe network, with annotations. While it was possible to process the layout of the network easily from these data, a significant amount of GIS processing was required to attach the annotations to specific pipes within that network. This was due to the reason mentioned above on the way in which attributes of pipes were provided. While the results were sensible, some errors may have occurred in processing. Figure 6 is the infrastructure derived from the digital maps. This network was abstracted to a more appropriate scale for the modelling. Refer to the Characterisation Section for details. Water Sources Year 199x The study area is a part of the Metropolitan Water Supply Figure 6, Map of potable water network system (MWS) which supplies the Perth metropolitan area and nearby urban centres such as Mandurah. Water sources for the MWS system include storage dams such as Canning Dam and small diversion structures in the Darling Range to the east of Perth and groundwater wells on the coastal plain. Groundwater is withdrawn from the shallow aquifers and the two deeper, confined aquifers under the Perth metropolitan area. Water is transported from these sources to consumers via large-diameter bulk water transfer mains to service reservoirs or directly off the trunk mains in some areas. The Greenmount service reservoir, the Yokine reservoir (via Yokine pipeline) and Wanneroo reservoir (via Gnangara Road trunk main) service the study area. The Greenmount reservoir and the Yokine pipeline were the primary sources until November 1998 when the Gnangara Road trunk main was commissioned for connection to the Wanneroo Yokine trunk main to allow Ellenbrook and Vines new urban developments to be supplied from Wanneroo reservoir. This link is a temporary measure until the Gnangara Water Supply Scheme is commissioned (see next section). CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page 17

24 Year 2020 The future water supply scheme of the study area will comprise the Gnangara reservoir to the north west of the study area that will supply the north west of the study area (i.e. Ellenbrook, Vines, West Swan and Upper Swan Estates ) via gravity (this scheme will be known as Gnangara Water Supply Scheme). However, there will be some pockets of high ground that cannot be gravity fed via Gnangara reservoir. These pockets will be supplied via local variable speed booster pumping stations. The Gnangara reservoir will be refilled from the Lexia groundwater treatment plant with potential for future augmentation from Wanneroo reservoir via Gnanagara road trunk main (Western Australia Water Corporation, 1999). The rest of the area will continue to be supplied from the Greenmount reservoir. Two new reservoirs are planned in the elevated areas of the Darling Scarp at Susannah Brook and Redhill (Dept. Planning and Urban Development, 1994) that will provide future augmentation to the MWS. Pipes Year 199x Pipes of the following materials were identified from the digital data: Asbestos cement Ductile iron Medium density polyethylene (PE) Poly vinyl chloride (PVC) 120m Reinforced Concrete Mild steel. Of these, asbestos cement is not longer used or available. Year 2020 No information was gathered on preference for a particular pipe material. Pumping Stations Year 199x The main pumping stations in the study area are the Great Northern Highway Booster, which pumps water into Copley Road Tank from the Greenmount reservoir, and the Bullsbrook pumping station which pumps water into Bullsbrook Tank from Copley Road Tank. There are three local pumping stations located in Vines, Ellenbrook and Herne Hill, pumping water into ground or elevated tanks in order to boost water supply in these estates. Year 2020 There are no major booster pumping stations planned. CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page 18

25 WASTE WATER Data Sources The waste water network was derived from several sources. Digital maps supplied by Western Australian Water Authority were supplemented by information on paper maps of "Perth to Mandurah Planned Wastewater System Darling Range NW (Water Corporation, 1998), scale 1: and "Areas Connected to Wastewater Treatment Plants (Water Authority of Western Australia, 1990) 1: The attribute information was supplemented by lists of pipes and their ages provided by CSIRO Building, Construction and Engineering (based on information from WAWA). The final network is given in Figure 7. Note that there are 3 exits from the study area to the Beenyup Treatment Plant. These are represented via the pipes exiting the study area on the left. This network was abstracted for modelling. Refer to the Characterisation Section for details. Waste Water Treatment Year 199x Figure 7, Map of waste water network The urban developments in Midland and Guilford are served by the Beenyup regional wastewater treatment plant (WWTP). Waste water produced in Ellenbrook area is collected via a series of sewers and trucked to the Beenyup WWTP. The urban developments in Bullsbrook and Vines are serviced by local treatment plants. The rest of the population in the study area use septic tanks. The Beenyup WWTP also serves the North West Corridor of Perth. This plant was built in 1960 and provides primary and secondary treatment. After treatment the effluent, under gravity flow, is discharged to the ocean at the Ocean Reef through two pipelines some 1600 metres offshore into 10 metre deep water (WAWA, 1995). By year 2000, the plant will have a design capacity of 150 ML/day, which is considered its ultimate capacity. Bullsbrook WWTP serves the local community at Bullsbrook. The capacity of the plant is 125 cubic metres per day. Treated effluent is discharged on site to channels for irrigating trees. The Vines Resort WWTP serves the local community in Vines. The capacity of this plant is not known at the time of writing. Like the Bullsbrook WWTP, treated effluent is discharged on site. Year 2020 The Wastewater 2040 strategy (WAWA, 1995) defines the planned changes in waste water transport and treatment. The goal is that as much of the flow as possible go to land (not ocean) and waste minimisation is in place. Though this is mainly a lifestyle decision, regulations such as dual flush toilets for new dwellings are in place. Septic tanks are not permitted in new rural residential developments. Composting toilets are installed with land application of greywater. All new urban development is on reticulated sewerage. Wastewater and drainage systems will be kept totally separate (p7-2, WAWA 1995)). The Strategy is to maintain the existing large wastewater systems for frontal development, and to review the use of all other types of wastewater treatment for non-frontal development and for isolated or small scale communities (p7-4, WAWA 1995). CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page 19

26 Thus, it is anticipated that Beenyup will still be the central treatment plant, though upgrades to its primary, secondary and sludge treatment facilities are planned. Predictions for 2020 are plant inflow of 135ML/d. Sewage from the north east corridor may be diverted to the proposed Alkimos Treatment Plant. However, that diversion will occur at a pump station outside the study area. Ellenbrook was previously serviced by a local package STP with road transport to Beenyup. It is anticipated that a major pump station and pressure main will be commissioned along Gnangara Road which connects to the Beenyup treatment plant. This pump station will also service a portion of Henley Brook and West Swan Estates. As the natural ground fall of this area is towards the east, the relative sewerage lines gravitate to a pump station, located near Henley Brook Avenue, which pumps north via a pressure main to the Gnangara Road trunk main. While it is anticipated that the urban areas in the Vines are still serviced by the Vines local treatment plant with onsite disposal, the new development is linked to Ellenbrook. The Bullsbrook Treatment Plant continues to serve the local community at Bullsbrook. The treated effluent is discharged on site to channels irrigating trees, and potentially by the Chequers golf course to the north of the plant. The Strategy document indicated that no major urban development is anticipated in the locality in the short to medium term (p7-6, WAWA, 1995). However, the land use and population data indicate a 300% increase in population, as a result of urban development. It may be that the plant does not have the capacity to handle this increased flow. Pipes Year 199x Pipes of the following material were identified from the mapping (p = pressurised; g = gravity): Asbestos Cement p & g Cast Iron p only Glass Reinforced Plastic p only Medium Density Polyethylene p only Mild Steel Cement Lined p only PVC (poly vinyl chloride) p & g Reinforced Concrete p & g Reinforced Concrete Plastic Lined g only Steel p only Vitrified Clay g only Diameters range from 100 to 950mm, in all types of material. Note that vitrified clay is only used in the older Midlands region. Year of construction was assigned to pipes based on the table of pipes that was provided by WAWA. Year 2020 Source maps showed proposed pipes. These had dimension marked, but not material type. Material type was assigned as described in Table 14 based on most common material used, with a preference for PVC for smaller pipes. Proposed pipes were assigned the construction year of Table 14, Material Type assigned to proposed wastewater pipes Dimension Material Type 150, 225, 300, 375 PVC (poly vinyl chloride) 450, 500 Reinforced Concrete Plastic Lined 600 (Pressurised) Mild Steel Cement Lined 600 (Gravity) Reinforced Concrete Plastic Lined CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page 20

27 Pumping Stations Characterisation of Perth North-East Corridor Study Area Year 199x 28 existing Pumping Stations were digitised from the paper maps. No information to describe these stations was processed. Year proposed Pumping Stations were digitised from the paper maps. STORM WATER Data Sources The stormwater network prepared for the project was of poor quality. It was created from 3 sources: (1) digital data of the layout from the West Australian Water Corporation which covered parts of Midlands and Guilford; (2) rough map digitised from Swan Valley Drainage Study 1: scale maps, prepared in 1982 by GHD-Dwyer (WA) Pty Ltd for Shire of Swan. These were part of the Catchment Plan Series and the Drainage Master Plan Series; (3) drainage network from 1: AUSLIG map; No infrastructure information was obtained for the lower right-hand portion of the catchment within the Shire of Mundaring. Year 199x With the exception of pipes under roads, the storm water infrastructure is either 'natural watercourse' or 'open drain'. All pipes in the network are reinforced concrete, though documentation indicates that some PVC pipes were laid in the early 1990s. Table 15 gives the pipe dimensions, total length and average year of installation. Figure 8, Map of storm water network Table 15, Stormwater Pipes - Dimensions, Total Length and Average Year of Installation Dimension (mm) Total Length Average year of installation m m m m m m 1986 CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page 21

28 Dimension (mm) Total Length Average year of installation m m m m 1977 Year 2020 By the Year 2020, planning documents (Dept. of Planning and Urban Development, 1994) indicate that all urban development will follow best management practices, including retention of natural drainage lines throughout the urban areas as open space strips incorporating nutrient stripping ponds and other devices to promote the local recharge of the groundwater table and the removal of nutrient and solid pollutants. Minor ponds will be incorporated at intervals along the natural water courses. Major retention basins/nutrient stripping ponds will be located at the eastern extremity of natural drainage lines. Thus, all water from new urban areas will firstly run through one or more minor ponds, and then through a major pond. CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page 22

29 CHARACTERISATION OF WATER SYSTEMS This section describes the process of characterising the potable water supply system. The waste and storm water systems were not included in the modelling component of the feasibility stage and thus were not characterised. POTABLE WATER Water Supply The Greenmount reservoir, Yokine reservoir and the Wanneroo reservoir (supplies water mainly to Ellenbrook and Vines estates) are represented as source nodes. These source nodes are linked to demand nodes and Table 12 identifies these links. A schematic diagram of the basic configuration of the water supply system of the study area is presented in Figure 9. Figure 9, Schematic diagram of the potable water supply system It was assumed that Greenmount, Yokine and Wanneroo reservoirs had enough water to supply to the study area - that is, water supplies to the study area were considered as unlimited. Hence there was no need to model behaviours of individual reservoirs. The supply heads at the Greenmount reservoir and the connection points of the Yokine and Wanneroo pipe lines to the distribution system of study area were taken as 68.5m, 76m and 65 m respectively (West Australian Water Corporation, 1999). These values were used to carry out the hydraulic analysis of the distribution system shown in Figure 6. Pipes The TAWS model has been designed to operate at the scale of mains infrastructure only (i.e. estate level or between clusters). For this reason, reticulation level pipes (i.e. pipe distribution system within the clusters) were removed from the network descriptions. Material and dimension of the final set of potable water pipes used for modelling Year 199x are listed in Table 16. CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page 23

30 Material Type Table 16, Potable Water Pipe Types Dimensions (mm) Asbestos Cement 100, 150, 200, 300, 450 Cast Iron 100, 150, 200, 300, 305, 380 Ductile Iron Cement Lined 150, 300 PVC (120 pressure rating) 100, 200 Reinforced Concrete 460 Mild Steel Cement Lined 205, 300, 400, 460, 500, 535, 700, 760, 900, 1000, 1065, 1200, 1220 Costing information for the different pipe types are documented in other Urban Water Program reports. Logical Network The logical network represents water supply flow paths between nodes. The logical network of the study area consists of 3 source nodes (Greenmount, Yokine and Wanneroo reservoirs), 57 demand nodes supplied by these reservoirs (see Table 12) and 57 links. Demand nodes in all estates except Ellenbrook, Vines and West Swan were supplied with the Greenmount reservoir and the Yokine pipeline. The Greenmount reservoir supplied water to West Swan and Wanneroo pipeline supplied water to Ellenbrook and Vines estates. The current configuration has each demand node supplied with a single source of water supply. Alternative sources can be included, depending on the scenarios being analysed. This logical network allows evaluation of the base case only. Physical Network The physical network is shown in Figure 10, Figure 11 and Figure 12. It comprises pipe sections (lines), pipe nodes (diamonds), demand nodes (squares), and source nodes (circles). This physical network was derived from the actual water supply network and includes only distribution pipes, that is, reticulation pipes are not included. Therefore, a single pipe node may supply water to a number of demand nodes. The physical network consists of 94 pipe sections, 296 pipes (some pipe sections consist of two pipes in parallel) and 96 pipe nodes. Figure 10, Water Supply Physical Network in Bullsbrook Estate CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page 24

31 Figure 11, Water Supply Physical Network in Vines, Ellenbrook, Upper Swan and Henley Brook Estates Figure 12, Water Supply Physical Network in Herne Hill, West Swan, Middle Swan, Caversham, Midland and Guilford Estates CSIRO Land & Water Consultancy Report for CSIRO Urban Water Program, June 2000 Page 25