Elevations within the area range from 42 m AHD in the northwestern corner to 30 m Australian High (AHD) along the southeastern border. Man-made drainage channels located north of the Pine Street Road Reserve connect to Saint Leonards Creek, which flows into the eastern boundary of the site.
Background
Town planning context
Purpose of this report
Policy framework
The cited guidance documents indicate the need for accurate baseline data on water quality prior to urban development. This will ensure that any future development can meet the stormwater management requirements of DWER, the engineering standards set by the CoS and the water quality requirements of the Water Corporation and the Department of Biodiversity, Conservation and Attractions (DBCA) while ensuring , that real water accepted are practically achievable quality criteria.
Previous studies
In addition to the above policies, a number of published guidelines and standards are available that give direction to the water discharge characteristics that urban developments should aim for.
LWMS objectives
Land use within the site includes residential lots, POS, road reserves, two stand-alone primary schools, two Water Corporation lots associated with production drilling, and some regional roads. The above land use corresponds to acceptable or compatible (with conditions) land use within an area that has been converted from a Priority 2 (P2) Public Drinking Water Resource Area (PDWSA) to a Priority 3* (P3*) PDWSA.
Sources of information
Climate
Geotechnical conditions
Topography
Soils and geology
Acid sulfate soils
Groundwater
- Public drinking water source area and production bores
- Groundwater resources
- Groundwater levels
- Maximum groundwater levels
- Annual average maximum groundwater levels
- Groundwater quality
The off-site AAMGL was calibrated in the same way, although the correction factors were developed from long-term monitoring wells more local to these sites. Nutrient concentrations can be compared to relevant guidelines for lowland rivers in south-western Australia presented in the NWQMS target concentrations (ANZECC and ARMCANZ 2000) and the Healthy Rivers Action Plan (HRAP) (SRT 2009).
Surface water
Surface water features
Otherwise, they connect man-made drains located south of the Pine Street Road Reserve within Lot 60 Park Street (see Figure 7). Albion LWMS (JDA Consulting Hydrologists 2009) determined that the pre-development peak flow under Park Street was 4.02 m3/s in the large rainfall event (see Appendix B).
Surface water quantity
This drain empties at the southern site boundary below Park Street within two culverts into a large sump within Avonlee Estate. The Swan Urban Growth Corridor DWMP (DoW 2009) includes the Albion region, extending from Park Street south to Harrow Street.
Surface water quality
Environmental assets and water-dependent ecosystems
Wetlands
Saint Leonards Creek
Current and historical land use
Summary of existing environment
Water supply, conservation and wastewater servicing
Stormwater management
Groundwater management
Fit-for-purpose water use
Scheme water
Groundwater
It is noted that Western Primary School is located on two lots (namely lot 112 and 113) which currently have licenses totaling 25,500 kL/year. As discussed in Section 5.3.2, it is estimated that the two primary schools will require approximately 15,225 kL/year for continuous irrigation.
Rainwater
Consequently, the status of groundwater permits and confirmation that the proposed irrigation requirements for POS and elementary schools can be met should be documented in future UWMPs (see Section 9.7). Additional sources of irrigation will be required in the event that the amount required for irrigation exceeds the amount available, but the existing allocations are more than sufficient to support the structural planning of the site.
Water conservation measures
Water efficient fixtures and appliances
With the introduction of WEFA, a significant reduction in own water consumption can be achieved. Water-efficient fixtures will be mandated through the building permit, while the use of water-efficient appliances can be encouraged through state and local government rebates, as well as advocate education at the point of sale.
Waterwise gardens
Educational materials
Water Use Analysis
Lot scale water use analysis
Estate scale water use analysis
- Gas pipeline corridor
- Saint Leonards Creek foreshore area
POS within the gas pipeline corridor will be subject to maintenance by CoS as part of the wider POS area. The foreshore area will be subject to maintenance by the CoS as part of the wider POS area.
Wastewater servicing
The main channel (which mediates frequent and minor rainfall events) will be planted in accordance with 'living stream' guidelines to achieve water quality and ecological outcomes. Grass and landscape structures (e.g. playground equipment) should be located within the adjacent POS area and beyond the live stream, as generally required by the CoS.
Water supply, conservation and wastewater servicing design criteria compliance
The living stream should be designed to integrate into the surrounding functional POS area, giving residents access to the improved main channel. These components and the WSUD measures that will be implemented as part of these components are described in the following sections.
Lot drainage
Rainwater tanks
The principle behind the site's stormwater management strategy is to maintain the existing hydrology by treating small precipitation as close to the source as possible to match the antecedent.
Soakwells and soakage structures
Development drainage
- Bottomless gully/side entry pits
- Tree pits
- Bio-pockets
- Swales
- Bio-retention areas
- Subsurface storage
- Flood storage areas
- Temporary FSA
- Saint Leonards Creek foreshore area
Egress from the bio-pockets will be via surface overflow and/or an appropriate exit structure (eg manhole within the bio-pocket). Runoff beyond the capacity of the previous WSUD measures will be routed to FSAs located within the downstream POS areas.
Non-structural water quality measures
Conceptual landscape design of the live stream (i.e. riparian zone) and POS covering the riparian zone has been described in Section 5.3.2.2 and detailed in Appendix I. The use of appropriate erosion controls will need to be considered in the detailed design of the main channel. occurs during division (DWER 2018).
Design assessment
- Drainage calculations
- Saint Leonards Creek foreshore area
- Treatment areas
- Detention areas and the living stream
- Drainage locations
BRAs will be installed outside and outside of the live stream and are sized to hold minor precipitation. The bank of Saint Leonards Creek (ie live stream) is also located in the central eastern part of the site as discussed in Section 6.2.9.
Stormwater design criteria compliance
The principle behind groundwater management is to maintain the existing hydrology across the site, provide adequate protection against groundwater flooding, and maintain or improve existing groundwater quality.
Groundwater level management
It is noted that underground drains may not be required if clearances to MGL are achieved from finished floor levels and WSUD measures (discussed in Section 6.2).
Groundwater quality management
Groundwater design criteria compliance
If temporary sewage pumping devices are necessary, they should be installed as far as possible from the wells. If this occurs, pumping should be located outside the WHPZs shown in Figure 5 and monitoring measures implemented to prevent sewer overflows (DWER 2018).
Geotechnical investigations
The requirement to prepare more detailed water management plans to support subdivision is generally imposed as a precondition for subdivision. While strategies have been provided within this LWMS to address on-site water management planning, it is a logical step that future subdivision designs and the supporting UWMP(s) will clarify details not included in the LWMS.
Imported fill specifications and requirements
The development of any future UWMPs should follow the guidance in UWMPs: Guidelines for the Preparation of Plans and Compliance with Subdivision Conditions (DoW 2008b).
Modelling and configuration of Saint Leonards Creek
Modelling and configuration of estate drainage structures
Wastewater servicing
Implementation of water conservation strategies
Confirmation of irrigation source and management of bores
Non-structural water quality improvement measures
Management and maintenance requirements
Construction period management strategy
Monitoring during subdivision works
Post-development monitoring
Condition
The intent of the monitoring programs and maintenance requirements below is to ensure that the stormwater and groundwater management functions of WSUD measures are achieved. Where appropriate, the management and maintenance objectives will be detailed in future UWMPs together with details of the corresponding monitoring programme.
Water quality
- Trigger criteria
- Contingency action plan
Trigger values have also been set considering the NWQMS trigger values ( ANZECC and ARMCANZ 2000 ), the Swan-Canning WQIP guideline values ( SRT 2009 ) and the WQIP for Saint Leonards Creek ( SRT 2011 ). Resample the water quality after implementing the agreed actions and repeat the sample comparison/analysis process d described above.
Temporary wastewater servicing monitoring
If the downstream concentrations are found to be generally consistent with the upstream concentrations, the trigger values may need to be revised in consultation with the CoS, Water Corporation and DWER. The development of the LWMS has been undertaken with the intention of creating a structure within which subsequent development can take place in accordance with an integrated water cycle management approach.
Roles and responsibility
More information about the responsibility for the implementation of the detailed criteria proposed in this LWMS can be found in Table E 1.
Funding
Review
Conclusions and recommendations
General references
Department of Water (DoW) 2007b, Water Quality Protection Note 83: Infrastructure Corridors Near Sensitive Water Sources, Perth. Department of Water (DoW) 2013b, Guidance for the approval of non-potable water systems in Western Australia, Perth. Department of Water and Environmental Regulation (DWER) 2017, decision making process for stormwater management in Western Australia, Government of Western Australia, Perth.
National Health and Medical Research Council and Natural Resource Management Ministerial Council (NHMRC & NRMMC) 2017, Australian Drinking Water Guidelines 2011 Version 3.4 Updated October 2017, National Water Quality Management Strategy. National Health and Medical Research Council and Natural Resource Management Ministerial Council (NHMRC and NRMMC) 2017, Australian Drinking Water Guidelines, National Water Quality Management Strategy, Australian Government, Canberra. Swan River Trust (SRT) 2009, Swan Canning Water Quality Improvement Plan, Government of Western Australia, East Perth.
Western Australian Planning Commission (WAPC) 2001, Gnangara Land Use and Water Management Strategy, WA State, Perth.
Online references
Assess the indicative permeability of the soil at the site for potential disposal of stormwater at the site by infiltration; and. A summary of the testing carried out for this study is presented in Table 2 and the laboratory test certificates are included in Appendix E. Within HA15 the Bassendean Sand was underlain, at a depth of 1.2 m, by Sandy Clay/ Sand with Clay (SC) of the Guildford Formation consisting of low plasticity clay and fine to coarse sand, wet.
The results of the laboratory tests completed on the samples extracted from the wells during the investigative field work are summarized in Table 4. The recommended soil parameters for the design of retaining walls are presented in Table 5. The recommendations and geotechnical parameters given in this report are based on the terrain conditions encountered at the time of the geotechnical investigation.
JDSi should be consulted if there is any prolonged delay in issuing this report and using the recommendations provided. The location of the site in relation to the surrounding area is shown in Figure 1, Site Plan and Location. Infiltration test results are presented in Appendix D and summarized in Table 2: Summary of Infiltration Test Results.
Note: Permeabilities above 15 m/day are not given due to the inaccuracy of the method in highly permeable material. In most of the area, the highest historical groundwater level is close to the existing ground level.
Example of a BRA
