IMPACTS TO HYDROLOGICAL PROCESSES AND INLAND … Impact Assessment Report...Regional Water Supply...

S t ra t eg i c A ss es sm en t f o r t h e P e r t h a n d P ee l R e g i o n s

© E C O L O G I C AL AU S T R AL I A P T Y L T D 161

7 IMPACTS TO HYDROLOGICAL PROCESSES AND INLAND WATER ENVIRONMENTAL QUALITY

7.1 KEY FINDINGS • Water is managed through an extensive array of policies and processes. The State is committed

to strategic reform of water legislation to provide a system that is flexible, progressive and capable of managing water today and into the future.

• The most significant threat to water dependent environmental values within the Advice Area comes from a drying climate; new hydrological regimes are inevitable in some areas.

• Increased recharge associated with land use changes may represent opportunity to balance falling groundwater levels resulting from reduced rainfall, however this hinges on strong allocation and licensing processes and the identification of alternative supplies built into land planning process.

• The State will continue to incorporate the most up to date knowledge on water availability into allocation planning, including consideration of climate change and environment water requirements, to inform decision making in the face of likely increased demand.

• In areas of limited groundwater availability, DoW will work with planning agencies and developers to address the shortfall and protect sensitive groundwater dependent ecosystems. This will be facilitated through the development of sub-regional water management strategies. Water constraints identified will form the platform for work to be undertaken through the Perth-Peel Regional Water Supply Strategy, which will be the strategic response for securing water sources for future development proposed.

• Better Urban Water Management (WAPC 2008a) is a key tool for ensuring appropriate management of water dependent values through development of new urban, industrial and rural residential areas. The State is committed to ensuring this document is fit for purpose through a number of enhancements including a broadening of the scope.

• Nutrients export risk are a critical issue in a number proposed urban and industrial areas in proximity of sensitive receptors such as the Ellen Brook and the Peel Harvey-Estuary. Specific commitments have been made to investigate appropriate mitigation options prior to rezoning of these areas.

• Monitoring and reporting of water quality in the Peel-Harvey and Swan-Canning will be improved through measures including the development of estuarine health indicators and water quality criteria for all sub-catchments.

• An extensive suite of management options, guided by Water Quality Improvement Plans, is proposed for the Swan-Canning and Peel Harvey catchments in order to manage nutrient issues



both from past practices and into the future and in the case of Peel Harvey will be overseen by a new Water Quality taskforce.

• Acceptability of development within P1 and P2 areas in Gnangara and Jandakot underground water pollution control areas will be confirmed through a comprehensive assessment of land and water factors before proceeding with rezoning in order to protect drinking water supplies.

7.2 EPA OBJECTIVE The following EPA objectives for hydrological processes and inland waters environmental quality are applicable to this assessment:

To maintain the hydrological regimes of groundwater and surface water so that existing and potential uses, including ecosystem maintenance, are protected.

To maintain the quality of groundwater and surface water, sediment and biota so that the environmental values, both ecological and social, are protected.

7.3 ENVIRONMENTAL POLICY AND GUIDANCE Key policy and guidance relevant to this assessment with regard to hydrological processes and inland waters environmental quality include but are not limited to:

• State Planning Policy 2.1 Peel-Harvey Coastal Plain Catchment (WAPC 2003b).

• State Planning Policy 2.2 Gnangara Groundwater Protection (WAPC 2005).

• State Planning Policy 2.3 Jandakot Groundwater Protection (WAPC 2003c).

• State Planning Policy 2.6 State Coastal Planning Policy (WAPC 2013).

• State Planning Policy 2.7 Public Drinking Water Source Policy (WAPC 2003d).

• State Planning Policy 2.9 Water Resources (WAPC 2006a).

• State Planning Policy 2.10 Swan Canning River System (WAPC 2006b).

• Environmental Protection (Peel Inlet-Harvey Estuary) Policy (EPA 1992).

• Guidance Statement No. 28: Protection of the Lake Clifton Catchment (EPA 1998).

• Position Statement No. 4: Environmental Protection of Wetlands (EPA 2004).

• Statewide policy No. 5: Environmental water provisions policy for Western Australia (Water and Rivers Commission 2000).

• EPA Guidance Statement 33 Chapters B4 Wetlands and B5 Waterways of Environmental guidance for land planning and development (EPA 2008c).

There are also various land use and water management strategies, water quality improvement plans, drainage and water management plans, allocation plans for surface water and groundwater resources and floodplain management strategies that are in operation across the Advice Area.



7.4 EXISTING ENVIRONMENT

7.4.1 Key values

The Advice Area supports a range of surface water and groundwater systems that have a high degree of interaction due to the nature of the landforms present. These systems include important groundwater aquifers, estuaries, wetlands, rivers, streams and their catchments. These systems are of value for their support of ecological processes, functions and assets as well many consumptive and non-consumptive uses, including:

• public and private potable and non-potable water supply;

• recreation and tourism;

• fisheries (recreational and commercial);

• cultural and heritage (Aboriginal and non-Aboriginal);

• landscape and aesthetics; and

• educational and scientific activities.

The EPA has advised that key water assets for consideration in planning and evaluating the impacts of future development within the Advice Area are wetland and rivers systems, including the Swan Canning and Peel-Harvey estuaries, and groundwater resources (EPA 2015a).

Groundwater

Groundwater aquifers within the Advice Area are valued for a range of functions including:

• Support of wetlands, caves and springs and their associated ecosystems, including subterranean fauna.

• Support of groundwater dependent vegetation.

• Drinking (potable) water supply from both the confined and unconfined aquifers.

• Non-potable water supply for domestic use, industry, irrigated agriculture, open space irrigation, all mostly from the unconfined superficial aquifer, with some from the Leederville aquifer.

• Its part in the integrated water cycle, including discharge to lakes, rivers, estuaries and the ocean.

• Limiting saltwater intrusion from the ocean salt water wedge.

Within the Swan Coastal Plain portion of the Advice Area, the superficial formations average approximately 50 m in thickness. Below the superficial formations there are a number of confined and semi-confined aquifers, the most extensive of which are the Leederville, which is highly variable but typically several hundred metres thick, and the Yarragadee, which can extend to a depth of greater than 1,000 m.

To the north of Perth (between the ocean, the Swan River, Ellenbrook and Moore River, centred about 15 km north-east of Wanneroo), the Gnangara groundwater system provides the largest source of potable water in south-west WA. Studies carried out in preparation of the Draft Gnangara Sustainability



Strategy showed that abstraction and use of Gnangara groundwater is worth $300 million a year to the Western Australian economy or a total net present value of $6.7 billion. In this location, the superficial formations host an aquifer of around 45 m thickness. The Gnangara and Jandakot Mounds are the two major superficial aquifer systems within the Advice Area.

The Gnangara Mound supports a wide range of groundwater dependent ecosystems. The Draft Gnangara Sustainability Strategy identified 45 significant wetlands supported by the Gnangara groundwater system. Those within the boundary of the Advice Area include:

• aquatic habitats in the karstic cave system around Yanchep National Park;

• permanent deeper surface waters (with good buffering capacity) in the northern linear chain wetlands of the Spearwood interdunal system (Loch McNess, Nowergup Lake, Yonderup Lake and Lake Goollelal);

• tumulus springs (organic mound springs) in the Ellen Brook region;

• surface waters in the Ellen Brook region of the eastern side of the Gnangara Mound (for instance, Twin Swamps) including the ephemeral clay-dominated swamps (such as Ellenbrook Nature Reserve); and

• habitat complexes in the large shallow wetland systems on the Bassendean Dune system (Melaleuca Park and Lexia wetlands).

The smaller Jandakot Mound occurs to the south of Perth (between the ocean and the Swan, Canning and Serpentine rivers) with an average aquifer thickness of 20 – 30 m. Jandakot Mound also supports important groundwater dependent ecosystems, including the Ramsar listed Thomsons and Forrestdale lakes. On both the Gnangara and Jandakot Mounds remnant Banksia woodlands with a shallow depth to groundwater table are known to be dependent on groundwater for part of their water needs.

These groundwater mounds comprise the key shallow groundwater features of the Advice Area. They are recharged directly by rainfall infiltration and, apart from a few drains, are characterised by the absence of surface flow. The mounds have developed because the rate of vertical rainfall infiltration is greater than the rate of horizontal groundwater flow through the aquifer (Davidson & Yu 2006).

Groundwater movement within the Advice Area is generally in a westerly direction, towards the Indian Ocean and on the Gnangara and Jandakot Mounds radially from the centre of the mounds to their discharge boundaries.

Rivers and estuaries

DoW’s Waterways and Wetlands publication (DoW 2009a), prepared as background to the Perth-Peel Regional Water Plan, identifies waterways as valuable natural assets, supporting the following values:

• Ecological values, providing habitat for aquatic and terrestrial flora and fauna, and supporting biodiversity and threatened species.

• Hydrological values, draining land, transport and storing water, and carrying flood waters.



• Economic values with the region’s waterways being also valuable tourism assets and prized recreational areas. They provide a source of water for drinking, fisheries, agriculture, mining and other industries.

• Social values including recreation, culture and heritage, landscape and aesthetics, and educational and scientific.

Within the Advice Area there are six major river systems, comprising the Swan-Avon, Canning, Helena, Serpentine, Murray and Harvey Rivers. Each of these rivers, and various associated tributaries has its headwaters on the Darling Plateau. These rivers drain to either the Swan River Estuary (Swan-Avon, Helena and Canning) or the Peel-Harvey Estuary (Serpentine, Murray and Harvey), and finally to the Indian Ocean (Figure 7-1).

In a largely cleared landscape, waterways and their associated riparian vegetation provide a significant role in provision of ecological corridors and linkages between remnants of uncleared landscape. These riparian zones act as refuges for terrestrial fauna, assist in fauna movement and support their own aquatic ecosystems.

Surface water sub-catchments of these and other surface water systems in the Advice Area represent potable and non-potable water sources. There are a number of reservoirs used for drinking water as well as numerous private dams for rural use.

The EPA in its interim strategic advice recognises Swan Canning River system and Peel-Harvey Estuary system as key assets to be protected. The Swan River Estuary is a permanently open estuary. Following the removal of the Fremantle sill in the late 1800s (and dredging of the large flood delta) the estuary became more salty. It now changes from fresh/brackish conditions in winter and spring, to salty conditions during summer and autumn. In the summer months, the Swan Estuary provides important feeding areas for migratory wading birds and is a significant nursery area for crustacea and marine fishes (IMCRA Technical Group 1998). The Swan Canning River Protection Strategy identifies the following values: ecosystem health; sense of Place; community benefit; and economic benefit (Parks and Wildlife 2015c).

Ecosystem health is considered a keystone value because the other values are intrinsically dependent upon it (Parks and Wildlife 2015c). Ecosystem health includes protecting water quality, environmental flow, biodiversity and foreshore condition, on which the other values depend. Rapid population growth and increased urban development in the Swan Canning catchment, has led to a decline in water quality, dwindling water resources and native vegetation. The Swan Canning River system has shown symptoms of eutrophication, especially algal blooms and fish kills, over a number of years. The Avon River (as a tributary) is known to be major contributor of sediment and nutrients into the Swan River.

The second of the Advice Area’s two estuary systems, the Peel-Harvey Estuary, in combination with the adjacent Yalgorup Lakes system, has been listed under the Ramsar Convention as a wetland of international importance. These wetlands are selected on the basis of their international significance in terms of ecology, botany, zoology, limnology or hydrology. Further detail on the values of the Peel-Harvey Estuary system can be found in the Commonwealth IAR document (Chapter 19).

Swan CanningEstuary

Catchment

Peel-HarveyEstuary

Catchment

SwanAvon/Lower SwanCatchment

Peel Estuary -Murray RiverCatchment

SwanAvon -Main AvonCatchment

Peel Estuary - Serpentine River

Catchment

SwanAvon -Canning River

Catchment

SwanAvon -Main AvonCatchment

Harvey Estuary -Harvey RiverCatchment

CoastalCatchment

Moore RiverCatchment

CoastalCatchment

Swan/AvonMain AvonCatchment

CoastalCatchment

YanchepCoastalLakes

Catchment

BartramRoad

Catchment

WannerooCoastalLakes

Catchment

Harvey Diversion -Harvey RiverCatchment

SwanAvon- Mortlock

Catchment

Canning River

Helena River

Murray Rive r

Swan Rive

r

Serpentine River

Avon River

Harve

y Rive

r

Figure 7-1: Waterways of the Advice Area and their catchments

±Prepared by: SM Date: 17/11/2015

0 10 20 30Kilometres

Datum/Projection: GDA 1994 MGA Zone 50Data Source: DoW (Mar 2013)

LegendAdvice.AreaWaterwaysCatchments



Wetlands

Ecological and other non-hydrological values of wetlands of the Advice Area are discussed in Chapter 5 (Impacts to Flora and Vegetation). Two specific hydrological values of wetlands are identified in EPA Position Statement No 4: Environmental Protection of Wetlands (EPA 2004), being hydrological balance and water quality protection, which are addressed here.

In terms of the hydrological balance, flood control and stormwater detention can be important hydrological functions of wetlands. Potentially damaging volumes of fast-flowing floodwaters are temporarily stored in wetlands (EPA 2004). This temporary storage slows the movement of water through the landscape and can protect downstream receiving environments.

In terms of water quality protection, wetlands may greatly influence the water quality of estuaries, rivers and streams by removing pollutants such as sediments, nutrients, organic and inorganic matter and some pathogens. Runoff and drainage water which pass through such wetlands are essentially ‘filtered’. This improvement in water quality comes from the wetland’s ability to retain nutrients such as nitrogen and phosphorus, to intercept other pollutants, and to trap sediment and reduce suspended solids (EPA 2004).

Wetlands within the Advice Area, as mapped in the Geomorphic Wetlands of the Swan Coastal Plain dataset, are shown in Figure 5-3.

7.4.2 Key Threats

This section discusses key threats that may be associated with development of a city for 3.5 million people. This includes development of the proposed footprints and associated land use changes, as well as the implications of an increased population. The EPA objectives for water factors, listed in Section 7.2, identify the maintenance of hydrological regimes and quality as key elements in ensuring that the environment is protected. In recognition of these objectives, it follows that any change in either hydrological regime or quality may constitute a threat to the key values described in Section 7.4.1. This could include:

• changes in surface water flows;

• change in groundwater levels or availability;

• changes in the water quality, sediments or biota of rivers, estuaries and wetlands; and

• changes in groundwater quality.

Cl imate change

Climate change is currently and will continue to exert significant effects on the hydrological regimes and quality of groundwater and surface water systems of the Advice Area and is a key threat to the values these systems represent. The potential risks due to climate change are discussed where relevant in the sections below, along with other key threats, in order to provide context to the threats that may be associated with development of a city for 3.5 million people.



Change in groundwater hydrology

Groundwater levels in the superficial aquifers (including the Gnangara and Jandakot Mounds) are influenced by recharge and abstraction. Recharge is a function of land use and climate. Abstraction occurs directly from the mounds and also in the deeper Leederville and Yarragadee aquifers. This deeper pumping can influence the Superficial aquifer, as it can induce increased downward leakage to the deeper aquifers where they are connected to the Superficial aquifer.

Without appropriate management, the biggest threats to groundwater hydrology within the Advice Area, and in particular that of the Gnangara and Jandakot Mounds that support so many important values, are from abstraction, land use changes and climate change.

Groundwater levels in the Superficial aquifer are highly dependent on recharge from rainfall. Across south-west Western Australia there has been a general trend of declining annual rainfall since the mid-1970s. CSIRO’s investigation of climate change (Bates et al. 2010) along with relevant global climate change models, predicts continued rainfall reduction in this region.

Preliminary modelling b Department of Water has shown that the area most sensitive to a drying climate is to the east of Lake Pinjar, near the crest of the Gnangara Mound. The modelling shows that groundwater levels near the coast and the Darling Scarp, and also in developed areas, are generally less sensitive to the reduced rainfall under a drying climate (see Section 7.8.1). The influence of climate change on groundwater levels should always be considered in the context of future land use changes and potential changes in groundwater abstraction.

Abstraction from the Jandakot groundwater system is currently within allocation limits and water levels across most of the Jandakot Mound are relatively stable. The Gnangara system is currently over-allocated and water levels in many parts of the system are declining. This has meant important wetlands and other environments have dried up, or are on a pathway to further decline in health and ecological function. It is likely that if further declines do occur, community concern will increase given the importance of the wetlands and surrounding areas to housing prices, local amenity and recreation, in addition to the ecology.

In 2004, the EPA concluded that the current management of the Gnangara Mound was no longer sustainable (EPA 2004). The EPA cited abstraction, land use change and climate change as contributing factors. Since this time the government has invested significant effort in attempting to balance abstraction with changed environmental conditions (see Section 7.5.4). Despite this it is recognised that due to the significant influence of the drying climate, new hydrological regimes are inevitable in some areas.

Where it is not managed, land use change has the potential to compound the effects of climate change through changes in recharge and through increased abstraction. However, land use change also has the potential to largely offset the effects of drying climate in some areas through increased recharge.

The construction process associated with development can represent a specific threat to groundwater due to a temporary demand for water supplies. Groundwater is often utilised in dust suppressions and other construction associated activities. In addition, where sub-surface infrastructure is proposed dewatering may be undertaken in order to facilitate installation. Again, this can lead to temporary drawdown of the localised groundwater table.



Regional groundwater declines or localised drawdown have the potential to have flow-on impacts such as:

• inducing sea water intrusion or salt water up-coning, contaminating drinking water, and increasing salinity in groundwater dependent wetlands and riparian vegetation;

• reducing the quantity of discharge into dependent wetlands causing them to dry out or change hydrological state, leading to loss of conservation values associated with a particular hydrological regime;

• acidification, resulting from exposure and oxidation of otherwise saturated sediments containing sulfides;

• changes to habitat for subterranean fauna;

• changes to ecological systems of wetlands sustained by groundwater;

• physical and chemical changes to caves and springs; and

• increased pressure on the sustainability of drinking and non-potable water supplies.

Change in surface water hydrology

Since the mid-1970s, the south-west of Western Australia has experienced a 10-15 per cent decline in average ‘wet season’ rainfall (DoW 2009a). The decline in rainfall has reduced stream flows in the region by around 50 per cent (DoW 2009a). Modelling suggests a decrease in mean annual rainfall of at least 7 per cent in the period 2021 to 2050 relative to the period 1961 to 1990 (Hope et al. 2015), which according to hydrological modelling investigations undertaken by DoW (DoW 2010), could correspond with a 21 per cent change in mean annual streamflow. If current climate trends continue, south-west WA will experience a significant increase in time spent in drought as well as further reductions in stream flow (Hope et al. 2015). These changes have the potential to impact on environmental water requirements of river, estuaries, wetlands and their associated riparian environments.

In addition, sea and estuary level rises associated with climate change could result in flooding of low lying coastal land.

The Swan River Trust (SRT) has reported that the combination of sea level rise and decreased stream flow will impact the Swan Canning River system’s ecology and is predicted to:

• increase penetration of marine water upstream and estuary area which will experience salinity stratification;

• affect biological processes such as oxygen demand, nutrient cycling and sediment retention;

• alter distribution and abundance of species along with seasonal patterns of productivity and food-web dynamics; and

• cause ongoing problems associated with eutrophication such as algal blooms and fish kills, particularly in the upper Swan River.

The Peel-Harvey system is likely to experience similar outcomes. These are described in Chapter 19 of the Commonwealth IAR.



Apart from climate change, changes in land use need to be managed to ensure that hydrological regimes are maintained. However, land use change can represent an opportunity as well as a threat to hydrological regimes. In some cases there are opportunities to use land use change to offset the effects of climate change through increased recharge.

Changes in land use can also introduce higher demand for surface water resource for uses such as irrigation and public drinking water.

Drainage networks and stormwater systems that are traditionally associated with land development on the Swan Coastal Plain alter the surface hydrological cycle. This can result in the potential for more local runoff and changes to physical topography altering surface drainage patterns. The introduction of large areas of impervious surfaces such as rooves, carparks, driveways and roads means rain is not infiltrated where it falls, and large volumes of water must be artificially drained. Subsoil drains are also often used to drain groundwater in order to allow development in areas with high groundwater tables. These changes to the hydrological environment can impact negatively on aquatic fauna and riparian environments of downstream waterways into which the drains deliver flows. In addition, these changes can also impact on water quality through transport of nutrients and contaminants. These water quality outcomes are discussed later in this section.

Changes in surface hydrology can be impacted directly by development where it is undertaken within a floodway or floodplain. For example, where infrastructure is designed inappropriately this can cause changes to the natural flooding regime, impacting on both upstream and downstream ecosystems. Additionally, floodplains are an important part of riparian ecosystems and any significant change in flooding regime could detrimentally impact on major flood levels relating to associated wetlands, nutrient cycling, plants or fauna that are supported by the existing flooding regime. Changes in flood regime can cause changes in recruitment, dispersal and resilience of riparian species.

Dams on key rivers and tributaries have also changed hydrological flows and ecological processes (such as movement of aquatic fauna).

Change in groundwater qual i ty

Risk to groundwater quality is strongly associated with land use. Particular land uses have a higher inherent risk of resulting in pollution to groundwater resources. Land use change within the Advice Area could pose a significant threat to groundwater quality where new development is replacing previously vegetated areas or low intensity rural uses. Many of the soils of the Swan Coastal Plain, particularly the Bassendean sands, have limited capacity for nutrient retention and interception of other organic and non-organic substances.

The direct relationship between land use intensification (development) and water quality contamination risk is well documented. This relationship is the result of the increased presence of contaminants, and increased contamination incident frequency, that occurs when more people, buildings, roads fuel and other chemical and biological products are introduced into an area. Pathogens, hydrocarbons, heavy metals and other chemicals are at increased risk of ending up in groundwater within these areas, which has a potential impact on public drinking water sources and groundwater dependent ecosystems.



The introduction of urban, industrial and rural residential development can also result in an increase in concentrations of nitrogen and phosphorus (hereafter referred to as ‘nutrients’) and organic matter into underlying groundwater systems, affecting water quality.

In addition, the excavation of brownfields areas for urban and industrial development and their associated infrastructure has the potential to intersect existing contaminated sites. Disturbance of a contaminated site could cause or exacerbate the mobilisation of contaminants into the groundwater.

Acidity through excavation, dewatering, over abstraction and plantation water use is another significant risk to groundwater quality associated with proposed future development. Release of acidity can lead to the mobilisation of heavy metals and nutrients within groundwater and threatens to reduce the value of shallow groundwater for irrigating public open space in the proposed development areas. This is greatest where regional groundwater levels rise following previous high water using land uses. It should be noted that acidification can also result from climate change and associated declines in groundwater tables. Figure 7-2 shows land within the Advice Area mapped as high-moderate risk of acid sulfate soils occurring within 3 m of the natural soil surface.

Other threats to groundwater include water salinisation as a result of sea water intrusion or salt water up-coning.

!H

!H

!H

!H

!H

!H

!H

!H

!H

!H

!H

!H

!H

!H

Perth

Chidlow

Waroona

Yanchep

Kwinana

Mandurah

Pinjarra

Mundaring

Ellenbrook

Bullsbrook

JarrahdaleSerpentine

Rockingham

Dwellingup

Figure 7-2: Risk mapping for acid sulphate soils in the Advice Area



Datum/Projection: GDA 1994 MGA Zone 50Data Source: DER (Sept 2014)

LegendAdvice.Area

Risk CategoryHigh to Moderate RiskModerate to Low Risk



Change in the water qual i ty, sediments or b iota of r ivers , estuar ies and wet lands

Climate change is likely to play a key role in future water quality of waterways of the Advice Area. Many of the effects are a follow on from the expected changes in hydrological regimes such as altered surface water flows and sea level rises, where changes in flows may affect the transport of contaminants, nutrients and sediments. In addition, increased atmospheric and water temperatures and more frequent warm spells and heat could lead to an increase in algal blooms and fish kills.

In addition, due to the interrelated nature of the hydrological system, many of the threats to groundwater quality within the Advice Area discussed above apply equally to quality of surface water systems. Surface water systems of the Advice Area receive discharge from groundwater so that any contamination or nutrient enrichment of groundwater systems is also likely to affect nearby waterways or wetlands. The introduction of urban, industrial and rural residential development could result in an increase in levels of nutrients and organic matter into surface water catchments, affecting water quality.

Decreased water quality as a result of nutrient enrichment has potential to lead to algal blooms, an increase in harmful algae, fish kills, changes in aquatic communities, dolphin deaths and loss of habitat. All of these occurrences have been recorded within waterways in the Advice Area. Wetlands may experience similar changes from increased eutrophication. Increased nutrients in surface water systems can also lead to an increase in nuisance midges and mosquitoes.

In addition to potential increases in nutrient application rates, modified hydrological pathways associated with development can increase the potential for contaminant movement into waterways and wetlands. Drains and stormwater systems are designed for movement of large volumes of water through the landscape and can be used to drain high groundwater tables to allow development. They can also provide a conduit for movement of contaminants, nutrients, organic loads and sediment into waterways. The Swan River Trust, in response to a report by the Auditor General, identified the influx of nutrients and organic matter from urban and rural catchments as being of particular concern to the health of the Swan Canning system (OAG 2014). Urban drains can flow all year where they intercept groundwater and in a report on the health of the Swan River, it was stated that these drains transport contaminants from small to medium-sized industry, agriculture and domestic sources to rivers and wetlands (OAG 2014). Rural drains and associated nutrients are also known to be problematic in the Peel-Harvey.

In the Swan Canning, it is recognised that the relative impact of urban drains as a source of nutrients and contaminants has increased, due to lower rainfall and associated loads of nutrients from Avon and Ellen Brook agricultural catchments. Targeting nutrient reduction in urban drains will therefore have greater impact on improving river health than in the past (OAG 2014).

Hydrocarbons and detergents, organic chemicals (solvents, degreasers), alkalis, acids and non-organic chemicals (metals) make their way into the river system through stormwater drains. Particularly from small businesses in industrial areas without waste disposal options best suited to their business.

Additionally, an increased population could lead to detrimental effects to water quality as a result of increased pressure from human activities. In particular, this is likely to cover increased nutrient and organic loads from an increase in activities such as recreation, littering, pet ownership and uncontrolled access.



Loss of riparian vegetation and associated sedimentation are another potential threat to the quality of rivers, estuaries and wetlands. Fringing (or riparian) vegetation is an integral part of these ecosystems and comprises both the terrestrial and emergent vegetation that borders and is influenced by the waterway. Fringing vegetation supports a diversity of fauna and the associated root mass provides for stabilisation of banks providing protection from erosion and resulting sedimentation. Fringing vegetation also helps to reduce nutrients and sediment entering waterways by slowing the rate of overland runoff, enabling sediments to settle and nutrients to be trapped and utilised on land (SRT 2015).

Disturbance to riparian vegetation from the proposed future development in the Advice Area may arise from the following:

• clearing;

• edge effects from adjacent construction activities;

• channel change (from clearing in the catchment or alteration of flow regimes);

• vehicle and public access;

• Changes to flood regime, as a disturbance that may arise, which may cause changes to recruitment, dispersal and resilience;

• effects of adjacent land uses; and

• fire.

The risk to groundwater quality from release of acid and heavy metals through the disturbance of acid sulfate soils is discussed under changes in groundwater quality. These risks apply equally to river, estuary and wetlands systems. A key consideration is the formation of gelatinous black organic sludges, known as monosulfidic black ooze (MBO), under anoxic conditions and in the presence of sulfate-reducing bacteria and organic material (for example the floor of a waterway). When disturbed (e.g. through dredging) these MBOs may release previously bound contaminants into waterways, as well as rapidly reducing the concentration of dissolved oxygen, potentially resulting in fish deaths.

7.5 CURRENT MANAGEMENT ARRANGEMENTS This section details how the key values and threats relating to hydrology and water quality are currently managed.

7.5.1 Strategic direction for management of resources

In 2009, DoW released the draft Perth-Peel Regional Water Plan 2010-2030: Responding to our drying climate in order to provide strategic direction for sustainable water management in the Perth-Peel region. The six objectives of the plan were to:

• take the drying climate into account in all aspects of water resource management;

• reduce water demand by using water more efficiently and effectively;

• provide water security for public and private water supply consumers;



• facilitate the use of alternative sources of water supply;

• restore and protect waterway and wetland health; and

• create water sensitive cities and towns.

Under the Plan, DoW identified 35 actions for completion between 2010 and 2030. Many of these actions have already been progressed by DoW. Building on the work of the Regional Water Plan DoW is now preparing the Perth-Peel Regional Water Supply Strategy. This strategy provides for the implementation of relevant actions identified in the Plan to meet planning needs and support future development to 2050. This strategy will include identifying alternate (and fit-for-purpose) water supply solutions to meet future water demand needs.

7.5.2 Consideration of climate change

The Regional Water Plan was prepared to take the drying climate of the Advice Area into account in all aspects of water resource management. The following actions were identified in the Regional Water Plan to better account for climate change in water planning:

• Develop a new approach for setting and achieving environmental management objectives for groundwater-dependent environmental values on the Gnangara and Jandakot Mounds that includes monitoring of climactic conditions and recognition of trends over time.

• Refine groundwater availability estimates through further groundwater investigations and assessments:

o in the Peel sub-region to advise south-western and south-eastern corridor development;

o in the primary recharge area for the Yarragadee aquifer on the north-eastern Gnangara Mound; and

o in the Gingin Groundwater Area.

• Increase groundwater monitoring of the seawater interface in coastal risk areas where groundwater abstraction also occurs (for example, Mandurah, Golden Bay, north-west coastal).

• Implement the water resource management recommendations of the Gnangara Sustainability Strategy, a cross-government initiative.

• Adjust allocation limits for water resources experiencing decline due to reduced recharge, in order to re-establish local water balances. Where needed, progressively reduce public and private water supply allocations to restore water balances.

Each of these measures is currently being implemented and contributes to a strategic approach to managing threats to water dependent ecosystems and values from future changes in climate. Some aspects of the Gnangara Sustainability Strategy have now been superseded by the Gnangara groundwater allocation plan.



7.5.3 Pines Harvesting

In 1996, the State Government decided to remove up to 23,000 hectares (ha) of pine plantations to the north of Perth in the Gnangara, Pinjar and Yanchep pine plantations, and not replace them, in order to increase water recharge on the Gnangara Mound. As part of the Strategic Assessment process, different alternatives have been considered for harvesting and subsequent post-harvest land use. The EPA will not be providing advice on the harvesting of pines and the action is not being considered in this impact assessment per se.

However, the decisions on harvesting of pines and what will replace them have significant impacts for groundwater levels within the Advice Area and provides context in which the impacts of other land use changes must be considered. The harvesting of pines provides a new ‘base-case’ groundwater scenario and has been taken into consideration in the impact assessment presented in Section 7.8.

Removing the pines will contribute towards offsetting the impacts of the drying climate and helping to maintain the long term productivity of the water resource, particularly in meeting some of the water needs for a population of 3.5 million. The groundwater level benefits will also assist the State in rebalancing the effects of groundwater abstraction and associated environmental impacts on the Gnangara groundwater system in order to meet the objective of protecting the quantity and quality of groundwater for use and the environment into the future.

7.5.4 Water allocation, planning and licensing to manage resources

Water allocation planning is one of the ways DoW manages the State's water resources and protects the diverse range of environments that depend on water resources. DoW manages water use by issuing water licences under the Rights in Water and Irrigation Act 1914. Under the Act a licence is required to take water from a watercourse or groundwater aquifer in proclaimed areas.

Allocation plans set out how much water is available from a particular resource or area and how much water needs to be left in the system to ensure its sustainability. Allocation plans also detail which local policies and conditions will be applied to licences to take water issued under the Rights in Water and Irrigation Act and how the objectives of the plan will be monitored, measured and evaluated.

These plans ensure that needs of the community and environment are protected whilst providing secure water supplies. Allocation planning:

• provides a consistent, transparent process for licensing;

• ensures the long-term sustainability of a region's water resources;

• brings certainty for water users; and

• protects water resources and water-dependent environments into the future.

Water allocation planning is based on scientific evidence and involves a significant amount of research and stakeholder consultation. Allocation plans retain flexibility to respond to new information. Climate predictions, hydrological and hydrogeological understanding and understanding of environmental water requirements are continually improving. Water allocation plans are non-statutory and guide regulatory



decisions. DoW’s process for developing allocation plans is explained in Water allocation planning in Western Australia: a guide to our process (DoW 2011).

Water allocation plans are in place across the majority of the Advice Area, covering all of the major groundwater abstraction areas. Refer to Table 7-1 for detail on allocation plans in the Advice Area.

Table 7-1: Existing allocation plans within the Advice Area

Allocation Plan Released

Groundwater

Peel Coastal 2015

Murray 2012

Gnangara 2009

Cockburn 2007

Rockingham – Stakehill 2007

Surface Water

Middle Canning River 2012

Importantly, approximately 30 per cent of the water resources within the Advice Area are over allocated. An additional 23 per cent have between 70-100 per cent of the total determined allocation limit allocated. These figures highlight the need for a focus on more efficient use of existing water and developing alternative water sources moving into the future.

Consistent with the National Principles for the Provision of Water for Ecosystems, DoW has adopted the concepts of ecological water requirements (EWRs) and environmental water provisions (EWPs) with some minor refinements of terminology (Water and Rivers Commission 2000). EWRs are the water regimes needed to maintain ecological values of water dependent ecosystems at a low level of risk. EWRs are determined on the basis of the best scientific information available and are the primary consideration in the determination of EWPs.

EWPs are the water regimes that are provided as a result of the water allocation decision-making process taking into account ecological, social and economic values. They may meet in part or in full the EWR. The water allocation decision-making process includes assessment of the proposed EWPs under the EP Act where environmental impacts may be significant (Water and Rivers Commission 2000).

Licensing the take of water

DoW uses water allocation plans to protect the diverse range of environments that depend on water resources from impacts of water abstraction. It also manages the effect water abstraction can have on the local environment through site specific water licensing decisions and local area policy.

The risk to the environment from the take of water is managed through:

• Setting sustainable allocation limits that are adjusted to factor in the projected drying climate.



• Environmental risk assessment of individual licences, at the point of take.

• Restricting take and managing risks through simple licence conditions or operating strategies, such as rules for when the water can be taken.

• Enforcing the three-day-week sprinkler restriction and winter sprinkler ban for domestic garden bore users.

• Determining suitable and unsuitable areas for the installation of new domestic garden bores.

• Setting environmental release rules for the Integrated Water Supply System reservoirs to support the downstream environment.

• Monitoring and reporting on how the environment is responding to the take of water and other influences such as the drying climate.

When an application is submitted to DoW for a licence to take water in a proclaimed area under the Rights in Water and Irrigation Act, 1914, DoW must consider a number of factors, including whether the proposed development is likely to be environmentally acceptable and ecologically sustainable. Licences may contain conditions to address any potential impacts.

Minister ia l cr i ter ia

Groundwater abstraction from both the Gnangara and Jandakot groundwater systems is managed in line with conditions and commitments, including water level criteria, set by the Minister of the Environment under the EP Act. These conditions and commitments are defined in Ministerial statement 819: Gnangara Mound Groundwater Resources and Ministerial statement 688: Jandakot Mound Groundwater Resources which set EWPs in the form of water level criteria at 30 groundwater dependent ecosystems (including wetlands) on Gnangara and 23 on Jandakot.

DoW monitors and reports on compliance with Ministerial conditions and commitments through annual and triennial compliance reports to the Office of the Environmental Protection Authority. The reports also outline the management, research and consultation DoW undertakes to manage the groundwater resources of the Gnangara and Jandakot systems in a sustainable manner.

Protect ing the envi ronment and water securi ty in Gnangara

For the Gnangara groundwater system, management actions are guided by the 2009 Gnangara groundwater areas allocation plan. The plan sets strategies to manage groundwater abstraction sustainably and steps to return the over-allocated system to balance, after 40 years of declining rainfall and recharge to groundwater. The plan has been a key step in adjusting groundwater management in the context of drier climate and has resulted in the following:

• Significantly reduced abstraction for public water supply.

• Increased compliance and enforcement activities.

• Increased protection of groundwater-dependent ecosystems, by moving abstraction to lower risk areas, including the deeper Leederville and Yarragadee aquifers.



DoW is continuing to work with licensees and stakeholders to ensure Perth has access to good quality, affordable groundwater supplies, water efficient public open spaces and healthy wetlands that support and enhance our way of life now and into the future. The Department is now preparing for the next Gnangara groundwater areas allocation plan, which will aim to set levels of abstraction that match a drier climate to 2030.

!H

!H

!H

!H

!H

!H

#0

#0

#0#0

#0#0

#0#0

#0

#0

#0#0

#0

#0 #0#0

#0

#0

#0

#0

#0#0

#0#0

#0

#0

#0

#0#0#0#0

#0

#0#0

#0

#0

#0

#0#0

#0

#0

#0 #0#0 #0

#0

#0

#0#0

#0

#0

#0

#0

#0#0#0#0#0

#0

#0#0

#0

Perth

Yanchep

Ellenbrook

Bullsbrook

Figure 7-3: Location of Ministerial criteria sites within the Advice Area


0 4 8 12Kilometres

Datum/Projection: GDA 1994 MGA Zone 50Data Source: DoW (2011)

LegendAdvice.Area

Ministerial criteria sites#0 Ground#0 Surface



7.5.5 Public drinking water source areas

Under the Metropolitan Water Supply, Sewerage and Drainage Act 1909 (WA) or the Country Areas Water Supply Act 1947 (WA) DoW can proclaim water reserves, catchment areas and underground water pollution control areas (UWPCAs), collectively known as public drinking water source areas (PDWSAs). By-laws created under these statutes enable DoW to manage potentially polluting activities, inspect premises and to take the necessary steps to prevent pollution (DoW 2012a).

The Perth Peel region contains 19 proclaimed PDWSAs in the Advice Area (Figure 7-4). All of these PDWSAs have publicly consulted and available drinking water source protection reports to guide land use planning and development decisions, consistent with the framework recommended in the Australian drinking water guidelines (NHMRC & NRMMC 2015). In the case of Gnangara and Jandakot UWPCAs and the Middle Helena Catchment Area a Land Use and Water Management Strategy was developed by the WAPC in consultation with DoW to guide development and water quality protection.

Statement of Planning Policy 2.7: Public Drinking Water Source Policy 2003 (SPP 2.7) outlines planning measures to ensure that land use and development within PDWSAs is compatible with the protection and long-term management of water resources for public water supply and protection of public health. The policy details three priority areas types for PDWSAs, as outlined below:

• Priority 1 (P1) areas are defined and managed to ensure there is no degradation of the quality of the drinking water source with the objective of risk avoidance. P1 areas occur within PDWSAs where the existing land uses have low risks to PDWSAs. Consistent with the preventive risk–based framework of Western Australian Government, changes of land use that introduce additional risks are not recommended. P1 areas would typically include Crown land, but may also include some private land.

• Priority 2 (P2) areas are defined and managed to maintain or improve the quality of the drinking water source with the objective of risk minimisation. P2 areas occur within PDWSAs where the land is zoned rural and the risks need to be minimised. Low levels of development consistent with the rural zoning are considered appropriate (generally with conditions) in P2 areas.

• Priority 3 (P3) areas are defined and managed to maintain the quality of the drinking water source for as long as possible with the objective of risk management. P3 areas occur within PDWSAs where the land is zoned for urban and commercial or light industrial uses. Within P3 areas, drinking water sources need to co-exist with higher intensity land uses compared to P1 and P2 areas. Key elements in the protection of P3 areas include the need for deep sewerage and implementing best management practices.

In addition, protection zones are defined in the immediate vicinity of drinking water abstraction points as these areas are the most vulnerable to contamination. Protection zones can be located within P1, P2 or P3 areas. There are two types of protection zones: wellhead protection zones are defined as a 500 m radius around public drinking water bores in P1 area and a 300 m radius in P2 and P3 areas. Reservoir protection zones are the second type and are defined in the Metropolitan Water Supply, Sewerage and Drainage By-laws 1981, as ‘that part of a catchment area which lies: a) upstream and within a catchment of a dam; and b) within 2 km of the top water level of any reservoir in which water is or can be stored. Within these zones by-laws may prohibit or restrict specific activities to prevent water source contamination or pollution. Special conditions, such as restrictions on storage and use of chemicals, may apply within these zones.



Water quality protection note No. 25: Land use compatibility tables for public drinking water source areas (DoW) outlines acceptability of specific land uses and activities based on DoW’s water quality protection policy, strategies and management objectives within PDWSAs. For each of the three priority areas, land uses are determined to be incompatible, compatible with conditions, or acceptable. This protection note is used to ensure that all development is consistent with Planning Policy 2.7.

In addition to SPP 2.7, the WAPC has State Planning Polices for the Gnangara and Jandakot Mounds to guide land use planning decisions to protect the groundwater quality. Statement of Planning Policy 2.2: Gnangara Groundwater Protection 2005 and Statement of Planning Policy 2.3: Jandakot Groundwater Protection Policy 2003 (soon to be updated) provide additional detail on acceptable land uses for areas within those specific pollution control areas. The main purpose of the these State Planning Policies are to prevent, control or manage development and land use changes in the policy areas that are likely to cause detrimental effects to the groundwater resources.

Mundaring WeirCatchment Area

Serpentine DamCatchment Area

Canning RiverCatchment Area

Gnangara UndergroundWater Pollution

Control Area

South Dandalup DamCatchment Area

Wungong BrookCatchment Area

Middle HelenaCatchment Area

North DandalupPipehead DamCatchment Area

Stirling DamCatchment Area

Perth Coastal andGwelup Underground

Water PollutionControl Area

Samson BrookCatchment Area

JandakotUndergroundWater PollutionControl Area

Victoria ReservoirCatchment Area

South DandalupPipehead DamCatchment Area

Conjurunup CreekPipehead DamCatchment Area

Serpentine PipeheadDam Catchment Area

Churchman BrookCatchment Area

West MirrabookaPublic DrinkingWater Source Area

Preston BeachWater Reserve

Rottnest IslandWater Reserve

Dwellingerup Catchment Area

Bindoon / ChitteringWater Reserve

Point Greywater reserves

Figure 7-4: Public Drinking Water Source Areas in Advice Area



Datum/Projection: GDA 1994 MGA Zone 50Data Source: DOW (Feb 2015)

LegendAdvice.Area

Public Drinking WaterSource Areas

GroundwaterSurface water



7.5.6 Drainage and urban water management

Statement of Planning Policy 2.9: Water Resources (SPP 2.9) (WAPC 2006a) provides guidance on how water resources should be regarded and managed through the land use planning system. The planning system has a key role in providing for total water cycle management in new developments areas. SPP 2.9 requires that new urban development consider applying Water Sensitive Urban Design (WSUD) principles and best management practices.

Guidance on the implementation of State Planning Policy 2.9 is provided in Better Urban Water Management (BUWM) (WAPC 2008a). This document provides a framework for how water resources should be considered at each planning stage by identifying the various actions and investigations required to support the particular planning decision being made. BUWM provides the planning mechanism to ensure hydrological regimes and water quality are maintained under land use changes and that water sensitive urban design (WSUD) is employed in design of new developments. WSUD ensures that water is infiltrated as close to where it falls as possible. The framework outlined in BUWM is intended to be applied to both new greenfield and urban renewal projects where residential, commercial, industrial and rural residential uses and development are proposed (WAPC 2008a).

The BUWM framework recognises the Stormwater Management Manual for Western Australia (DoW 2004) as the key guidance document for management of stormwater and application of WSUD in land development. The manual was developed in partnership with the SRT and other stakeholders. It advocates the use of WSUD where appropriate and provides high-level policies, planning principles, and practical on ground best practice advice in stormwater management.

In recognition of the need to provide clear guidance for proposals associated with proposed future development, Drainage and Water Management Plans have been prepared by DoW for a number of high priority urban expansion areas. These Plans recognise the inter-related nature of water issues and provide integrated advice on water management, drainage, groundwater and floodplain management to guide planning decisions at an early stage of the planning process. All subsequent water management plans and strategies, local structure plans, local planning scheme amendments and subdivision plans prepared for areas of proposed new development must demonstrate compliance with the strategies, objectives and design criteria detailed in these Plans.

Plans have been developed for the following areas within the Advice Area:

• Byford

• Jandakot

• Murray

• North East Corridor

• Southern River

• Forestdale

• Swan Urban Growth Corridor

Drainage and Water Management Plans for North-East Baldivis and Birrega-Oaklands Drains are currently in development.



Collaboration between agencies and LGAs is essential to managing water quality within the urban drainage system. An agreement on urban drainage in the Swan Canning catchment was signed by the SRT, DoW, Water Corporation and WA Local Government Association (WALGA) in 2012 to find ways for the agencies to work together to improve water quality in both the river system and the urban drainage network. The original project under this agreement focusses on improving urban drainage governance and managing the quantity and quality of drainage and flood water. The agreement is currently under review by the partners.

7.5.7 Avoidance of development in waterways and floodplains

There are a range of processes relating to development in the vicinity of waterways which work together to prevent inappropriate development within or in close proximity of these sensitive environments.

Within any ‘proclaimed surface water area, river or irrigation district’ under the Rights in Water and Irrigation Act, and in unproclaimed areas where access to a watercourse is via a public road or reserve, any direct modification or interference with the bed or banks of a waterway or watercourse requires a permit from DoW (this provision also applies to wetlands). This provides a level of regulation in regard to riparian disturbance and alterations to hydrology.

Where development is proposed, the identification of waterways and wetlands occurs through Better Urban Water Management, described in the Section above. Water management plans and strategies developed under the framework provide for the protection, rehabilitation and management of the waterway and identification of appropriate foreshore areas. The process for identifying waterway foreshore areas is outlined in DoW’s Operational policy 4.3: Identifying and establishing waterways foreshore areas (DoW 2012b) determined at the district or local planning level.

Whilst floodplain management primarily ensures the protection of life and infrastructure, it is also important in order to ensure that proposed development does not impact on the hydrological regime of a waterway. In order to ensure that proposed development does not detrimentally impact on the existing 100 year ARI flooding regime of the general area, a Floodplain Management Policy has been developed for the Peel Region. The revision of this policy has been compiled in a current document (WAPC 2015a). The 2015 Draft Peel Region Scheme Floodplain Management Policy applies to key waterways of the Peel Region including the Serpentine River, Murray River, Peel Inlet, Harvey Estuary, Nambeelup Brook and North Dandalup River.

This policy has been prepared to formalise the consideration of floodplain management requirements by the responsible authorities when preparing local planning schemes and scheme amendments, as well as when considering subdivision and development applications for land within floodplains and adjacent to the Peel Inlet and Harvey Estuary (WAPC 2015a). This policy is currently implemented by the WAPC and relevant local governments through the administration of the Planning and Development Act 2005, the Peel Region Scheme and local planning schemes, and the subdivision and development control processes they contain.

Whilst this process has not been formalised in the Swan Canning catchment, consideration of floodplain management remains integrated in the planning system. Where a proposal could affect the Swan Canning Development Control Area, Parks and Wildlife provides advice to either the Environment Minister, WAPC or Local Government. Advice is provided by Parks and Wildlife, in consultation with



DoW, in accordance Policy SRT/E3: Flood prone land, which identifies appropriate development and setbacks for development within the floodplain. Where the Development Control Area is not affected, DoW provides advice to WAPC including consideration of flood issues.

7.5.8 Wetlands

Generally, current management arrangements relating to wetlands are addressed in Section 5.6. However, there are a number of processes and mechanisms which specifically relate to management of the hydrological regimes and water quality of wetlands.

Managing wetlands and providing for their ecological water requirements, such as maintaining specific water levels, are addressed through water allocation planning and licensing. This is discussed in Section 7.5.4 and includes the management, monitoring and reporting outlined in Ministerial statements 819 and 688.

Another existing mechanism for ensuring the protection and management of wetland hydrology is through water management plans and strategies prepared under BUWM discussed in Section 7.5.6. These plans and strategies provide for specific management measures for the protection and maintenance of water quality and level requirements of CCWs and REWs through the planning system.

7.5.9 Swan Canning River system

Hydrological impacts to the Swan Canning River system are managed through a number of mechanisms in addition to those previously discussed in regards to water allocation (Section 7.5.4), BUWM (Section 7.5.6) and floodplain avoidance (Section 7.5.7). These are mostly overseen by Parks and Wildlife, through its functions under the Swan and Canning Rivers Management Act 2006 to lead and coordinate management action for the Swan and Canning rivers.

Development along the Swan and Canning Rivers

Parks and Wildlife, with advice from the SRT has a statutory planning role for development and approval of activities within the Swan Canning Development Control Area (Figure 7-5). Statement of Planning Policy 2.10: Swan-Canning River System 2006 (SPP 2.10) provides the planning framework for this role including:

• providing for the preparation of precinct plans to coordinate development and activities;

• providing a context for consistent and integrated planning and decision making in relation to the river; and

• ensuring that activities, land use and development maintain and enhance the health, amenity and landscape values of the river, including its recreational and scenic values.

Planning and management of development along the Swan and Canning River foreshores consists of the following processes.

• Part 5 development application



o Where development is proposed on land (i.e. on a lot) or in waters that are wholly in the Development Control Area, the Director General of Parks and Wildlife is the primary assessing authority under Part 5 of the Swan and Canning Rivers Management Act.

o The Director General makes a recommendation to the Minister for Environment, who makes the final determination on the application. In formulating advice, the Director General must consult with the SRT and provide the SRT’s views to the Minister.

• Clause 30A(2)a development application

o Under Clause 30A(2)a of the Metropolitan Region Scheme, the SRT provides advice to the WAPC on developments that are located on land that is partially in, or abutting waters in, the Development Control Area. In routine cases, this SRT function will be performed under delegated authority by Parks and Wildlife officers. Complex issues may be considered by the SRT Board.

• Clause 30A(2)b development application

o Proposed developments located on land that abuts other land in the Development Control Area, or that are likely to affect waters in the Development Control Area, are subject to Clause 30A(2)b of the Metropolitan Region Scheme.

o The SRT provides advice on this type of development application to the local government (who act under delegated authority from the WAPC). In routine cases, this SRT function will be performed under delegated authority by Parks and Wildlife officers. Complex issues may be considered by the SRT Board.

Through Parks and Wildlife, the SRT’s advice is sought under local town planning schemes and the Central Perth and Midland Redevelopment Schemes, administered by the Metropolitan Redevelopment Authority. The SRT provides binding advice to the WAPC for developments that are on land within the Development Control Area or abutting the waters of the Area. It also provides non-binding advice to the WAPC, local government and developers on land abutting the Development Control Area or likely to affect waters in the Area.

!H

!H

!H

!H

Perth

Mundaring

Ellenbrook

Bullsbrook

Figure 7-5: Swan Canning river system management boundaries

±Prepared by: JL Date: 17/11/2015

0 3 6 9Kilometres

Datum/Projection: GDA 1994 MGA Zone 50Data Source: DPaW

LegendAdvice.AreaSwan River Trust -Riverpark BoundarySwan River Trust -Development ControlArea



Swan Canning Riverpark

The Swan Canning Riverpark (Riverpark) comprises the Swan and Canning rivers and public foreshore reserves surrounding them (Figure 7-5). The Swan Canning River Protection Strategy has been developed to provide for its management. The Strategy states that the ecological integrity of the Riverpark, particularly its water quality, is paramount for maintaining ecological health and community benefit (SRT 2015). The Strategy presents the long term vision, values and objectives to improve the health of the Riverpark in a broad strategic management context. The Strategy is designed to clearly identify the pressures on the Riverpark and actions to address them, and agree who, across Government and its partners, are best placed to deliver them. The Swan Canning River Protection Strategy proposes eight management objectives to underpin the identified values of the Riverpark.

The Swan Canning Water Quality Improvement Plan (Swan Canning WQIP) (SRT 2009), coordinated by Parks and Wildlife, is the key management framework to reduce nitrogen and phosphorus input from catchments into the Swan Canning River system. There are also a range of other programs of the SRT, State agencies and regional catchment councils that address nutrient and non-nutrient contaminants. A key focus of the WQIP is the management of fertiliser application in the catchment, which will continue to be a key focus for management of the Swan Canning River system.

In 2012 the SRT, DoW, the Water Corporation and WALGA signed the Urban Drainage Partnership Agreement to develop and implement cooperative strategic and operational programs for specific areas of river management. The agreement was designed to progress strategic issues relating to urban drainage and water quality within the Swan Canning Estuary catchment.

The objectives of the urban drainage partnership agreement include:

• Reaching common understanding on the current state of the urban drainage system;

• Addressing gaps in adoption and implementation of best practice water sensitive urban design principles and design outcomes in new urban development and where practical, in existing urban development that impacts on the catchment;

• Integrating the capacity of the urban drainage systems to become multi-functional systems capable of maintaining flood protection and supporting the protection and enhancement of ecological health and community amenity; and

• Agreement on specific recommendations regarding governance for integrated drainage management.

Other mechanisms Parks and Wildlife has at hand to manage impacts of future development including in the catchment of the Swan and Canning Rivers include:

• Parks and Wildlife can issue infringements for the unauthorised discharge of potentially environmentally harmful materials under the Environmental Protection (Unauthorised Discharges) Regulations 2004, within the Development Control Area. DER would be notified and is responsible for ensuring businesses comply with environmental legislation throughout the broader catchment.

• Parks and Wildlife is able to issue infringements for a range of offences under the Swan and Canning Rivers Management Regulations 2007.



Swan Estuary Marine Park

Three areas of the Swan Estuary are included in a Marine Park vested under the Conservation and Land Management Act 1984. These are Alfred Cove, 200 ha adjacent to the suburbs of Attadale and Applecross; Pelican Point, a 45 ha area in Crawley; and Milyu, 95 ha adjacent to the Como foreshore and Kwinana Freeway. Together with the adjacent nature reserves the Swan Estuary Marine Park is managed by Parks and Wildlife. The Swan Estuary Marine Park and Adjacent Nature Reserves Management Plan 1999-2009 (CALM 1999) was overseen by the Marine Parks and Reserves Authority, which under the Act manages human impacts in marine parks and reserves, through enforcement and licensing under related regulations.

Cl imate adaptat ion

Risks to the Swan Canning River system due to climate change are managed by Parks and Wildlife through the adoption of an adaptive management approach which includes:

• assessing foreshore vulnerability;

• improving water quality through oxygenating water, trapping nutrients and ensuring adequate river flow;

• using monitoring and modelling to predict future changes;

• managing biodiversity;

• protecting infrastructure.

A Climate Change Risk Assessment Project was developed in 2008 to address some of these strategies. This project produced a risk assessment methodology to enable local government to assess the risk of climate change-induced sea level rise on infrastructure, the environment and community use of the rivers.

7.5.10 Peel-Harvey Estuary system

Management of the Peel-Harvey Estuary system is outlined in Chapter 19 of the Commonwealth IAR (Table 19-16). Management is shared across a number of agencies, with water quality actions guided by the Water Quality Improvement Plan for the Rivers and Estuary of the Peel-Harvey system- Phosphorus Management (Peel-Harvey WQIP) (EPA 2008b). This is the key management framework for reducing nutrient inputs from catchments into the Peel-Harvey river system.

The Peel Inlet-Harvey Estuary Environmental Protection Policy (EPA 1992) and State Planning Policy 2.1 Peel-Harvey Coastal Plain Catchment (WAPC 2003b) provide a policy framework for the Peel-Harvey Estuary system; however, in its interim strategic advice, the EPA identified this policy framework as “out of date, and is not considered to have been effective, particularly in guiding future land use in the catchment” (EPA 2015a).



7.5.11 Contaminated sites

A regime for the assessment and management of contaminated sites in WA is established by the Assessment of Site Contamination National Environment Protection Measure, the processes established under the Contaminated Sites Act, and the Assessment and Management of Contaminated Sites - Contaminated sites guidelines December 2014 (DER 2014a). DER is the delegated authority for managing contaminated land. Together the measures ensure that:

• Screening processes are in place for identifying potential contaminated land at critical decision points (for example redevelopment of land to a more sensitive land use).

• Potentially contaminated land subject to redevelopment is investigated and assessed using a risk based framework, and against specific investigation levels for particular contaminants – this usually occurs at change of land use and can also be triggered by condition at other planning stages.

• Remediation or clean-up is undertaken when required to reduced contaminant levels to an acceptable risk level for the intended future use of the land.

• There is confidence and transparency in the process through requirements for third party auditing and the registration of land subject to remediation processes.

These processes are well developed and understood, and will be applied to future development in the Perth and Peel regions. Future development scenarios envisaged through the sub-regional frameworks do not present any novel challenges with respect to contaminated land and therefore this issue is not considered further in the assessment.

7.5.12 Acid sulfate soils

The potential for acid sulfate soil risk is assessed by DER and DoW in applications for mining, excavation, dewatering for urban or industrial development to ensure that risks are minimal.

Where dewatering is required, the licensing process described in Section 7.5.4 allows conditions to be set which manage potential impacts from acid sulfate soils.

WAPC Planning Guidelines (WAPC 2008b) are aimed at ensuring that the potential for acid sulfate soils are adequately investigated and if not avoided, appropriate mitigation measures are established. The Guidelines indicate for example that any structure plan involving land depicted in either the DEC’s geographic data atlas or Landgate’s shared land information platform’s WA atlas map viewer or Landgate’s interest enquiry service as being wholly or partially within an area of “high to moderate acid sulfate soils” should address the issue of acid sulfate soils, and include an acid sulfate soils investigation that:

• Determines the likely presence and distribution of acid sulfate soils on the land, or alternatively, the absence of acid sulfate soils, based on at least step 1 of the DEC’s Identification and Investigation of Acid Sulfate Soils guideline.

• Demonstrates the capacity of the land to sustain the pattern and distribution of proposed land uses having regard to:



o the likely extent and severity of acid sulfate soils;

o potential impacts on surface and groundwater quality and quantity;

o potential impacts on ecosystems and biodiversity;

o potential impacts on existing land uses in the vicinity;

o any likely engineering constraints and impacts on infrastructure; and

o cumulative impacts.

• Where practicable, the pattern and distribution of proposed land uses within the plan area should seek to avoid the introduction, or an intensification, of development that is likely to result in significant amounts of excavation, drainage, or groundwater extraction on land where the presence of acid sulfate soils has been confirmed by an acid sulfate soils investigation.

7.6 AVOIDANCE TO DATE A number of areas within the Advice Area have been deliberately avoided in the development of the sub-regional frameworks as a response to key water values that could be impacted. In accordance with Statement of Planning Policy 2.7: Public Drinking Water Source Policy 2003 (SPP 2.7) designated Public Drinking Water Source Areas (PDWSAs) have largely been avoided in locating urban and industrial expansion areas. There are no urban or industrial expansion areas proposed within surface water PDWSAs. Whilst there are approximately 1,800 ha of urban and industrial expansion areas proposed in P1 and P2 areas of the Gnangara and Jandakot PDWSAs combines, this area represents a small fraction (4 per cent) of the overall P1 and P2 areas which total approximately 48,000 ha.

As part of the identification of future rural residential development to be included in the future development footprint for the Strategic Assessment, a review was undertaken of potential risks or impacts to significant environmental values (both State and Commonwealth values). This review led to the reduction in areas for future rural residential development, consistent with the provisions of SPP 2.5.

A key issue identified in this review was the potential cumulative risk to the water quality of the Peel Harvey Estuary from future rural residential development within its catchment. DoW has modelled the potential nitrogen and phosphorus inputs that would result from the rural residential areas identified within the Peel Harvey catchment (but not yet re-zoned) and estimated that the identified developments could result in an additional 86,981 kg/year of nitrogen inputs and 27,987 kg/year of phosphorous inputs. Four proposed sites resulted in the majority of the estimated increase in nutrient inputs (86,052 kg/year nitrogen and 21,208 kg/year phosphorous). In consideration of these potential impacts, and of other strategic planning considerations, such as the existing supply of rural residential land in the area, and the efficient provision of services and amenities, these sites were excluded from the rural residential future development footprint.

Another area of avoidance of particular note to water resource protection is the avoidance in the sub-regional frameworks of the East Keralup area. In advice to the Minister provided in 2008 under the EP Act the EPA identified significant issues of managing water quality and drainage within the Keralup Masterplan area. It stated that “available information suggests that that the current export of nutrients from the Keralup site will significantly increase should this property be rezoned and developed for urban



purposes” (EPA 2008a). For this, among other reasons, East Keralup is no longer proposed to be developed for urban expansion.

7.7 POTENTIAL IMPACTS The following potential impacts to hydrological processes and inland waters environmental quality may be associated with future planned development:

• changes in groundwater level and availability (including impacts to wetlands);

• changes in surface hydrology and flows;

• changes in water quality from nutrients and organic loading;

• increased contamination risk to groundwater, surface water and wetlands; and

The potential impacts of future development on water must be considered in context of the effects of climate change on water availability in the Advice Area as they may act to exacerbate the already significant impacts that are occurring to water resources and the values they support from a drying climate.

7.8 IMPACT ANALYSIS

7.8.1 Changes in groundwater levels and water availability

Proposed future development within the Advice Area has potential to impact on two aspects of groundwater hydrology. Firstly, land use change is likely to cause changes in groundwater recharge. Secondly, increased population and changed land use have potential to result in an increased demand for groundwater resources.

Groundwater recharge

DoW has undertaken a modelling exercise across the Advice Area using the Perth Regional Aquifer Modelling System (PRAMS), in order to determine potential changes in groundwater levels in the Superficial aquifer as a result of the proposed future development under future climate scenarios.

A number of modelling scenarios were run using PRAMS 3.5, the current authorised version of the model being used by DoW and Water Corporation for licensing and planning decisions. Scenarios were run to investigate groundwater levels at 2030 under the proposed future land use change and development and pine plantation management compared to maintaining current land use. The preliminary results of these scenarios are presented here to inform this impact assessment. Data and assumptions used in the modelling are outlined in Table 7-2.



Table 7-2: Data and assumptions relevant to the PRAMS modelling undertaken by DoW

Input Data used/ assumption

Land use at 2030 Proposed future development (urban, industrial and rural residential) likely to occur by 2030, determined in consultation with DoP, consistent with the sub-regional Frameworks.

Pines harvesting scenario

Likely changes to pine plantations, including replanting of 5,000 ha in the Yanchep Plantation and clearing of the other remaining areas of pines on the Gnangara Mound, with the cleared area to be managed as grassland in order to maximise groundwater recharge.

Abstraction

Continuation of an annual abstraction regime and pattern that is similar to the current regime and pattern (this includes private licensed abstraction, public water supply abstraction and abstraction exempt from licensing such as domestic garden bores).

Climate

Median and dry future climate sequences developed using DoW’s future climate tool (DoW 2015). This peer reviewed tool was built using global climate models that perform well in Western Australia and helps ensure robust, up-to-date and defensible climate science in decision making.

Figure 7-6 and Figure 7-7 illustrate the differences in modelled water levels in the Superficial aquifer at the year 2030, relative to if current land use was maintained. The 2030 land use in Figure 7-6 includes proposed land use changes, including the scenario for the harvesting of pines (with some replanting) that has been committed to by the State government and has expected benefits to water levels in the Superficial aquifer across large parts of the Gnangara area. The model assumes these areas will be managed as grassland to maintain the benefits to recharge and water levels.

Figure 7-7 does not factor in any changes to the current distribution of pine plantations has been provided in order to assess the impact on groundwater levels that can be attributed solely to the proposed urban, industrial or rural residential land use changes.

At the year 2030, the proposed land use changes improve modelled groundwater levels in the Superficial aquifer across significant parts of the Advice Area compared to a scenario where current land use is maintained. In large part, this difference is due to the harvesting of pines and the greatest difference (approximately 4 m) would be in an area directly to the east of the Yanchep National Park. Within the Yanchep National Park itself, modelled water levels are between 0.1 to 1 m higher than they would be without the proposed land use changes. The only area where water levels in the Superficial aquifer would be lower than if current land use was maintained, is in the Yanchep plantation in an area where a commitment has been made to replant of 5,000 ha of pines as offsets for Carnaby’s cockatoo. The area affected by the replanting extends to just south of Moore River in the north, to the western edge of the Yeal Nature Reserve in the east and the northern edge of the Yanchep National Park in the south (Figure 7-6).



However, not all of the modelled benefits from land use change relate to the harvesting of pines. Figure 7-7 suggests significant benefits associated with the land use changes in the East Wanneroo area, up to around 2.8 m near the CCWs of Lake Mariginiup and Lake Jandabup, to the east of Lake Joondalup, are primarily due to the proposed urban, industrial and rural residential development. Also, the less sizeable benefits to groundwater levels seen in both Figure 7-6 and Figure 7-7 to the south of the river, up to around 0.5 m, are as a result of the proposed urban, industrial and rural residential development rather than changes to pines.

Importantly, based on the modelling undertaken, there is no expected decline in groundwater levels as a direct result of the urban, industrial and rural residential land use changes on which the EPA will provide advice as part of the Strategic Assessment.

Recharge is a factor of rainfall, land use and geology. Land use changes (including land clearing, drainage networks and stormwater systems) alter groundwater recharge. The modelled benefits occur where pines are removed or where urbanisation results in an increased presence of impervious surfaces and decrease in the level of water lost through evapotranspiration from vegetation. This leads to a higher proportion of rainfall entering the Superficial aquifer as recharge than would occur under pines, native vegetation or agricultural land uses. Clearing of vegetation, roof runoff, road runoff and importing water for lawns and gardens can increase recharge locally. It should be noted that ‘additional’ water resulting from land use change and increased recharge is unlikely to result in additional groundwater being available for use; but will assist the State in rebalancing the effects of groundwater abstraction and environmental impacts on the Gnangara groundwater system and to meet the objective of protecting the quantity and quality of groundwater for use and the environment into the future. The ‘additional’ water could also be a drainage problem in areas where there are existing high groundwater levels on clay soils.

Figure 7-6 and 7-7 report relative changes to groundwater levels at the year 2030, using current land use as a comparison. In order to predict actual water levels, a number of climate scenarios have been applied to the model. Figure 7-8 uses the median future climate sequence and Figure 7-9 shows groundwater level change under the dry future climate. Under the median future climate, average annual rainfall is slightly greater than from 2004–2013 (a period which included two of the driest years on record – 2006 and 2010). Under the dry future climate, average annual rainfall is less than that from 2004–2013. These figures show the changes in groundwater levels associated with the proposed land use changes and pines harvesting/replanting from the start of the modelling sequence to the modelled equilibrium at 2030.

Under the future median climate, the land use changes contribute to modelled rises in Superficial aquifer groundwater levels across significant parts of the Advice Area. The most significant rises, up to around 4 m, are to the east of Yanchep National Park. This would aid the recovery and support the viability of the Yanchep Caves ecosystem. The groundwater level benefits would contribute to conserving environmental values such as CCWs, Yanchep National Park, Bush Forever sites, TECs and threatened/priority flora/fauna. Significant modelled rises are also seen in the East Wanneroo area, the Gwelup area and over parts of the Jandakot Mound. The main area where modelled groundwater levels fall is in the area where the 5,000 ha of pines is planned to be replanted.

Under a future dry climate (Figure 7-9) however, the land use changes contribute to modelled rises in Superficial aquifer groundwater levels across smaller parts of the Advice Area. There are also significant falls in groundwater levels across large parts of the Advice Area with the largest falls (up to



around 4 m) in an area close to the crest of the Gnangara Mound to the east of Lake Pinjar. The model similarly predicts significant falls in groundwater levels in the area where the 5,000 ha of pines is planned to be replanted.

Overall, the proposed land use changes and development together with the harvesting of pines from the Gnangara, Yanchep and Pinjar plantations proposed within the Advice Area are likely to have a positive impact on groundwater levels which will assist the State in rebalancing the effects of groundwater abstraction and climate impacts on Perth’s groundwater systems. However, the benefits to groundwater levels will vary in relation to how fast the climate continues to dry and will also depend on the areas of cleared pines continuing to be managed as grassland.

Figure 7-6: Difference in groundwater levels in the Superficial aquifer under 2030 land use compared to current land use (median climate)

Figure 7-7: Difference in groundwater levels in the Superficial aquifer under 2030 land use compared to current land use with no change in distribution of pines (median climate)

Figure 7-8: Difference in groundwater levels in the Superficial aquifer under 2030 land use compared to current levels (median climate)

Figure 7-9: Difference in groundwater levels in the Superficial aquifer under 2030 land use compared to current levels (dry climate)



Increased demand

The projected increase in population and growth of the city will lead to an increase in demand for water. Although groundwater will continue to be a part of the water source mix for a variety of uses across the Advice Area, DoW has advised the level of use will need to diminish over time, especially from the Gnangara groundwater system, which is currently over-allocated. The declines in rainfall and recharge and the need to protect groundwater dependent environmental and amenity values, means that increases in the demand for water will predominantly need to come from alternative water sources.

As a result of the proposed future development there will be increased demand for water across the Advice Area for:

• public water supply (scheme water);

• the irrigation of public open space such as parks and sporting fields;

• the irrigation of private gardens and domestic use (backyard bores); and

• industrial uses.

Allocation and licensing processes described in Section 7.5.4 will continue to be key tools in managing groundwater within sustainable limits. However, many of the groundwater subareas in the Perth and Peel region are currently fully or over-allocated with no further groundwater available for allocation. Table 7-3 and Table 7-4 show indicative shallow groundwater availability within the Advice Area.

Table 7-3: Indicative water availability within the Advice Area to the north of the Swan River (data from DoW)

Groundwater area Groundwater subarea Water availability

Gnangara Reserve Limited

Gnangara Wanneroo Wellfield No

Mirrabooka Ballajura No

Mirrabooka Henley Brook No

Mirrabooka State Forest No

Perth Shire of Swan North Yes

Swan Bandy Spring No

Swan Cockman Bluff No

Swan Neaves No

Swan Radar No

Wanneroo Adams No

Wanneroo Carabooda No

Wanneroo Carramar No

Wanneroo Lake Gnangara No

Wanneroo Mariginiup No

Wanneroo Nowergup No

Wanneroo Pinjar No



Table 7-4: Indicative water availability within the Advice Area to the south of the Swan River (data from DoW)

Groundwater area Groundwater subarea Water availability

Cockburn Kogalup Limited

Cockburn Thompsons Limited

Cockburn Valley No

Jandakot Airport No

Jandakot Canning Vale Yes

Jandakot Mandogalup Limited

Jandakot Wright No

Murray Coolup Yes

Murray Nambeelup Yes

Murray Pinjarra Yes

Murray Waroona Yes

Perth City of Armadale Limited

Perth City of Gosnells Limited

Perth Jarrahdale Limited

Perth Shire of Kalamunda No

Perth Shire of Mundaring Yes

Perth Shire of Swan South No

Rockingham Karnup West No

Serpentine Byford 2 Yes

Serpentine Byford 3 Yes

Serpentine Serpentine 3 Yes

South West Coastal Mandurah No

Stakehill Churcher East Limited

Stakehill Karnup East No

Stakehill Maramanup Limited

Stakehill Outridge Limited

This presents challenges for some of the planned urban and industrial growth areas, especially in the Gnangara groundwater areas to the north of the Swan River (for example North East urban growth corridor and East Wanneroo). In these areas DoW has been working, and will continue to work, with local governments and developers to reduce demand through improved design of public open spaces and watering rates, rationalising their existing use, investigating options for trading groundwater, and developing appropriate alternate water sources.

The lack of available groundwater will continue to represent a limitation for growth in these sub-areas and, along with climate change and reduced rainfall, is driving the investigation of alternative water supplies. Facilitation of the identification of alternative supplies is essential if groundwater levels are to be maintained. This process will need to be integrated into the planning process for new urban and industrial area.

As land use changes, for example from rural to urban, there will be opportunities to transfer groundwater currently licensed for uses such as agriculture to licences for uses such as public open



space. There will also be also be opportunities to reduce abstraction through this transfer process in over-allocated areas or where this is likely to contribute to conserving groundwater-dependent ecosystems such as CCWs.

Outside of demand driven by an increased population, the proposed future development will also lead to demand for water for construction activities and also dewatering for basic raw materials extraction associated with urban growth. These activities are temporary in nature and if alternatives are not accessible, abstraction will be managed through the current licensing process to ensure that impacts are minimised.

These potential impacts will be managed through robust allocation and licensing processes and identification of alternative supplies. Section 7.9.3 provides further information on commitments that will be made in order to ensure that the potential impacts from the likely increased water demand are managed in order to protect groundwater dependent environmental values.

Impacts to wet land hydrology

Potential direct impacts to the ecological values of wetlands from proposed future development are discussed in Chapter 5 (Impacts to Flora and Vegetation). This section considers impacts to wetlands as a result of changes in hydrology. Most of the wetlands of the Swan Coastal Plain are supported by groundwater, so declines in water levels in the Superficial aquifer can have significant impact and lead to the loss of values supported by a particular hydrological regime.

The most significant risks to hydrology of these wetland is through groundwater level declines as a result of current and future abstraction, as well as from the continued drying climate. In their interim strategic advice the EPA noted that a key issue for the development of the next Gnangara groundwater allocation plan will be the extent to which wetlands and other groundwater-dependent ecosystems should be allowed to adapt in the face of a changing climate, rather than maintaining values reflective of past water regimes. Preliminary modelling of groundwater levels under future climate and land use suggests there will be areas where current or historic values can be maintained or improved through the management of abstraction but that in some areas (e.g. to the east of Lake Pinjar) consideration may need to be given to acceptable rates of groundwater decline.

However, based on the results of the modelling discussed above, the risk of groundwater dependent wetlands drying as a direct result of the land use changes proposed is low. In fact, the land use changes are likely to counteract declines in some areas resulting from continued abstraction and the drying climate, into the future.

As discussed in Chapter 5 (Impacts to Flora and Vegetation), at a more localised scale, a total of 461 CCWs and 364 REWs are within the development footprint, with an additional 165 CCWs and 97 REWs within 50 m of one of the footprints. This gives an indication of the number of wetlands which could potentially be affected by localised changes in hydrology resulting from land use changes under the proposed future development.

Of this combined total, 271 of the CCWs and 206 of the REWs are within the urban, industrial or rural residential footprints. In addition to allocation and licensing processes, Better Urban Water Management (BUWM) is the key tool for managing the impacts to wetland hydrology for wetlands in proximity to future urban, industrial or rural residential developments. See Section 7.5.6 for a discussion of BUWM



and how this will serve to protect wetlands values from changes in hydrology as a result of the proposed future development.

Approximately half of the CCWs and REWs that intersect or are within 50 m of one of the footprints sit within or in close proximity to the infrastructure footprint. Depending on the type of infrastructure, and the proportion of the wetland intersected, these may be filled or drained and cease to be a wetland, or may experience indirect impacts to hydrology where the construction process of the infrastructure itself impacts groundwater flow or levels.

Only 36 CCWs or REWs are within 50 m of the BRM footprint. Of these, 13 are within the footprint and are likely to be filled or drained and will cease being wetlands. Of the remaining 23, impacts to hydrology of wetlands within 50 m of BRM extraction will be managed through existing processes which allow conditions to be set to require management of hydrological impacts either by DMP or by Local Government, depending on the project.

Commitments for the protection and management of wetland hydrology associated with the proposed future development are described in Section 7.9.5.

7.8.2 Changes in surface hydrology and flows

The Swan Canning River system and Peel-Harvey Estuary system are recognised by the EPA as two key surface water assets within the Advice Area (EPA 2015a). Potential impacts to the hydrology and flows of the Peel-Harvey system are considered in Chapter 19 of the Commonwealth IAR. Therefore the focus of impact discussions below is on the Swan Canning River system as well as wetlands which depend on surface water flows. However, much of the discussion is also relevant to the Peel-Harvey.

As discussed in Section 7.5.9, Parks and Wildlife and the SRT hold a range of powers within the Development Control Area to manage development activities which may impact on the Swan Canning River system. Sixty-five hectares of the urban footprint falls within the Area. Of this, the large majority (98 per cent) is associated with urban consolidation activities in existing zoned areas and is flagged for urban corridors, activity centres or station precincts. A further 85 ha is also intersected by the infrastructure footprint - either proposed new infrastructure or potential clearing within existing rail and road reserves.

Outside of the Development Control Area, a substantial portion of the Advice Area is within the greater catchment of the Swan Canning River system. Within the catchment there are intersects with all of the proposed development footprints. As discussed in Section 7.5.9, through Parks and Wildlife, the SRT is able to provide non-binding advice on issues outside of the Development Control Area which are likely to affect the waters in the Area and will continue to do so where significant hydrological impacts are expected.

Potential impacts to the hydrology of the river system associated with the proposed future development include:

• Changes in groundwater affecting discharge to rivers and streams (discussed in Section 7.8.1).

• Taking of water for various uses including dust suppression and irrigation.

• Direct discharge to rivers or streams from dewatering activities.



• Inputs from drainage of new urban or industrial areas.

• Interference with beds, banks or floodplains causing changes in hydrology.

The following paragraphs address each of the remaining potential impacts (apart from the first which is addressed in the previous section). Potential impacts are generally managed through the existing processes discussed in Section 7.5.

Section 7.5.4 details the licensing process that applies to proclaimed rivers or surface water areas under the Rights in Water and Irrigation Act. The upper and middle reaches of both the Swan-Avon and the Canning Rivers fall within these areas and are covered under this process. The lower and estuarine reaches are considered low risk in terms of impacts to surface hydrology given tidal influences. This licensing process also manages any potential impacts from direct discharge into waterways, through the proclamation of groundwater areas.

BUWM is the primary mechanism for managing surface water hydrology impacts from new urban, industrial and rural residential areas. The guideline requires hydrological regimes to be maintained or improved through water sensitive urban design. Brownfield and infill development as well as small scale subdivisions or development proposals are generally considered low risk, and do not require management plans and strategies to be required under BUWM. However the framework provides for the assessment of these proposals where significant water management issues are present.

The urban, industrial and rural residential footprints of the proposed future development all intersect areas of mapped floodway and flood fringe (Figure 7-10) in various places. These areas may require that additional land be set aside for conveyance, storage and retention of flood water to ensure the maintenance of hydrological regime. Areas of proposed development where boundaries currently intersect mapped floodways include:

• Henley Brook urban expansion area, a small tributary of the Swan River;

• Bullsbrook South industrial investigation area crossing the Ellen Brook;

• along Wungong Brook at Champion Lakes and Darling Downs in urban expansion areas;

• urban expansion at West Pinjarra;

• urban consolidation activities along the Swan and Canning Rivers; and

• numerous rural residential developments.

The majority of North-east Baldivis industrial is within the floodplain, within an area that provides significant regional water storage before flood water discharges to the Peel Main Drain.

Existing processes outlined in Section 7.5.7, including the identification of appropriate setbacks, will ensure that environmental values associated with floodways and floodplains are taken into consideration through the land planning process.

!H

!H

!H

!H

!H

!H

!H

!H

!H

!H

!H

!H

!H

Perth

Chidlow

Waroona

Kwinana

Mandurah

Pinjarra

Mundaring

Ellenbrook

Bullsbrook

Jarrahdale

Serpentine

Rockingham

Dwellingup

Figure 7-10: Intersection of development footprint with 100 year ARI floodplain areas


0 7 14 21Kilometres

Datum/Projection: GDA 1994 MGA Zone 50Data Source: DoW (Sept 2014), DoP

LegendAdvice.Area100 Year ARI Floodplain.Advice.AreasIntersected by BRM footprintIntersected by InfrastructurefootprintIntersected by Urban, Industrial &Rural residential footprint



Proposed infrastructure also crosses the floodplain in many locations. In some of these locations there is existing infrastructure and so additional impacts will be limited. In others, this could potentially introduce new impacts. This will continue to be managed through existing licensing processes, the powers of Parks and Wildlife, as described in Section 7.5.9, and conditions set through the infrastructure approvals process.

Overall, changes in surface water hydrology are considered to be adequately managed by existing processes. Adherence to Drainage and Water Management Plans and a strong BUWM framework will contribute to achieving optimum outcomes.

Most wetlands in the Advice Area are groundwater dependent; however the impacts and management described in this section apply equally to any wetlands which are dependent on surface water to support environmental values.

7.8.3 Changes in water quality from nutrients and organic loading

In 2014 the Auditor General tabled a report in parliament titled Our Heritage and Our Future: Health of the Swan Canning River System. This report was prepared in order determine whether the environmental health of the Swan Canning River system is adequately protected by existing mechanisms. The auditor and the SRT (in its response to the report) identified nutrients as the key threat to the river system. Equally, nutrients are recognised as a key threat to the Peel-Harvey system. This is discussed in detail in Chapter 19 and Appendix D of the Commonwealth IAR. Nutrient enrichment is also considered a key threat to wetlands of the Advice Area.

Nutrient point sources are considered easier to manage than diffuse nutrient pollution. Most industries associated with point source nutrient emissions have to comply with local government regulation or are controlled through government (DER) licensing. Point source emissions are beyond the scope of this assessment and only the potential impacts of diffuse sources of nutrients are considered in this Section.

Different land uses are associated with varying nutrient export risks owing to differences in nutrient inputs and transport pathways. As detailed in Section 7.4.2, new urban, rural residential and industrial land uses under the proposed future development may contribute to increased nitrogen and phosphorus inputs. Relative to these proposed land uses, BRM extraction and Infrastructure footprints are not considered to present a significant risk of increased nutrients or organic loading to groundwater or surface water and have not been considered further.

Nutrient inputs within industrial land uses are generally low, depending on the type of industrial activities allowed in the area. However in some cases, due to costs of reticulated sewerage for large blocks, industrial areas remain unsewered which can potentially lead to high nutrient export rates.

Generally, urban expansion areas identified in the footprint occur on land that is currently used for rural purposes (Table 7-5). Research by DoW on nutrient inputs relating to various land uses found that residential developments generally have greater nutrient inputs than rural land uses on a per area basis. This was found to be particularly the case for urban areas with small to medium block sizes between 400 and 730 m2 (Kelsey et al. 2010). The development of these new urban residential areas brings the potential for greater use of domestic fertilisers and organic wastes, which can result in high levels of nutrient contaminants including phosphorus, ammonia and other nitrogen compounds (Trefry



et al. 2006). New urban areas also incorporate areas of irrigated and fertilised public open space. Due to the high usage demands on these areas, nutrient inputs can be significant.

Conversion of rural land to rural residential although not as intensive can have the added nutrient sources from septic systems or leach drains.

Table 7-5: Areas of existing land uses in proposed urban and industrial expansion areas

Proposed land use Existing land use Area (ha)

Urban

Rural - cleared 5,936

Rural - remnant vegetation8 8,912

State Forest - pines 432

Industrial

Rural- cleared 11,107

Rural - remnant vegetation8 1,439

State Forest - pines 729

It is noted that not all changes in land use may result in increases in nutrient input. For example, the conversion of historically intensive agricultural use rural land to urban and industrial land could actually decrease nutrient input into hydrological systems from a decrease in amount of fertiliser being applied to this land.

Certain land characteristics including historical nutrient loads in the soil, soil capacity to retain nutrients and the depth to groundwater can also impact on the nutrient risk profile of a particular area. Many of the areas targeted for future urbanisation are in water-sensitive environments with high water tables, wetlands of conservation significance and nutrient legacies from agricultural activities. Particularly vulnerable areas include the Swan Urban Growth Corridor, and those portions of the South West and South East urban corridors that bound an extensive area of palusplain (i.e. seasonally waterlogged flat wetlands). Extensive rural drainage networks, constructed decades ago to enable agriculture, have significantly altered these areas. The issue of drainage providing a conduit for movement of nutrients into receiving waterbodies is discussed in Section 7.4.2.

Based on existing data for nutrient inputs by land use type, an increase in nutrient inputs could be expected to result from the expanded urban footprint. Where these increased nutrient inputs are not appropriately contained and managed, they have the potential to result in increased concentrations

8 It should be noted that a large portion of the remnant vegetation identified within the urban and industrial footprint will be protected through future statutory planning processes.



within groundwater and surface water, pollute waterways and important groundwater resources, and also have implications for the estuaries and marine environments to which they discharge.

DoW has recently undertaken work in order to classify land within the Advice Area according to a nutrient enrichment risk to receiving water bodies. This risk assessment mapping was undertaken using a combination of landscape characteristics (representing nutrient leaching likelihood) as well as a consequence variable.

The consequence variable reflects the sensitivity and values of the receiving environment. Sensitive receptors within the Advice Area include the Swan Canning River system, the Peel-Harvey Estuary system, Ramsar sites and CCWs. For example, within the Peel-Harvey coastal catchment, areas draining directly to the estuary or within 1,000 m of it were given the highest consequence rating, based on the sensitivity to nutrient enrichment, ecological and social values. Areas draining to major tributaries had a lower consequence rating, followed by areas further from the main drainage lines. For other Ramsar sites, land within 500 m of the boundary was given the highest consequence rating.

For the purpose of this risk assessment, likelihood refers to the likelihood of phosphorus leaching from a given land unit to where it and has the potential to contribute to eutrophication of surface water. This was based on phosphorus export hazard maps from Department of Agriculture and Food Western Australia (van Gool et al. 2005). It should be noted that the phosphorus export hazard mapping developed for use in assessing leaching potential under broadacre agricultural land use. It therefore does not consider the changed hydrological pathways (introduction of drainage) that may occur under urban or industrial land use or the presence of septic tanks or ATUs which may act as nutrient point sources.

Relative risk has been calculated for all new urban, industrial and rural residential areas within the Advice Area on a scale of 1-10, with 10 being those areas with highest risk of contributing to nutrient enrichment (Figure 7-11). Although eutrophication risk data is proposed to be developed for nitrogen in the future, at the time of writing, data was available for phosphorus only.

This regional, broad-scale risk mapping is a guide to the probable level of intervention required in an area. Results need to be considered in the context of the spatial extent as well as the current and proposed land uses.

NorthEllenbrook

North Pinjar

BullsbrookSouth

Maddington-Kenwick

SouthForrestdale

South Pinjar

Figure 7-11a: Eutrophication risk mapping for urban, industrial and rural residential expansion areas (North)


0 7 14Kilometres


LegendAdvice Area

ZoningUrban ExpansionIndustrial ExpansionRural Residential

Phosphorus Risk0-33- 44-55-66-77-88-99-10

Nambeelup

North DandalupNorth

Ravenswood

WestPinjarra

Figure 7-11b: Eutrophication risk mapping for urban, industrial and rural residential expansion areas (South)


0 7 14Kilometres


LegendAdvice Area

ZoningUrban ExpansionIndustrial ExpansionRural Residential

Phosphorus Risk0-33- 44-55-66-77-88-99-10



In the South of the Advice Area water quality is of particular concern given the legacy issues of the Peel-Harvey. Of the proposed urban areas, North Ravenswood and West Pinjarra expansion areas represent the highest threat to water quality, given their relatively large size combined with high eutrophication risk. Together these areas cover 3,135 ha and are in relatively close proximity to the Peel Inlet. The risk assessment indicates that development of these areas for urban land use represents a high risk to water quality and will require significant management and mitigation.

Nambeelup industrial expansion area also covers a large area and rates highly for eutrophication risk. With a proposed future industrial land use, the likelihood of high nutrient input rates is much lower than for urban areas, depending on the type of industrial activities allowed in the area. Export risk could be associated with either future point source discharges or with diffuse nutrient inputs if the area was not connected to the sewer. In the case of Nambeelup, planning for this area is somewhat progressed and Drainage and Water Management Strategy (DWMS) has been approved by DoW. The DWMS and PRS amendment have confirmed the industrial area is to be connected to Water Corporation sewer services, and an Engineering Servicing Report has been provided to this effect. Any potential future point source discharges will be managed through DER licensing processes and are beyond the scope of this assessment.

In the north of the Advice Area, the North Ellenbrook and Bullsbrook South proposed industrial expansion areas together cover a large area. This significant parcel of land is adjacent to an intermodal terminal and provides a strategic employment node for residents in the North West Corridor. Therefore, it is a high priority for development. They are located in a low-lying area of the Ellen Brook catchment with a very high nutrient risk where any additional nutrient input will flow directly into the Ellen Brook, a tributary of the Swan Canning River system. Further development in this area will need to be carefully controlled to ensure no further detrimental impact to the Swan-Canning Rivers.

Other proposed developments covering substantial areas with high nutrient export risk include proposed urban and industrial areas around Pinjar, the Maddington Kenwick industrial area, West Mundijong industrial, expansion of urban areas in Piara Waters/ Harrisdale and Forrestdale and South Forrestdale urban and industrial.

In both the north and south of the Advice Area a number of rural residential areas also rate highly in terms of eutrophication risk. Most notable of these is North Dandalup, given the relative size of the area. Most other areas of proposed rural residential with high eutrophication risk are relatively small areas.

Within the Central sub-region, where land has been ear-marked for urban consolidation activities, effects of the proposed future development are less certain. Land use changes within this zone are likely to be varied, including denser urban form, new areas of public open space, public infrastructure and commercial premises. Accordingly, nutrient export could also increase or decrease, depending on what these land use changes entail.

The current BUWM framework aims to provide an appropriate mechanism to ensure that nutrient export risks from new urban areas are managed. Discussion of the application of BUWM to the proposed future development is provided in Section 7.9.2. Appropriate urban designs that minimise fertiliser application and allow on-site nutrient capture are likely to be necessary to protect adjacent streams, wetlands and estuaries and will be implemented through this framework.



7.8.4 Increased contamination risk to groundwater, surface water and wetlands

The proposed future development involves land use intensification, as a means to accommodate and provide employment for an expanded population in the Perth-Peel region. Largely, this involves rezoning of rural land to urban and industrial uses. It is likely that under more intensive land use, part of the Advice Area will experience a higher incidence of contamination occurrences. In addition an increased population and urban infill activities could lead to a similar outcome and increases the risks of intersecting contaminated sites or acid sulfate soils.

There is also a significant amount of new infrastructure proposed. Infrastructure corridors pose the following water contamination risks (DoW 2007):

• Soil erosion and resultant turbidity in surface water bodies.

• Disturbance of contaminated sites and acid sulfate soils.

• Contaminant emissions during corridor construction.

• Pollution resulting from equipment malfunctions and conduit damage.

• Waste dumping and vandalism resulting from increased access.

• Use of chemicals including paints, solvents and pesticides for service maintenance.

New basic raw materials extraction also poses a risk of contamination, primarily through storage of fuels and chemicals.

Intersect ion of exist ing contaminated si tes

There are numerous known contaminated sites within the Advice Area and most likely many unknown or unreported sites. Many of these sites represent old landfill sites, where disposal of municipal waste in and along the Swan River and in wetlands was a common occurrence in previous times. This region is the key focus for urban infill, with the likely result that more of these sites will require management or remediation.

There is potential for contaminated sites to impact on water quality of surface water, groundwater and wetlands. However, it is considered that the Contaminated Sites Act discussed in Section 7.5.11 provides an adequate framework for managing the risks associated with contaminated sites. No changes to existing management are considered necessary at this strategic level of assessment.

Acid sul fate soi ls

Approximately 3,500 ha of land identified as high to moderate risk for acid sulfate soils will potentially be disturbed through future development. As described in Section 7.5.12, the DER Acid Sulfate Soil Guidelines and associated processes provide a mechanism for dealing with this risk within future urban, industrial and rural residential development areas. At the subdivision and development application stages, the Guidelines acknowledge that avoidance is not always be possible (although desirable) and a specific acid sulfate soil investigation and subsequent development of a management plan are required. It is considered that these Guidelines provide an adequate framework for managing the risks



associated with acid sulfate soils. Risks associated with installation of sub-surface infrastructure are similarly managed through existing approvals processes.

There is also a risk that rising water-tables associated with new urban and industrial areas, while not causing additional acidification, could exacerbate the impacts of historic soil acidification on shallow groundwater. In the areas of development on the western and southern flanks of Gnangara Mound, acidification has already occurred in the soils where these have been exposed by previous water-table decline during the last two decades. The rise in water-tables with extra recharge to groundwater following urbanisation could potentially make the acidification of the shallow groundwater worse. In the absence of mitigation measures, groundwater acidification is likely to persist for at least several decades and be slowly treated by natural processes over the long-term. Where this is identified as an issue, water table recovery may need to be managed through existing allocation processes.

No changes to existing management of acid sulfate soils are considered necessary at this strategic level of assessment.

Stormwater

Stormwater is a known pathway for contaminant transport. Introduction of new urban and industrial areas has potential to increase transport of contaminants into waterways as a result of increased runoff from impervious areas. The importance of the application of water sensitive design in new urban and industrial areas is discussed in Section 7.8.3 and applies equally in relation to management of contamination risks. BUWM is the key mechanism in managing these potential future impacts.

Publ ic Drinking Water Source Areas

As discussed in Section 7.5.5, the Gnangara and Jandakot Mounds, as well as a number of other important water resources used for drinking water supply are protected through their designation as PDWSAs. Development within PDWSAs increases water quality contamination risks due to the introduction of more chemicals, fuels and infrastructure required to service higher density development.

There are areas of future urban and industrial development, as well as various new infrastructure alignments, proposed within the Gnangara UWPCA and Jandakot UWPCA. As a result of the decision not to progress urban development at East Keralup, a number of additional urban expansion sites were needed to be identified to make up the required area of urban land to support a city of 3.5 million. Through a strategic planning process it was determined that some areas of the Gnangara UWPCA that are currently pine plantation will be converted to urban land use following the harvesting of pines. Of particular note are the Pinjar South proposed industrial development, West Ellenbrook proposed urban area, and part of the Nowergup (1) proposed industrial area, all of which intersect existing P1 areas of the Gnangara UWPCA. There is also proposed urban development within P1 and P2 areas of the Jandakot UWPCA (Figure 7-13).

The areas that were identified for future urban and industrial development in both Gnangara and Jandakot were considered to provide the best balance between the development requirements of the State and ongoing protection of the drinking water source. The P1 areas proposed for development in Gnangara and Jandakot will need to be changed to P3 areas when the MRS zoning of that land is



complete. If the areas proposed for development will no longer be used for public drinking water supply a change to the boundary of the PDWSA may be warranted.

There are also some intersects with P3 areas in the following groundwater PDWSAs:

• Perth Coastal and Gwelup UWPCA (including the proposed Yanchep station);

• Preston Beach Water Reserve; and

• West Mirrabooka Public Drinking Water Source Area (including a Light rail max depot)

P3 areas already provide for urban and light industrial/commercial development.

GnangaraUWPCA

JandakotUWPCA

Perth

Yanchep

Kwinana

Mundaring

Ellenbrook

Bullsbrook

Rockingham

Figure 7-12: Potential impacts to Jandakot and Gnangara UWPCA's from thedevelopment footprint


0 6 12 18Kilometres

Datum/Projection: GDA 1994 MGA Zone 50Data Source: DOW (Feb 2015), DoP

LegendAdvice.Area

Protection AreasPriority 1Priority 2Priority 3Intersected by BRMfootprintIntersected by UrbanfootprintIntersected by Industrialfootprint



In the case of surface water public drinking water source areas, there are no intersects with proposed urban or industrial areas. Therefore, activities associated with these footprints will not contribute to an increased contamination risk to surface water PDWSAs.

In the Mundaring Weir Catchment Area 36 ha of basic raw materials extraction is proposed within P2 areas of the PDWSA. Potential impacts from these situations are currently managed through the placement of conditions by either the DMP or local government, which may apply to the storage of fuels and chemicals, depth of excavation and rehabilitation criteria. Chemical underground storage tanks are precluded in sensitive P1 and P2 areas.

Other intersects include an area (<1 per cent of the P2 area) of proposed rural residential land use within the Middle Helena Catchment PDWSA. Under existing processes, conditions would generally be placed on these developments regarding the location of building envelopes outside of reservoir protection zones and conditions on wastewater disposal. With appropriate conditions, it is not considered that these developments will significantly affect water quality within the PDWSAs.

Approximately 10.2 km of water supply pipelines in proposed in the Middle Helena Catchment Area (P1) but is not expected to represent a significant risk to water quality.

Potential impacts to surface water PDWSAs are not considered to warrant any additional management commitments at this strategic level of assessment. Commitments relating to the potential impacts to groundwater quality are discussed in Section 7.9.4.

7.9 MITIGATION AND MANAGEMENT The following sections identify commitments that are being made to address current gaps in management of hydrological processes and inland waters. These commitments aim to address the potential impacts identified in Section 7.8 to ensure that the EPAs objectives for these factors can be met.

7.9.1 Strategic reform

The Government of Western Australia is currently working on a reform program for water legislation and policy that will result in new legislation enacted within coming years. The intention is to modernise institutional arrangements to provide a systems that is flexible, progressive and capable of managing water today and into the future. The process seeks to achieve the following objectives (DoW 2013):

• Enhance confidence

o Increase security of access

o Improve clarity of rules

o Greater transparency of process

o Community participation in decision-making

• Reduce government intervention

o Minimise and simplify regulation



o Balancing of risks

o Adoption of a market-based mechanisms where appropriate

• Enable flexibility to adapt and respond

o Mechanisms to vary licence volumes in line with seasonal conditions

o Establish consumptive pools where appropriate

• Secure water supply for the future

o Planning to address risk of over allocation

• Secure water for the environment

o Protection of water-dependent ecosystems

o Protection of water resources and long term water quality.

Commitment: Support the drafting and enacting of modernised water resource management legislation.

7.9.2 Urban water management

In October 2008 the WA State Government published BUWM, which aims to integrate the consideration of water in the planning and design process, as directed by SPP 2.9. The framework is designed to facilitate better management and use of our urban water resources by ensuring an appropriate level of consideration is given to the total water cycle at each stage of the planning system.

The BUWM framework will remain the primary mechanism for protection of surface water flows and quality through the land planning process. The WAPC will continue to administer and provide for best practice water management across new greenfield and any urban renewal projects with significant water management issues, through the land planning system in accordance with BUWM. The draft Perth-Peel Regional Water Plan (see Section 7.5.1) provides context and support for BUWM and guidance to WAPC on water planning priorities to be considered in these planning stages.

A review and revision of BUWM is now a priority, to improve the policy process by:

• Enhancing the focus on integration of water and land planning, using BUWM as a pathway to achieve better outcomes.

• Refining the curve and text description of documents to better reflect established processes, which have evolved since initial implementation.

• Broadening the scope of BUWM to also specifically apply to infill and brownfield areas.

• Removing the requirements for extensive technical information, and improving the focus on outcomes. Detailed technical guidelines now exist that provide specific guidance/standards and



removing the specific detail from BUWM will allow the document to remain robust as technologies and best practice change.

• Reviewing reference to policies and ensure revised document is consistent with new Liveable Neighbourhoods and changes to other agency policies/guidelines.

• Strengthening the language.

Nutrients are likely to present a key challenge to maintaining or improving water quality for a number of areas within the development footprint due to the unique conditions on the sites including factors such as historical nutrient loads in the soil, soils with low capacity to retain nutrients, shallow depth to groundwater and proximity to sensitive receptors,.

In the first instance this will be addressed through the development of a District Water Management Strategy. At this stage of planning, design principles and criteria are embedded in order to guide future development of more detailed strategies and design. Standard development methodologies may not achieve water quality objectives. It is proposed to develop an innovative approach to solving these critical issues to reach an acceptable outcome.

Additional mitigation and management actions relating to urban water are also discussed in various sections below including:

• development of sub-regional water management strategies (Section 7.9.3);

• water supply and alternative source identification (7.9.3); and

• protection of wetlands (7.9.5).

Commitment: Continue to improve urban water management through the following actions:

• Continue to implement the Better Urban Water Management Framework through the land planning process, including in infill areas and brownfield developments.

• Review and update the existing framework.

• Development of sub-regional water management strategies to support sub-regional structure plans.

Commitment: Any future development within the North Ellenbrook, Bullsbrook South, Ravenswood North or Pinjarra West precincts will require specific consideration of arising water quality issues. These precincts are located in environmentally sensitive hydrological catchments and may require additional design measures to address water quality and quantity. Such measures should be identified as early in the land use planning process as possible, in accordance with the Better Urban Water Management Framework.



7.9.3 Water supply, allocation and alternative sources

At a strategic level, through water supply planning and allocation planning, DoW is aiming to manage groundwater abstraction at a sustainable level as well as support the implementation of alternative water source options. This includes reducing abstraction from the Gnangara groundwater system in line with the drying climate to ensure that the impacts of groundwater use on the environment are reduced and the long term productivity of groundwater resources is maintained.

In order to address the increased demand for public water supply (scheme water), Water Corporation have developed Water Forever Whatever the Weather- Drought-proofing Perth (Water Corporation 2011), a 10 year plan aimed at reducing use from climate dependent water sources (including groundwater in the shallow aquifers)9. This plan forms part of the implementation of Water Forever - Towards Climate Resilience, a broader 50 year plan released in 2009 which recognises that the groundwater allocation from the Gnangara and Jandakot systems for the integrated water supply scheme will progressively decrease from the current level over time.

Measures being undertaken by Water Corporation and DoW to meet future demand and limit environmental impacts include:

• transferring groundwater abstraction to the deeper aquifers where the impacts of abstraction on groundwater dependent ecosystems is reduced;

• balancing abstraction in the deep aquifers by replenishing them with increasing volumes of recycled water;

• continuing to make gains in water use efficiency and improve average household water use;

• working with proponents who are interested in accessing wastewater, primarily for industry and public open space; and

• investigating new sources such as expanding seawater desalination capacity or accessing water from outside of the metropolitan area (e.g. Gingin).

DoW has also been working with private self-supply groundwater users to ensure they are educated about the need to adapt their water use to the drying climate and look for appropriate alternatives to meet their water demands.

9 It should be noted that the deeper Leederville and Yarragadee aquifers are also climate dependent to some degree as they are recharged through the shallow Superficial aquifer and pumping from the deep aquifers contributes to drawdown in the Superficial in areas where the aquifers are connected, such as in the northern half of the Gnangara Mound.



Water management st rategies

DoW has recently started developing a Perth-Peel Regional Water Supply Strategy that will identify projected future water demand for Perth and where the water will be available and where alternative supplies are likely to be required.

It is intended that sub-regional water management strategies will be developed by DoP in conjunction with each of the Sub-regional Structure Plans. Regional water supply strategies generally inform the sub-regional water management strategies, but in this case, DoP and DoW intend to work on these documents concurrently to ensure consistency. The sub-regional water management strategies will identify water related constraints and opportunities associated with proposed areas for urban and industrial expansion. They will map the ‘state of play’ with regard to water resources, present general principles/standards for water management and identify gaps that will need to be addressed prior to future development. The constraints identified will form the platform for work to be undertaken through the Perth-Peel Regional Water Supply Strategy, which will be the strategic response for securing water sources for future development proposed.

Al locat ion planning

DoW’s allocation plans will continue to set water availability using best available knowledge of demand and future climate. Allocation plans retain flexibility to respond to new information such as improved climate predictions or new understanding of environmental water requirements. Water allocation plans are in place across the majority of the Advice Area and are regularly evaluated to review the management arrangements and the extent to which the objectives are being met.

DoW has developed a future climate tool that helps predict rainfall in the drying climate (DoW 2015). This peer-reviewed tool was built using global climate models that perform well in Western Australia and is being used in modelling being undertaken as part of the development of the next Gnangara groundwater allocation plan.

As discussed in Section 7.8.1, there is limited groundwater availability in the Advice Area and a substantial proportion of groundwater subareas are fully or over-allocated with others likely to become fully allocated in the near future. The Gnangara system is currently over-allocated and water levels in many parts of the system are declining. The Gnangara groundwater areas allocation plan (DoW 2009b) has been a key first step in adjusting groundwater management in the context of a drier climate. Work for the next phase of Gnangara allocation planning began during 2013–14. It will update the strategies being used for the purpose of increasing their effectiveness at reducing groundwater use and protecting groundwater-dependent ecosystems, and signal the long term need for water users to adapt to the drying climate.

Meet ing water requirements in areas of l imited groundwater avai labi l i ty

The limited groundwater availability in the Advice Area presents challenges for future urban and industrial expansion, including water requirements for irrigation of public open space. Strategic alignment of water and land planning processes is needed to best manage the limited groundwater



availability. Where there is a shortfall in groundwater supply to meet increased demand DoW will work with planning agencies and developers to address the shortfall. This will include:

• Improved public open space design and practise to minimise irrigation requirements and maximise water use efficiency.

• Implementation of water-sensitive urban design in new greenfield and infill developments.

• Trading for part or all of water entitlements from existing users.

• Identifying alternate water supply options, such as managed aquifer recharge, wastewater reuse and stormwater harvesting and recycling.

In light of predictions of a drying climate and increased demand for water from an expanding population, it is recognised that there is a need to diversify supply and move away from reliance on sources that are rainfall dependent. The development of sub-regional water management strategies and the Perth-Peel Regional Water Supply Strategy will identify demand gaps, viable alternative supply options and provide strategic direction.

It is noted that there are six actions to ‘Facilitate the use of alternative sources of water supply’ identified in the Regional Water Plan (DoW 2009a) including development of a transparent and efficient approvals process for alternative water sources, which safeguards the environment, public health and water resources. These will be implemented through the finalisation and implementation of the Perth-Peel Regional Water Supply Strategy.

Commitment: Continue to review environmental water requirements, including consideration of effects of climate change, and incorporate into allocation plans.

Commitment: Continue to promote managed aquifer recharge into aquifers of the Gnangara system, including development of a longer-term plan to align the groundwater abstraction bore fields with artificial recharge sites, to better balance the recharge and take of water.

Commitment: Continue to implement measures to reduce water use, increase water recycling and develop alternative fit-for-purpose water sources including the following:

• Ongoing review and implementation of water management plans, strategies and implementation plans that form the primary mechanism to guide the development of fit for purpose water supplies across all sub-regions.

• Identification of appropriate alternative water supplies at all levels of development planning.

• Water availability will continue to be guided by allocation plans developed in line with current legislation that consider future climate predictions.

• Increasing the focus on water use efficiency, including for private supply water users.

• Water licence applications will continue to be guided by allocation plans and assessed and managed in line with current legislation and policy.



Commitment: Ensure the irrigation needs of Public Open Space, particularly in expansion and urban infill areas is addressed through the planning process by:

• identifying potential water sources and constraints at the district level, in accordance with the Better Urban Water Management framework. This should include water for irrigation of public open space, having consideration of impacts of use, availability, allocation, infrastructure and management requirements including a conceptual evaluation of alternate water supply options should groundwater be unavailable; and

• designing Public Open Space with due consideration of the available water supplies.

7.9.4 Public Drinking Water Source Areas

In order to address proposed future development that is planned within public drinking water source areas, WAPC has commenced reviews of SPP 2.2 and 2.3. Through these reviews, WAPC will review the most current information on both water and land factors in order to ensure an informed decision on the future of the Jandakot and Gnangara UWPCAs.

DoW is currently preparing drinking water source protection reviews for Gnangara and Jandakot UWPCAs to provide input into the SPPs. The revisions of SPP 2.2 and 2.3 will include reference to Water Quality Protection Note No. 25: Land use compatibility tables for public drinking water source areas, which outlines appropriate development and activities within each of the priority areas (P1, P2 and P3) and management measures that can help address contamination risks.

As a result of this review, the boundary of the Gnangara UWPCA could be amended or the priority areas could be changed from P1 to P3, to reflect new MRS zonings.

Commitment: Protect water quality in public drinking water source areas including the following actions:

• Update current policy to provide improved guidance on land use planning and development in drinking water source areas.

• Undertake a strategic assessment of land and water factors where incompatible land uses are proposed in PDWSAs.

7.9.5 Wetlands

Wetlands within new urban, industrial and rural residential areas will continue to be considered under Better Urban Water Management as per existing requirements. Commitments listed in the Land chapter will contribute to the protection of hydrology of these wetlands by ensuring that an appropriate buffer to the wetlands is determined through the planning process (see Chapter 5- Impacts to Flora and Vegetation).



Where CCWs are within 50 m of proposed heavy road or rail infrastructure, a hydrological assessment will be required to be undertaken to ensure that dewatering, construction and dust suppression will not impact on water levels and water quality in nearby wetlands.

See also specific commitments for Becher Point Wetlands, Lake Thomson and Lake Forrestdale in Action Plan F.

Commitment: Protect and maintain water quality and level requirements for CCWs and REWs where retained through the following actions:

• Water management plans and strategies prepared under the Better Urban Water Management framework to include measures for the protection of wetland water levels and quality, and recognition of abstraction and dewatering requirements.

• Hydrological assessment to be undertaken for major road or heavy rail infrastructure within 50m of a wetland.

7.9.6 Nutrients- Swan Canning and Peel-Harvey

Swan Canning

Nutrients have been identified as the biggest threat to the Swan Canning River system. Measures that will continue to be implemented in support of improved water quality in the Swan Canning include the commitments relating to urban water management discussed in Section 7.9.2. This includes a revision of the BUWM framework and continued support for the processes it describes. BUWM will provide a key tool in managing the threat of increased nutrients from future development.

As identified in Section 7.8.3, the proposed North Ellenbrook and Bullsbrook South expansion areas represent a particular risk to water quality in the Swan Canning catchment, given their relatively large size combined with high eutrophication risk. Any future development within these areas will require specific consideration of water quality issues in accordance with the BUWM Framework.

It is recognised, however, that ‘legacy issues’ are a dominant factors in the health of the system, particularly relating to water quality. A package of commitments has been provided to address both legacy water quality issues as well as future risks to the system from the proposed development.

The actions of the Swan Canning WQIP will continue to be implemented to ensure management of catchment issues relating to nutrients. A description of specific nutrient management actions are described in Section 7.9.8.

In additional, the State will continue its support of the provision of deep sewerage throughout the catchment, promote urban drainage initiatives and structural interventions and continue to support on-ground nutrient reduction projects based on specific soil types and land uses of sub-catchments.

Parks and Wildlife and the SRT will continue to be supported in order to provide oversight and management of future developments that may have implications for catchment water quality and quantity.



Commitment: Recognise and support Parks and Wildlife as the single point of co-ordination within Government to oversee roles, responsibilities and actions under the Swan Canning River Protection Strategy and Water Quality Improvement Plan relating to protection of the environmental values of the Swan Canning system.

Peel-Harvey

Impacts to the Peel-Harvey system are discussed in detail in Chapter 19 of the Commonwealth IAR, as part of consideration of the Peel Yalgorup Ramsar site. A number of commitments relating to the Peel Harvey system are listed in Action Plan F of the Strategic Conservation Plan, including the establishment of the Peel Regional Park and expansion of Yalgorup National Park and the implementation of a monitoring program including limits of acceptable change.

Measures that will continue to be implemented in support of improved water quality in the Peel-Harvey include the commitments relating to urban water management discussed in Section 7.9.2. This includes a revision of the BUWM framework and continued support for the processes it describes. BUWM will provide a key tool in managing the threat of increased nutrients from future development.

As identified in Section 7.8.3, the proposed North Ravenswood and West Pinjarra expansion areas represent a particular risk to water quality in the Peel-Harvey Catchment, given their relatively large size combined with high eutrophication risk. Any future development within these areas will require specific consideration of water quality issues in accordance with the BUWM Framework.

The Commonwealth IAR recognises, however, that legacy issues are the dominant factor in the health of the system, particularly relating to water quality. A package of commitments has been provided to address both legacy water quality issues as well as future risks to the system from the proposed development.

Currently the Peel-Harvey WQIP addresses phosphorus only, though it is planned to also establish nitrogen targets. A key focus of the Peel-Harvey WQIP is the management of fertiliser application in the catchment, which will continue to be a key focus for management of the Peel-Harvey system. The actions of the Peel-Harvey WQIP will continue to be implemented to ensure management of catchment issues relating to nutrients. A description of specific nutrient management actions are described in Section 7.9.8.

Land use planning

The Peel-Harvey coastal catchment is also under increasing pressure due to land changes that have altered natural water and nutrient cycles. DoW has advised that despite the work of Government agencies, catchment groups and individuals, nutrient inflow to the Peel-Harvey remains at levels that are generally far above the estuary’s ability to cope. The future development of the Peel region to meet a city population of 3.5 million in the Perth-Peel region will place increased pressure on an already stressed system.

New intensive horticultural developments, specifically in-ground vegetable production, pose an added risk to the system, and of all current broad-scale land uses, traditional intensive horticulture has the greatest nutrient pollution impact on a per hectare basis. DAFWA and DoW have advised that new in-



ground vegetable production will likely result in a tenfold increase in the application of phosphorus and nitrogen fertiliser. As most of the soils are incapable of retaining the surplus phosphorus applied to crops most will end up in the waterways.

The horticultural industry is being increasingly drawn to the Peel-Harvey area as land availability in the traditional farming areas, such as Baldivis and Wanneroo, is reduced through urban expansion. Approvals for proposals for new traditional intensive horticulture development are a local planning matter. These are considered by local government authorities through the development application process under the provisions of the relevant local planning scheme. Local planning schemes are the principal statutory tool in relation to development (land use) control. There are a number of State Government instruments to guide local planning decisions in the Peel area to protect the environmental values of the Peel-Harvey catchment. These include SPP 2.1 which has specific advice on intensive agriculture development and a significant number of EPA Bulletins and Guidelines.

There is increasing concern across relevant State Government agencies that current processes may not be sufficient to manage land use decisions regarding intensive horticulture in the Peel region. A commitment has therefore been made to provide a more rigorous planning mechanism to ensure that such developments are controlled. This can be done through State Planning Policies and Special Control areas under Local Planning Schemes.

In addition, as a means for improving the health of the Peel-Harvey Estuary arising from legacy issues, the State proposes to establish the Peel Harvey Water Quality Taskforce. The Peel Harvey Water Quality taskforce will be chaired by the Minister for Water and will be responsible for coordinating actions across the entire Peel-Harvey catchment area to reduce nutrient impacts. Together with the proposed establishment of the Peel Regional Park and extensions to the Yalgorup National Park, this taskforce will address potential impacts to the limits of acceptable change for the Peel-Yalgorup Ramsar site.

Commitment: Establish the Peel Harvey Water Quality taskforce as a coordinating body to oversee roles, responsibilities and actions relating to protection of the environmental values of the Peel-Harvey system.

Commitment: Review the State Planning Policy 2.1 for the Peel-Harvey Coastal Plain Catchment (SPP 2.1) and the Environmental Protection (Peel Harvey Estuary) Policy and consider development of Planning and Development Act 2005 mechanisms to prevent high nutrient export activities on soils with a low phosphorus retention capacity.

Addit ional nutr ient management measures

Improved knowledge and tools

In order to fill the gaps in science and knowledge needs as required, a number of commitments have been made in the Strategic Conservation Plan to address these gaps for the Peel-Harvey and Swan-Canning System including the development of:

• water quality objectives for all sub-catchments;



• nitrogen targets for the Peel-Harvey;

• estuarine health indicators;

• catchment numerical modelling; and

• ecosystem response models.

To guide management actions to reduce nutrients from the catchment, water quality objectives will be set such that progress towards achievement can be measured and reported. However, although water quality variables such as salinity, oxygen and nutrients provide information about the physical condition of the estuary and a measure of the stressors, they do not of themselves reflect the response of the estuary to changes in river flows, nutrients or organic matter. Biotic indicators are used as a measure of this, such as macro and microalgae for short term responses and seagrass growth and extent and sediment chemistry for longer term responses. Together with water quality variables these estuarine health indicators allow condition to be assessed and progress on improvement in water quality to reported.

Catchment nutrient and water balance modelling is used to identify where in the catchment nutrients are derived by land use and land use type and most importantly show which management actions will be the most effective in reducing nutrient inflows at a sub-catchment scale. Estuary response modelling provides understanding of how efforts to reduce nutrients and organic matter may lead to improvements in estuary condition and at what rate. Combined, catchment modelling to identify where to act and with what action, and the estuary models to inform of expected resulting changes in estuary condition, this can provide a powerful measurement tool so that management actions can optimised based on effectiveness and cost benefit.

One other critical information need and serious gap is measures of the effectiveness of management actions at the scale of the works. This information provides critical feedback on how well specific actions work and allows improvement or change of action to optimise expenditure. This information also is incorporated into models to underpin cost benefit considerations.

Catchment and estuary monitoring provides the basic measurement data that underpins the calibration and validation of the models as well as provide direct objective measures of change over time reflecting both the results of management actions and climate changes. Annual catchment nutrient reports will document these changes, whilst estuary health report cards benchmarked to international best practice will integrate all measures and provide high impact analysis and reporting in a simple easily digested format.

Targeted mandatory soil testing on the coastal plain

Reducing the over-application of agricultural fertiliser is thought to be the most cost effective long term intervention to prevent further deterioration of both the Peel-Harvey and Swan Canning Estuaries. Agriculture in the coastal plain catchments contributes approximately 80 per cent of the total phosphorus inflows into the Peel-Harvey Estuary and one-third of the total phosphorus inflows into the Swan Canning Estuary.

Available research suggests that, due to historic fertiliser application, approximately 70 per cent of paddocks in the Peel-Harvey coastal catchment do not currently require additional phosphorus application to maintain farm productivity. From the sampling of properties undertaken as part of the



Fertiliser Partnership arrangements even greater over application of phosphorus is evident in the Swan Canning coastal catchment. The research suggests that if phosphorus was applied based on soil testing calibrated for local soil types then phosphorus losses from agriculture in these coastal plain catchments could be reduced by 25 per cent.

The proposed program aims to reduce the over application of fertilisers at targeted sites in the Peel-Harvey and Swan Canning coastal catchments as well as improve soil productivity, agronomic yield and economic outcomes for agricultural fertiliser users.

The proposed program would apply to properties over 40 ha in the Peel-Harvey and Swan Canning coastal plain catchments where the land is used for commercial agricultural production and consist of two parts:

• soil testing and agronomic advice and reporting; and

• a targeted extension program.

Landholders covered by the regulations will be required to undertake and submit a valid soil test at least once every three years and receive independent agronomic advice prior to the application of fertiliser.

The proposed regulation leaves the ultimate decision regarding fertiliser application with the landholder (i.e. it is not proposed to regulate fertiliser use).

The program will capture approximately 800 properties in Peel-Harvey and a further 200 properties in the Swan Canning coastal catchment. It is proposed that the State meet the costs of the soil testing and independent agronomic advice for the first three years of the program estimated at $6 million, with detailed costings to be finalised as part of the 2016 State budget process.

Drainage intervention (Peel-Harvey)

The extensive engineered drainage system on the Peel-Harvey coastal plain carries the bulk of the nutrient run-off from agricultural land uses to the rivers and estuaries in the Peel Region. While there has been some progress in constructing interventions to remove nutrients from the Swan Canning drainage system there has only been very limited work of this nature to date in the Peel-Harvey coast catchment.

In order to meet the phosphorus inflow target for the Peel-Harvey it is necessary to achieve a further reduction of 30-35 tonnes/year of phosphorus inflow on top of the reductions that are projected to be achieved through the targeted mandatory soil testing program. In the absence of other alternatives that can be effective on this scale, it is proposed to implement a drainage intervention program to deliver this reduction.

Based on work undertaken by DoW, Peel-Harvey Catchment Council and the DPC, in liaison with Water Corporation and Parks and Wildlife, it is estimated that a drainage program to reduce phosphorus inputs to the estuary from drains by 30-35 tonnes/year would cost approximately $110 million over 20 years.

The key components of this program are summarised as follows:

• constructed wetlands augmented with offline treatment technologies;

• stock exclusion and riparian zone management;



• application of phosphorus binding clays or equivalents;

• sedimentation basins for organic carbon removal;

• drain maintenance;

• drain modification at subcatchment and landholder scale; and

• urban stormwater retrofitting.

This program would build on the five drainage intervention projects (totalling $3.85 million) targeting the reduction of phosphorus, sediment and organic matter in the Peel-Harvey catchment that have been developed and submitted to Royalties for Regions for funding as part of a broader Regional Estuaries Initiative. Elements of the long term program could commence immediately following completion of the strategic assessment process, based on an expansion of work undertaken with the proposed Royalties for Regions funding. However, for other components of the program further work will need to be undertaken on tenure, design and risk issues (e.g. hydraulic and flood modelling).

The long term program would be split into three stages:

• design and establish pilot projects for rural drainage interventions and complete urban stormwater retrofits (over five years);

• implement proven designs for rural drainage interventions in priority sub catchments over 10 years); and

• evaluation and refinement of projects and ongoing management arrangements (over five years).

The first five years of the program are proposed to allow refinement of the most promising nutrient capture techniques and to evaluate efficacy of the various options. Substantial community consultation and site identification would allow land access (both public and private) to be resolved for the second phase.

Many of the interventions would be similar in concept to the Wetland Treatment System, which has been constructed at the lower end of Ellenbrook to reduce nutrient inflows from agriculture into the Swan River, with early results showing a high degree of effectiveness.

Bagged fertiliser regulations

The State Government has already implemented the Environmental Protection (Packaged Fertiliser) Regulations to reduce the amount of phosphorus contained in domestic use fertilisers. These regulations first came into force on 1 January 2011 and have since limited the amount of soluble phosphorus in garden and lawn fertilisers to a maximum of 2 per cent and 1 per cent respectively. Previously garden fertiliser contained twice this amount of soluble phosphorus. These regulations will remain in place.

Promotion of the use of soil products

Western Australia’s sandy soils are characterised by low natural fertility, poor water-holding capacity, poor nutrient retention and a tendency to become water-repellent. The greater demands on these soils to sustain consumers have required regular inputs of nutrients and high quality water. In most cases, the required nutrients are applied in the form of water-soluble chemical fertilisers. This practice is not



environmentally sustainable and has been identified as one of the major contributors to algal pollution problems in the Perth and Peel rivers and estuaries.

The addition of appropriate natural (compost and clay) and/or recycled (soil products) materials to soils has the potential to improve water and fertiliser selection and efficiency, while having no detrimental impact on production quantity or quality.

One of the current barriers to this process is uncertainty about which soil products can safely be used. Soil products are waste derived materials that have been evaluated in such a way that their use will not cause unacceptable risk to the environment. Although there is considerable interest in the use of soil products, until recently there have been inadequate regulated standards to identify the beneficial constituents and potential contaminants in order to understand the application risks.

To address this, State agencies are actively progressing steps to progress a regulatory system for the use of Waste Derived Material to land, providing the materials used do not compromise environmental values. The intention is that materials that meet the standard will be classified as a 'soil product' in the first instance. The next phase will focus on doing further work on matching the soil product type and application rate to the characteristics of specific soil types.

Commitment: Implement key actions necessary to improve and maintain the health of the Peel-Yalgorup wetland system, particularly through the reduced inflow of nutrients, using a whole of catchment management approach, including:

• implementing mandatory best practice soil testing, agronomic advice and optimisation of fertiliser use in agriculture;

• reporting fertiliser use;

• facilitating the greater uptake of soil products to reduce nutrient runoff and leaching, and improve water holding capacity on poor soils;

• instigation of a drainage intervention program;

• continuing bagged fertiliser regulation;

• development of nitrogen targets and to guide catchment management decisions;

• development of actions to reduce sediment and organic loading;

• improvement in the monitoring and reporting on the health of the river system including the publication of annual water quality report cards;

• improve regulation of agricultural point sources;

• undertaking of whole of catchment numerical modelling to provide revised load reduction targets that will support drainage management actions, guide investment planning and provide the basis for compliance testing against targets, with modelling to be reviewed every five years; and

• development, operation and maintenance of an estuarine ecosystem response model to inform management decisions.



Commitment: Implement key actions necessary to improve and maintain the health of the Swan-Canning River System, including:

• implementing mandatory best practice soil testing, agronomic advice and optimisation of fertiliser use in agriculture;

• reporting fertiliser use;

• facilitating the greater uptake of soil products to reduce nutrient runoff and leaching, and improve water holding capacity on poor soils;

• continuing bagged fertiliser regulation;

• ensuring regular monitoring and reporting on the health of the river system including the publication of annual water quality report cards;

• undertaking of whole of catchment numerical modelling to support drainage management actions and guide the WQIP, and review every five years; and

• development, operation and maintenance of an estuary response model to inform management decisions.

Commitment: Undertake activities that improve the knowledge and understanding of the water quality of the Peel-Harvey and Swan-Canning catchments to support decision making including:

• developing estuarine health indicators; and

• setting water quality objectives for all sub-catchments.

7.10 SUMMARY OF OUTCOME FOR EPA OBJECTIVE Many of the key threats to hydrological regimes and inland water environmental quality from the proposed future development can be adequately managed through existing processes. Particularly critical in maintaining or improving hydrological regimes are allocation and licensing processes and the continued implementation of BUWM. A commitment has been made to update BUWM to ensure the framework remains robust and fit-for purpose.

In some cases the land use changes proposed could go some way to counteracting the decline in groundwater levels resulting from a drying climate. This will depend on identification of suitable alternative supplies for irrigation of Public Open Space in areas where there is limited groundwater availability. DoW will need to work together with planning agencies and developers to address this need and will be guided by a Perth-Peel Regional Water Supply Strategy.

In relation to inland water environmental quality, an increase in nutrient loads to sensitive receptors, including the Swan Canning and Peel-Harvey river systems, from development of new urban, industrial and rural residential areas is a key threat. A commitment has been made to ensure that appropriate mitigation measures are identified prior to rezoning in particular high risk areas.



In addition, the State has commitment to a whole-of-catchment approach to nutrient management for the Swan Canning and Peel-Harvey systems which will see the implementation of targeted actions guided by Water Quality Improvement Plans and informed by improved monitoring and modelling.

Any intensification of land use is linked to an increased risk of contamination and this will be the case where land use change is proposed within the Advice Area. This risk will be managed through existing processes which can require conditions on certain developments and provide mechanisms for the management of contaminates sites and acid sulfate soils. In the case of sensitive P1 areas of the Gnangara PDWSA, acceptability will be determined through a transparent analysis of land and water factors.

Modernised legislation will help ensure EPA’s objectives for hydrological regimes and inland water environmental quality can continue to be met into the future as development within the Advice Area takes place.



8 IMPACTS TO AIR QUALITY 8.1 KEY FINDINGS • Monitoring indicates that Perth generally does not have poor air quality, with occasional

exceedances of national standards caused by major wildfires which along with wood fire burning for heating and vehicle emissions, are the main causes of detrimental air quality.

• The inclusion of passenger light and heavy rail infrastructure combined with urban consolidation supports a more compact urban form for a larger population, and the expected improved uptake of public transport will lead to substantial avoidance of air emissions from vehicles on roads.

• Existing permitting and planning measures to manage air quality are generally adequate but need broader spatial coverage and implementation, with mitigation proposed that would expand air quality monitoring, extend the application of the Perth Air Quality Management Plan to the Peel region, and determine and implement buffers that separate emissions sources in industrial areas from sensitive land uses such as residential areas.

• A quantitative determination of the impacts to air quality has not been possible, however, the proposed mitigation and management measures put forward address key gaps in current management measures for air quality in the Perth and Peel region. Combined with substantial avoidance already achieved, implementation of these measures will mean that the EPA's objective for Air Quality can be met over time.

8.2 EPA OBJECTIVE The following EPA objective for air quality is applicable to this assessment:

To maintain air quality for the protection of the environment and human health and amenity, and to minimise the emission of greenhouse and other atmospheric gases through the application of best practice.

8.3 ENVIRONMENTAL POLICY AND GUIDANCE The following policy and guidelines are relevant to this assessment with regard to air quality:

• National Environment Protection (Ambient Air Quality) Measure (2003) (Ambient Air NEPM).

• National Environment Protection (Air Toxics) Measure (2004) (Air Toxics NEPM).

• Perth Air Quality Management Plan (DEP 2000).

• State Planning Policy 4.1 State Industrial Buffer (and draft revision) (WAPC 1997).

• Environmental Protection (Kwinana) (Atmospheric Wastes) Policy 1999 and Environmental Protection (Kwinana) (Atmospheric Wastes) Regulations 1992.



• EPA Guidance Statement 3: Separation distance between industrial and sensitive land uses (EPA 2005) and draft revision released September 2015.

• EPA Guidance Statement 12: Minimising Greenhouse Gas Emissions (EPA 2002b).

• A guideline for managing the impacts of dust and associated contaminants from land development sites, contaminated sites remediation and other related activities (DER 2011).

8.4 EXISTING ENVIRONMENTS

8.4.1 Key values

Air consists of numerous gases and small liquid or solid particles, some of which are necessary for survival of living organisms (DEP 2000). Air quality can be adversely affected when there is an excess of the normal components of air, when chemical reactions occur between common components of air to produce potentially harmful air quality or when contaminants are released to the atmosphere (DEP 2000).

Monitoring of the Ambient Air Quality NEPM standards occurs in the Perth region at eight specific locations. There are currently no monitoring locations in the Peel region. Lead has not been monitored in Perth since 2001, as previous monitoring results consistently indicated lead levels well below the NEPM (average lead level in Perth Central Business District in 2001 was 0.022 µg/m3) (AQCC 2011). It is noted that the varying meteorological conditions across the Perth region and the extent of the monitoring network, means that there are instances of poor air quality in specific areas at times that is not detected at the eight designated monitoring locations.

Monitoring results generally indicate that Perth air quality is good however, there are occasions when the NEPMs are exceeded (AQCC 2011). In 2012, the NEPM standards for ozone (O3) and particulates (PM10) were exceeded at a number of locations, with the NEPM advisory reporting standard for particulates (PM2.5) also exceeded at a number of locations. These exceedances primarily occurred in January and February of 2012, with the February exceedances considered to be associated with widespread smoke plumes caused by major wildfires resulting from lightning strike in the south-west (AQCC 2014).

8.4.2 Key threats

Emission sources

Sources of air emissions relevant to the Perth and Peel regions include:

• Industrial and commercial sources (includes boilers, power generation, combustion processes, refining).

• Motor vehicles.

• Domestic solid fuel heating or incineration.

• Bushfires.



• Construction (dust).

The two main causes of detrimental air quality in the Perth region are vehicle emissions and smoke, with issues of photochemical smog10 (O3) and haze generally arising in summer and winter respectively (DEP 2000). Smoke originates from natural events such as bushfires, but is also associated with wood fire burning to heat homes. Vehicle emissions are associated with private vehicle use as well as road freight.

Industrial emissions also have the potential to adversely impact on air quality. The Kwinana Industrial Area is a heavy industrial area, with sulphur dioxide emissions of particular concern (although ambient levels have been within standards and levels set for many years) and particulates causing occasional dust and amenity issues (EPA 2009b). The key threats are:

• A lack of sufficient separation between in the Kwinana Industrial Area and urban areas supporting sensitive land uses, arising from expansion of industry and residential encroachment.

• Dispersion of emissions over Perth. The Kwinana Industrial Area is located such that emissions can be carried offshore during easterly winds and then pass over the city area when the sea breeze occurs later in the day (Select Committee on Perth's Air Quality 1997).

Considerat ion of cl imate change

Research by the Indian Ocean Climate Initiative for the south-west of Western Australia suggests that (IOCI 2012):

• high-pressure weather systems could be more prevalent and the incidence of low-pressure systems could decrease equivalently;

• both maximum and minimum temperatures will warm by mid-century through to the end of the century under a high greenhouse gas scenario; and

• hot spells will generally become more intense by 2100, with the frequency and duration differing depending on the area of the south-west.

The meteorological conditions associated with these changes will influence the air quality of the Perth and Peel regions, with this to be considered in any future air quality modelling undertaken in the region. The predictions for warmer weather and more intense hot spells could particularly increase the risk of bushfires (and resultant smoke) and without intervention, facilitate creation of photochemical smog.

10 Photochemical smog is caused when sunlight reacts with nitrogen dioxide and volatile organic compounds such as petrol vapours (DEP 2000).



8.5 CURRENT MANAGEMENT ARRANGEMENTS Mitigation measures for air are established in a range of existing State Planning Policies, guidelines and approval requirements. The measures include:

• Compliance / adherence to standards at source, and in the receiving environment.

• Minimum buffers, separation distances and set-backs for maintaining adequate separation between activities generating emissions and more sensitive land uses.

• Risk assessment processes to ensure management attention is placed on highest risk activities.

• Best practice management measures applied at source – with a focus on avoidance and minimisation wherever possible.

• Adherence to appropriate standards of practice, secured through construction EMPs and approval conditions under the EP Act.

To avoid land use conflicts, strategic management and mitigation of impacts focuses on the maintenance of minimum buffers, separation distances and setbacks to establish adequate separation of future development generating air emissions, from sensitive land uses.

The Environmental Protection (Kwinana) (Atmospheric Wastes) Policy 1999 was originally gazetted in 1992, with a formal review occurring and gazetting of the unchanged Policy in 1999. The Policy defines three areas for which sulphur dioxide standards and limits are set:

• Area A – heavy industrial area.

• Area B – treated as a de facto buffer surrounding Area A, portions are sometimes used for industrial purposes.

• Area C – outside Area A and B, predominantly rural and residential areas.

The sulphur dioxide standards and limits become more stringent from Area A to Area C. Standards and limits have also been set for total suspended particulates. Monitoring is undertaken by industry and government to ensure the standards and limits are met.

Existing State Planning Policies also play a strong role in embedding these measures in planning and decision making on future development. In particular, State Planning Policy 4.1 State Industrial Buffer (SPP 4.1) (WAPC 1997) is intended to provide a consistent approach to securing buffers. SPP 4.1 is supported by the EPA's Guidance Statement No. 3: Separation Distances between Industrial and Sensitive Land Uses. Both the State Industrial Buffer policy and the EPA's guidance on separation distances are currently under review and the EPA recently released a draft revision of the guidance statement (EPA 2015d).

Recently, the Western Australian Government has also proposed (through the draft Planning and Development Legislation Amendment (Western Trade Coast Protection Area) Bill) to formalise the boundary of the Western Trade Coast Protection Area. The Protection Area would include the Kwinana Industrial Area, Rockingham Industry Zone, Latitude 32 Industry Area and the Australian Marine Complex, as well as a buffer of surrounding land which separates this industry from surrounding residential areas. Regulations are proposed that would separate new sensitive land uses from the potential impacts of industrial activity. Classes of sensitive land use such as residential housing, short-



stay accommodation, schools, hospitals and child care centres are proposed to be prohibited in the Protection Area. The intended outcome is to address issues of encroachment by providing the necessary clarification and long term certainty for land use planning within the boundaries of the Protected Area, for both industry and land-owners.

The key existing management measures are outlined in Table 8-1. Table 8-1: Key existing management measures for identified threats to air quality

Existing management measure

Threat

Winter haze/ photochemical

smog

Land use buffers/ conflicting land

uses

Enforcement of the National Environment Protection (Ambient Air Quality) Measure (2003)

x

Perth Air Quality Management Plan (DEP 2000) x

State Planning Policy 4.2: Activity Centres for Perth and Peel (WAPC 2010b)

x

Development Control Policy 1.6: Planning to support Transit Use and Transit Oriented Development (WAPC 2006c)

x

Environmental Protection (Kwinana) (Atmospheric Wastes) Policy x

Guidance Statement 3: Separation Distances between Industrial and Sensitive Land Uses (under review) (EPA 2005)

x

Draft Statement of Planning Policy 4.1: State Industrial Buffer Policy (amended) (WAPC 2009) (under review)

x

8.5.1 National Environment Protection Measures

National Environment Protection Measures (NEPMs) have been established for air quality, which are applicable to all States and Territories of Australia, to protect and manage this aspect of the environment. NEPMs are made by the National Environment Protection Council under the Commonwealth National Environment Protection Council Act 1994.

The Western Australian Government is a signatory to two ambient air NEPMs, specifically the National Environment Protection (Ambient Air Quality) Measure (Ambient Air Quality NEPM) established in 1998 and the National Environment Protection (Air Toxics) Measure (Air Toxics NEPM) established in 2004 (Government of Western Australia 2009). The Ambient Air Quality NEPM sets standards for six criteria pollutants, as well as an advisory reporting standard for one pollutant (Table 8-2). The Air Toxics NEPM provides a framework for monitoring, assessing and reporting of five air toxics (Table 8-2), with the intention of developing standards based on the information gathered.



The desired environmental outcome for both NEPMs relates to the adequate protection of human health and well-being.

Table 8-2: Summary of NEPMs for ambient air quality and air toxics

Sourced from: National Environment Protection (Ambient Air Quality) Measure; and National Environment

Protection (Air Toxics) Measure, as amended. Note: On 29 April 2014, Ministers signalled their intention to vary the

National Environment Protection (Ambient Air Quality) Measure to establish a more stringent reporting standard for

particle pollution (PM2.5 and PM10).

Pollutant Averaging period Maximum

concentration Monitoring

investigation level

Ambient Air Quality NEPM – Standards

Carbon monoxide (CO) 8 hours 9.0 ppm Not applicable (N/A)

Nitrogen dioxide (NO2) 1 hour

1 year

0.12 ppm

0.03 ppm N/A

Photochemical oxidants (as ozone; O3) 1 hour

4 hours

0.10 ppm

0.08 ppm N/A

Sulphur dioxide (SO2)

1 hour

1 day

1 year

0.20 ppm

0.08 ppm

0.02 ppm

N/A

Lead 1 year 0.50 µg/m3 N/A

Particles as PM10 1 day 50.0 µg/m3 N/A

Ambient Air Quality NEPM – Advisory Reporting Standard

Particles as PM2.5 1 day

1 year

25 µg/m3

8 µg/m3 N/A

Air Toxics NEPM – Monitoring Investigation Levels

Benzene Annual average N/A 0.003 ppm

Benzo(a)pyrene as a marker for Polycyclic Aromatic Hydrocarbons

Annual average N/A 0.3 ng/m3

Formaldehyde 24 hours N/A 0.04 ppm

Toluene 24 hours

Annual average N/A

1 ppm

0.1 ppm

Xylenes (as total of orth, meta and para isometers)

24 hours

Annual average N/A

0.25 ppm

0.2 ppm



8.5.2 Perth Air Quality Management Plan

The Perth Air Quality Management Plan was prepared in 2000 and sought to ensure that clean air was achieved and maintained in the Perth region over the next 30 years (DEP 2000). This Plan was further refined with the release of a publication titled ‘Implementing the Perth Air Quality Management Plan’ in 2002, with the actions of both documents overseen by an Air Quality Coordinating Committee comprised of representatives from government, industry and the community.

8.6 AVOIDANCE TO DATE The sub-regional planning frameworks support a more compact urban form for a significantly increased population through:

• increased residential density and urban infill targets; and

• support for passenger light and heavy rail infrastructure.

The resultant more compact urban form and expected improved uptake of public transport is likely to reduce the number of vehicles on roads, with associated air emissions. This is a key avoidance outcome.

Measures applied during planning of the future development footprints have resulted in avoidance of impacts to air quality through:

• incorporation of opportunities for sequential land use in the development of the BRM footprint;

• avoidance of low lying areas that would require excessive BRM for fill; and

• efforts in co-location of infrastructure.

The measures for avoidance relating to extraction of BRM have benefits because of the potential for BRM extraction to cause air emissions during operations and conflict with surrounding sensitive land uses such as urban development. During master planning, nodes of BRM resources were identified constituting groupings of strategically located BRM resources that were sufficiently large to supply future development. As these areas are likely to host long-term BRM quarries, new sensitive land use such as urban development was planned to avoid these areas and their surrounding buffers. However, existing and proposed BRM quarries outside of the nodes have provided the opportunity sequential land use principles to be applied in several localities.

In the case of extraction sites identified for future long term development for urban residential purposes, measures allowing for the efficient transition between land uses will be adopted. This will involve restricting encroachment of nearby urban development while BRM activities are operating (buffers around the BRM quarry sites), undertaking extraction on a programmed basis, and quarry closure planning aligned to be compatible for an intended future (sequential) land use. Both a spatial and a programmed temporal buffer between BRM activities and sensitive land uses will therefore be created.

Further details in regards to the implementation of BRM operations are contained in Action Plan D of the Strategic Conservation Plan. Combined with reduced demand for BRM for fill (through avoidance of low lying areas during footprint planning for future urban development), the effect of these measures will



be to considerably avoid land use conflict from BRM extraction and processing-related dust emissions and urban development.

8.7 POTENTIAL IMPACTS The following potential air quality impacts are associated with implementation of the future development

footprints and an increase in population to 3.5 million:

• increased winter haze from wood-burning heaters and increased summer photochemical smog from vehicle use (associated with increased population);

• industrial facilities (e.g. power stations, processing plants) are likely to emit pollutants;

• physical disturbance of the land surface during vegetation clearing and earthworks (including BRM extraction) is likely to generate dust;

• wind erosion of exposed surfaces can generate dust; and

• landfill facilities and wastewater treatment plants are likely to emit pollutants and odours.

Emissions from specific sources or industries are not the subject of this strategic assessment. Instead the focus is on the broader associated land uses, particularly in the context of appropriate separation of land uses likely to support activities generating air emissions (industrial, BRM and infrastructure future development) and sensitive land uses (such as future urban development). The transition from current industrial or commercial areas, to future residential areas and the implications in terms of air quality will also need to be carefully considered.

8.8 IMPACT ANALYSIS

8.8.1 Airshed capacity

Perth’s air quality is influenced by a number of variables, including:

• Meteorology;

• seasonal variations;

• population density (currently spread over a relatively large area);

• vehicle emissions; and

• commercial and industrial centres.

No specific airshed modelling under future growth scenarios has been undertaken and specific modelling for individual activities (e.g. industrial facilities, wastewater treatment plants) is beyond the scope of a strategic assessment. However, a process for requiring future modelling and emissions inventory is identified in Section 8.9.

In the absence of quantitative modelling it is still possible to make some qualitative observations. Implementation of the sub-regional frameworks and delivery of the future development will affect air



quality in the Perth and Peel regions, particularly in association with an increased population. A larger population will potentially increase winter haze from wood-burning heaters and increase summer photochemical smog from vehicle use.

DER advises that vehicle registrations in Western Australia increased by 18 per cent between 2007 and 2012, with an annual average increase of 3.5 per cent and that Western Australians have 828 vehicles per 1000 residents, the second highest in Australia. In addition to the increase in vehicle numbers, there has been an increase in the vehicle kilometres travelled (VKT). Estimated VKT in Perth have increased by over 20 per cent from 2000-01 to 2012-13 (WAAG 2015). DER advises that this has resulted from the increase in population, vehicle fleet growth, more individual travel, and the increased distance of travel associated with the spread of population over a relatively large area. Over 80 per cent of trips made in the Perth metropolitan region are made by private car and occupancy is low (WAAG 2015); however public transport usage in recent years has increased at a significantly greater rate than the population (DoT 2011).

The sub-regional frameworks have been targeted at developing activity centres to minimise the travel that is required between people’s home and workplace or other regularly utilised facilities (e.g. shopping centres). The central sub-region is also proposed to be a focus for infill, with this primarily occurring along established infrastructure networks, including public transport routes that could limit private vehicle use.

It is noted that there will be a range of other factors that affect the contribution of vehicles to air emissions in the future, including emission controls and standards, uptake of alternative vehicle technology and different vehicle fleet composition.

8.8.2 Land use buffers and the interface with conflicting land uses

Potential impacts from reduced air quality are likely where future development of BRM, industrial and infrastructure occur in close proximity to sensitive land uses such as urban residential, aged-care, hospitals or child-care. Avoidance measures to date reduce the likelihood of conflicting land use (see Section 8.9); however, as current land uses transition for example from rural to urban or from industrial to urban, sensitive land uses may encroach on existing activities generating air emissions and conflicts may still arise.

8.8.3 Dust

Diffuse sources of dust arise from activities such as land clearing activities, earthworks during construction, remediation of contaminated sites, demolition works, bulk materials handling, mining and quarrying activities including the storage, transport and stockpiling of soil or other material on site (DER 2011). Smaller particle sizes (< 10 µm) are implicated in health effects such as irritation of airways and aggravated asthma, while larger size particles (up to 50 µm) primarily cause nuisance effects such as reduced visibility or discolouration from settling on surfaces. In some circumstances such as where dust arises from contaminated land, health impacts can arise from contaminants (such as polycyclic aromatic hydrocarbons, heavy metals and asbestos) contained within the particles themselves (DER 2011).



8.9 MITIGATION AND MANAGEMENT Implementation of the sub-regional frameworks is expected to result in an overall increase in air emissions in the Perth and Peel regions associated with an increased population, as well as point source emissions related to specific projects such as industrial developments. The absence of airshed modelling for future growth scenarios constrains specific impact prediction the State is committing to measures for improving knowledge of current and future emission sources to inform strategic land use planning (see Action Plan G) by:

• Updating the Perth Emissions Inventory to include current and future major sources of air emission sources within the Perth and Peel regions.

• Updating the Perth Air Quality Management Plan and expanding to include the Peel region.

• Developing an assessment framework for determining cumulative air emissions from proposed industrial areas in order to facilitate consideration of the acceptability of air quality impacts

The EPA's interim strategic advice highlights the role of separation distances as an important consideration in determining a land use planning buffer to mitigate adverse impacts when air emissions cannot be contained and notes that the pressure for industrial development and urban development can erode buffers separating emissions sources from sensitive land uses.

Action Plan G of the Strategic Conservation Plan provides for the determination and implementation of buffers around strategic industrial areas and development of a policy to guide their implementation (the EPA has sought public comment on a draft revision of guidance on separation distances). The most appropriate planning layer to incorporate buffers will be an important consideration, noting that buffers need to be determined on a particular land use rather than a zoning.

Air emissions from transport will significantly increase with a larger population. While the more compact urban form to be achieved through the sub-regional frameworks will provide avoidance, further mitigation is proposed by developing and implementing long term integrated transport planning for the Perth and Peel region that responds to air quality considerations by using knowledge and data to inform decision making, and ensuring transport and land use planning strategies have a common focus on reduced traffic congestion. Increased uptake of active travel and public transport will also mitigate impacts to air and measures to support to implement and support awareness and behaviour change are also identified in Action Plan G.

Establishment of a permanent air quality monitoring station within the Perth central business district and in the Peel region (in Mandurah) is proposed to support the above mitigation and management measures.



Commitment: Improve the knowledge of the current state of air quality, and current and future major sources and types of air emissions, to inform strategic land use planning through the following actions:

• Update the Perth Emissions Inventory to identify the contributors to current air quality within the Perth and Peel regions, as well as identifying the future major sources and types of air emissions for the purpose of strategic land use planning.

• Update the Perth Air Quality Management Plan and expand to include the Peel region.

• Establish a permanent air quality monitoring station within the Perth central business district and in the Peel region (in Mandurah).

Commitment: Develop an assessment framework for determining cumulative air emissions from proposed industrial areas within the Perth and Peel regions in order to facilitate consideration of the acceptability of air quality impacts.

Commitment: Manage air quality impacts through the determination and implementation of buffers around strategic industrial areas and through the development of a policy to guide the implementation of buffers around industrial areas.

Commitment: Develop and implement long-term integrated transport planning for the Perth and Reel region that aligns with sub-regional structure plans and responds to air quality considerations that:

• ensures transport and land use planning strategies are complementary in identifying measures to reduce traffic congestion and improve air quality; and

• uses air quality knowledge and data to inform decision making.

Commitment: Encourage increased uptake of active travel and public transport through continuing to implement and support behaviour change and awareness programs.

8.10 SUMMARY OF OUTCOME FOR EPA OBJECTIVE Although a quantitative determination of the future impacts to air quality has not been undertaken, the proposed mitigation and management measures put forward in Action Plan G of the Strategic Conservation Plan address key gaps in current management measures for air quality in the Perth and Peel region. Combined with substantial avoidance already achieved, implementation of these measures will mean that the EPA's objective for Air Quality can be met over time.

Date post:	22-Mar-2020
Category:	Documents
Upload:	others
View:	2 times
Download:	0 times

IMPACTS TO HYDROLOGICAL PROCESSES AND INLAND … Impact Assessment Report...Regional Water Supply...

Documents