plantation forestry and water management guideline · plantation forestry and water management...

Plantation forestry and water management guideline

This guideline is part funded by the Australian Government under Water for the Future’s- Water Smart Australia program.

Department of Water

June 2009

Department of Water 168 St Georges Terrace Perth Western Australia 6000 Telephone +61 8 6364 7600 Facsimile +61 8 6364 7601 www.water.wa.gov.au

© Government of Western Australia 2009

June 2009

This work is copyright. You may download, display, print and reproduce this material in unaltered form only (retaining this notice) for your personal, non-commercial use or use within your organisation. Apart from any use as permitted under the Copyright Act 1968, all other rights are reserved. Requests and inquiries concerning reproduction and rights should be addressed to the Department of Water.

ISBN 978-1-921637-65-0 (print) ISBN 978-1-921637-66-7 (online)

Acknowledgements

The Department of Water would like to thank the Forest Products Commission for providing photos for the online version of this guideline.

For more information about this report, contact the Water Allocation Planning Branch.


Contents 1 Guideline purpose................................................................................................................1

1.1 About this guideline ....................................................................................................1 1.2 What do local government and the plantation forestry industry want? .......................1 1.3 A water resource management issue .........................................................................1

2 Current management ...........................................................................................................2

2.1 Our current roles in managing plantation forestry.......................................................2 2.2 Providing advice to local government .........................................................................2 2.3 Allocating water for use ..............................................................................................3

3 Future management.............................................................................................................5

3.1 Licensing plantation water use ...................................................................................5 3.2 We are preparing new policy ......................................................................................5

4 WA Snapshot .......................................................................................................................6

4.1 Plantation forestry is concentrated in the south west corner ......................................6 4.2 Clearing of forests increased stream salinity in some areas ......................................8 4.3 Reforestation is improving water quality and reducing dryland salinity.......................8

5 Some basic science .............................................................................................................9

5.1 New plantation forests decrease available water .......................................................9 5.2 Measuring water use and impacts on available water ................................................9 5.3 Comparing forest and pasture water use....................................................................9 5.4 Effects on available water vary ...................................................................................9

6 Current research ................................................................................................................10

Glossary ......................................................................................................................................11

Appendices Appendix 1. Plantation forestry in the Gnangara groundwater areas..........................................12

Appendix 2. Plantation forestry in the Gingin, Jurien and Arrowsmith groundwater areas .........15

Appendix 3. Plantation forestry in the Whicher surface water area.............................................17

Appendix 4. Plantation forestry in the South West groundwater areas .......................................20

Appendix 5. Plantation forestry in the Upper Collie catchment ...................................................22

Figures Figure 1 Decision process for plantation development applications ....................................3 Figure 2 Location of water management plan areas ............................................................4 Figure 3 Plantation forestry in the Perth region....................................................................6 Figure 4 Plantation forestry in the South west region...........................................................7 Figure 5 Plantation forestry in the South coast region .........................................................8

Tables Table 1 Factors that determine how much plantation forestry reduces stream flow

and groundwater level............................................................................................9

Department of Water iii


1 Guideline purpose

1.1 About this guideline

The purpose of this guideline is to clarify the Department of Water’s role in the management of plantation forestry. Our target audience is local government and the plantation forestry industry.

This guideline covers current and future management arrangements, a snap shot of plantations and their effects on water resources in Western Australia, some basic science, current research and some important definitions.

1.2 What do local government and the plantation forestry industry want?

The Department of Water has identified plantation forestry as a major water resource management issue through stakeholder engagement as part of the development of water management plans across the South West of the state. Local governments suggested that we should manage plantations through licensing and regulation. The plantation forestry industry requested clarification of a number of definitions, expressed interest in how we calculated plantation water use and identified the need for research into plantation water use. The industry also indicated a willingness for ongoing communication and cooperation with the Department of Water.

This guideline is a response to this stakeholder feedback.

1.3 A water resource management issue

The conversion of pasture to plantation forestry is a significant water resource management issue for Western Australia. It can result in less groundwater and stream flow. This has a negative impact by reducing the amount of groundwater and surface water available for other water users and the environment. In some areas, plantations can trigger the release of sulfuric acid and metals from soils into streams. In other areas, development of plantation forestry can have a positive effect by reducing stream salinity and reducing the effects of soil salinity on plant growth.

Department of Water 1


2 Current management

2.1 Our current roles in managing plantation forestry

The Department of Water cannot regulate plantation water use under current water resource management legislation, the Rights in Water and Irrigation Act (1914). This means that while we can grant a water access entitlement for the purposes of irrigated agriculture, we cannot grant a similar water access entitlement for a plantation forest.

However, the Department of Water currently has two roles in the management of plantation forestry and water resources:

1. To provide advice to local government on potential water availability and water quality impacts associated with plantation development applications.

2. To consider current and projected plantation development in deciding how much water is available in a particular surface or groundwater resource or area for all users. We usually do this as part of preparing a water allocation plan.

2.2 Providing advice to local government

Proponents submit plantation development applications to local government. Local government may require a plantation developer to undertake a water resource impact investigation and provide a statement.

Local government may ask the Department of Water for advice on water resource management issues related to proposed plantation developments. We may provide advice on expected changes to water availability and water quality.

The Department of Environment and Conservation is the lead state government agency for providing advice on acid sulfate soils and impacts on river and wetland ecology. Their decisions are made under the Environmental Protection Act (1986).

Local governments make final decisions under the Planning and Development Act (2005) on whether plantation developments can proceed and under what conditions. Local government also manages other issues, such as aesthetic amenity, development of prime agricultural soils and community demographics. This process is shown in Figure 1 below.

2 Department of Water


Figure 1 Decision process for plantation development applications

2.3 Allocating water for use

Water allocation planning involves deciding how much water is available for consumptive use and how this water can be accessed. The department considers the effects of plantation forestry on water resources in these decisions. A number of allocation plans have already been developed, or are underway, for areas across the state with plantation forestry. These include:

The Gnangara groundwater areas cover the northern half of the Perth metropolitan region. Decreasing rainfall, over-allocation, and urban expansion are stressing groundwater resources in this area. Clearing of pine plantations in the central and northern parts of the Gnangara groundwater area will continue in accordance with the Wood Processing (Wesbeam) Agreement Act 2002, which commits the State Government to provide wood to the Laminated Veneer Lumber Plant from its plantations until 2029. The Forest Products Commission will investigate the potential for modifying harvesting strategies to increase water availability within the constraints of the Act. In 2005, the total area of plantation forestry was about 24,000 hectares.

The Gingin, Jurien and Arrowsmith groundwater areas extend from about 50 kilometres north of Perth to Geraldton. Plantation forestry is sparse, because low rainfall and sandy soils limit tree growth and the types of trees that can grow. In 2005, plantation forestry covered approximately 9,500 hectares.

The Whicher (surface water) area and South West groundwater areas are located about 250 kilometres south of Perth and cover most of the same area. Plantation forestry is expanding, particularly in areas that were cleared and previously used for pasture. In 2005, plantation forestry covered approximately 38,500 hectares of the area covered by these two plans.



The Upper Collie catchment is located approximately 200 kilometres south of Perth. Plantation forestry was established in the upper parts of the catchment to reduce the salinity of water flowing into Wellington Reservoir. In 2005, the total area of plantation forestry was about 19,000 hectares.

Figure 2 Location of water management plan areas



3 Future management

3.1 Licensing plantation water use

The Intergovernmental Agreement on a National Water Initiative recommends that plantation water use is licensed under certain circumstances. The Western Australian government signed the agreement in 2006.

The state government is preparing new legislation, called the Water Resource Management Bill. The draft Bill proposes to allow the Department of Water to licence plantation water use when a detrimental effect on other water users is expected.

We will generally licence plantation forestry where there is competition for water and where available water will decrease as a result of plantation forestry. Competition for water is high or increasing in the water planning areas identified in this guideline (see Current Management). We will generally not licence new plantation forestry where stream and dryland salinity can be significantly reduced (see WA Snapshot).

3.2 We are preparing new policy

The Department is currently developing policy to support the implementation of the Water Resource Management Bill. This policy will define:

What is a detrimental effect of plantation forestry on other water users. How water volumes for plantation forestry water access entitlements and licences are

calculated. How to determine whether a plantation forest is accessing groundwater, surface water

or both. Any special features of a plantation forestry water access entitlement or licence.



4 WA Snapshot

4.1 Plantation forestry is concentrated in the south west corner

Click on the links below to see maps showing the distribution of plantation forestry across different rainfall zones in Western Australia. These maps show that plantation forestry is concentrated in the south west corner.

Figure 3 Plantation forestry in the Perth region



Figure 4 Plantation forestry in the South west region



Figure 5 Plantation forestry in the South coast region

4.2 Clearing of forests increased stream salinity in some areas

Settlers cleared south west forest areas mostly between the 1940s and 1970s to develop pasture for grazing and crops. This reduced the volume of water used by vegetation. In some areas (particularly low rainfall areas), groundwater levels rose and increased volumes of saline groundwater entered streams. Some fresh streams became saline.

4.3 Reforestation is improving water quality and reducing dryland salinity

Some areas originally cleared for agriculture are being reforested with plantations. This is lowering groundwater levels and decreasing the volume of saline groundwater entering streams and reducing stream salinity.

Reforestation in upper catchment areas is reducing the volume of water recharging to deep groundwater. The result is a decrease in waterlogging and the area of dryland salinity in lower parts of valleys.

Plantation forestry has reduced stream and dryland salinity in areas that receive an average annual rainfall of less than about 900 mm.



5 Some basic science

5.1 New plantation forests decrease available water

Afforestation is the conversion of bare or cultivated land into forest. Water taken up by roots is transpired from leaf pores to the atmosphere. Water also evaporates to the atmosphere from leaf litter and soil. Trees can also access water in the soil and shallow groundwater. New plantation forestry reduces water available from streams and groundwater.

5.2 Measuring water use and impacts on available water

Evaporation and transpiration are together referred to as evapotranspiration. Evapotranspiration measures of how much water is used by forests, but does not measure overall effects on available water. Impacts on available water can be determined by measuring or modelling change in stream flow and change in groundwater level.

5.3 Comparing forest and pasture water use

Forests use more water than pasture. The difference in water use by the two land uses is larger in high rainfall areas. This difference is important in predicting and managing the effects of land use change on available water.

5.4 Effects on available water vary

Each plantation forest is unique and effects on stream flow and groundwater levels vary. Variation can result from the factors identified in Table 1.

Table 1 Factors that determine how much plantation forestry reduces stream flow and groundwater level

A large reduction in stream flow or groundwater level is related to:

A small reduction in stream flow or groundwater level is related to:

Large area of plantation forestry small area of plantation forestry plantation forests in valleys and close to streams plantation forests in upper areas of catchments high tree density low tree density high leaf cover or density low leaf cover or density no thinning or harvesting of trees thinning and harvesting of trees mature trees with large canopies immature trees with small canopies light or medium textured soils clay soils fresh groundwater saline groundwater shallow groundwater deep groundwater



6 Current research There are a number of research projects being implemented across Australia to improve information and modelling tools for estimating plantation water use. The National Water Commission, CSIRO, CRC Forestry, the Department of Water, the Forest Products Commission and industry are each supporting one or more of the following four projects.

Methods to accurately assess water allocation impacts of plantations aims to develop nationally consistent methods to assess (1) risk of new plantations to water access entitlements at the catchment scale, and (2) site scale impacts (e.g. soils, plantation thinning) of plantations on stream flows.

South West sustainable yields aims to build and run a new surface water model using existing data to model catchment yields under scenarios including current plantation development as well as proposed plantation development.

Impacts of plantations on water security: Review and scientific assessment of regional issues and research needs aims to develop regionally specific recommendations regarding the information needs for the forest industry to engage with state government agencies for the purpose of implementing the National Water Initiative.

Water use and water use efficiency of eucalyptus plantations: From stand to catchment scale aims to (1) investigate the effect of plantation establishment and growth cycles on surface water flows, (2) develop and implement a modelling approach that better links stand and catchment estimates of water use, and (3) develop an approach for describing the trade off between carbon capture, water use and other outcomes associated with plantation production.



Glossary Afforestation is the conversion of bare or cultivated land into forest.

Consumptive use is for private and public benefit purposes including irrigation, industry, urban, livestock and domestic use.

Evapotranspiration is the combined processes of evaporation from the ground and vegetation surfaces (i.e. after rainfall) and transpiration from vegetation.

Farm is a business enterprise engaged predominantly in agriculture other than plantation forestry.

Farm forestry is part of a mix of activities on a farm, is not the main product of the farm in terms of financial returns, and where the planted area of trees is a small proportion of the total farm area.

Overland flow is the movement of water over land surface before passing to a waterway, infiltrating soil, or evaporating.

Plantation area is the vegetated buffer area plus the planted area.

Plantation establishment is the period that includes site preparation, weed control, planting, fertilising, infill planting and seedling protection for a period of approximately two years.

Plantation forest is a non-irrigated crop of trees grown or maintained so that the wood, bark, leaves or essential oils can be harvested or used for commercial purposes, including through the commercial exploitation of the carbon absorption capacity of the forest vegetation.

Rotation is the number of years between plantation planting and harvest.

Riparian zone is the area adjacent to, or surrounding a water body or waterway that is influenced by the passage and storage of water.

Reforestation is the establishment of forests on land that is cleared, but was previously forested.

Thinning is the removal of a portion of trees in a plantation. Thinning may be used to procure a specific product, to increase the growth rate of retained trees, or increase available water.

Values are what people view as important or of worth.

Water access entitlement is a perpetual or ongoing entitlement to exclusive access to water.

Water interception is the use of water associated with land use activities including plantation forestry, farm dams, bores, and storing of overland flows. Sections 55, 56 and 57 of the National Water Initiative imply that water interception is the capture or use of water not included in water licensing or water entitlement systems.

Water management area is based on hydrological boundaries, is defined in a water management plan, and is subject to a set of water management rules.



Appendix 1. Plantation forestry in the Gnangara groundwater areas



Allocation limits, water availability and area of plantation forestry in Gnangara groundwater sub-areas

Sub-area name Map

reference Allocation

limit (ML/yr)1 Is water

available?2

Area of plantation

forestry (ha)

Adams 1 1000 no 4 Ballajura 2 6000 no 0 Bandy Spring 3 350 no 14 Beechboro 4 1000 yes 0 Beermullah Plain South 5 3000 no 170 Carabooda 6 6400 no 4 Carramar 7 1700 yes 6 Central Swan 8 1000 no 0 City of Bayswater 9 2300 yes 0 City of Fremantle North 10 700 yes 0 City of Nedlands 11 2300 no 0 City of Perth 12 1500 no 0 City of Stirling 13 11150 no 0 City of Subiaco 14 1000 yes 0 Cockman Bluff 15 1500 yes 157 Deepwater Lagoon South 16 3500 yes 0 East Swan 17 750 no 0 Eglinton 18 15450 yes 0 Guilderton South 19 11000 no 0 Gwelup 20 7950 no 0 Henley Brook 21 1600 no 0 Improvement Plan 8 22 5500 no 0 Jandabup 23 200 no 4 Joondalup 24 1500 yes 0 Lake Gnangara 25 7500 no 0 Lake Mungala 26 3400 no 0 Landsdale 27 1400 yes 0 Mariginiup 28 4000 no 0 Neaves 29 2000 no 0 Neerabup 30 2650 yes 387 North Swan 31 2000 no 94 Nowergup 32 2000 no 25 Pinjar 33 500 no 2 Plantation 34 600 yes 1 Quinns 35 24650 yes 1 Radar 36 2000 no 0 Reserve 37 9000 no 15673 Shire of Peppermint Grove 38 100 yes 0 Shire of Swan North 39 1000 yes 0 South Swan 40 4000 no 0 State Forest 41 1000 yes 297 Town of Bassendean 42 500 yes 0




Sub-area name Map



available?2

Area of plantation

forestry (ha)

Town of Cambridge 43 3500 yes 0 Town of Claremont 44 700 yes 0 Town of Cottesloe 45 300 yes 0 Town of Mosman Park 46 500 yes 0 Town of Vincent 47 1000 yes 0 Wanneroo Wellfield 48 12000 yes 7061 Whiteman Park 49 1000 no 0 Whitfords 50 22430 no 0 Yanchep 51 10870 yes 0 Total 208950 23900

1 Allocation limits for superficial aquifer 2 Contact a Swan-Avon regional office for the latest information on water availability


Appendix 2. Plantation forestry in the Gingin, Jurien and Arrowsmith groundwater areas



Allocation limits, water availability and area of plantation forestry in the Gingin, Jurien, and Arrowsmith groundwater sub-areas

Sub-area name Map



available?2

Area of plantation

forestry (ha)

Arrowsmith

Allanooka 1 0 no 0 Darling 2 2500 yes 9 Dongara 3 8000 yes 0 Eneabba Plains 4 14600 yes 138 Mingenew 5 0 no 0 Morrison 6 0 no 0 Tathra 7 0 no 0 Twin Hills 8 0 no 276 Total 25100 423

Jurien

Badgingarra 9 0 no 60 Cervantes 10 30000 yes 0 Dinner Hill 11 3200 yes 1130 Nambung 12 4000 yes 255 Watheroo 13 900 yes 132 Total 38100 1577

Gingin

Beermullah Plain North 14 9600 yes 236 Bindoon 15 2400 yes 0 Deepwater Lagoon North 16 1900 no 0 Eclipse Hill 17 4400 yes 719 Gingin Townsite 18 5001 yes 253 Guilderton North 19 9900 no 0 Karakin Lakes 20 24000 yes 491 Lake Mungala 21 3400 no 0 Lancelin 22 27400 no 1592 Moora 23 800 yes 0 Namming Lake 24 13300 yes 281 North Moore River Park 25 12900 yes 0 Red Gully 26 6600 yes 1378 Seabird 27 22100 yes 183 South Moore River Park 28 7500 yes 4 Victoria Plains 29 4400 yes 2047 Wedge Island 30 81700 yes 494 Total 237301 7678

1 Combined allocation limits for superficial and surficial aquifers if both are present 2 Contact a Mid West Gascoyne regional office for the latest information on water availability



Appendix 3. Plantation forestry in the Whicher surface water area



Allocation limits, water availability and area of plantation forestry in the Whicher surface water sub-areas

Sub-area name Map


limit (ML/yr) Is water

available?1

Area of plantation

forestry (ha)

10 Mile Brook 1 1000 No 0 Adelaide 2 0 No 0 Ballan 3 0 No 15 Beenup 4 290 Yes 3 Biljedup 5 330 Yes 34 Boodijidup 6 3210 Yes 164 Bramley 7 1810 Yes 413 Buayanup 8 201 Yes 1376 Calgardup 9 2530 Yes 172 Capel River Central 10 980 Yes 41 Capel River North Branch 11 4700 Yes 38 Capel River South Branch 12 2730 Yes 317 Capel River West 13 490 No 113 Carbunup 14 165 Yes 69 Carlotta 15 5850 Yes 1824 Chapman 16 2100 Yes 99 Cowaramup 17 450 Yes 0 Dunsborough Coast 18 3000 Yes 296 Ellen 19 1180 Yes 34 Ellis 20 130 Yes 530 Five Mile Brook 21 87 Yes 0 Glenarty 22 1110 Yes 203 Gunyulgup 23 1090 No 0 Gynudup Brook and Tren Creek 24 1380 Yes 747 Lower Margaret 25 1670 Yes 3 Lower Blackwood Estuarine Reach 26 2840 Yes 1202 Lower Blackwood Hardy Estuary 27 1200 Yes 183 Lower Blackwd Hut Reach 28 260 Yes 58 Lower Blackwood Nannup Reach 29 2600 Yes 2374 Margaret Town 30 910 Yes 114 McAtee 31 0 No 0 McLeod SW 32 4270 Yes 439 Middle Margaret 33 3200 Yes 298 Milyeannup 34 30 Yes 0 Naturalist 35 310 Yes Poison 36 0 No 5 Quininup 37 550 No 0 Readia 38 0 No 0 Red Gully 39 80 Yes 58 Rosa 40 0 No 328 Rushy 41 1050 Yes 94 Scott 42 16010 Yes 6186




Sub-area name Map


limit (ML/yr) Is water

available?1

Area of plantation

forestry (ha)

St John 43 750 Yes 5331 Tanjannerup 44 140 No 199 Turner SW 45 2140 Yes 159 Turnwood 46 360 Yes 538 Upper Chapman 47 2800 Yes 123 Upper Margaret 48 170 No 3933 Vasse Diversion 49 3340 Yes 853 West Bay 50 940 Yes 301 Wilyabrup 51 2480 No 81 Wonnerup 52 4240 Yes 1949 Total 87153 31297

1 Contact a South West regional office for the latest information on water availability


Appendix 4. Plantation forestry in the South West groundwater areas



Allocation limits, water availability and area of plantation forestry in the South West groundwater sub-areas

Sub-area name Map reference Allocation limit (ML/yr)1

Is water available?2

Area of plantation forestry (ha)

Australind 3 690 yes 0 Beenup 12 2400 yes 1582 Blackwood Plateau North 15 300 yes 9111 Blackwood Plateau South 14 300 yes 170 Blackwood-Karri 24 no limit yes 352 Bunbury East 20 2700 yes 0 Bunbury West 21 2000 yes 0 Bunbury-Karri 25 no limit yes 125 Busselton-Capel 19 18500 yes 2228 Cape to Cape North 17 400 yes 722 Cape to Cape South 23 400 yes 2254 Coastal 1 4100 yes 0 Cowaramup 26 2400 yes 2053 Dardanup 22 290 yes 121 Donnybrook 18 500 no 81 Dunsborough-Vasse 16 9900 yes 620 Harvey 8 11500 yes 1307 Jasper 10 2000 yes 2080 Kemerton Industrial Park North 5 790 yes 343 Kemerton Industrial Park South 4 210 no 51 Lake Preston North 2 9300 yes 1416 Lake Preston South 9 10500 no 1777 Myalup 6 7350 yes 704 Rosa 13 1100 yes 269 Scott 11 2000 yes 5225 Wellesley 7 2150 yes 39 Total 91780 32630

1 Allocation limits for superficial aquifer (Green: Combined allocation limits for superficial and Leederville aquifers) 2 Contact a South West regional office for the latest information on water availability



Appendix 5. Plantation forestry in the Upper Collie catchment




Allocation limits, water availability and area of plantation forestry in the South West groundwater sub-areas

Sub-area name Map reference Allocation limit (ML/yr)

Is water available?1

Area of plantation forestry (ha)

Collie River Central 1 86600 yes 2117 Harris River 2 15000 no 22 Lower Harris 3 1220 yes 13 Collie River East Branch 4 14000 no 8904 Collie River Lower East Branch 5 1000 yes 1023 Bingham River 6 0 no 1207 Collie River South Branch 7 5020 yes 5893 Total 122840 19179

1 Contact a South West regional office for the latest information on water availability

plantation forestry and water management guideline · plantation forestry and water management...

Documents