groundwater management strategy · the groundwater resources of the lower gascoyne river are the...

(Carnarvon) WA

Groundwater Management Strategy

Managing Groundwater Resources of the Lower Gascoyne River

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Managing The Groundwater Resources of the Lower Gascoyne River (Carnarvon)

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MANAGING THEGROUNDWATER RESOURCES

OF THELOWER GASCOYNE RIVER

(CARNARVON)WA

GROUNDWATER MANAGEMENT STRATEGY

Prepared byWater and Rivers Commission

Water Allocation Branch,Resource Management Division,Midwest Gascoyne Region and

Carnarvon Water Allocation Advisory Committee

January 2004


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Acknowledgments

This Groundwater Management Strategy has been prepared by the Water Allocation Branch and the Midwest/GascoyneRegion of the Water and Rivers Commission, with the assistance of the Carnarvon Water Allocation AdvisoryCommittee.

The Strategy development team consisted of:

Ron Shepherd Regional Manager, Midwest/Gascoyne Region

Alan Bradley Program Manager Environmental Management, Midwest/Gascoyne Region

Wayne Astill Environmental Engineer, Midwest/Gascoyne Region

Kevin Firth Senior Water Resource Officer, Midwest/Gascoyne Region

Claire Thorstensen Gascoyne Program Manager, Midwest/Gascoyne Region

Darryl Abbott Natural Resource Management Officer, Midwest/Gascoyne Region

Rebecca Blyton Planning Officer (Project Manager), Perth

Phillip Kalaitzis Program Manager, Water Allocation Planning, Perth

Members of the Carnarvon Water Allocation Advisory Committee

Member Organisation

Ron Shepherd - Chairperson Water and Rivers Commission

Bruce Teede Grower representative

Bruce Munro Grower representative

Marcus Holla Grower representative

Paul Nevill Grower representative

Bill Doble Department of Indigenous Affairs

Dale Rogers Shire of Carnarvon

Ron Copeland Shire of Carnarvon

Dave Bauer Carnarvon LCDC

Steve Greeve Water Corporation


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Reference Details

This document is protected by copyright. Information in this Strategy may be reproduced provided that any extracts arefully acknowledged. The recommended reference for this publication is:

WRC (2004). Managing the Groundwater Resources of the Lower Gascoyne River (Carnarvon) WA – GroundwaterManagement Strategy. Water and Rivers Commission

ISBN 1-92084-964-5 [PDF]

CONTACT FOR FURTHER INFORMATION

For further information on any aspect of this Strategy, you may contact:

Water and Rivers Commission Gascoyne District OfficeMidwest Gascoyne Region211 Robinson StreetCARNARVON WA 6701Telephone (08) 9941 4921Facsimile (08) 9941 4931

PUBLIC COMMENT ON THIS STRATEGY

Public notification that the draft Strategy had been prepared was published in the Government Gazette and twonewspapers (State and local). Written submissions on the draft Strategy were accepted by the Commission during Apriland May 2003. This Strategy was also referred to relevant agencies, including the Department of Land Administration.

The submissions on the draft Strategy provided information, opinions and suggested courses of action, includingalternative approaches to the proposed management initiatives. Many of the suggestions were taken on board andincorporated in this Strategy. Other submissions were not considered as they were either outside the scope of thisStrategy or too individual to warrant amendments to be made to this Strategy.

The Commission would like to thank the people of Carnarvon and other stakeholders who made a written submissionon the draft Strategy.


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Foreword

Increasing demand on the Nation’s scarce water resources is a growing issue for communities and Governments acrossAustralia.

Western Australia’s water resource legislation, the Rights in Water and Irrigation Act 1914, provides a framework forstrategic planning for water resources allocation and use to allow water users and managers to respond to the newdemands. Key components of planning include community involvement in decision making, environmental waterprovisions, and flexibility in developing local policies that reflect the management needs of local water resources andcommunity desires.

I am pleased to release the Groundwater Management Strategy for the Groundwater Resources of the Lower GascoyneRiver (Carnarvon), WA. It demonstrates the environmental, economic, and social gains that can be achieved byadapting water resource management to changing needs of water users and knowledge of the resource. The strategy isan outcome of the State Government’s investment in priority recommendations of the Lower Gascoyne ManagementStrategy.

The groundwater resources of the lower Gascoyne River are the lifeblood of the irrigation community. Thehorticultural activity, significant to both the regional and State economy, is dependent on access to the river’sgroundwater resources. This Groundwater Management Strategy is a blueprint for increased opportunity for thehorticultural industry and local community as it outlines strategies for sustainable use of the resource. Importantly it isinnovative in describing local allocation strategies that provide greater flexibility in water allocation than has been inplace for over 30 years.

This Strategy, in conjunction with the State Government initiative to transfer the Carnarvon Irrigation Scheme to agrowers' cooperative, should act as a foundation for industry expansion and economic growth for the region.

I thank community members of the Carnarvon Water Allocation Advisory Committee, and members of the Water andRivers Commission planning team for their efforts in preparing this Strategy.

I commend this Groundwater Management Strategy to you and encourage everybody interested in water resourcemanagement to work to secure the future of Carnarvon.

D Carew-HopkinsA/CHIEF EXECUTIVE


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Contents

Acknowledgments .............................................................................................................ii

Reference Details..............................................................................................................iii

Foreword ........................................................................................................................... iv

Contents ............................................................................................................................v

Summary ............................................................................................................................1

1 Background information...........................................................................................91.1 Name of Strategy.................................................................................................................. 91.2 The Water Accounting Year .................................................................................................. 91.3 Date of commencement of this Strategy ............................................................................... 91.4 Life of this Strategy ............................................................................................................... 91.5 Area to which this Strategy applies ....................................................................................... 91.6 Waters to which this Strategy applies.................................................................................. 121.7 The purpose of this Strategy ............................................................................................... 121.8 Administration and Enforcement ......................................................................................... 121.9 Conflict resolution process .................................................................................................. 131.10 The Carnarvon Water Allocation Advisory Committee...................................................... 131.11 Where this Strategy can be obtained ............................................................................... 14

2 Groundwater allocation, use and availability........................................................152.1 Introduction ............................................................................................................... 152.2 Historical water use patterns............................................................................................... 152.3 Groundwater allocation and usage...................................................................................... 152.4 Assessing the available resource........................................................................................ 182.5 The amended allocation limit ............................................................................................... 192.5.1 The Allocation Limit for Basin A........................................................................................ 202.5.2 The Allocation Limit for Basins B – L................................................................................ 202.6 Town water supply requirements ........................................................................................ 202.7 Other industry water supply requirements........................................................................... 212.8 Future demand for water versus future supply .................................................................... 212.9 Climate variability................................................................................................................ 222.10 Aligning entitlements in Basin A to the estimated allocation limit ...................................... 22

3 Understanding the groundwater resource ............................................................233.1 Quantity characteristics of the resource 233.1.1 Climate 233.1.2 The aquifer systems of the Lower Gascoyne River 243.1.3 The impacts of abstraction on the rate of recharge and groundwater availability 27


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3.1.4 The impacts of abstraction on groundwater levels 273.2 Quality characteristics of the resource 303.2.1 The impacts of abstraction on salinity levels and salt water intrusion 303.3 Groundwater/surface water interactions 31

4 Assessment of the environmental impacts of developing the resource............334.1 Ecological water requirements and environmental water provisions.................................... 334.2 Identification of the value of groundwater dependent ecosystems (ecological and socialwater requirements)................................................................................................................... 334.2.1 Chinaman's Pool, Rocky Pool and temporary pools ......................................................... 344.2.2 The riparian (river bank) vegetation .................................................................................. 344.3 Water to support values (Environmental Water Provisions).................................................. 344.3.1 Chinaman's Pool, Rocky Pool and temporary pools .......................................................... 344.3.2 The riparian (river bank) vegetation .................................................................................. 354.3.3 Management provisions - Ecological water provisions ..................................................... 35

5 Water allocation principles.....................................................................................375.1 Background......................................................................................................................... 375.2 Allocation principles ............................................................................................................ 375.3 Basis for allocation.............................................................................................................. 385.3.1 Basins B-L groundwater resources .................................................................................. 385.3.1.1 Management Provisions - Basins B-L ............................................................................ 395.3.2 Basin A groundwater resource ......................................................................................... 405.3.2.1 Management Provisions - Basin A ................................................................................. 405.3.3 Maximum monthly draw ................................................................................................... 415.3.3.1 Management Provisions - maximum monthly draw ........................................................ 415.3.4 Water quality restrictions and monitoring.......................................................................... 415.3.4.1 Management Provisions - water quality.......................................................................... 425.3.5 Issue and renewal of licences in Basin A ......................................................................... 425.3.5.1 Management Provisions - issue of licences.................................................................... 425.3.6 Requests for additional and/or new entitlements .............................................................. 435.3.6.1 Management Provisions................................................................................................. 435.3.7 Non-plantation entitlements in Basin A............................................................................. 445.3.7.1 Management Provisions................................................................................................. 445.3.8 Unused allocations in Basin A.......................................................................................... 455.3.8.1 Management Provisions................................................................................................. 465.3.9 Domestic and stock use ................................................................................................... 465.3.9.1 Management Provisions................................................................................................. 465.4 The Drought Strategy.......................................................................................................... 475.4.1 Drought Management Provisions ..................................................................................... 485.5 Groundwater pumping ........................................................................................................ 495.5.1 Metering of use ................................................................................................................ 495.5.1.1 Management Provisions................................................................................................. 50


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5.5.2 Restricted pumping .......................................................................................................... 505.5.2.1 Management Provisions................................................................................................. 505.5.3 Unrestricted pumping ....................................................................................................... 515.5.3.1 Management Provisions................................................................................................. 515.5.4 Unauthorised pumping ..................................................................................................... 515.5.4.1 Management Provisions................................................................................................. 525.5.5 Over pumping .................................................................................................................. 525.5.5.1 Management Provisions................................................................................................. 525.5.6 Water wastage and improper use..................................................................................... 535.5.6.1 Management Provisions................................................................................................. 535.6 Well construction and decommissioning ............................................................................. 535.6.1 Management Provisions – Well construction and decommissioning................................. 545.7 Water Supply Contamination .............................................................................................. 555.8 Groundwater access ........................................................................................................... 555.8.1 Basin A prolongations ...................................................................................................... 555.8.1.1 Management Provisions................................................................................................. 565.9 Land matters....................................................................................................................... 565.9.1 Sale of property with respect to licence transfers ............................................................. 565.9.1.1 Management Provisions................................................................................................. 565.9.2 Wells located outside a property’s prolongation ............................................................... 575.9.2.1 Management Provisions................................................................................................. 575.9.3 Splitting a water entitlement on the same property ........................................................... 575.9.3.1 Management Provisions................................................................................................. 575.9.4 Subdivision of prolongations ............................................................................................ 575.9.4.1 Management Provisions................................................................................................. 575.9.5 Amalgamation of prologations........................................................................................... 585.9.5.1 Management Provisions................................................................................................. 585.9.5.2 Recovering the cost of groundwater management ......................................................... 58

6 Transferable water entitlements principles and rules for Basin A......................606.1 Application to transfer (trade) a water entitlement ............................................................... 616.2 Principles of trading water entitlements............................................................................... 616.3 Local trading rules............................................................................................................... 626.4 Refusal of trading................................................................................................................ 636.5 Assessing an application to trade........................................................................................ 64

7 Implementation program ........................................................................................657.1 The planning cycle .............................................................................................................. 65

8 Monitoring and reporting........................................................................................678.1 Background......................................................................................................................... 678.2 Groundwater salinity ........................................................................................................... 678.2.1 Other chemical parameters .............................................................................................. 688.3 Aquifer status and water levels ........................................................................................... 68


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8.4 Resource monitoring program............................................................................................. 698.5 Water level and river red gum health monitoring program................................................... 698.6 Monitoring the effectiveness of this Strategy....................................................................... 70

References .......................................................................................................................71

Publication feedback form..............................................................................................73

Figures

Figure 1 Gascoyne River catchment...............................................................................10

Figure 2 Carnarvon Groundwater Area and Carnarvon Water Reserve..........................10

Figure 3 Basin A plantations and Basins B-L ..................................................................11

Figure 4 Licensed allocations for 176 properties in Basin A............................................16

Figure 5 Annual irrigation usage between 1972/73 and 2000/01 in Basin A.....................17

Figure 6 Annual irrigation usage between 1972/73 and 2000/01 from the scheme

supply in Basins B-L ...........................................................................................17

Figure 7 Annual irrigation and town water supply usage between 1972/73

and 2000/01 in Basins A-L compared to the estimated Allocation Limit...............18

Figure 8 The long term monthly average annual rainfall and rain days for

Carnarvon and Three Rivers................................................................................23

Figure 9 A three dimensional representation of the river bed and groundwater resource..25

Figure 10 Basin A 'L Series' monitoring well 34 hydrograph ..............................................28

Figure 11 Basin A 'L Series' monitoring well 38 hydrograph ..............................................29

Figure 12 Basins B-L Observation Well Series OB 23/77 hydrograph...............................29

Figure 13 Cross section of river bed showing salt migration..............................................30

Figure 14 The periods of river flows (days) and droughts (days) over time ......................32

Tables

Table 1 The Allocation Limits for Basins A and B – L ....................................................19

Table 2 Hydrogeological characteristics of the riverbed sand............................................26


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Table 3 Hydrogeological characteristics of the older alluvium ...........................................26

Table 4 Summary of the monitoring requirements for Basins A to L..............................69


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Summary

Groundwater within the aquifer systems associated with the Lower Gascoyne River provide a permanentwater supply for Carnarvon’s potable water, associated horticultural industries and dependent ecosystemsalong the river. The climate of Carnarvon is characterised by high temperatures, high evaporation andseasonally variable rainfall, contributing to the vulnerability of these groundwater resources to excessivepumping between periods of river flow.

The groundwater supply consists of public and private water supply areas for which the Water and RiversCommission license the allocation and use. The resources have been subdivided into Basin A wheregroundwater is abstracted by private bores, and Basins B – L, a public water supply area currentlyoperated by the Water Corporation in accord with a licence issued by the Commission, where water isdistributed by the Gascoyne Water Cooperative. The riverbed and floodplain sediments are separated intotwo types: the riverbed sand and the older alluvium. Groundwater abstraction from Basin A is from boththe riverbed sand and the older alluvium whereas abstractions in Basin B-L are predominantly from theolder alluvium.

Surface water flows along the Gascoyne River are significant but intermittent and fully recharge the sandaquifers following a flow event. During periods of river flow, licensees in Basin A are provided withunrestricted access to both groundwater and surface water. During no-flow periods, licensees arerestricted to their licensed annual entitlement. When the river ceases to flow, the storage of groundwaterin the total system, with a salinity of less than 500 milligram/litre total dissolved salts, is conservativelyestimated at 340,000 megalitres (ML). The sustainable yield of the system has been estimated bymodelling as 18,000 ML/yr. Water quality varies significantly both laterally and vertically betweenproperties in Basin A. Pumping restrictions prevent salt water intrusion into the groundwater supplies.

Groundwater use for horticulture began more than 80 years ago. Many local rules developed by theCarnarvon Water Allocation Advisory Committee and its predecessors have evolved over this time andprovide a basis for the sustainable management of these resources within an arid environment. Uniquemanagement guidelines have been developed in this Strategy to optimise water use during periods of riverflow as well as provide drought security for licensees during frequent periods of no river flow. Recordsindicate that the Gascoyne River has been dry for more than twice the time it has been flowing sincemonitoring began. Therefore, the objective of long-term sustainability is to manage groundwaterabstractions between recharge events of which the longest no-flow period since flow monitoring began inthe mid-1950s has been recorded as approximately 24 months.

This Strategy was developed in consultation with the community through the Carnarvon Water AllocationAdvisory Committee to ensure that it reflects the needs and issues of the diverse Carnarvon community.As agreed with the community, this Strategy will be reviewed by its seventh year (2010).

This Strategy contains some changes to the way the groundwater resources are currently managed toensure long-term sustainability of the resource and its dependent ecosystems, and equitable sharingbetween growers. Many of the existing rules and regulations developed by past advisory committeeshave been included in this Strategy as they are both practical and workable. Others have been discarded,amended or improved to reflect the current needs of the community.


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The way groundwater is allocated to users has changed significantly as a result of the scheme supply(Basins B - L) being privatised. Growers will no longer hold a conjunctive licence that gave them accessto groundwater from Basin A and scheme water from Basins B – L, up to a combined annual limit of upto 72 ML/yr per property. Instead, growers will be issued with a groundwater licence to abstract waterfrom Basin A only and will need to apply to the Gascoyne Water Cooperative to access the schemesupply.

The current licensed allocation is beyond the estimated Sustainable Yield for Basin A. This situation isaddressed in the Strategy through entitlement reductions resulting from an inability to extract salinegroundwater (salinity trigger) and the removal of inactive allocations.

Other initiatives include a drought strategy which, essentially, allows growers to replace their Basin Aallocation totally from the scheme water if the need arises during a drought or if water quality deterioratesto an unusable level in Basin A. Such access to scheme water provides greater reliability duringprolonged drought periods and better security of supply.

This Management Strategy has been developed to address and resolve the long-standing issues such asillegal or unauthorised pumping, splitting of entitlements, prolongations and drought access. Its primegoal however, is to set out the management initiatives that will ensure water use is optimised, droughtsecurity is provided and key environmental goals are met. This Strategy sets the basis for the developmentof statutory Local Area Water Management Plan in accordance with the Rights in Water and IrrigationAct 1914.

SUMMARY OF STRATEGY PROVISIONS

4.3.3 Ecological Water Provisions page 35

a) Groundwater abstraction from the Gascoyne River and its banks to cease when the salinity level inany production bore exceeds 1000 mg/L TDS (Basins A – L). This is particularly applicable to BasinA.

b) Groundwater abstraction to be restricted to 10 ML/month from any one property and/or prolongation(Basin A only).

c) All new wells are to be screened in the older alluvium only (or as deep as possible where there is noclear differentiation between the riverbed sand and older alluvium), except for sand spears or where itcan be demonstrated that abstraction from the riverbed sands will have no detrimental effect on theecological values of the Gascoyne River.

d) A 500m buffer zone from the river bank to be established for a distance of 2km downstream ofRocky Pool within which pumping from production wells will not be permitted.

e) Aquifer water levels in Basins B – L may be drawn down to the levels experienced during the 18month no-flow period in 1994 (or in 1984 if at a particular site it demonstrated a greater drawdown),as shown in monitoring bores (to be determined during the first year of the Strategy).

f) The water service provider must give prior notice to the Commission if the water levels in Basins B-L are expected to fall below the levels specified in 3.1.1(e) and remain so for extended periods. If so,


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the rate of draw is not to exceed 5 mm/day, defined as an average daily rate over a period of onemonth in monitoring bores identified in the water service provider’s Operational Strategy.

5.3.1.1 Basins B-L page 39

a) The Allocation Limit for Basins B – L is 12,200 ML/yr including 1,800 ML/yr for the existing townwater supply and a further 1,800 ML/yr reserved for future town water supply. However theAllocation Limit may change with new information on the aquifer response to pumping and recharge.

b) The proportion of the sustainable yield available to water service providers will be 10,400 ML/yrfrom Basins B-L (including 1,800 ML/yr for TWS).

c) The water service entitlement of 10,400 ML/yr may be temporarily increased during droughtconditions to cater for growers’ demands. Following the drought conditions, the allocation will revertto 10,400 ML/yr.

5.3.2.1 Basin A page 40

a) The Allocation Limit for Basin A will remain at 5,800 ML/yr. However the Allocation Limit maychange with new information on the aquifer response to pumping and recharge.

b) Licences issued to take water from Basin A will not include any entitlement to take water from otherbasins or areas.

c) Licensed entitlements in Basin A were reviewed where the groundwater salinity level of productionwells exceeded 1000 mg/L TDS during the restricted period from 1 July 2001 to 30 June 2003. Thislicence review provided for a maximum entitlement of 72 ML/yr to a minimum entitlement of36ML/yr.

d) During the next seven years, entitlements to Basin A licences will be reviewed where theprolongation has exceeded 1000 mg/L TDS during any 12 month restricted pumping period, and thequantity of water taken has been less than the annual entitlement.

e) Subject to 4.3.2.1(d), 72 ML/yr has been allocated to each Basin A licence with an existing allocationunit of one. Those licences with an allocation unit less or more than one will receive a proportionateamount of 72 ML/yr.

5.3.3.1 Maximum monthly draw page 41

a) Licensees in Basin A are restricted to a maximum draw of 10 ML/ calendar month from any oneprolongation or property.

b) The maximum monthly draw does not apply during unrestricted pumping periods.

5.3.4.1 Water quality page 42

a) When salinity levels reach 850 mg/L TDS (approximately 150 �S/cm EC) in individual wells,growers will be notified and monitoring will be undertaken on a more regular basis.


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b) Licensees are required to cease pumping from wells where salinity levels have reached 1000 mg/LTDS (176 �S/cm EC).

c) Licensees are required to install individual water sampling points on each well.

5.3.5.1 Issue and renewal of licences in Basin A page 42

a) Licences issued to take water from Basin A will not include any entitlement to take water from otherbasins or areas.

b) Groundwater well licences for Basin A will be issued for a period of seven years and will allow forthe regular review of allocations and compliance with conditions.

5.3.6.1 Requests for additional and/or new entitlements page 43

a) The Commission will generally not allow new entitlements in Basin A except in exceptionalcircumstances.

b) In considering whether to allow new entitlements in Basin A, the Commission will consider theestimated sustainable yield and likely impacts on the water resource.

c) Basin A licensees may submit an application for an initial allocation increase to a maximum of 10ML/yr, to be merit assessed utilising the applicant’s metered use, salinity data and impacts onneighbouring wells.

d) Basin A licensees may submit an application to further increase their annual allocation in incrementalstages of up to 10 ML/yr.

e) Review and amend additional water allocations above the 72 ML/yr if the additional water results inunacceptable environmental or social impacts.

5.3.7.1 Non-plantation entitlements in Basin A page 44

a) Licensees who take water for non-irrigation purposes are permitted to abstract groundwater up totheir annual entitlement from Basin A unless the salinity level exceeds the licensed salinity thresholdprior to the pumping of the entitlement.

b) Licensees who take water for non-irrigation purposes may apply for an increased allocation withinthe licensed salinity threshold, up to a maximum allocation of 10 ML/yr.

c) Licensees who take water for non-irrigation purposes located in marginal quality groundwater areasare required to cease pumping when salinity levels in individual wells reach 2500 mg/L TDS.

d) Licensees who take water for non-irrigation purposes located in good quality groundwater areas arerequired to cease pumping when salinity levels in individual wells reach 1000 mg/L TDS.

5.3.8.1 Unused allocations in Basin A page 45

a) Basin A licences that utilise less than their annual entitlement over the next 7 years will have theirentitlement reviewed by the end of the seventh year.


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b) Entitlement reductions will generally equal 50% of the difference between the licensed entitlementand the average of the highest three annual metered draws over the 7 years.

c) Entitlement reductions that do not equal 50% of the difference between the licensed entitlement andthe average of the highest three annual metered draw (excluding unrestricted pumping periods) overthe 7 years, will be referred to CWAAC for advice.

5.3.9.1 Domestic and stock use page 46

a) Stock and domestic use in Basin A will be licensed, with groundwater abstraction to cease wheresalinity levels in individual wells exceed 1000 mg/L TDS.

b) Licence exemptions will occur for properties that have no other alternative water supply to abstractgroundwater for domestic and stock use. These are as follows:

i. ‘Block’ allocations: issued to properties without access to scheme water or an alternativewater supply to abstract up to 650 kL/yr. This volume provides sufficient water for domesticuse including the irrigation of lawns and gardens used in connection with a dwelling (i.e. notfor commercial gain).

ii. ‘Residential’ allocations: issued to residential zoned properties without access to schemewater or an alternative water supply to abstract up to 650 kL/yr. This volume providessufficient water for domestic use including the irrigation of lawns and gardens used inconnection with a dwelling (i.e. not for commercial gain).

iii. ‘Special rural’ allocations: issued to rural zoned properties without access to scheme water oran alternative water supply to abstract up to 2000 kL/yr.

c) Groundwater abstraction for non-intensive stock and domestic use in Basins B – L is exempt fromlicensing.

5.4.1 Drought management provisions page 48

a) The maximum amount of water that can be sustainably abstracted for irrigation purposes from BasinsB – L is 14,400 ML/yr up to a period of 24 months.

b) At the end of drought conditions, the abstraction from Basins B-L for irrigation purposes will be nomore than 8,600 ML/yr.

c) An analysis of the condition of Basin A will be undertaken after one year, 18 months and 24 monthsof the drought with the additional allocation for Basins B – L determined by deducting the predictedabstraction for Basin A from the available allocation in Basins B – L. For example, if it is determinedthat 4,000 ML/yr can be abstracted from Basin A at the start of Stage 1 drought conditions (after 6months of no flow), the allocation for Basins B – L will be 14,400 – 4,000 = 10,400 ML/yr.

d) If the drought continues for more than 12 months, a Stage 2 drought allocation can be made

e) If the drought continues for more than 18 months, a Stage 3 drought allocation can be made.


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f) If the drought continues for more than 24 months, a Stage 4 drought allocation can be made

g) When the Gascoyne River flows across Bibbawarra Crossing, the Commission will declareunrestricted pumping if the volume of flow is sufficient enough to recharge the aquifers

h) The declaration will be at the Commission’s discretion and no unrestricted pumping should occurprior to the declaration.

5.5.1.1 Metering of use page 50

a) Metering of water use in Basin A and Basins B - L will be maintained as a standard managementrequirement of licensees and therefore all groundwater abstracted must pass through a meter.

b) It is the responsibility of growers in Basin A to ensure that the water pumped is of a meterablequality (i.e. free of mud, sand and large particles) to prevent damage to the meters

5.5.2.1 Restricted pumping page 50

a) When the river ceases to flow at the Bibbawarra Crossing, the following month starts as restrictedpumping as determined and announced by the Commission.

b) Licence conditions will allow a maximum monthly draw of 10 ML per property, in addition to awater quality cease-to-pump threshold of 1000mg/L TDS.

5.5.3.1 Unrestricted pumping page 51

a) Unrestricted pumping may be declared by the Commission during periods of river flow.

b) Unrestricted pumping should not commence without the Commission’s announcement.

c) When the Gascoyne River flows across the Bibbawarra Crossing, the Commission will declareunrestricted pumping if the volume of flow is sufficient enough to recharge the aquifers.

d) Water abstracted during periods of unrestricted pumping is to be metered.

e) Water passing through the meter during unrestricted pumping is excluded from the licensee’s annualentitlement.

5.5.4.1 Unauthorised pumping page 52

a) Licensees found to be bypassing their flow meters or causing the flow meters to read inaccuratelywill be subject to enforcement actions as determined by the Commission

5.5.5.1 Over-pumping page 52

a) All pumping by a Basin A licensee that exceeds the monthly maximum draw during periods ofrestricted pumping will be recognised as unauthorised pumping and will be subject to enforcementactions as determined by the Commission

5.5.6.1 Water wastage and improper use page 53


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a) Water wastage or improper use of the groundwater resource for the purpose of establishing anartificially high historical use may be subject to enforcement actions as determined by theCommission.

5.6.1 Well construction and decommissioning page 54

a) Investigate the development of local by-laws to accommodate the construction of wells withouthaving to apply for a 26D licence.

b) All well constructions and alterations into the clay, known locally as ‘second water’, are to be carriedout by a certified driller, except for sand spears for surficial water.

c) To minimise interference effects, any new well must be located not less than 30 metres from anyexisting wells on neighbouring properties/prolongations.

d) Licensees are required to decommission all unsealed abandoned wells by removing all equipmentand securely capping the well.

5.8.1.1 Basin A prolongations page 56

a) The Commission will promote and support actions to formalise legal access to Basin A prolongationsfor licensees with a Basin A entitlement.

b) The Commission will generally not support the establishment of new prolongations except inexceptional circumstances or for land exchanges associated with the removal of flood affectedproperties.

c) In considering whether to support the establishment of new prolongations, the Commission willconsider environmental impacts, the number of prolongations in existence, and the estimatedsustainable yield.

d) The Commission will encourage the establishment of management conditions for Basin Aprolongations for the purposes of public safety and environmental protection.

5.9.1.1 Sale of property with respect to licence transfer page 56

a) When selling a property the owner can apply to either transfer the licence to the new owner, to aperson(s) other than the new owner, keep the licence and use it on another property or surrender thelicence in accordance with the groundwater transfer strategy.

b) When selling a property, if an agreement has been made to transfer the licence to the new owner, anapplication must be made to transfer the licence to the new owner up to 30 days after the property issold or 30 days after change of occupancy.

c) Alternatively, the licence may be transferred to a person or persons other than the new owner. To doso an application must be made for each transfer either before the property is sold or before thelicence is terminated.

5.9.2.1 Wells located outside a property’s prolongation page 57


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a) The Commission will generally support access to wells located outside a property’s legalprolongation if an agreement based on adjustments of up to 10% change of prolongation boundariesis reached with the relevant legal prolongation holder regarding the use of the wells.

b) Access to wells located outside a property’s prolongation lapses upon sale of the property unless anagreement is reached with the prolongation holder regarding the use of the wells.

5.9.3.1 Splitting a water entitlement on the same property page 57

a) The Commission will not generally allow the formal splitting of an annual entitlement to cater forpartnerships and other similar arrangements on the same property, except in exceptionalcircumstances.

b) In considering whether to allow the formal splitting of an entitlement the Commission will considerthe impact on the water resources in the area.

5.9.4.1 Subdivision of prolongations page 57

a) The Commission will generally not support the subdivision of a prolongation.

b) In considering whether to support a subdivision of a prolongation, the Commission will consider thelikely effect on sustainability of water resources in the area.

5.9.5.1 Amalgamation of prolongations page 58

a) The Commission will generally not support the amalgamation of a prolongation.

b) In considering whether to support an amalgamation of prologations, the Commission will considerthe likely effect on sustainability of water resources in the area.


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1 Background information

1.1 Name of Strategy

This Strategy should be referred to as the Groundwater Management Strategy: Managing theGroundwater Resources of the Lower Gascoyne River (Carnarvon), WA (this Strategy). This Strategy isthe first comprehensive strategy to be developed for the management of groundwater resources of theCarnarvon Area. The management provisions in this Strategy align with the amended Rights in Water andIrrigation Act 1914 (the Act).

1.2 The Water Accounting Year

For the purposes of groundwater management planning, the Water Accounting Year commences on 1January and ceases 31 December. All management decisions and monitoring practices, undertaken by theCommission, will be based on the Water Accounting Year.

1.3 Date of commencement of this Strategy

This Strategy takes effect on 1 January 2004 to align with the Water Accounting Year.

1.4 Life of this Strategy

This Strategy will be implemented on 1 January 2004 and the Commission will consider by 2010,whether action needs to be taken to review, amend or revoke this Strategy.

1.5 Area to which this Strategy applies

a) This Strategy applies to the groundwater resources of the Carnarvon area which includes theproclaimed Carnarvon Groundwater Area and the Carnarvon Water Reserve that cover the lowerreaches of the Gascoyne River which is one of Western Australia’s major river systems within theIndian Ocean Drainage Division, draining the Gascoyne River Basin and entering the Indian Oceanat Carnarvon, approximately 980 km north of Perth (Figures 1 and 2).

b) The Carnarvon Groundwater Area (referred to in this Strategy as Basin A, the private water supplyarea), was originally proclaimed on 3 May 1963. Basin A extends from 5 km above the river mouth(ARM) eastwards to 19 km ARM . This area provides water for irrigation to the plantations along theLower Gascoyne River from privately owned wells or spearpoints directly into the aquifers.

c) The Carnarvon Water Reserve, situated in the Gascoyne Groundwater Area, is referred to in thisStrategy as Basins B – L, the public water supply area. Basins B – L (excluding Basin I) consists of aborefield extending east 19 km ARM to Rocky Pool, approximately 54 km ARM and is arbitrarily


10

divided into 10 basins (Figure 3). The Water Corporation has been issued with a licence by theCommission to take groundwater from Basins B – L. The Gascoyne Water Cooperative has anagreement with the Water Corporation to supply the water in Basins B – L to the CarnarvonIrrigation District.

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1.6 Waters to which this Strategy applies

a) This Strategy applies to water that percolates from the ground to a well or other works, as defined ins.2 of the Act as ‘underground water’ or ‘underground water resource’, and commonly referred to as‘groundwater’ or ‘groundwater resource’.

b) The Gascoyne River has deposited large accumulations of alluvial sediments along its lower reacheswhich contain significant groundwater resources. For the purposes of this Strategy, the groundwaterresources extending from the river mouth to Rocky Pool will be referred to as the AlluvialGroundwater Resources of the Lower Gascoyne River, which incorporates the proclaimed CarnarvonGroundwater Area and the Carnarvon Water Reserve.

1.7 The purpose of this Strategy

The purpose of this Strategy is to ensure that the groundwater resources of the Lower Gascoyne River areallocated equitably and used sustainably in the long term for the benefit of the Carnarvon community,taking into consideration the inherent social, economic and environmental impacts of such usage.

Also, to set out the initiatives that are to guide the management by the Commission of the groundwaterresources in Carnarvon, including:

a) how water will be allocated and used to meet various needs, including the needs of the environment;

b) the matters that will be taken into account in considering licensing matters; and

c) the monitoring and reporting to be carried out to ensure the objectives of this Strategy are achieved.

To reflect the suite of issues affecting water management at Carnarvon, information used to develop themanagement guidelines contained in this Strategy has been gathered from a number of sources includingthe Draft Rules of River (1998), groundwater modelling (Dodson, 2001), Ecological Water Requirements(SMEC, 2001) and monitoring data from the Water and Rivers Commission and Water Corporationdatabases.

This Strategy has been prepared by the Commission, in close consultation with the Carnarvon WaterAllocation Advisory Committee (CWAAC), to provide information to organisations, industry andindividuals about the way in which the groundwater resources of the Lower Gascoyne River are to bemanaged over the period from 1 January 2004 to 31 December 2010 inclusive.

1.8 Administration and Enforcement

The Water and Rivers Commission has the duty of enforcing and administering this Strategy.


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1.9 Conflict resolution process

Conflicts relating to the acceptance or otherwise of licence conditions, will be dealt with in accordancewith the provisions of Part III Division 3B of the Act.

Conflicts related to bore interference affecting neighbours’ ability to access groundwater or to fullyexercise their annual allocation will be dealt with by the Commission with assistance from the CWAAC.

1.10 The Carnarvon Water Allocation Advisory Committee

The CWAAC was initially set up in 1998 by the Water Corporation. Previously, the Committee’sfunction was to provide advice on allocation issues such as periods of restricted pumping, allocationrestrictions and interpretation of the local Rules of the River Draft (1998). The Committee was re-established by the Commission in 2001 to represent the Carnarvon water users and its role was expandedto assist the Commission to develop a Management Strategy that reflected the needs and demands of theCarnarvon community.

It is the Commission’s intention to investigate the establishment of the CWAAC as a Water ResourceManagement Committee (WRMC) under the provisions of s.26GK of the Act.

Membership of CWAAC

Originally, membership consisted of irrigators and representatives from the Water Corporation and theWater and Rivers Commission. The membership in 2001 has been expanded to better reflect the broadercommunity by including representatives from the Shire of Carnarvon, the local Land ConservationDistrict Committee (LCDC), the Water Corporation, Water and Rivers Commission, Department ofIndigenous Affairs and local irrigators. The environmental issues and concerns are covered by the LCDCrepresentative.

The membership of CWAAC will be reviewed during the WRMC establishment process.

Role – Terms of Reference

The CWAAC’s overall principles, goals and objectives provide a balanced approach to groundwatermanagement. With community support, the CWAAC can respond to changing groundwater issues andneeds while cooperating with the Commission’s regulatory program to ensure a dependable supply ofgood quality water in the long term.

The CWAAC was presented with a draft copy of the Strategy and was asked to review and adapt thewater sharing principles and management guidelines to ensure that they reflect the needs and demands ofthe Carnarvon community.


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1.11 Where this Strategy can be obtained

Copies of this Strategy may be inspected and/or obtained at the following locations:

Water and Rivers CommissionGascoyne District OfficeMidwest Gascoyne Region211 Robinson StreetCARNARVON WA 6701

and

Water and Rivers CommissionHead Office libraryThe Hyatt Centre, 2nd floor, 3 Plain Street,EAST PERTH, WA 6004.

This Strategy is also available on the Internet at the following website:

www.wrc.wa.gov.au/using/policy.htm


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2 Groundwater allocation, use andavailability

2.1 Introduction

The Commission is required by legislation to protect the Carnarvon groundwater resource from long-termdepletion and degradation. In order to achieve this, abstraction needs to be sustainable over the long termwithout unacceptable impacts to the resource and dependent socio-economic and environmental values.Further, in response to issues raised by the Carnarvon community, the resource has also been allocated ina way that maximises water availability and maintains the security of supply.

If water level and water quality monitoring indicate further resources are available, or that the currentallocation is too high, then the estimated Sustainable Groundwater Yield will be adjusted accordingly. Toensure that the resource is managed sustainably and the current level of supply is maintained, no newgroundwater entitlements will be issued by the Commission in Basin A (and therefore no newprolongations will be formed except for land exchanges associated with the removal of flood affectedproperties).

2.2 Historical water use patterns

Basin A provides water for irrigation to the plantations along the Gascoyne River from privatelyconstructed wells and spearpoints. Basins B – L consist of a borefield that is operated by the WaterCorporation under licence from the Commission to provide water for town water supply and irrigationpurposes. The Gascoyne Water Cooperative has a management contract with the Water Corporation tomanage the irrigation scheme.

Not all plantation owners can physically abstract groundwater from Basin A. Reasons include not havingaccess to the river or a ‘prolongation’, or by being located in an area where there are either very limitedsupplies due to a thin cover of riverbed sand within their prolongation, or there is brackish groundwaterwithin the older alluvium.

Approximately 176 licences have been issued by the Commission to landholders on either side of theGascoyne River to take and use water from Basin A for horticultural purposes. All licensees, exceptthose without physical access to the scheme, also have the opportunity to receive water from the publicwater supply scheme in Basins B-L. The reliance on scheme water increases with time since the last riverflow event, due to increasing salinity levels and decreasing bore yields in Basin A. Some growers alsodepend entirely on scheme water during river flow events as the access to their bores in Basin A is cut off.

2.3 Groundwater allocation and usage

At present, the total licensed allocation for Basins A – L is approximately 15,500 ML/yr for irrigation (ofwhich 5,000 ML/yr is licensed to the Water Corporation from Basins B – L and 10,500 ML/yr is


16

individually licensed to growers in Basin A ) and 1,800 ML/yr for Town Water Supply (licensed to theWater Corporation from Basins B – L). An additional 1,800 ML/yr is held in reserve for future townwater supply. The 15,500 ML/yr currently allocated also includes several ‘fixed’ licences. ‘Fixed’licences have been issued to non-plantation users such as caravan parks and industry, allowing non-irrigators, generally located in marginal areas, to abstract water up to 2500 mg/L TDS. See Section 5.3.7for more details. In this Plan, ‘fixed’ licences will be referred to as ‘non-plantation’ licences.

Each grower’s licensed allocation is based on a unit of allocation which in the past was equivalent to 72ML/yr. In total there are approximately 170 units of allocation issued. The majority of licensees inCarnarvon have been issued with a licence for one unit of allocation (72 ML/yr), however a fewproperties have entitlements smaller or greater than 72 ML/yr. Allocations in excess of 72 ML/yrgenerally indicate an amalgamation of one or two 72 ML/yr units. Figure 4 shows the spread of licensedallocations between the 176 licence holders.

Figure 4 Licensed allocation for 176 properties in Basin A, sorted from highest to lowest

The following groundwater usage data is based on the previous allocation structure where most growerswere issued with a single licence allowing them to abstract up to 72 ML/unit of allocation/yr from BasinA, or abstract a lesser volume from Basin A and receive a supplementary volume from the public watersupply scheme (Basins B – L), to a maximum of 72 ML/unit of allocation/yr. Metered water use recordshave been kept since 1972 for Basin A and since 1961 for Basins B-L.

The usage graphs should be read with some caution as metered usage figures may contain errors.However, they illustrate the groundwater usage patterns over the last 28 years and can also be used torelate the overall performance of the aquifer system as it is stressed by usage and climatic events.

� The maximum annual usage recorded for irrigation in Basin A is 5,943 ML in 1999/2000 (Figure 5)and 5,647 ML for Basins B – L in 1982/83 (Figure 6).

� The maximum recorded usage of groundwater for irrigation from Basins A – L in any one year isabout 11,000 ML in 1987/88 (Figure 7).

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� The total annual usage after 1987/88 in Basins A-L has steadily declined (Figure 7) with total useaveraging around 8,000 ML/yr in the 1990s.

Figure 7 shows the total system metered usage compared to the Allocation Limit. It is anticipated thatmetered use will markedly increase in Basins B – L in the near future as restrictions on Basins B – Lcease (due to the removal of the conjunctive licence and the cessation of 10 ML/month restriction inBasins B – L).

Figure 5 Annual irrigation usage between 1972/73 and 2000/01 in Basin A

Figure 6 Annual irrigation usage between 1972/73 and 2000/01 from the scheme supply in Basins B-L

Basin A abstractions

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Figure 7 Annual irrigation and town water supply usage between 1972/73 and 2000/01 in Basins A-Lcompared to the estimated Allocation Limit.

2.4 Assessing the available resource

There has been an increasing demand to improve the security of supply and make available additionalwater for horticultural use. In response, groundwater flow modelling was used by the Commission todetermine how much additional water could be sustainably abstracted (Dodson, 2001). Additionalmodelling will be undertaken during the next seven years to review the Allocation Limit.

To determine the limit as to how much groundwater could be abstracted on a sustainable basis (AllocationLimit) from Basins B-L, the groundwater flow model estimated the recharge, throughflow, discharge andstorage characteristics of the flow system. Normally, the Allocation Limit is based on a long-termaverage annual recharge. However, in the Lower Gascoyne River, the volume of recharge varies widelydue to the variations in river flow and no-flow intervals, making it difficult to determine the SustainableYield with any degree of certainty. Taking this into account, the groundwater model simulated a numberof recharge scenarios to determine how much water could be sustainably abstracted from the system. Thisinformation and the information gathered from the Environmental Water Requirements assessments(Section 4) undertaken by SMEC (2001), were used to determine the amended Allocation Limit.

To ensure that there was an increase in the security of supply during extended no-flow periods, thegroundwater flow model was also used to assess how much water could be abstracted over a 24 monthno-flow period. This volume has taken into consideration the environmental requirements of thesurrounding ecosystem. A 24 month period of no river flow was chosen due to the 0.1% probability,based on flow records, of having a 22 month no river flow period from Nine Mile Bridge with anrecurrent interval of 43 years.

TOTAL GROUNDWATER USE IN CARNARVON

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2.5 The amended allocation limit

The breakdown of how water will be shared between plantation use and town water supply (TWS) isoutlined in Table 1. The Allocation Limit for the whole system (Basins A to L) will be increased from14,400 ML/yr, based on a 12 month no river flow period (restricted pumping period – refer to 5.5.2), to18,000 ML/yr accommodating a 24 month no river flow period. This figure will remain as the AllocationLimit for Basins A to L until additional information and further modelling outcomes are available.

After 24 months of no river flow, the Allocation Limit will be subjected to review based on the results ofthe Aquifer Status Report. If necessary, decisions to temporarily restrict pumping will be made by theCommission in consultation with the Carnarvon community.

Table 1 The Allocation Limits for Basins A and B – L

Allocation Limit (AL) (ML/yr) Components of the AL (ML/yr)AL for Basins A – L:

18,000During a 2 year no river flow period

Available for irrigation: 14,400Available for TWS: 1,800Held in reserve for future TWS: 1,800Total Allocation: 18,000

AL for Basin A+:5,800

Immediately following a river flow event,not including unrestricted pumping

periods (refer to 4.5.3)

Available for irrigation: 5,800Available for TWS: 0Maximum Allocation: 5,800

Current entitlements ++ 10,890Allocation for Basins B – L

Up to 18,000During a 2 year no river flow period

with 0 water usage in Basin A

Allocation (100%):Available for irrigation from the scheme: 8,600Available for TWS: 1,800Held in reserve for future TWS: 1,800

Following a river flow: 12,200 (Basin A = 5,800)

Maximum Allocation*Available for irrigation from the scheme: 14,400Available for TWS: 1,800Held in reserve for future TWS#: 1,80024 months after a no- flow period: up to 18,000

(18,000 minus the available water in Basin A)

* The Allocation Limit for the whole system (Basins A – L) cannot exceed 18,000 ML/yr for the term ofthis Strategy. The maximum allocation is designed to meet the increased demand on Basins B – Lresources as Basin A groundwater abstraction ceases due to increased salinity levels and reducedpumping yields.

+ The Allocation Limit for Basin A will remain at 5,800 ML/yr for the period of this Strategy. TheAllocation Limit will then be reviewed using the additional information obtained during this period.

++ The current entitlements of 10,980 ML/yr will be reduced over the next 7 years to the sustainableyield of Basin A

# The reserved town water supply (TWS) can be accessed within the term of this Strategy if the townwater supply use exceeds 1,800 ML/yr.


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2.5.1 The Allocation Limit for Basin A

Of the 18,000 ML/yr available for consumption, 5,800 ML/yr is available from Basin A for the first yearafter a river flow. As the time since the last river flow event increases, groundwater abstraction in BasinA will begin to reduce due to increasing salinity levels and decreasing bore yields.

2.5.2 The Allocation Limit for Basins B – L

The remaining 12,200 ML/yr is available from Basins B-L following a river flow event. The breakdown(sharing) of the Allocation Limit between town water supply (TWS) and irrigation use immediatelyfollowing a river flow event is as follows:

� 1,800 ML/yr for the current town water supply;� 1,800 ML/yr held in reserve for future town water supply;� 8,600 ML/yr available from the scheme for irrigation and other purposes.

The total Allocation Limit for the whole system (Basins A – L) can not exceed 18,000 ML/yr.

For example, immediately after a river flow event, the Allocation Limit will be 12,200 ML/yr of which8,600 ML/yr is available for irrigation, 1,800 ML/yr for current TWS and 1,800 ML/yr for future TWS(100% allocation). After a period of no river flow, Basin A begins to shut down due to increasing salinitylevels and/or decreasing bore yields. Consequently, the demand for Basins B – L groundwater resourcesincreases, as this is the only available water resource. The Allocation Limit can potentially be increasedup to 18,000 ML/yr (3,600 for TWS and 14,400 ML/yr for irrigation), that is the maximum allocation forBasins B – L, to meet increasing demands. However, it is important that an adaptive managementapproach is taken whereby the Allocation Limit is increased in stages. If the no-flow period extendsbeyond 24 months, which is unlikely based on historical trends, the Allocation Limit may be decreased(based on monitoring results) and restrictions on pumping may be introduced.

2.6 Town water supply requirements

The Carnarvon town water supplies are drawn from Basins B – L which are used solely by the WaterCorporation to supply water for irrigation and town water supply. There is currently 1,800 ML/yrallocated for town water supply with an additional 1,800 ML/yr held in reserve. These allocations aresufficient to meet the current town water supply needs and future growth over the next 25 years or duringdrought conditions.

Over the last 21 years, the metered records show that the maximum water pumped for Carnarvon’s townwater supply use in any one year was 1,855 ML/yr based on a population of approximately 6000. Thisexceeded the current allocated amount by 55 ML. The average water use during the last six yearsconsistently ranged between 1,400 ML/yr and 1,500 ML/yr. Therefore there is a 300 ML buffer availableif this average is increased. Options to distribute this surplus water allocation will be explored by theGascoyne Water Cooperative and the Water Corporation.

The population of Carnarvon has experienced some fluctuations in recent years. In 1996 the populationwas 6,385 (ABS) and has slightly declined to 6,219 residents in 2000 according to a preliminary estimate(Ministry for Planning). The population is expected to increase to approximately 8,800 residents in 2026under a low growth scenario and 10,600 residents under a high growth scenario (WRC, 1996). Thepredicted population growth is assumed to result from new industry developments and the expansion of


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existing industries. In addition, the tourism industry since 1995/96 has been reported to be growing at arate of 9% and therefore consideration must be given to the impact of increased tourism on town watersupply demands.

Under the low population growth scenario, the water consumption for the town is expected to increase toapproximately 2,200 ML/y and to 2,700 ML/yr under a high population growth scenario. The currentreserve allocation of 1,800 ML/yr exceeds these growth estimates and, thus, represents a precautionarymanagement approach.

Therefore on the basis of the available information, the Allocation Limit for town water supply willremain at 1,800 ML/yr from Basins B-L for the term of this Strategy. The reserved allocation for futuretown water supply will also remain at 1,800 ML/yr from Basins B-L. The reserved allocation can beaccessed within the term of this Strategy if the town water supply use exceeds 1,800 ML/yr currentlyallocated including temporary utilisation during drought periods if necessary.

2.7 Other industry water supply requirements

The allocations that have been detailed in Section 2 provide for the existing needs of business operationsin the town and those with existing licences to access Basin A. However, new industry developmentproposals may be progressed within the next seven years outside of the existing townsite and irrigationdistrict (for example, on north and south common, or Brickhouse Station) that require additional water.These industries could include light to heavy industrial operations, intensive livestock productionactivities, aquaculture, and non-irrigation district horticulture.

Section 2.5.1 has identified that Basin A is over-allocated to existing licensees in the irrigation district.Therefore, no new groundwater licence allocations will be issued in Basin A.

Section 2.5.2 details that Basins B-L are fully allocated for town water supply, reserved future town watersupply, and irrigation requirements. However, current water utilisation patterns indicate that the proposedallocation for irrigation of 8,600 ML/yr may not be fully utilised within the term of this Strategy.Therefore, provision should be made to allow any new industry access to any unutilised amount of the8,600 ML/yr allocation subject to approval by the Commission.

2.8 Future demand for water versus future supply

Basin A groundwater is limited in quantity and quality, is over-allocated but not fully utilised. Growerswith access to Basin A water only, wanting additional water to expand their enterprises, will need toaccess the scheme water unless they can demonstrate that additional groundwater can be pumped asdescribed in 5.3.6 of this Strategy.

Future demand for additional water, can be met to some degree from the Basins B-L supply. It isanticipated that as demand outgrows supply from Basins B-L, additional investigations will be undertakento assess the possibility of increasing supply from the development of the groundwater resourcesupstream of Rocky Pool. However, there is sufficient water available in the medium term as currentscheme water for irrigation purposes from Basins B-L is not being fully utilised as the maximum annualuse recorded for irrigation over the last 10 years in Basins B-L was only 4,026 ML in 1991/92.


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2.9 Climate variability

Climate variability (and climate change) due to global warming resulting from the increasedconcentration of greenhouse gases in the atmosphere. It is a problem where cause and effect are separatedover very long time scales and there are large uncertainties about the impacts. Climate variability maypose future risks or opportunities to water supply, particularly for Carnarvon which is located midwaybetween drier and wetter scenarios.

The Sustainable Groundwater Yield for the groundwater resources of the Lower Gascoyne River wascalculated on the basis of the current understanding of the prevailing climate conditions. A long-termshift to drier or wetter years may impact on the rainfall patterns that will affect the river flow patterns andrecharge characteristics and ultimately alter the availability of water. A change to drier conditions withinthe Gascoyne River catchment could result in a reduction in the Sustainable Groundwater Yield that mayrequire a corresponding reduction in water allocations and water use. On the other hand, a long-term shiftto wetter years could have the opposite effect.

Climate variability is a whole of community concern and whilst there is no immediate need to incorporateclimate variability when developing this Strategy, both water managers and water users should be awarethat climate variability is real and it may impact on the availability of water in the future and the way it isallocated and used. A change to drier conditions in the Gascoyne River catchment may have a profoundimpact on the length of drought conditions.

2.10 Aligning entitlements in Basin A to the estimatedallocation limit

The Commission recognises that due to the unique and fluctuating nature of the groundwater in the LowerGascoyne aquifers, the primary water resource management tools are the salinity threshold and themonthly abstraction limits. Unlike other groundwater systems in WA that rely on a sustainable yield astheir prime management tool, the sustainable yield is a secondary management tool in Carnarvon.

At the commencement of this Strategy, the licensed entitlements in Basin A total 10,890 ML/yr, which is5,090 ML/yr above the Allocation Limit of 5,800 ML/yr. As described above, metered abstraction inBasin A has not exceeded 5,900 ML in any one year since metering began in 1972/73 due to acombination of aquifer yields, water quality constraints and land development constraints.

Over the next seven years however, the Basin A Allocation Limit of 5,800 ML/yr will be reviewed on thebasis of aquifer use and its quantity/quality response to pumping. It is anticipated that as some propertiesapply for additional allocation under the provisions of this Strategy (10 ML/year increases), the additionalallocation will be balanced by properties that are not able to abstract their full entitlement due to lowyields and/or water quality constraints. Over the next seven years, these properties will have their annualentitlements amended to reflect these conditions. At the end of the seven year period, total entitlements inBasin A will be aligned to a revised Allocation Limit. The process is described in 5.3.2 of this Strategy.


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3 Understanding the groundwaterresource

3.1 Quantity characteristics of the resource

This section provides an overview of the groundwater resources in the Carnarvon area. The informationcontains facts and interpretations that have been used as a basis for the management rules and guidelines.

3.1.1 Climate

The climate of Carnarvon is semi-arid and is characterised by high temperatures, high evaporation andseasonally variable rainfall (the mean annual rainfall is 233 mm). Rainfall and river flows are eithergenerated by summer tropical cyclone activity (January to March) or by mid-winter storms produced bycold front systems originating from the southwest (May to September). Figures 8a and 8b highlight thelong-term monthly average annual rainfall and rain days for Carnarvon and Three Rivers. Three Rivers islocated in the upper part of the catchment and influences summer river flow. Figure 8a helps highlightthe months when there will most likely be a river flow event.

Figure 8a The long-term monthly average annual rainfall and rain days for Carnarvon


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Figure 8b The long-term monthly average annual rainfall and rain days for Three Rivers

Due to Carnarvon’s highly variable and unpredictable climate, management guidelines need to be flexibleto cater for periods of drought (restricted pumping) and periods of river flow (unrestricted pumping).Consequently, to ensure that the resource is managed sustainably, it is important that the condition of theaquifer and groundwater availability are monitored and reviewed regularly so that allocation limits can beset accordingly.

3.1.2 The aquifer systems of the Lower Gascoyne River

The groundwater resources of the Lower Gascoyne River are contained in a regional, unconfined to semi-confined aquifer system made up of alluvial (floodplain) sediments laid down by the Gascoyne River.The aquifer systems covered by the Plan are bound to the west (on the coast) by a salt water interface andto the east (inland) by a geological anticline at Rocky Pool.

The river and floodplain sediments are separated into two types of aquifers: the riverbed sand aquifer(sometimes referred to in the past as first water/top water) located in the immediate vicinity of the riverbed, and the much larger older alluvium aquifer (sometimes referred to in the past as bottom water/secondwater) which is hydraulically connected to the overlying riverbed sand.

The two aquifers are further divided into 11 arbitrary Basins (Basins A – L, excluding Basin I, from westto east). Groundwater abstraction from Basin A is predominantly from the riverbed sand whilstabstractions from Basins B – L occur predominantly from the older alluvium.

The riverbed sand (top water)

The riverbed sand is an unconfined aquifer that is located between the banks of the Gascoyne River andvaries in width from 100 m to 1200 m. The aquifer is made up of recently deposited, highly permeablesands that contain fresh groundwater of recent age.

The hydrogeological characteristics of the riverbed sand are detailed in Table 2. Additional informationon the hydrology of the area is available from Allen (1972), Martin (1990) and Dodson (2001).


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Figure 9 A three dimensional representation of the river bed and groundwater resource

The older alluvium (second water)

The older alluvium is a semi-confined to unconfined aquifer which is located directly below the riverbedsand. The older alluvium contains a much greater volume of water than the riverbed sand, however thesalinity levels and water quality are highly variable.

The older alluvium is a multi-layered aquifer, with permeable and non-permeable layers. It is made up ofold riverbed material ranging from coarse gravel to clay, variably cemented, within discontinuous channelbeds. The older alluvium is hydraulically connected with the overlying riverbed sand aquifer.

In Basins B – L, the water level of the older alluvium is deeper than in Basin A. This deeper water tablecreates an increase in the hydraulic gradient between the two aquifers causing the riverbed sand water toseep into the older alluvium at a greater rate in Basins B-L than within Basin A. This greater infiltrationinto the older alluvium may have contributed to the lower salinity levels within the older alluvium to theeast of Nine Mile Bridge.

The older alluvium is dominated by a groundwater mound which occurs beneath the Gascoyne River andis influenced by river flow. The mound is a result of vertical water infiltration during a river flow beinggreater than the rate of horizontal groundwater throughflow within the older alluvium. This is becausethe clay layers within the older alluvium restrict the lateral flow of water away from the mound. Duringperiods of no river flow, the mound subsides.


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Table 2 Hydrogeological characteristics of the riverbed sand

Characteristic DescriptionThickness/

Depth� Variable thickness. Up to 12 m deep but averages about 3.5 m.

GroundwaterStorage

� Dependent on river flow, evapotranspiration, vertical infiltration and groundwaterthroughflow.

� Approximately 23 GL to 28 GL at the cease to flow level. Approximately 22% of this isin Basin A.

Soil Type � Grain size varies from boulder to fine sand, and rarely silt or clay.

Salinity � Generally fresh. Total Dissolved Solids (TDS) range from 200 to 500 mg/L.

Recharge� Recharge is predominantly by river flow with major flow events completely recharging

the aquifer. The riverbed sand is rapidly filled during a river flow event.

Discharge

� Groundwater is lost by infiltration (leakage) to the lower aquifer, evapotranspiration,groundwater abstraction and groundwater throughflow.

� Evaporation losses are higher immediately after a river flow, losing up to 22 mm/day.However, as the water level lowers the rate of decline decreases.

� If too much groundwater is abstracted, then the quality of the resource may be affected.

Bore Yield� Properly constructed production wells tapping this system are capable of yielding up to

40 L/s (3500 m3/day).

Hydraulic Gradient� The hydraulic gradient is low due to low topographic relief and high hydraulic

conductivity.

HydraulicConductivity

� Ranging from 100 – 1000 m/day.

Groundwater Flow� The rate of groundwater flow varies between 40 and 1700 m/year, however this is

dependent on the hydraulic gradient and hydraulic conductivity.

The hydrogeological characteristics of the older alluvium are detailed in Table 3 below. Additionalinformation on the hydrology of the area is available from Allen (1972), Martin (1990) and Dodson(2001).

Table 3 Hydrogeological characteristics of the older alluvium

Characteristic Description

Thickness/Depth

� Maximum thickness is 65 m, thinning from west to east with an average of 45 m. Thesaturated thickness is generally greater in the south.

GroundwaterStorage

� Conservatively estimated between 100 GL to 340 GL for groundwater containing less than500 mg/L TDS within Basins B-L.

� Estimates in storage are limited by the extent of drilling exploration to the north and southof the river.

Soil Type

� Predominantly clay but consists of irregular alternating layers of red, brown – yellow sandand silty clay, clayey and sandy silt, and clayey sand and sand (with some cementation).

� The thickness of the sandy layers ranges from 0.5 m to 14 m and extends laterally overseveral kilometres.

Salinity � Away from the river, much of the groundwater is brackish to saline (1000 to 6000 mg/LTDS).


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Recharge

� The aquifer is recharged by downward leakage from the riverbed sand. On the floodplainthe older alluvium may be recharged by direct infiltration of rainfall or from floodingassociated with large flow events.

� The lower the water table in the older alluvium, the greater the infiltration rate from theriverbed sand. Therefore to increase recharge it is more efficient to abstract water fromthe older alluvium than from the riverbed sand.

Discharge� Discharge is mainly due to extraction and to a lesser extent by throughflow, leakage

downward and evapotranspiration.

GroundwaterFlow

� Groundwater flow is away from the mound to the north and south, before swingingwestwards towards the coast.

Bore Yield� Properly constructed production wells tapping this system are capable of yielding up to 58

L/s (5000 m3/day).

HydraulicGradient

� There is a steep hydraulic gradient away from the river, with the gradient flattening withincreasing distance from the river.

HydraulicConductivity

� Ranging from 10-2 – 102 m/day.

3.1.3 The impacts of abstraction on the rate of recharge and water availability

Abstracting water from the older alluvium rather than from the riverbed sand is a more efficient pumpingscenario. Given that the riverbed sand recharges the older alluvium, the lower the water level is in theolder alluvium, the greater the hydraulic gradient, and the greater the rate of recharge. However, it isimportant that excess pumping of the older alluvium does not occur as this will cause the water level todecline to a depth where the maximum rate of recharge from the riverbed sand will not be sufficient forthe water level to recover its original level during a river flow event. If groundwater pumping was still tooccur, the water level would continue to decrease below the sustainable level and potentially cause salinegroundwater to migrate towards the river sands and severely impact on the groundwater dependentecosystems along the river.

3.1.4 The impacts of abstraction on groundwater levels

Groundwater abstraction from production wells results in the decline of water levels as groundwater istaken from storage. This decline is measured in neighbouring monitoring wells as potentiometric headlevels. The rate at which the water level declines, as measured in a monitoring well, depends on theabstraction rate of the individual production wells, the number, location and spacing of the productionwells and the proximity of the monitoring well to the production wells. The effects of groundwaterabstraction on water levels in Carnarvon are generally monitored quarterly, and sometimes monthly bymonitoring well networks throughout Basin A and Basins B- L. The results are documented in anAquifer Status Report that is available to the community through the Commission.

The following monitoring well hydrographs have been chosen from the monitoring well network toillustrate the impact of groundwater pumping on the water levels in Basin A and Basins B-L over a27 year and 20 year period respectively.

The hydrographs highlight the pattern of drawdown/recovery over the period. The y-axis shows thedrawdown/recovery operating zone that is important for maintaining the environmental values. Another


28

feature to note is that the amplitude (difference) of the ‘peaks and troughs’ in these monitoring wells canbe related to the distance from production wells – the higher the amplitude between drawdown andrecovery, the closer the monitoring well is to a production well. The ‘peaks and troughs’ shown can alsobe related to river recharge events. The drawdown levels are measured in metres AHD (AustralianHeight Datum). AHD, used as a fixed point reference by surveyors, is based on a mean sea level andindicates how high a specific location is above sea level. The dashed line on the hydrographs representsthe ground surface.

It is important to note that with nearly all the wells examined within Basins B – L, there is almost fullrecovery in the water level in the whole system, which means that over the period of monitoring, therehas been no significant permanent head loss. This is not unexpected due to the high rechargecharacteristics of the river. The important relationship which stems from this observation is therelationship between the full water recovery and the annual pumping regime. In other words, the systemas a whole is sustainable at the current level of usage as far as water quantity is concerned. However,prolonged periods of drawdown, which may be caused by continuous pumping during a period of lowrecharge, may impact on the groundwater dependent ecosystems such as the riparian vegetation.

Figure 10 Basin A ‘L Series’ monitoring well 34 hydrographThe dashed line represents ground level

The ‘L Series’ monitoring well 34 (Figure 10) is located north of the Gascoyne River, near the easternend of Basin A. This monitoring well is showing that in this particular location, the water level over a 26year period, fluctuates between about 2 m depth to about 5.5 m depth below the ground surface.

Basin A: L Series Well 34

-10123456789

1973 1979 1984 1990 1995 2001

Hea

d m

AH

D


29

Figure 11 Basin A:‘L Series’ monitoring well 38 hydrographThe dashed line represents ground level

The ‘L Series’ monitoring well 38 (Figure 11) is the easternmost well in Basin A and located within theriverbed. The monitoring well shows a drawdown/recovery pattern operating between about 2 m depthand 6.4 m depth below the ground surface. The larger peaks and troughs indicate that this monitoring wellis in a closer proximity to a production well than the previous well 34.

Figure 12 Basins B-L: Observation Well Series OB 23/77 hydrographThe dashed line represents ground level

The observation well 23/77 (Figure 12) is located on the southern bank of the Gascoyne River aboutmidway in Basins B-L. The short-lived sharp peaks in this monitoring well reflect the rechargecharacteristics of the Gascoyne River.

Basin A: L Series Bore 38

0123456789

10

1973 1979 1984 1990 1995 2001

Hea

d m

AH

D

B a sin s B - L : O b se rva tio n W e l l 23 /77

1 61 71 81 92 02 12 22 32 42 52 62 72 82 93 0

19 76 198 0 1 98 4 1 98 8 1 99 2 19 96 20 00

Hea

d m

AH

D


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3.2 Quality characteristics of the resource

3.2.1 The impacts of abstraction on salinity levels and salt water intrusion

Salt water intrusion into the Carnarvon groundwater supplies can be far more damaging than a temporaryshortage of supply. The interaction between surface water and groundwater and the impacts ofevapotranspiration and groundwater pumping influence the groundwater salinity in Carnarvon. Over-pumping is the main threat to the sustainable use of the resource as it can cause salt water to migratetowards the supply areas making the water useless for irrigation and human consumption (withoutexpensive treatment).

The extent of fresh groundwater in Basin A is much less than in Basins B – L. This results in brackishgroundwater being encountered earlier during a no river flow interval in Basin A than in Basins B – L.Monitoring of salinity within Basin A and Basins B-L indicates an increase in salinity levels over no-flowintervals (Figure 13).

In general, groundwater with salinity levels less than 500 mg/L Total Dissolved Salts (TDS) in the easternbasins extends approximately 2 km both north and south of the Gascoyne River, although more salinewater may still be encountered in some parts. The groundwater salinity on the north side of the GascoyneRiver gradually increases in the direction of flow to 1000 mg/L TDS, approximately 3-4 km from river.To the south of the river, there is a broad area containing between 500 to 1000 mg/L TDS. The less salinewater to the south may be due to greater recharge directed to this area owing to the course of the river.West of Water Supply Island, the salinity increases to 10,000 mg/L TDS with increasing proximity to thesaltwater interface (connection with seawater). In Basins B – L, the extent of fresh groundwater in theolder alluvium to the north and south of the Lower Gascoyne River increases to the east.

Figure 13 Cross section of river bed showing salt migration1) when the aquifers are fully replenished2) during drought. Note ingress of salt.


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Riverbed sand

Salinity levels in the riverbed sand are generally lower than the salinity levels in the older alluvium. Thesalinity levels in the riverbed sand are a direct result of evapotranspiration (water is evaporated, ortranspired by trees, to the atmosphere leaving behind particles of salt and therefore increasing theconcentration of salt in the remaining groundwater). The impact of evaporation on salinity levels in theriverbed sand decreases as the water level is lowered by groundwater abstraction.

It is important to note that the lateral movement of salt water is not uniform throughout the aquifer.Variations in water quality occur both vertically and horizontally between neighbouring plantations.Consequently, regional salinity monitoring is undertaken to highlight broad salinity trends, howeverindividual sampling of wells (and the cessation of pumping when salinity levels exceed 1000 mg/L TDS(see Section 5.3.4) is necessary to ensure that the resource is managed sustainably.

Older alluvium

The salinity distribution within the older alluvium is harder to define. Pockets of fresh water can befound in sandy areas where there is direct connection with the riverbed sand. Pods of brackish water arefound in areas where the older alluvium has poor hydraulic connection with recharge due to clay lensespreventing infiltration.

Salinity levels in the older alluvium are influenced by the lateral movement of salt water rather thanevaporation. When groundwater is abstracted, the water removed from storage is replaced with water thatis drawn in laterally from areas where more saline water may be encountered. The aquifer recovers whenthe river flows again, as fresh surface water replaces storage lost during the no river flow interval.Therefore, the net result has been a reduction in the chloride concentration, particularly within the BasinsB – L wellfield and especially from wells within the deepest screened intervals.

Water quality in the older alluvium has improved. Based on a recent analysis of water quality monitoringresults, chloride concentrations have decreased in most instances in the older alluvium. This is due togroundwater of a higher chloride level being abstracted from the older alluvium and the aquifer beingrecharged with water that has a lower chloride level than what was stored.

3.3 Groundwater/surface water interactions

The Gascoyne River plays an important role in Carnarvon as it is the main source of recharge for thegroundwater flow system. The intermittent river flows are a result of rainfall run-off in the rivercatchment.

Continuous records of river flows have been recorded at the Nine Mile Bridge gauging station since 1957.Since that time, records indicate that the river has been dry for more than twice the time that it has beenflowing. The mean annual flow duration at the Nine Mile Bridge since 1957 has been approximately 110days. The month that a river flow is most likely to occur is June followed by February, however in someyears there has been no river flow at all.

The probability of having no river flow for more than 22 months (from Nine Mile Bridge) is 0.1% with anannual recurrence interval of 43 years. Consequently, groundwater management strategies, such as the


32

Drought Strategy, are centered around a 24 month no-flow period as the probability of a no-flow eventexceeding this time frame is low.

Figure 14 highlights the worst drought events and times when the river flowed for more than 200 daysbetween 1957 and 1998. This can help build up a picture of what might be expected in the futurealthough the expected effects of climate change (see Section 2.9) need to be taken into considerationwhen dealing with future scenarios.

Figure 14 The periods of river flows (days) and droughts (days) over time.

The percentage of flow volume lost to recharge increases with a reduction in stream discharge. Duringlarge floods, groundwater recharge represents a very small percentage of total stream discharge.Increased storage depletion within the riverbed sands by groundwater abstraction may impact on flowswith a total discharge of up to 22GL at Fishy Pool when there has been no flow for 12 months or more.

(Feb-57 to Oct-98)

800

600

400

200

0

200

400

600

800

No

flow

dur

atio

n

Flo

w d

urat

ion

(day

s)

10418 days of no flow

4661 days of flow


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4 Assessment of the environmentalimpacts of developing the resource

4.1 Ecological water requirements and environmental waterprovisions

The groundwater resources of the Lower Gascoyne River must be managed on a sustainable basis for theeconomic, social, cultural and environmental benefit of the people in Carnarvon. For sustainability tooccur, the average rate of usage must be less than the average annual recharge measured over a specifictime period. Temporary losses from storage may be tolerated during short-term drought (no river flow)events, but the losses should be balanced by intervening additions to storage during river flow events.

Groundwater recharge in the Lower Gascoyne River is essentially totally dependent on river flow.Although river recharge can be regarded as ‘instantaneous’ from a hydrological perspective, the longerterm effects of pumping, such as salt water intrusion, are not instantly noticeable and this must be takeninto consideration when allocating groundwater.

In addition, provision must also be made for the support of ecosystems, such as the river red gums(Eucalyptus camaldulensis), that are dependent on groundwater. In general, groundwater dependentecosystems obtain their water requirements from the shallower aquifers and therefore groundwaterabstraction must be managed in a way that minimises impacts to the ecosystem. The Commission’sEnvironmental Water Provisions Policy for Western Australia (Statewide Policy No.5, 2000), sets out theprinciples on how water should be allocated to protect ecological values through the establishment ofEcological Water Requirements and Environmental Water Provisions. These are defined as:

Ecological Water Requirements (EWRs) are the water regimes needed to maintain ecological values ofwater dependent ecosystems at a low level of risk. EWRs are determined on the basis of the best scientificinformation available and are the primary consideration in the determination of Environmental WaterProvisions.

Environmental Water Provisions (EWPs) are the water regimes that are provided (to ecosystems) as aresult of the water allocation decision-making process taking into account ecological, social andeconomic impacts.

4.2 Identification of the value of groundwater dependent ecosystems (ecological and social water requirements)

The first step in establishing the Ecological Water Requirements for the Lower Gascoyne River was toidentify the key ecological and social values and features. This work was carried out by independentconsultants (SMEC, 2001) who produced a report titled Ecological Water Requirements for the LowerGascoyne River. The report concluded that the key ecological and social features dependent ongroundwater in the Lower Gascoyne are the in-stream pools and the riverbank vegetation.


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4.2.1 Chinaman’s Pool, Rocky Pool and temporary pools

Chinaman’s Pool, Rocky Pool and the temporary pools along the river bed are, by nature, dynamiccomponents of the river system. They were identified as key groundwater dependent ecosystems as theyare directly supported by the water table. The pools are of high ecological value as they have a uniqueecologic community, are vulnerable (due to a low species diversity which is currently threatened byexotic species), and contain recognised biodiversity value.

The pools were also identified as having high social value due to their recreational and aestheticimportance to the Carnarvon community.

4.2.2 The riparian (river bank) vegetation

Given the irregular nature of flow in the Gascoyne River, the riverbank vegetation, such as the river redgums, has some dependence on groundwater to maintain ecosystem values. The riverbank vegetation is aunique ecological community in the region and is significant to the river geomorphology and otherecological species, and acts as a buffering system (e.g for stabilisation of banks, windbreak, stabilisationand enrichment of soils). However, the river red gums are vulnerable to water stress, with the SMECinvestigations noting that the loss of river red gums can be quite sudden without significant identifiablesigns of stress. However, experience in the Carnarvon area is that signs of stress are evident in thevegetation along the river, initially as wilting and yellowing of leaves, followed by leaf drop. This hasnot, however, resulted in tree death.

The riverbank vegetation was also identified as being of high recreational and aesthetic importance to theCarnarvon community.

4.3 Water to support values (Environmental Water Provisions)

Environmental Water Provisions (EWPs) take into account environmental impacts as well as social andeconomic impacts. That is, they build on the EWR recommendations by incorporating vital consumptiveand social uses. It is concluded that since there are no conflicting impacts and that the disturbance to thewater regimes needed to maintain the ecological values (pools and riparian vegetation) has been minimal,the EWPs should be set to meet the EWRs.

4.3.1 Chinaman’s Pool, Rocky Pool and temporary pools

Although identified as a key groundwater dependent ecosystems, the impacts of groundwater abstractionon the ecological values identified for the pools is likely to be minimal. This is because the condition ofthe pools is affected more by extended periods of no flow and the associated increases in salinity than bygroundwater abstraction.

Chinaman’s Pool is more influenced by the tide than by groundwater abstraction as it is located in amarginal groundwater area where groundwater abstraction is limited by the 1000 mg/L TDS cease-pumping threshold.

At Rocky Pool, the riverbed sand is directly underlain by calcareous mudstone that outcrops either side ofthe river owing to an anticline. As a result the surface water pool is unlikely to be impacted by


35

groundwater abstraction due to the presence of the low permeable mudstone. In addition there is a bufferbetween the Water Corporation production wells and Rocky Pool to minimise the impact of groundwaterabstraction.

A water requirement was not assigned to the temporary pools. This is because the location of thetemporary pools along the river bed varies considerably after each river flow event as they are totallydependent on the distribution of sand.

4.3.2 The riparian (riverbank) vegetation

To maintain the health of the vegetation along the Lower Gascoyne River, groundwater levels and the rateof groundwater level decline must be managed. The Commission is adopting an adaptive managementapproach for the establishment of EWPs and therefore as the level of understanding increases, the EWRsand the EWPs will be refined.

SMEC (2001) proposed that the riverbank trees draw most of their water from a depth of 5 m below theground surface, at times when water is readily available. During times of stress however, the trees candraw their water requirements from depths of up to 20 m. In addition, SMEC concluded that the treescould adapt to declining groundwater levels by downward root growth at a rate of 5 mm per day, shouldthe groundwater level fall below 5 m from the ground surface.

Maximum groundwater drawdown levels in monitoring bores on the river bank during a period of 18months of no river flow, the longest period of no flow monitored, ranged from approximately 3.25 m to10.3 m. The monitoring bores were located on the river bank, surrounding production bores and near riverred gums. In this Plan, groundwater abstraction will be managed to the groundwater drawdown levelsrecorded during the 18 month period of no flow, and should drawdown fall significantly below theselevels, it should not do so at a rate greater than 5 mm/day. Based on the current level of knowledge, usingthese levels and the Statutory provisions in Section 4.3.3, the impact of groundwater abstraction on thehealth of the river red gums is likely to be negligible.

SMEC (2001) estimated the annual water requirement for the river red gums to be between 4,250 ML/yr(for optimal health) and 1,600 ML/yr (during periods of drought). However, groundwater managementin the Lower Gascoyne will be based on a water level and water quality regime and not on volumes.

The current volume of groundwater available for consumptive use from Basins A – L is 18,000 ML/yr.Prior to additional water being released in Basins A – L, additional EWP studies would be required tofurther understand the river red gum dependency on groundwater including increasing the understandingof how recruitment is impacted by water levels. This will involve in part, an ongoing monitoring programthat assesses the health of the river gums at various groundwater levels.

4.3.3 Management provisions - Ecological water provisions

This part is made in accordance with s.26GY(2)(a) of the Act.

The following groundwater abstraction regime will apply to ensure the resource is managed sustainablyand the impacts to groundwater dependent ecosystems are minimised:


36

a) Groundwater abstraction from the Gascoyne River and its banks to cease when the salinity level inany production bore exceeds 1000 mg/L TDS (Basins A – L). This is particularly applicable to BasinA.

b) Groundwater abstraction to be restricted to 10 ML/month from any one property and/or prolongation(Basin A only).

c) All new wells are to be screened in the older alluvium only (or as deep as possible where there is noclear differentiation between the riverbed sand and older alluvium), except for sand spears or where itcan be demonstrated that abstraction from the riverbed sands will have no detrimental effect on theecological values of the Gascoyne River.

d) A 500m buffer zone from the river bank to be established for a distance of 2km downstream ofRocky Pool within which pumping from production wells will not be permitted.

e) Aquifer water levels in Basins B - L may be drawn down to the levels experienced during the 18month no-flow period in 1994 (or in 1984 if at a particular site it demonstrated a greater drawdown),as shown in monitoring bores (to be determined during the first year of the Strategy).

f) The water service provider must give prior notice to the Commission if the water levels in Basins B-L are expected to fall below the levels specified in 3.1.1(e) and remain so for extended periods. If so,the rate of draw is not to exceed 5 mm/day, defined as an average daily rate over a period of onemonth in monitoring bores identified in the water service provider’s Operational Strategy.

Provisions (a), (b) and (c) will be regulated by licence conditions. Provisions (d), (e) and (f) will form partof the water service provider’s Operating Strategy for Basins B-L.


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5 Water allocation principles

5.1 Background

The Carnarvon Groundwater Area is a Proclaimed Groundwater Area under the Act, and access and useof groundwater is subject to licensing. Licences are issued under s.5C and s.26D of the Act.

The Draft Rules of the River (1998), developed by the CWAAC and its predecessors, as far back as 1959,provided the starting point for allocating water in Carnarvon. The Rules of the River have been reviewed,expanded and applied to a management framework to ensure the resource is managed sustainably andequitably.

The groundwater management provisions detailed in this part, which apply to Basins A-L, aim tomaximise water resource availability for consumptive use, while meeting key environmental goals andcontributing to a sustainable and productive natural environment. These provisions will remain in placeuntil the review of this Strategy.

5.2 Allocation principles

The Commission will take into account the following principles when considering matters concerninglicences under the Act:

a) Groundwater is vested in the Crown and is not tied to the land under which it lies;

b) The use of groundwater should be consistent with the desired local, regional and State economicdevelopment. Its use should generate outputs which are socially, economically and environmentallysound as well as of high value to the community.

c) Groundwater management and allocation decisions should consider the social, cultural, economicand environmental impacts and apply a balanced approach where appropriate;

d) All water source development must include consideration of, and appropriate investment in,conservation measures;

e) Ensure fairness and equity in the allocation process;

f) Groundwater users and community stakeholders must be an integral part in managing waterresources;

g) Continuing community education on groundwater matters and involvement in the decision makingprocess are essential in sustaining a strong and effective groundwater management effort;

h) Existing users should be protected from unacceptable impacts as determined by the Commission;

i) In considering all applications for licences, the Commission will have regard to the factors as listedin Schedule 1 clause 7(2) of the Act.


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Similarly, the Commission will grant, renew, amend, suspend, cancel or transfer licences in accordancewith the following principles:

a) The Precautionary Principle

This principle states that where there are threats of serious or irreversible environmental damage, lack offull scientific knowledge and certainty should not be used as a reason for postponing measures to preventthe environmental damage.

b) Intergenerational Equity

This concept refers to decision making processes that effectively integrate both long and short-termeconomic, environmental social and equity considerations.

c) Integrated management

i. Integrated management in this Strategy refers to the management of the inter-relationshipsbetween surface water and groundwater. In this context, this Strategy will manage the impact ofgroundwater abstraction on dependent ecosystems which include surface water ecosystems.

ii. Decisions should effectively integrate both short-term and long-term economic, environmental,social and equity considerations.

iii. Water management should be integrated with relevant policies of other Government agenciesfostering a holistic management approach.

d) Adaptive management

i. Management tools and policies must be able to respond to increasing knowledge of resourcedynamics and their interactions with other ecosystems.

ii. They must also be able to take into account changing community attitudes and perceptions ofsustainability.

iii. Adaptive management in this Strategy is used to mean management of water resources in a cycleof assessing, planning, implementing, monitoring, reviewing and responding to change, andwhich also includes provision for re-allocating to accommodate results of reviews.

5.3 Basis for allocation

5.3.1 Basins B - L groundwater resources

Situation summary

� The allocation for the irrigation district from Basins B – L (currently licensed to the WaterCorporation) is not fully utilised.

� There is a need for improved flexibility in the management regime to facilitate a greater use, withinsustainable limits, of the Basins B – L resource.


39

� The issuing of a single conjunctive allocation to growers for Basins A – L is discontinued.

Details: The water resources in Carnarvon are divided into two main management areas; Basin A(private water supply area) and Basins B – L (public scheme water supply area). In the past, growers wereissued with a single conjunctive licence allowing them to abstract 72 ML/yr from Basin A and/or BasinsB – L in any configuration.

This arrangement was considered to be restrictive as water use was limited by a monthly maximumpumping rate and their annual Allocation Limit. The separation of Basin A and Basins B – L licencesprovides an opportunity to introduce more flexibility and greater water availability, and will result ingreater utilisation of Basins B – L water. This has the benefit of reducing the usage pressures on the moresensitive Basin A resource and improving the viability of the scheme infrastructure. It also allows thesustainable expansion of the horticultural industry in Carnarvon.

Whilst the 72 ML/yr will initially remain for Basin A at the commencement of this Strategy, growers arenow required to apply to the Gascoyne Water Cooperative (Cooperative) to obtain a water entitlementfrom the scheme.

The Carnarvon town water supply wellfield in Basins B-L is currently operated by the Water Corporationunder licence to the Commission. Conditions have been placed on the Water Corporation’s licence toensure that the resource is used sustainably.

In October 2001, the Cooperative entered into an Operations and Management Agreement with the WaterCorporation. This agreement delegates the responsibility of distributing the water from Basins B – L tothe Cooperative. Water from Basins B – L is to be provided to growers based on contracts between theCooperative and the individual growers. Water distributed to growers from Basins B – L will be at thediscretion of the Cooperative on the basis that the total consumption is within the Water Corporation’slicensed entitlement and within the provisions of this Strategy.

The Cooperative will distribute water to the irrigation district under a Bulk Water Supply Agreement withthe Water Corporation. The management arrangements for growers to access a quantity of water fromBasins B – L will be defined in an Allocation Management System prepared by the Cooperative.

5.3.1.1 Management Provision – Basins B - L


a) The Allocation Limit for Basins B – L is 12,200 ML/yr including 1,800 ML/yr for the existing townwater supply and a further 1,800 ML/yr reserved for future town water supply. However, theAllocation Limit may change with new information on the aquifer response to pumping and recharge.

b) The proportion of the sustainable yield available to water service providers will be 10,400 ML/yrfrom Basins B-L (including 1,800 ML/yr for TWS).

c) The water service entitlement of 10,400 ML/yr may be temporarily increased during droughtconditions to cater for growers’ demands. Following the drought conditions, the allocation will revertto 10,400 ML/yr.


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5.3.2 Basin A groundwater resource

Details: The introduction of a single licence to abstract water from Basin A allows the currentmanagement arrangements to be reassessed to ensure that the water is allocated sustainably and equitably.

The level of licensed entitlements in Basin A, which currently exceeds the estimated Allocation Limit ,has the potential for groundwater abstraction to exceed the estimated Allocation Limit of 5,800 ML/yr.There is a large proportion of growers not using their full allocation, and there are some licensedentitlements that have not been activated for several years. The community is seeking a review of theallocation management regime to facilitate greater use, within sustainable limits, of the Basin A resource.

A primary objective of water reform in Western Australia is to ensure that water resources are managedwithin their Sustainable Yield. For Basin A, if all growers were to maximise their individual licensedallocation, then water use would exceed the Allocation Limit of 5,800 ML/yr. This is illustrated throughundertaking a calculation of the maximum annual use recorded by each property in any one year over thelast 11 years. This would provide a total of 7,500 ML/yr, although maximum metered use in any one yearfrom 1972/73 has not exceeded 6,000 ML, and includes both restricted and unrestricted periods. Actualuse however, may be higher due to suspected un-metered use. This situation poses a possible risk to thesustainability of the Basin A resource, particularly if the unused allocations are reactivated.

As a result of the discontinuation of conjunctive licences, a new annual entitlement has been establishedfor Basin A licences. The new annual entitlement is 72 ML/yr for each Basin A licence which equates toan existing allocation unit of one. It is acknowledged that the total of all licensed entitlements exceed theestimated Allocation Limit of 5,800 ML/yr. This situation is addressed in this Strategy throughentitlement reductions resulting from an inability to abstract saline groundwater (salinity trigger) and theremoval of unused allocations (Section 5.3.8 of this Strategy).

Prior to commencement of this Strategy, the Commission reviewed water usage and salinity levels duringthe restricted period from 1 July 2001 to 30 June 2003. This was done to determine the 1000 mg/L TDStrigger in prolongations for the purpose of reducing entitlements to reflect a sustainable pumping level.This initial licence amendment is to a minimum entitlement of 36ML/yr.

During the life of this Strategy, similar entitlement reduction reviews based on the salinity trigger willoccur following any further 12 month restricted pumping periods.

5.3.2.1 Management provisions – Basin A


a) The change with new Allocation Limit for Basin A will remain at 5,800 ML/yr. However, theAllocation Limit may information on the aquifer response to pumping and recharge

b) Licences issued to take water from Basin A will not include any entitlement to take water from otherbasins or areas.

c) Licensed entitlements in Basin A were reviewed where the groundwater salinity level of productionwells exceeded 1000 mg/L TDS during the restricted period from 1 July 2001 to 30 June 2003. This


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licence review provided for a maximum entitlement of 72 ML/yr to a minimum entitlement of36ML/yr.

d) During the next seven years, entitlements to Basin A licences will be reviewed where thegroundwater in production wells has exceeded 1000 mg/L TDS during any 12 month restrictedpumping period, and the quantity of water taken has been less than the annual entitlement.

e) Subject to 4.3.2.1(d), 72 ML/yr has been allocated to each Basin A licence with an existing allocationunit of one. Those licences with an allocation unit less or more than one will receive a proportionateamount of 72 ML/yr.

5.3.3 Maximum monthly draw

Situation summary

Concentrating groundwater abstraction over a short period of time may affect the water quality and wateravailability of neighbouring properties.

Details: Concentrated groundwater abstraction from one bore by a licensee can cause groundwaterlevels to drop within the surrounding area. This drop in water level is known as a radial cone ofdepression and can impact on the pumping rates and water quality of the licensee’s own bore as well asthe bores on neighbouring properties. The greater the pumping rate and the amount of water abstractedwithin a time period, the larger the area affected and the radial cone of depression.

To prevent impacts on neighbours who may require water during different periods of the year, themaximum draw per calendar month, from any single property or prolongation in Basin A will berestricted. There are no monthly restrictions placed on growers obtaining additional water from Basins B– L on the basis that the total B - L draw does not exceed the water service provider’s licensed allocation.

5.3.3.1 Management Provisions – maximum monthly draw


a) Licensees in Basin A are restricted to a maximum draw of 10 ML/ calendar month from any oneprolongation or property.

b) The maximum monthly draw does not apply during unrestricted pumping periods.

5.3.4 Water quality restrictions and monitoring

Situation summary

� Abstraction at rates greater than recharge in Basin A will result in the movement of the saline watertowards the river, putting at risk the sustainability of the resource.

� Water high in salinity cannot be used by licensees for horticultural production.

� Pumping restrictions in Basin A, based on a water salinity threshold, are provided for through currentlicense conditions.


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Details: Saline groundwater is a major threat to the horticultural industry. When groundwater isabstracted, salt water is drawn in laterally. This practice is sustainable as long as the salinity levels do notexceed 1000 mg/L TDS for individual bores.

Salinity level readings are taken by measuring electrical conductivity (EC) of the water sample and thenconverting it to Total Dissolved Salts (TDS). An electrical conductivity reading of 176 micro-siemens/centimetre (�S/cm) at 25oC is equivalent to 1002 mg/L TDS. Monitoring is carried out in-situ(taken at the site).

A restriction is to apply to all to all licences so that no water can be taken with a TDS of greater than 1000mg/L TDS (176 �S/cm EC). The well(s) therefore remains unusable until the salinity levels fall below1,000 mg/L TDS.

To ensure that abstraction does not continue once salinity levels reach 1000 mg/L TDS (176 �S/cm EC),individual wells are monitored regularly by the Commission or delegated authority, with the frequency ofmonitoring dependent on well location (refer to Section 8 for details on the current monitoring practices).The salinity trigger is activated when all wells in a prolongation or property exceed the salinity threshold.

The Commission has adopted the practice of formally notifying well owners by letter, and requiring thelicensee to cease using the well upon receipt of the letter until the water quality recovers. In many cases,not all licensees have individual sampling points or they have used inconsistent sampling points, resultingin mixed water samples being used to analyse salinity trends. This prevents high salinity levels beingdetected (contributing to aquifer degradation) or may result in all wells being rendered unusable if onlyone well is actually exceeding the TDS limit.

5.3.4.1 Management Provisions – water quality

a) In Basin A, when salinity levels reach 850 mg/L TDS (approximately 150 �S/cm EC) in individualwells, growers will be notified and monitoring will be undertaken on a more regular basis.

b) Licensees are required to cease pumping from wells where salinity levels have reached 1000 mg/LTDS (176 �S/cm EC).

c) Licensees are required to install individual water sampling points on each well.

5.3.5 Issue and renewal of licences in Basin A

Situation summary

� Licences will generally be issued in Basin A for a maximum period of seven years.

Details: Licences will be issued to abstract water from Basin A only. The duration of a licence will beextended from past practice to seven years. To coincide with the implementation of this Strategy, licencesthat expired on 30 June 2003, were extended to 31 December 2003.

5.3.5.1 Management Provisions – issue of licences

This part is made in accordance with Schedule 1 clause 12 of the Act.


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a) Licences issued to take water from Basin A will not include any entitlement to take water from otherbasins or areas.

b) Groundwater well licences for Basin A will be issued for a period of seven years and will allow forthe regular review of allocations and compliance with conditions.

5.3.6 Requests for additional and/or new entitlements

Situation summary

� New industries may be established in Carnarvon that may require a water entitlement.

� The resources in Basin A are currently over-allocated and therefore the issue of new entitlementswithin Basin A may jeopardise the security of supply and the sustainability of the resource.

Details: For many years the Commission has not allowed any additional entitlements in Basins A – L.

The groundwater resources in Basin A are currently over-allocated to existing licensees in the irrigationdistrict. If growers wish to obtain additional water, they will either need to apply for more water from thepublic scheme through the Cooperative, or apply to the Commission for an increased allocation asdetailed below.

Applications for an additional allocation of up to 10ML /yr will be favourably considered where theymeet the criteria of this Strategy and the Act. When determining these applications a merit assessment isused, based on the applicant’s metered use and salinity data, and potential impacts on neighbouring wells.This opportunity is provided on the basis that the prolongation demonstrated during extended dry periodsthat it had the capacity to deliver more water whilst remaining within the salinity threshold and notcausing any adverse environmental impacts or impacts on neighbouring wells.

Further, at any time during the life of the Strategy, licensees can submit an application to further increasetheir annual allocation in incremental stages of up to 10 ML/yr. The assessment of the application willrequire that there has been a continuous period of restricted pumping to assess demand and aquiferimpacts. The licensee will need to demonstrate that there has been full metered usage of existingallocation and that the prolongation has the capacity to deliver this higher volume on a long-term basiswithout unsustainable impacts.

The above allocation increase application opportunity will also be available to those licensees that havereceived an allocation reduction (Section 5.3.2 of this Strategy) and can demonstrate that they have sincediscovered new or improved water access in their prolongations.

If unpredictable and unacceptable impacts occur due to additional water being allocated, allocationreduction reviews may take effect by an amendment to the license. This may occur if the salinity triggereventuates in a period of restricted pumping (see Section 5.3.2 of this Strategy). Similarly a review willbe undertaken if it is identified that additional abstraction in a prolongation is impacting on neighbouringprolongations, or adversely impacting on the aquifer or the environment.

5.3.6.1 Management Provisions

This part is made in accordance with s.26GY of the Act.


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a) The Commission will generally not allow new entitlements in Basin A except in exceptionalcircumstances.

b) In considering whether to allow new entitlements in Basin A the Commission will consider theestimated sustainable yield and likely impacts on the water resource.

c) Basin A licensees may submit an application for an initial entitlement increase to a maximum of 10ML/yr, to be merit assessed utilising the applicant’s metered use, salinity data and impacts onneighbouring wells.

d) Basin A licensees may submit an application to further increase their annual entitlement inincremental stages of up to 10 ML/yr.

e) Review and amend additional water entitlements above the 72 ML/yr if the additional water results inunacceptable environmental or social impacts.

5.3.7 Non-plantation entitlements in Basin A

Situation summary

� Non-plantation users in Basin A are generally located in areas of marginal water quality.

� Non-plantation users in Basin A will continue to be issued with a fixed annual allocation to ensurethe resource is managed sustainably.

Details: A non-plantation entitlement (previously known as a fixed allocation), is an entitlementissued to non-plantation users such as caravan parks and industry to abstract groundwater in Basin A.

Historically, a non-plantation entitlement has been held constant until three years after a river flow whenit was then set to zero unless salinity thresholds are reached first. However given that the volume ofwater abstracted by non-plantation allocation licensees will be influenced by salinity levels rather than athree year no river flow period, the approach will be amended to include only salinity levels and theAllocation Limit as the management considerations.

5.3.7.1 Management provisions


a) Licensees who take water for non-irrigation purposes are permitted to abstract groundwater up totheir annual entitlement from Basin A unless the salinity level exceeds the licensed salinity thresholdprior to the pumping of the entitlement.

b) Licensees who take water for non-irrigation purposes may apply for an increased allocation withinthe licensed salinity threshold, up to a maximum allocation of 10 ML/yr.

c) Licensees who take water for non-irrigation purposes located in marginal quality groundwater areasare required to cease pumping when salinity levels in individual wells reach 2500 mg/L TDS.

d) Licensees who take water for non-irrigation purposes located in good quality groundwater areas arerequired to cease pumping when salinity levels in individual wells reach 1000 mg/L TDS.


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5.3.8 Unused allocations in Basin A

Situation summary

� Not all annual allocations have been fully utilised in Basin A in the past, creating unused allocations.

� Unused allocations may threaten the sustainability of Basin A if they are all activated.

� Unused allocations tie up water that may be needed by others.

� Unused allocations cannot be traded.

Details: There is a perception amongst some Carnarvon growers that although the unused proportionof a grower’s allocation cannot be activated due to hydrogeological conditions (e.g. low aquifer yieldsand/or low water quality), the value of the full allocation still remains imbedded in the value of theproperty.

A key objective of this Strategy is that business operations are only allocated the water that they need fortheir land use, or on the basis of demonstrated historic use. This philosophy aims at preventing anyspeculative ‘in the bank’ allocations and thus provides for equitable allocation of the resource. It is also acritical principle in a situation where a water trading regime eventuates. In the Carnarvon IrrigationDistrict the current licence allocations do not reflect either the scale of horticultural development onproperties, or historical metered water use. This situation is addressed in this Strategy.

The water resources in Basin A are over-allocated, however the past 30 years of metering records showthat a large proportion of allocations have not been fully utilised during this period. Unused allocationsmay pose a threat to the sustainability of the resource if they are all activated. Historically, if a propertyhad not used any of its water allocation for more than ten consecutive years, it would be considered aninactive property and should have the allocation withdrawn. Licensees holding unused allocations with noreal intention of using them for economic benefit in the short term, are restricting development. However,the 10-year approach is considered to be too long term in a groundwater system where water use could beoptimised by trading. In addition it does not address the unused portions of an allocation. As highlightedin Section 6 – Transferable Water Entitlements Principles and Rules, licensees cannot trade unusedallocations.

Removal of unused allocations is necessary to reduce the total water allocation in Basin A so that itbecomes consistent with the current estimated Allocation Limit of 5,800 ML/yr (see Section 5.3.2 of thisStrategy).

The Basin A licensees that utilise less than their annual allocation over the next 7 years will have theallocation reviewed at the end of the seventh year. In most circumstances the allocation reduction willequal 50% of the difference between the licensed entitlement and the average of the highest three annualmetered draw (excluding unrestricted pumping periods) over the 7 years. This action will target andreduce the amount of unused entitlements. In determining entitlement reductions, the Commission willtake into consideration factors such as drought, extended unrestricted pumping periods, waterconservation (or wastage) practices and compliance history.


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This part relates to the amendment of licences under s 24(2)(d) of Schedule 1 of the Act.

a) Basin A licences that utilise less than their annual entitlement over the next 7 years will have theirentitlement reviewed by the end of the seventh year.

b) Entitlement reductions will generally equal 50% of the difference between the licensed entitlementand the average of the highest three annual metered draws over the 7 years.

c) Entitlement reductions that do not equal 50% of the difference between the licensed entitlement andthe average of the highest three annual metered draw (excluding unrestricted pumping periods) overthe 7 years, will be referred to CWAAC for advice.

5.3.9 Domestic and stock use

Situation summary

� Close management of Basin A resources is required to manage the resource sustainably.

� Taking water for domestic and non-intensive stock use has minimal impact on the environment andother users where the volume of water use is small and the draw is not concentrated.

Details: Due to the high demand on Basin A resources and the possibility that if groundwater isdrawn in areas where salinity levels exceed 1000 mg/L TDS, it is likely to exacerbate salinity problemswithin the irrigation district. Consequently the construction of any well in the Carnarvon GroundwaterArea, for any purpose, including domestic and stock use, requires a 26D licence (construction licence). A5C licence (production licence) to take water is issued only in areas where salinity levels of less than1000 mg/L TDS can be demonstrated. This is typically within a prolongation.

The licensing of non-intensive stock and domestic use in Basins B – L (part of the GascoyneGroundwater Area) is not necessary as long as the volume drawn is relatively small and the draw isspread over a large area. A licence would be required where the pumping of water and resultantdrawdown effects impact upon other groundwater users and the local environment.


This part is made under s 26GY(2)(b) of the Act

a) Stock and domestic use in Basin A will be licensed, with groundwater abstraction to cease wheresalinity levels in individual wells exceed 1000 mg/L TDS.

b) Licence exemptions will occur for properties that have no other alternative water supply to abstractgroundwater for domestic and stock use. These are as follows:

i. ‘Block’ allocations: issued to properties without access to scheme water or an alternativewater supply to abstract up to 650 kL/yr. This volume provides sufficient water for domesticuse including the irrigation of lawns and gardens used in connection with a dwelling (i.e. notfor commercial gain).


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ii. ‘Residential’ allocations: issued to residential zoned properties without access to schemewater or an alternative water supply to abstract up to 650 kL/yr. This volume providessufficient water for domestic use including the irrigation of lawns and gardens used inconnection with a dwelling (i.e. not for commercial gain).

iii. ‘Special rural’ allocations: issued to rural zoned properties without access to scheme water oran alternative water supply to abstract up to 2000 kL/yr.

c) Groundwater abstraction for non-intensive stock and domestic use in Basins B – L is exempt fromlicensing.

5.4 The Drought Strategy

Situation summary

� There is a need for greater long-term drought security.

� Abstraction in Basin A is limited by saline groundwater intrusion during periods of extended no riverflow.

� There is greater dependence on Basins B – L groundwater resources with increasing time since thelast river flow.

� The lack of drought security may be impacting on the growth of the horticultural industry.

Details: Allocations have historically been set on an annual basis by the various CWAACsestablished in Carnarvon. The committees used an allocation formula outlined in the Rules of the RiverDraft and information from the Aquifer Status Report to set annual Allocation Limits. The Aquifer StatusReport, described in more detail in Section 8.3, contains information on water levels (in the riverbedsands and older alluvium aquifers) and river flow data.

However, the practice of allocating water on an annual basis is addressed in this Strategy to provide alonger term view and improved drought security. With the help of a groundwater flow model, theAllocation Limit for Basins A – L has been set at a limit that can sustain a 24 month no river flow period.Historical river flow data indicates that the probability of a 22 month period of no river flow is one in 43years.

The allocation of groundwater during this two year period of no river flow is termed the DroughtStrategy. In summary, the Drought Strategy allows the Allocation Limit from Basins B – L to betemporarily increased during extended periods of no river flow to cater for the expected additionaldemand for fresh water due to the decreasing water quality in Basin A. The Drought Strategy is describedin more detail below:

Basin A

Groundwater usage in Basin A is limited by water quality and therefore a Drought Strategy for Basin A isnot appropriate. Water users in Basin A are encouraged to make provisions for their own drought securityby applying for an appropriate volume of scheme water.


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Basins B – L

As access to Basin A groundwater reduces due to increased salinity, the demand for Basins B – Lresources increases. Groundwater modelling has shown that the whole system can sustain an annualabstraction rate of 18,000 ML.

Allocation Limit for Basins A-L 18,000 ML/yrCarnarvon town water supply from Basins B-L 1,800 ML/yrTown water supply reserve from Basins B-L 1,800 ML/yrMaximum volume available (for irrigation use) 14,400 ML/yr (5,800 ML/yr Basin A plus 8,600

ML/yr Basins B-L)

Taking into consideration the town water supply that is licensed and held in reserve, if Basin Acompletely shuts down due to high salinity levels and low pumping yields (which is very unlikely), themaximum amount of water that can be sustainably abstracted for irrigation purposes from Basins B – L is14,400 ML/yr up to a period of 24 months. This forms the basis of the Drought Strategy.

In normal non-drought conditions, the licensed allocation for irrigation purposes from Basins B-L is5,000 ML/yr. However, during drought conditions, this allocation can be temporarily increasedincrementally to a maximum of 14,400 ML/yr to cater for all irrigation water requirements in Basin A,under the assumption that no groundwater is being abstracted from Basin A. This scenario is highlyunlikely as some properties in Basin A will be able to continue pumping due to their favourable location.The assumption above should be considered as a worst case scenario. Following drought conditions, theallocation for Basins B-L will again revert to its non-drought allocation of 5,000 ML/yr.

It is assumed that demand for Basins B – L resources will occur in stages hence the Drought Strategy willalso be implemented in stages to be announced by the Department:

� Stage 1 drought conditions following 6 months of no river flow over Bibbawarra Crossing




Any drought initiatives beyond 24 months will require very close monitoring of the environmentalimpacts of continued pumping and possible reductions in allocations and usage in Basin A. The DroughtStrategy must be accompanied by the monitoring described in Section 8.

When the Gascoyne River flows across Bibbawarra Crossing, the Commission will declare the droughtover if the volume of flow is sufficient enough to recharge the aquifers. The drought strategy will cease tobe in operation and the Allocation for Basins B – L will return to the non-drought allocation of 5,000 ML.

5.4.1 Drought management provisions

This part is made in accordance with s.26GY of the Act

a) The maximum amount of water that can be sustainably abstracted for irrigation purposes from BasinsB – L is 14,400 ML/yr up to a period of 24 months.


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b) At the end of drought conditions, the abstraction from Basins B-L for irrigation purposes will be nomore than 8,600 ML/yr.

c) An analysis of the condition of Basin A will be undertaken after one year, 18 months and 24 monthsof the drought with the additional allocation for Basins B – L determined by deducting the predictedabstraction for Basin A from the available allocation in Basins B - L. For example, if it is determinedthat 4,000 ML/yr can be abstracted from Basin A at the start of Stage 1 drought conditions (after 6months of no flow), the allocation for Basins B – L will be 14,400 – 4,000 = 10,400 ML/yr.

d) If the drought continues for more than 12 months, a Stage 2 drought allocation can be made

e) If the drought continues for more than 18 months, a Stage 3 drought allocation can be made.

f) If the drought continues for more than 24 months, a Stage 4 drought allocation can be made

g) When the Gascoyne River flows across Bibbawarra Crossing, the Commission will declareunrestricted pumping if the volume of flow is sufficient enough to recharge the aquifers.

h) The declaration will be at the Commission’s discretion and no unrestricted pumping should occurprior to the declaration.

5.5 Groundwater pumping

5.5.1 Metering of use

Situation summary

� Information on groundwater usage is needed to manage the resource sustainably.

� Metering is the most effective method of calculating groundwater use in Carnarvon.

Details: Metering was first introduced in Carnarvon in the early 1960s to obtain a betterunderstanding of how much water was being used by the growers and the metering record in Carnarvon isone of the longest in the State. Under the Act, the fitting of flow meters can be a condition of a licencewhich requires that all groundwater abstracted must be metered.

It is the responsibility of licensees to ensure that flow meters are fitted to all draw points and monthlyextraction is recorded. The current practice is that flow meters are fitted and read monthly by theCommission or delegated authority and entered in the Commission’s licensing database for officialrecords. The metered usage figures are used to establish an historical usage pattern to identify unusedallocations and to establish usage trends. This information can be used to determine historical usage in theevent that the management of the groundwater resource by salinity levels and monthly allocationsbecomes unsustainable.

It is the licensee’s responsibility to ensure that the Commission is informed if meters are not functioningcorrectly or accurately, and their flow meters are properly calibrated, working and correctly recording allwater that is abstracted from the licensee’s wells at all times. It is also in the licensee’s interest tomaintain an accurate usage record to establish a bona fide historical use pattern. Apart from the


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Commission’s management requirements, accurate historical usage records can add to property values,particularly if a potential property buyer requires proof of the water availability of the property.

Failure to maintain operational meters will disadvantage growers and compromise the sustainablemanagement of the resource and may breach the Act. Furthermore, to ensure that mud, sand and largeparticles etc. are not continually damaging meters, it is essential that the water pumped is of a meterablequality. If meters are being continually damaged due to the deliberate pumping of poor quality water, orfrom inadequately maintained pipes, licences may be suspended, repair costs recovered and infringementnotices issued.


This part is made in accordance with Schedule 1 clauses 46 and 47 of the Act.

a) Metering of water use in Basin A and Basins B - L will be maintained as a standard managementrequirement of licensees and therefore all groundwater abstracted must pass through a meter.

b) It is the responsibility of growers in Basin A to ensure that the water pumped is of a meterablequality (ie free of mud, sand and large particles) to prevent damage to the meters.

5.5.2 Restricted pumping

Situation summary

A period of restricted pumping during no river flow months is required to manage the groundwaterresource sustainably and to minimise the impacts to neighbouring properties.

Details: During periods of no river flow, the aquifers in Basin A can be quickly depleted and/or thewater quality can be degraded by salt water intrusion. Exceeding the monthly maximum may affect thewater quality and availability for neighbouring properties.

Restricted pumping is defined as the abstraction of groundwater to a licensee’s annual entitlement in theWater Accounting Year.

Restricted pumping will be declared during periods of no river-flow. To minimise confusion, anannouncement will be made by the Commission, via a notice in the local paper and/or notices placed instrategic locations in Carnarvon, stating that following a period of unrestricted pumping (Section 5.5.3),restricted pumping will commence at the start of the following month. All water pumped from the start ofthe following month will be deducted from the licensee’s annual allocation. This means that unrestrictedpumping will be available up to the end of the month preceding the announcement for restricted pumping.

5.5.2.1 Management Provision – restricted pumping


a) When the river ceases to flow at the Bibbawarra Crossing, the following month starts as restrictedpumping as determined and announced by the Commission.

b) Licence conditions will allow a maximum monthly draw of 10 ML per property, in addition to awater quality cease-to-pump threshold of 1000 mg/L TDS.


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5.5.3 Unrestricted pumping

Situation summary

� Large quantities of water flow out to sea during flow events of the Gascoyne River.

� During a substantial flow event, the aquifer systems are basically full and reject additional recharge.

� During a substantial flow event, pumping is unrestricted.

Details: Due to the total river flow volume greatly exceeding the storage capacity of the riverbedsand, a significant volume of fresh water flows out to sea, however river flow events are highly variableand infrequent. For most of the year, the Gascoyne River does not flow (Figure 14). During peak flowevents, more than 3,000,000 ML can flow down the Gascoyne River with the majority of flows exceeding44,000 ML. To ensure water use is optimised when the river is flowing, unrestricted pumping ispermitted.

Unrestricted pumping may be declared by the Commission during periods of river flow. The beginning ofan unrestricted pumping period is determined by the Commission and announced via notice in the localpaper and/or notices placed in strategic locations in Carnarvon. If it has been an extended period sincethe last river flow, growers should not presume that a visible flow at the Bibbawarra Crossing willautomatically lead to an announcement for unrestricted pumping. This is because the river flow may nothave been large enough to fully recharge the aquifer and therefore unrestricted pumping may have anegative impact on the aquifer.

5.5.3.1 Management Provisions – unrestricted pumping

a) Unrestricted pumping may be declared by the Commission during periods of river flow.

b) Unrestricted pumping should not commence without the Commission’s announcement.

c) When the Gascoyne River flows across Bibbawarra Crossing, the Commission will declareunrestricted pumping if the volume of flow is sufficient enough to recharge the aquifers.

d) Water abstracted during periods of unrestricted pumping is to be metered.

e) Water passing through the meter during unrestricted pumping is excluded from the licensee’s annualentitlement.

5.5.4 Unauthorised pumping

Situation summary

Some growers have been illegally pumping in excess of their licensed monthly and annual allocation.This may jeopardise the sustainable management of the resource and disadvantage other growers.

Details: Unauthorised pumping by licensees from their own bores not only threatens the quality ofwater in the aquifer at the location where the bore(s) are located, but also disadvantages other growerswho are doing the right thing, as the threat is also extended to neighbouring properties. The short-termgain from the unauthorised water use may cause long-term and irreversible damage to the aquifer. It is


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also in the licensee’s best interest to ensure that all water use is metered as any non-metered water usewill not be considered in the establishment of historical use or any other prior right (see Section 5.5.1).Accurate metered usage is also a benefit to the licensee on the sale of the property.

During 2001/2002, extensive investigations by the Commission revealed that a significant number ofproperties had meter bypasses to take water without recording its use. Action was taken to have thelicence holders remove the bypass or have their groundwater licence suspended. This approach allowedlicensees to quickly remove their bypass without further penalty during this period of change. Usingbypasses may be economically viable in the short term, but will work against growers in the long term byreducing their bona fide historical usage rights.

The Carnarvon community recognises that unauthorised pumping, involving bypass infrastructure, is amajor problem for the industry. Recent initiatives have been introduced to manage this issue. Further, it isa condition of the licence, under s.5C of the Act that all groundwater abstracted must be metered.

If unauthorized pumping of water continues, it could be considered an offence under s.5C of the Actpunishable by a maximum penalty of $10,000, and could lead to a range of enforcement measures.

5.5.4.1 Management Provisions – unauthorised pumping

This part is made in accordance with s.5C of the Act.

a) Licensees found to be bypassing their flow meters or causing the flow meters to read inaccuratelywill be subject to enforcement actions as determined by the Commission.

5.5.5 Over pumping

Situation summary

Exceeding the monthly maximum restriction may affect the water quality and water availability ofneighbouring properties.

Details: Exceeding the monthly maximum may result in higher salinity levels and lower bore yieldsbeing reached earlier. This not only affects the licensee’s individual wells but also neighbouringproperties.

The Commission has now issued licences to growers only for Basin A, and any pumping in excess of themonthly maximum draw will not be accepted. Over pumping will be treated as unauthorised pumping(Section 5.5.4) and will be dealt with under the Act. The exception to this is when there is a period ofunrestricted pumping (Section 5.5..3).

5.5.5.1 Management Provisions – over-pumping

This part is made in accordance with s.5C of the Act.

a) All pumping by a Basin A licensee that exceeds the monthly maximum draw during periods ofrestricted pumping will be recognised as unauthorised pumping and will be subject to enforcementactions as determined by the Commission.


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5.5.6 Water wastage and improper use

Situation summary

� There is the potential for inefficient water use practices to occur.

� Water wastage could occur by licensees in an attempt to obtain an artificially high historical usagepattern.

Details: Water wastage or improper use of the groundwater resource for the purpose of establishingan artificially high historical use will be subject to the provisions under s. 26GC of the Act.

Monitoring crop-area water use can assist in determining artificially high water use. Based onDepartment of Agriculture advice, the water needs for a particular crop can be calculated on an area basis.Inspection of a licensee’s crop type and area can give a good indication of compliance with the allocation.Water wastage also impacts unfairly on other licensees. The Commission will continue to promote theadoption of water efficiency practices.

Section 26GC of the Act provides the Commission with powers to give directions to persons, restrictingor prohibiting the amount of water they may take from the resource, the rate at which they may take it orthe purpose for which it may be used, or any combination of the above. Failure to comply with the noticeis an offence, with a maximum penalty of $4,000 and a daily penalty of $400. Furthermore, should waterwastage be identified, the licensee’s historical water use may be reduced.

Growers who deliberately waste water also need to recognise that the costs (electricity and maintenance)associated with the pumping of water will still be borne by them and there may be no gain in the way ofan increased allocation at the end of the review.

5.5.6.1 Management Provisions – water wastage and improper use

This part is made in accordance with s.26GY(2)(a) of the Act

b) Water wastage or improper use of the groundwater resource for the purpose of establishing anartificially high historical use may be subject to enforcement actions as determined by theCommission.

5.6 Well construction and decommissioning

Situation summary

� Wells are often damaged by river flow events.

� Unsealed wells are a potential hazard to public health and safety.

Details: The Commission issues two main types of licenses to water users: 26D licences to constructor alter a well (construction licence) and 5C licences to take and use the water (production licence).


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Prior to constructing or altering a well (including bores and spears), the proponent is required to submit a26D licence application form to the Commission which outlines the well specifications and purpose of thenew well and includes a plan of the proposed well location.

Well construction is to be completed by a certified driller. Furthermore, any new well drilled must belocated not less than 30 metres from any existing wells on neighbouring properties and/or prolongations.

Spearpoints also require a 26D licence, but are usually installed by the excavation of a shallow trench inthe riverbed sand. Spearpoints are only used to harvest the surficial groundwater that exists during orimmediately after a river flow.

Due to the high demand for 26D well construction licences when drillers are in town, and the increasedlevel of understanding of the shallow aquifer system, it is recommended that the development of local by-laws be investigated to eventually replace the need for well construction licensing. The local by-lawswould specify the conditions under which wells, including sand spears, could be constructed, e.g. therequirement to submit bore logs, without the need for individual licences and conditions. Until local by-laws are developed, all growers are required to apply for a well construction licence (26D licence) prior toaltering or constructing a well.

When licensees are no longer using a well they are required to de-equip and securely cap the well toremove any potential physical hazards. Unsealed abandoned test holes, bores and wells constitute apotential hazard to public health and safety, and to the preservation of the quantity and quality of thegroundwater resource. This will become a condition on the 5C licence (the take and use licence).Alternatively, under s.26G of the Act, the Commission can direct closure or part closure of a well.

5.6.1 Management Provisions – Well construction and decommissioning

This part is made in accordance with s.26L of the Act.

a) Investigate the development of local by-laws to accommodate the construction of wells withouthaving to apply for a 26D licence.

This part is made in accordance with s.26D of the Act.

b) All well constructions and alterations into the clay, known locally as ‘second water’, are to be carriedout by a certified driller, except for sand spears for surficial water.

c) To minimise interference effects, any new well must be located not less than 30 metres from anyexisting wells on neighbouring properties and/or prolongations.

d) Licensees are required to decommission all unsealed abandoned wells by removing all equipmentand securely capping the well.


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5.7 Water Supply Contamination

Situation summary

There is a potential for both scheme water and Basin A groundwater to be contaminated due to the backflow of water held in storage tanks.

Details: There are three mechanisms in place to prevent the groundwater from being contaminated inthe Lower Gascoyne. To protect the scheme there are penalties prescribed under the Country AreasWater Supply Act 1947 for using unauthorised, and failing to repair, fittings for the supply of water thatcould allow contamination to occur.

To protect Basins B – L resources, growers drawing water from the scheme are required to install a150 mm air-gap, or a reduced pressure zone back-flow prevention device to protect the scheme supplyfrom back-flow contamination.

To protect Basin A from chemicals being siphoned back into the aquifer, it is the responsibility ofgrowers in Basin A to ensure that backflow through Basin A flow meters is prevented.

5.8 Groundwater access

5.8.1 Basin A prolongations

Situation summary

� Groundwater of higher quality is found in the aquifers directly beneath the bed of the GascoyneRiver.

� Growers do not have secure property rights for prolongations.

� Growers need to take greater responsibility for maintaining the condition of prolongations.

Details: The majority of properties with river frontage in Carnarvon access groundwater byconstructing wells within prolongations to take advantage of the higher quality groundwater in the riverbed. A prolongation adjoins a grower’s property and is an extension of the property’s side boundariesinto the middle of the adjacent river bed. In general, prolongations comprise of the road and riverforeshore reserve, which is vested in the Shire of Carnarvon, and the Gascoyne River bed, which isunvested Crown land (managed by the Department for Planning and Infrastructure).

Although management guidelines exist for the extraction of water from prolongations, growers do nothave legal access to the land upon which they construct their wells.

A process outside of the Act provisions will be supported by the Commission during the duration of thisStrategy to formalise the area of a grower’s prolongation to provide legal access to the Gascoyne Riverbed and banks for obtaining water supplies and maintaining their wells. This process will aim to providelegal access to growers. Management conditions should be introduced requiring licensees to controlweeds, cover unused wells and remove rubbish from their prolongations. Licensees will receivedocumentation (possibly in the form of a permit) outlining the boundaries of their prolongation and


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management conditions that must be observed. The administrative costs of undertaking this procedurewill be passed on to licensees.

When formalising the area of each prolongation, the Commission will provide existing licence plans toassist in formalising prolongation boundaries.

5.8.1.1 Management Provisions – Basin A prolongations

a) The Commission will promote and support actions to formalise legal access to Basin A prolongationsfor licensees with a Basin A entitlement.

b) The Commission will generally not support the establishment of new prolongations except inexceptional circumstances or for land exchanges associated with the removal of flood affectedproperties.

c) In considering whether to support the establishment of new prolongations, the Commission willconsider environmental impacts, the number of prolongations in existence, and the estimatedsustainable yield.

d) The Commission will encourage the establishment of management conditions for Basin Aprolongations for the purposes of public safety and environmental protection.

5.9 Land matters

Situation summary

� There needs to be a clear understanding of the rights and responsibilities of buyers and sellers of landin relation to water allocation.

5.9.1 Sale of property with respect to licence transfers

Water licences can be sold separately from the land title as they are not attached to the property. Whenselling a property the owner can transfer the licence to the new owner or to a person(s) other than the newowner, keep the licence and use it on another property, or surrender the licence in accordance with thegroundwater transfer strategy (Section 6 of this Strategy).

5.9.1.1 Management Provisions – sale of property

This part is made in accordance with Schedule1, Division 7 of the Act and Statewide Policy No.6Transferable (Tradeable) Water Entitlements for Western Australia.

a) When selling a property the owner can apply to either transfer the licence to the new owner, to aperson(s) other than the new owner, keep the licence and use it on another property or surrender thelicence in accordance with the groundwater transfer strategy.

b) When selling a property, if an agreement has been made to transfer the licence to the new owner, anapplication must be made to transfer the licence to the new owner up to 30 days after the property issold or 30 days after change of occupancy.


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c) Alternatively, the licence may be transferred to a person or persons other than the new owner. To doso an application must be made for each transfer either before the property is sold or before thelicence is terminated.

5.9.2 Wells located outside a property’s prolongation

In accordance with Section.5.8.1 of this Strategy, the Commission will support endeavours to establishlegal access to Basin A prolongations. Access to wells located outside a property’s legal prolongation canbe obtained if an agreement is reached with the relevant legal prolongation holder regarding access to andthe the use of the well. In response to water resource management requirements for Basin A aquifers,neighbouring growers can agree on adjustments to their legal prolongation boundaries up to 10%. Oncethe agreement is reached, a copy must be provided to the Commission for a formal adjustment of theplans and recording of the agreement. A fee may be introduced for this procedure.

5.9.2.1 Management Provision –wells located outside a property’s prolongation

a) The Commission will generally support access to wells located outside a property’s legalprolongation if an agreement based on adjustments of up to 10% change of prolongation boundariesis reached with the relevant legal prolongation holder regarding the use of the wells.

b) Access to wells located outside a property’s prolongation may lapse during the resolution of legalaccess to the prolongation, or subsequently, upon sale of the property, unless an agreement is reachedwith the prolongation holder regarding the use of the wells.

5.9.3 Splitting a water entitlement on the same property

5.9.3.1 Management Provisions - Splitting a water entitlement on the same property

This part is made in accordance with s.26GY(2)(b)(iii)

a) The Commission will not generally allow the formal splitting of an annual entitlement to cater forpartnerships and other similar arrangements on the same property, except in exceptionalcircumstances.

b) In considering whether to allow the formal splitting of an entitlement the Commission will considerthe impact on the water resources in the area.

5.9.4 Subdivision of prolongations

In accordance with Section.5.8.1 of this Strategy, the Commission will support endeavours to establishlegal access to Basin A prolongations. The subdivision of any legal prolongation will affect thesustainability of the resource. The proposed management direction following subdivision, to access waterfrom any new property created, the owner will need to apply to the Gascoyne Water Cooperative for awater contract to access Basins B – L scheme water.

5.9.4.1 Management Provisions – Subdivision of prolongations

This part is made in accordance with s 26GY(2)(b)(ii) and (iii)


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a) The Commission will generally not support the subdivision of a prolongation.

b) In considering whether to support a subdivision of a prolongation, the Commission will consider thelikely effect on sustainability of water resources in the area.

5.9.5 Amalgamation of prolongations

5.9.5.1 Management Provisions – Amalgamation of prolongations

This part is made under s 26GY(2)(b)(ii) and (iii)

a) The Commission will generally not support the amalgamation of a prolongation.

b) In considering whether to support an amalgamation of prologations, the Commission will considerthe likely effect on sustainability of water resources in the area.

5.9.5.2 Recovering the costs of water resource management

Situation summary

� The national Council of Australian Governments (COAG) Water Reform Framework Agreementrecommends full cost recovery for services associated with the management of water resources inAustralia.

� The Commission provides and funds monitoring services in Basin A that are not being provided toother water users in Western Australia.

Details: The Western Australian Government is committed to implementing the agreements of thenational COAG Water Reform Framework in a manner that is appropriate for Western Australia, thepeople and the State’s water resources. The ARMCANZ/COAG National Water Framework PolicyPosition Paper (December 1996) detailed the following recommendation:

‘The full cost of groundwater management should be identified by the States.

The cost of direct management activities should be recovered from users and, within the context of theoverall water cycle, appropriate apportionment of indirect costs be given consideration.

Outside of urban water supplies, the remaining subsidies should be transparent where full cost-recoveryis not achievable.

The necessary charges should be implemented progressively by 2001 and particular attention should begiven to timely resolution where, and as, trading in groundwater is likely to be demanded by the market.

Public communication on these matters will be important.’

There is a historic practice of undertaking metering and groundwater monitoring in Basin A, and thisStrategy details how these activities will continue. The activities are currently undertaken and funded bythe Commission, which is inconsistent with the approach taken throughout the rest of the State. Thisapproach is also inconsistent with the Commission’s Statewide Policy No. 3 (Policy statement on watersharing) which details that where necessary monitoring (and annual reporting) of the resource should be


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undertaken to ensure that groundwater abstraction is sustainable and the responsibility of the licensedwater user. The Monitoring Strategy of the Water Corporation for Basins B-L is an example of theapplication of this policy approach.

The Basin A monitoring services currently provided by the Commission include:

� provision of meters, repairs and maintenance;

� monthly meter reading and abstraction notices for each property;

� groundwater salinity monitoring in property bores and wells as required;

� quarterly aquifer L series well monitoring, and L series maintenance; and

� Aquifer Status Reports as required.

All Carnarvon growers with licensed access to Basin A benefit from the sustainable use of the waterresource which results from this management. It is recognised that all Basin A licensees shouldcontribute to meeting these costs.

It may not be necessary into the future for the Commission to be the agent that provides the monitoringservices. In the life of this Strategy, other service delivery options will be investigated, including theprovision of this service by the Cooperative.

The Commission’s 2002/2003 financial year budget for water resource management and monitoringservices for the Carnarvon Groundwater Area is approximately $150,000.


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6 Transferable water entitlementsprinciples and rules for Basin A

Situation summary

� The groundwater resources in Basin A are fully allocated.

� There is a high demand for good quality water in Basin A.

� Details: The ability to trade water entitlements in WA is provided by Schedule 1, Division 7 of theAct. The Statewide Policy No. 6 – Transferable (Tradeable) Water Entitlements for WA, 2001,provides a policy foundation for the implementation of a water market in WA. This policy coversdefinitions, principles, eligibility, implementation, monitoring, review and reporting on licensetransfers.

A license transfer is not compulsory. It is an opportunistic and market-based tool that can be used forbusiness flexibility and social, economic and environmental benefits. Groundwater trading refers to thebuying, selling and leasing of a licensed entitlement, or part thereof, from one licensee to another. Aperson transferring (selling or leasing) all or part of their licensed entitlement, is the ‘vendor’ or‘transferor’. A person purchasing or leasing the entitlement is the ‘purchaser’ or ‘transferee’.

Transfers may be temporary or permanent. An arrangement where a person leases their licensedentitlement, or part thereof, to another eligible person, on a temporary basis, is described as a temporarytransfer. An arrangement where a person sells their licensed entitlement, or part thereof, to anothereligible person, on a permanent basis, is described as a permanent transfer.

In theory, transfers can take place at any time between consenting parties, however it normally occurswhen groundwater systems are fully allocated and there are no more entitlements available from theCommission. This is the case in Basin A. Under the Commission’s Transferable (Tradeable) WaterEntitlements for WA, Policy N.o 6, unused allocations cannot be transferred.

People wanting access to water in Basin A, or wanting to expand their enterprise, can only do so legallyby either applying for a 10 ML/yr incremental increase (Section 5.3.6), or:

� purchasing an entitlement from a licensee who has established a metered historical use. Where thereare no flow meters installed, it is the responsibility of the entitlement holder to demonstrate theirhistorical use to the satisfaction of the Commission so that the transferable volume can bedetermined. If this cannot be demonstrated satisfactorily, the Commission will make thedetermination;

� leasing an entitlement on a temporary basis from a licensee who has established a metered historicaluse;

� purchasing a property with an allocation and securing the water entitlement; or

� improving water use efficiency .


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There are natural limits on the amount of groundwater that can be transferred from one enterprise toanother within an aquifer system because of hydrogeological constraints on the movement ofgroundwater. In addition, it is important that transfers of entitlements do not have adverse environmentalimpacts, or unacceptable impacts on other users. For these reasons, a set of trading rules will apply to alltemporary and permanent transfers. These rules may change from time to time and the Commissionreserves the right to restrict trading at any time, for example where local impacts preclude furtherdevelopment of the water resource.

NOTE: Trading can only commence once prolongations have been legally recognised.

This part is made in accordance with Schedule 1, Division 7 of the Act.

6.1 Application to transfer (trade) a water entitlement

a) All trades are subject to Commission approval prior to the trade taking place in accordance withSchedule 1 clause 31(1) of the Act

b) Applications for trading must be applied for on the prescribed forms available from the Commissionand must be accompanied by the prescribed fee in accordance with Schedule 1. clause 32(1)(a) of theAct.

c) Trades can only occur between water users who are licensed to take water. Where a potentialpurchaser does not hold a licence to take water, the application to trade must be accompanied by alicence application in accordance with Schedule 1. clause 29(3). This application will be subject tostandard licence assessment procedures which may or may not result in licence approval.

6.2 Principles of trading water entitlements

Licensed entitlements, or part thereof, may be traded within Basin A in accordance with the local tradingrules listed below.

a) All trades must be consistent with the objectives of Statewide Policy No 6;

b) The licensed entitlement to take water shall be transferred only where the proposed location andmanner of use of the transferred water has no detrimental impact on the water resource, waterdependent ecosystems or existing water users.

c) Licensees contemplating entering the trading market, should ensure that their purchased entitlementcan be accessed on a sustainable basis before they enter into a trade. This may require some pumptesting and impact reporting. Permission will be required pursuant to s.26D of the Act to carry out apump test prior to the purchase of the new entitlement. This is particularly important if the volume ofwater pumped during the pumping test exceeds the licensee’s annual allocation.

d) The Commission will support individuals or groups to purchase entitlements on the market and ‘use’the water as market-based environmental water by leaving it in the river or aquifer.

e) The unused component of a licensed entitlements is not tradeable.


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f) Unused entitlements resulting from efficiency gains may be traded. However, such gains will have tobe clearly and unambiguously demonstrated to the Commission;

g) Only used entitlements that have been measured by flow meters will be eligible for trading.

h) Where a licensee is able to clearly demonstrate to the Commission’s satisfaction that extenuatingcircumstances have resulted in an inactive entitlement, trading the unused entitlement, or part thereof,may be approved.

i) Additional purchased entitlements will be subject to the same rules as base entitlements.

j) As far as practicable, arrangements for trading entitlements reside with the transferor and thetransferee.

k) The Commission will not be involved in setting the market price for trading groundwaterentitlements.

l) The Commission will endeavour to minimise the turnaround time from an application to trade to theapproval to trade.

m) The Commission will disclose the prices paid for trades.

6.3 Local trading rules

a) Trading can occur once a licensee (transferor) has demonstrated full allocation use during continuousrestricted pumping over a two year period;

b) The 10 ML per month and 1000 mg/L TDS limits will remain on prolongations;

c) For prolongations that share common boundaries, a trade can provide for water to be drawn from thetransferor’s prolongation, or from the adjacent transferee’s prolongation and piped across theboundary;

d) For prolongations that do not share common boundaries, a trade provides for water to be drawn onlyfrom the transferee’s prolongation. Piping from non-adjacent properties will not be permitted;

e) Applications for trading may require advertising for a period of one month, with comments soughtfrom potentially affected parties. The Commission will determine whether or not advertising isrequired;

f) An application for trade of water entitlements may be refused at the discretion of the Commission.Upon refusal, the applicant may make a submission in writing to the Commission for a review of theapplication under appeal provisions as provided for by the Act;

g) Temporary transfers are valid for one year only and therefore must be applied for on an annual basis.Longer term arrangements between vendor and purchaser may be approved;


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h) A permanently transferred entitlement will be added to a purchaser’s existing (or new) licence andsubject to the conditions attached to the existing (or new) licence. Additional conditions may beadded to minimise any potential local impacts of the additional volume;

i) Riparian right, stock and normal domestic entitlements are tied to the land and therefore are nottradeable, except as a consequence of the sale or lease of land.

j) Trading will be permitted only into local areas where there is clearly sufficient groundwater resourceto allow additional abstraction without causing long term groundwater depletion, or unacceptablelocal impacts on the environment or other users, or unacceptable changes to groundwater qualityfrom the additional abstraction, or unacceptable impacts on local GDEs, or where licence conditionscan overcome such impacts.

k) The traded volume will form part of the purchaser’s history of use record, and not the vendor’s. Theuse is related to the abstraction point which can only be determined by metering.

l) If a vendor’s total annual entitlement is permanently traded, the vendor’s licence will be cancelled.All irrigation bores on the property must be abandoned, un-equipped and sealed to the Commission’ssatisfaction. Any re-purchase of entitlement for the property will be subject to interference andenvironmental rules existing at the time of that purchase.

m) Trade of groundwater entitlements should not cause unacceptable adverse effects on groundwaterdependent ecosystems or on the water quality of the aquifer by:

� increasing the entry of saline water into the aquifer from surrounding aquifers;

� increasing the salinity of the land on which the transferred water is to be used or the landsurrounding the area on which the transferred water is to be used, including long-term salinityeffects;

� decreasing the water level in the aquifer beyond the limits specified in this Strategy; or

� decreasing the structural integrity of the aquifer.

n) Trade of groundwater entitlements should not cause unacceptable interference effects with boresowned by other water users.

6.4 Refusal of trading

This part is made in accordance with Schedule 1 clause 31 of the Act

a) The Commission reserves the right to refuse trades of water entitlements in order to :

� preserve the market from distortion;

� prevent non-efficient uses and monopolies in water;

� encourage water use efficiency;


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� preserve complementarity and diversity in the market;

� protect other uses and the environment from unacceptable impacts;

� ensure that the outcomes are beneficial to the State; or

� meet policy and planning objectives

b) Upon refusal, the applicant may appeal against the Commission’s decision pursuant to Schedule 2 ofthe Act.

6.5 Assessing an application to trade

a) Before determining an application to trade a groundwater entitlement, the Commission may requirean assessment of the impacts of the trade to be made, at the expense of the applicant, or by an expertappointed or approved by the Commission in accordance with Schedule 1 clause 33 of the Act.


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7 Implementation programThe Commission uses its authority, management principles, goals, and objectives to guide themanagement of the groundwater resources in the Lower Gascoyne River. The groundwater managementprogram will be implemented using four primary mechanisms: rules, Management Strategy,administrative action, and public information/consultation/participation.

Rules and regulations

Rules and regulations are used to supplement and interpret the procedures and criteria contained in thelegislative authority of the Act. Rules and regulations provide certainty and clarity to the managementprocess, and help define the basic management framework.

Management Strategy

The Commission’s Groundwater Management Strategies add detail to the provisions of the Act. They aretailored to individual water resources to meet the needs and objectives of the local communities.

Administrative Action

Administrative action is the Commission’s discretionary water management tool which it uses to developand distribute water resources data, to issue licences, to enforce the provisions of the Act, and to provideexplanations of these provisions to the public.

Public Information/Consultation/Participation

The Act and the Commission’s policy development require extensive community consultation andparticipation in the decision-making process when developing a Management Strategy. Whilst theStrategy will set in place the operational criteria that will manage the allocation and use of thegroundwater resources, the community will have an important role to play in ensuring that the criteriaused will achieve workable outcomes, and outcomes that can be monitored and measured over time tojudge the Strategy’s success.

Responsibilities

The Commission, in consultation with the community, is responsible for the development, approval,implementation, administration and review of the Strategy. Licence holders are responsible for complyingwith the terms and conditions on their water licences and providing information to the Commission asmay be requested for implementation of the Strategy’s provisions.

7.1 The planning cycle

Planning, by its nature, must be a continuous process, adapting to new conditions and information. Whilsta static management plan or strategy may be considered to be an obstacle to effective and adaptivemanagement, continuous changes can be a hindrance to long-term planning for licensees. Changes to aplan or strategy should be addressed within a given planning cycle. It is envisaged that this Strategy willbe implemented for at least seven years from 1 January 2004 to 31 December 2010. It will be reviewed by


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2010 and consideration given as to what action will be taken to continue with it, amend it or revoke it.This does not preclude making amendments to the operating rules within the planning cycle, howevercare must be taken to ensure that such changes are made in consultation with the community and areacceptable to the community.

Major changes to the operating rules should therefore be implemented at the beginning of the nextplanning cycle. The planning cycle can be divided into three major components: preparation, approvaland review.

Preparation

The preparation of a plan includes the collection and collation of data and information, developingobjectives, generating and evaluating options, identifying preferred options with community consensuswhere possible, and the writing up of the plan. This plan was developed by the Commission incooperation with the Carnarvon Water Allocation Advisory Committee, community members and otherstakeholders.

Approval

The draft Strategy was available for public consultation and submissions for two months. On the basis ofpublic submissions, modifications were made to the Strategy . Before this Strategy was finalised, asummary of the public submissions, and a Commission report indicating its opinion of the merits of thesubmissions and requests, were submitted to the Water and Rivers Commission Board for approval. Thedate of implementation of this Strategy is 1 January 2004.

Review

The review of this Strategy will be completed by 2010. The revised Strategy will be again available forpublic comment and any amendments submitted to the Board for approval. Implementation of the newStrategy for the second planning period and the planning cycle will begin again.


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8 Monitoring and reporting8.1 Background

The groundwater resources of the Lower Gascoyne River are over-allocated and therefore a high level ofactive management is required. This ensures that the aquifers are used sustainably, localised over-abstraction does not occur and the early effects of saline intrusion are identified. Current monitoringincludes water level and salinity level monitoring.

The Commission coordinates the overall monitoring strategy for water levels and water quality for BasinsA – L and actively monitors Basin A. The information gathered on water levels and water quality iscollated to produce an Aquifer Status Report. The Water Corporation is responsible for activelymonitoring Basins B – L and does so with adherence to their operating strategy, which is reviewed byCommission officers for compliance.

8.2 Groundwater salinity

The monitoring of groundwater salinity, using TDS as the indicator, commenced in 1974 to identify theearly effects of saline intrusion and to measure salinity levels in private wells.

Regional monitoring, using monitoring bores, is undertaken to provide a broad overview of salinity trendsin Basin A. The results are collated to produce salinity contour maps and are included in the aquiferstatus report. In addition to regional monitoring, monitoring of private wells is also undertaken to provideearly warning of changes in groundwater salinity. This is due to inconsistencies in the lateral movementof salt (both vertically and horizontally) throughout the aquifer.

Monitoring of private wells is conducted either monthly or quarterly depending on the location of thewell. Wells located in more saline areas are monitored more frequently. Furthermore, as the periodbetween river flows increases, the condition of the aquifer deteriorates and, as a result, the frequency ofthese monitoring programs is increased accordingly. The salinity measurements are stored in a databaseand are used to detect trends in salinity over time and to assist in determining which wells require morefrequent monitoring.

The TDS monitoring is conducted on-site by measuring the electrical conductivity (EC) of the watersample and then converting it to total dissolved solids (TDS). Wells must cease to be pumped whensalinity levels exceed 1000 mg/L TDS which traditionally has been viewed as the sustainable limit. Pastmonitoring results show that with the exception of a few wells near Water Supply Island and the LewersCreek area, salinity increases are localised with variations being a reflection of river flow and droughtperiods. Where wells exceeded the 1000 mg/L TDS threshold, they have generally recovered afterrecharge events. No well has experienced any long-term elevated salinity trends (Dodson, 2001).


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8.2.1 Other chemical parameters

There are some localised areas of groundwater that contain above average concentrations of fluoride andboron. This occurs naturally in the Lower Gascoyne and has not been exacerbated by groundwaterabstraction. Generally, growers are responsible for managing levels, given that boron and fluoride occurnaturally. This is because these anolytes are not indicators for unsustainable water resource managementpractices in the same way as saline intrusion. However, as undertaken in the past, opportunistic samplingmay occur.

8.3 Aquifer status and water levels

A network of monitoring wells within Basins A – L are used to provide regular (quarterly and sometimesmonthly commencing on the cessation of a river flow) assessments on the state of the aquifer and itsresponse to pumping. The monitoring wells are used to identify current water levels, peak storage levels,and storage decline rates for each of the management basins.

Within Basin A there are 39 wells that monitor water level and storage decline rates on a monthly orquarterly basis. The monitoring wells were installed in transects to monitor water levels in the river bed,on either side of the banks (interface region) and further away from the river (Table 2 in this Strategy).Within Basins B – L there are a number of wells monitored by the Water Corporation, as outlined in theiroperating strategy, in addition to the wells monitored by the Commission.

The water level results are collated into an Aquifer Status Report. The purpose of this report is to providebackground information to the managers and the community on the current and historic aquifer storageand depletion and river flow information. Up until now, this information has been the basis for informeddecisions to be made with regards to setting annual allocations and for making quota reductions whenrequired. Collectively, this information was used by the CWAAC to determine allocation quotas andpossible water reductions during extended periods of no river flow. The report will still be produced toassist in reviewing the conditions of the aquifer. The frequency of the production of Aquifer StatusReports varies depending on the time since the last river flow, and the level of groundwater storage.


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8.4 Resource monitoring program

Table 4 outlines the baseline monitoring program to be undertaken to ensure the sustainable managementof the resource. However, should the use of the resource increase, additional monitoring initiatives mayneed to be introduced.

Table 4 Summary of the monitoring requirements for Basins A to L

Basin Monitoring

Basin A

� Monthly salinity monitoring of private production wells in Subarea 0003 on cessationof river flow. Pumping to cease in wells where salinity exceeds 1000 mg/L TDS.

� Quarterly salinity monitoring of private production wells in Subareas 0001 & 0002 oncessation of river flows. Pumping to cease in wells where salinity exceeds 1000 mg/LTDS.

� Salinity and water level monitoring of wells used to determine the aquifer conditionand produce an Aquifer Status Report. Also used to produce salinity contouring maps.Monitored on cessation of river flows and quarterly thereafter. Monitoring of privatebores is also used to produce salinity contouring maps.

� Weekly and opportunistic salinity sampling of Gascoyne River baseflows.

Basins B – L

� Quarterly water level and salinity monitoring of production wells.

� Quarterly water level and annual salinity monitoring of monitoring wells as specifiedin operating strategy.

� Salinity and water level monitoring of wells used to determine the aquifer conditionand produce an Aquifer Status Report. Monitoring on cessation of river flow andquarterly thereafter.

� Annual major component sampling of production wells.

8.5 Water level and river red gum health monitoring program

Monitoring is required to ensure that groundwater dependent ecosystems are not adversely impacted byabstraction from Basins A – L aquifers.

A monitoring program should be introduced to increase the level of understanding of the river red gums’dependence on groundwater (especially for varying climatic conditions) and refining their waterrequirement. The monitoring program will also assist in detecting any changes in the ecologicalcommunity as a consequence of the current groundwater abstraction regime, enabling appropriate actionto be undertaken.

The monitoring program may be refined or amended as monitoring results are gathered and the level ofunderstanding is increased. The data gathered relating tree health to groundwater depletion will be used toprovide information to reassess the EWPs during the review of this Strategy.


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8.6 Monitoring the effectiveness of this Strategy

The Commission will report on:

� implementation of the management provisions of this Strategy;

� achievement of this Strategy’s specified outcomes; and

During the seventh year, consideration must be given to either review, revoke, amend or correct thisStrategy after taking into account any relevant report or information based on the monitoring of the statusof the resources and groundwater modeling updates.


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References

ALLEN, A.D.(1972) Results of the investigation into groundwater resources along the Lower Gascoyne River forCarnarvon irrigation and town water supplies. WA Geological Survey, Record 1972/9.

DODSON, W.J. (2001) Basin A water quality review, Lower Gascoyne River. Water and Rivers CommissionHydrogeology Report No. 192 (unpublished).

DODSON, W.J. (2002) Groundwater recharge from the Gascoyne River, WA. Hydrogeology Report No. HR 204(unpublished).

ENVIRONMENTAL WATER PROVISIONS POLICY FOR WESTERN AUSTRALIA (Statewide Policy No.5, 2000),Water and Rivers Commission

MARTIN, M.W. (1990) Groundwater resources of the older alluvium, Gascoyne River, WA. WA Geological Survey,Hydrogeology Report No. 1990/21 (unpublished).

RULES OF RIVER (1998). Water Corporation WA (internal document)

SMEC (2001). Ecological Water Requirements for the Lower Gascoyne River. SMEC Australia Pty Ltd.


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groundwater management strategy · the groundwater resources of the lower gascoyne river are the...

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