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Water - New South Wales - Water Technical Report

Surface and Groundwater Management, Availability, Allocation and Efficiency of Use
New South Wales Technical Report

Surface Water Methodology

NSW is in the midst of implementing a series of major water reform initiatives, which is changing many of the fundamental ways in which water is managed and shared between extractive users and the environment. A key element of the change is the NSW approach of providing an environmental flow share over the full range of flows in rivers. As a consequence of still being in the process of developing many of the initiatives, which is utilising a significant portion of government resources, some of the reporting requirements of the National Land and Water Resources Audit cannot be fully met at this stage.

Where appropriate, links have been provided from the Audit data to the appropriate NSW government Internet site. The NSW government sites are updated on a regular basis.

Definition of Surface Water Management Area

For this Audit, 55 Surface Water Management Areas (SWMA), as designated by the NSW Department of Land and Water Conservation (DLWC), have been adopted as the reporting units for NSW. These surface water management areas largely coincide with the old Australian Water Resources Council (AWRC) basins. The only exceptions are the basins in which major storages are operated by the DLWC and the Barwon Darling management area. The SWMA boundaries are shown in Figure 1.

NSW Surface Water Management Areas

Map of Surface Water Management Area in NSW

In those basins with major storages, the AWRC basin has been subdivided to distinguish between those parts of the basins in which the DLWC controls part of the river system to assure supply (regulated SWMAs) and those parts where it does not (unregulated SWMAs). In a number of the other basins, such as the Hawkesbury-Nepean, the Shoalhaven and the Snowy, significant regulation is carried out by other agencies but these basins have not been included in the DLWC regulated category. All other catchments where no major storages exist are also regarded as "unregulated" SWMAs.

The boundary of these regulated SWMAs has generally been obtained by buffering the main stream downstream of the storages and including major irrigation areas and districts and areas of major groundwater usage. It has been assumed that there is little or no contribution to resources from these regulated areas.

The regulated SWMAs include the Murray-Riverina, Lower Darling, Murrumbidgee, Lachlan, Macquarie, Namoi, Gwydir and Border Rivers within the Murray -Darling basin, and the Bega, Hunter and Richmond Rivers in coastal NSW. The DLWC has also defined the Barwon Darling River between Wilcannia and Mungindi as a separate SWMA to distinguish between the specific management of the water resources in this area and other unregulated flow areas.

Because of the very different available resource, water use and management rules for regulated and unregulated SWMAs they have been treated separately in the Audit and for many sections of this report these two types of management areas are reported on separately.

There are also several SWMAs in NSW where only part of the total AWRC basin is in this state. For these areas (distinguished by SWMA Name then (NSW Part Only)) the data and reports in the Audit have been restricted to include NSW's contribution only.

Compilation of Surface Water Use Data

Regulated SWMAs

Estimates of Level one water usage and mean current use have been provided for all regulated SWMAs. However, the source and methods used to derive these figures differ between management areas. Although the methods vary, in all cases the best estimate of current usage has been provided. The source of all current use data is the DLWC, except where otherwise stated.

All regulated usage in NSW has been metered since at least the early 1980s. However, due to growth and climatic variability, metered usage does not necessarily give the best estimate of the level of water that can be used in an SWMA under current conditions. In order to account for these factors and to adequately address current water management in NSW, it has been necessary for the DLWC to develop simulation models that are capable of modelling water quantity in an integrated manner. The DLWC has developed monthly and more recently, daily simulation models to meet this need. The later models, which operate on a daily time-step, are known as Integrated Quantity/Quality Models (IQQMs). The Department has IQQMs for most of the major regulated SWMAs in NSW and the Barwon-Darling.

Using these hydrologic models, the DLWC has begun defining the volumes of water that can be extracted from each of its regulated SWMAs with the water reform management practices in place. These models have therefore been used to provide a more accurate assessment of the long-term average usage under current conditions. Actual metered usage has only been provided where simulation models are unavailable. The following is a summary of the methods used:

The best estimates of usage under current conditions that NSW can provide are derived from simulation models that are capable of producing a long-term sequence of annual use (about 100 years) based on the current level of development and current management rules. The average usage produced from these models takes into account the full range of climatic extremes and resource availability that is likely to influence current usage. As indicated in Table 2, these models were used to derive the mean annual use for the six of the regulated SWMAs. These models were also used to derive the Level 1 annual usage data for four of the regulated SWMAs.

For some regulated SWMAs a simulation model is available, but only for producing a long-term sequence of annual use (about 100 years) based on the Murray Darling Basin Ministerial Council (MDBMC) Cap development and MDBMC Cap management rules. In most cases this level of usage is similar to that likely under current conditions. The average usage produced from these models takes into account the full range of climatic extremes and resource availability that is likely to influence the MDBMC Cap level of usage. As indicated in Table 1, these models were used to derive the mean annual use and the Level 1 annual usage data for the four of the regulated SWMAs.

For those SWMAs where a model was not available, it was necessary to use actual metered usage data to estimate current usage. Five years of annual level 1 usage data from 1992/93 to 1996/97 has been provided for these areas. The mean annual use provided is simply the mean of these five years of data. This data is limited by the fact that it is unlikely to take into account the full range of climatic extremes and resource availability that are likely to influence current usage. Unfortunately the long-term annual sequence from the simulation models used for both the Hunter and Gwydir were not available. Therefore, the Level 1 annual usage estimates provided for 1992/93 to 1996/97, represent actual metered usage.

Summary of the methods and sources of usage data

Method & Source of Usage Data
Simulation Model based on the current level of development and current management rules Simulation Model based on the MDBMC Cap level of development and MDBMC Cap management rules Actual Historical Metered Usage

Mean Annual Use

Current Conditions

Murrumbidgee (410.R)

Lachlan (412.R)

Macquarie (421.R)

Namoi (419.R)

Gwydir (418.R)

Hunter (210.R)

Murray (409.R)

Border Rivers (416.R)

Lower Darling (425.R)

Barwon-Darling (499)

Clarence (203.R)

Bega (219.R)

Surface Water Use

Annual Current Use for each of the five years from 1992/93 to 1996/97

Murrumbidgee (410.R)

Lachlan (412.R)

Macquarie (421.R)

Namoi (419.R)

Murray (409.R)

Border Rivers (416.R)

Lower Darling (425.R)

Barwon-Darling (499)

Clarence (203.R)

Bega (219.R)

Gwydir (418.R)

Hunter (210.R)

In addition, the following points about the usage data provided for NSW need to be noted:

Unregulated SWMAs

Water usage data is not available for any NSW unregulated SWMAs. Usage within these areas is not yet metered and the DLWC ceased the collection of the types of data that can be used to estimate usage on these rivers, by way of user surveys, in 1994/95.

NSW has taken the approach that it is better to await the availability of reliable and realistic usage estimates than to divert limited resources to the calculation of usage estimates using unreliable information. Also NSW has begun a process of converting licences on these rivers from an areal basis to a volumetric basis. Meters will be installed to monitor usage on these rivers as part of this volumetric conversion process.

In the SWMAs which provide major urban water supplies, such as the Hawkesbury Nepean, Shoalhaven and Williams (part of the Hunter) Rivers, the urban use is based on metered diversions. Sydney's water use occurs in three surface water management areas (212, 213 & 214). However, water usage for the city of Sydney could not be subdivided to represent the use in each of these SWMAs. Therefore all water use for the city of Sydney is entered for SWMA 212. The source of this data is Sydney Water and the Sydney Catchment Authority.

Compilation of Surface Water Allocation Data

Regulated SWMAs

The allocations provided for all regulated SWMAs are reported as the sum of all licensed entitlements associated with each category of use.

NSW does maintain a record of historical allocation levels. However, this information was not provided for the Audit, because it cannot be directly compared to the mean current use Level one water usage and mean current use provided using the DLWCs models.

A brief overview of the entitlement and allocation arrangements that apply in NSW is provided below.

All water users on the regulated rivers of NSW, are issued with a water licence that specifies a maximum volume of water that may be extracted, referred to as the licensed entitlement, and the purpose(s) for which the water may be used. . Entitlements are defined as either General Security or High Security or a component of both, depending on the purpose of use.

High Security licences will receive their full entitlement each year, unless inflows below the minimum historical sequence occur. A General Security allocation is announced each year, expressed as a percentage of the General Security licensed entitlement, that can be extracted during that water season. For example, a 100% allocation indicates that a user has the opportunity to use their full entitlement. The annual allocation will differ from Basin to Basin, depending on the availability of water in the system.

A resource assessment process is undertaken by the DLWC periodically to determine the available resources for general security licensees. This process assumes that inflows for the remainder of the water year will recede towards the historical minimum from the time of assessment. From the available resources (water in storage and expected inflows), resources are set aside for high security entitlements, evaporation, environmental requirements including end of river system flows, river system transmission losses including stock and domestic needs, and a minimum storage reserve volume. The remaining resource is shared between the "general security" users in proportion to their entitlements.

During the water year, as resources improve, the allocation to general security users may be increased. In most basins the announced allocation is limited to a maximum of 100%. When the dam spills or tributary inflows below the dam are assessed to be in excess of downstream requirements, general security licence holders may also be permitted to extract water as "off allocation". Access to "off allocation" is in addition to the announced allocation for general security users. In response to the Murray-Darling Basin cap, an annual limit has been placed on the total volume of off-allocation that can be diverted from each of the regulated basins, and no high security users are permitted to extract supply as off-allocation.

Unregulated SWMAs

NSW does not have allocation (entitlement) data for the unregulated SWMAs. Historically, licences issued within these areas have simply specified an area authorised for irrigation, maximum pump capacity and purpose of use.

NSW has begun the process of converting licences on these rivers from an areal basis to a volumetric basis. Allocations will only be available for these management areas once the volumetric conversion process has been finalised. See the further explanation in the Management, Principles, Goals and Objectives section.

Sydney City's water supply (allocation) comes from three surface water management areas (212, 213 & 215). However, the total allocation for the city of Sydney could not be subdivided to represent the volume supplied (allocated) in each of these SWMAs. Therefore the total volume of water allocated for use for the city of Sydney is entered for SWMA 212. The source of this data is Sydney Water and the Sydney Catchment Authority.

Hydrological Characterisation

Where possible, the location of all known gauging stations within the SWMAs have been made available. This includes stations operated by Authorities other than the DLWC. However the recorded streamflow data provided was obtained from the NSW state archive managed by the DLWC from sites operated by the DLWC. Data from other organisations has not been included.

Data was made available at key stations only. This data was restricted to those sites where data availability was typically at least 30 years in length and/or where the data contained at least one major wet and dry decade and/or where there were no other sites available which met the first two criteria.

Where naturalised flows were provided they were obtained from two sources. The natural flow sequence was either simulated using an Integrated Quality Quantity Model (IQQM), or it was simulated using a Sacramento rainfall-runoff model. Within the IQQM system, inputs are routed through the model assuming no infrastructure and no irrigation demands. The Sacramento model routes rainfall data through a rainfall/runoff model calibrated over periods of little or no water abstraction, either in that catchment or in a hydrologically similar catchment, and is used to extend or create natural flows.

Rainfall data was also supplied for most sites where streamflow data was supplied. The rainfall data was obtained from either the DLWC operated raingauges at the gauging station or from Bureau of Meteorology rain gauges close to the stations.

Mean Annual Flow and Mean Annual Outflow

Inland

The Mean Annual Flow (MAF) for the SWMAs in the Murray Darling Basin have been determined as the natural flow at a representative site at which the majority of the tributaries have contributed flow to the main stream and the flow is at it's highest. After this point ,typically, major extractions, losses and diversions occur, which reduce estimates of basin discharge. This MAF is assigned to the unregulated SWMA section of the basin as this is where the runoff is produced.

The water from the unregulated SWMA above regulated SWMAs does not exit the basin, rather it is passed through as an inflow to the regulated SWMA below it. Accordingly the Mean Annual Outflow (MAO) for these unregulated SWMAs has been set to zero and the outflow from the basin is attributed to the regulated SWMA.

For the sake of simplicity and because it is almost impossible to accurately determine what portion of flow originates from within the regulated sections of these basins, the MAF in the regulated SWMAs has been set to zero.

The Mean Annual Outflow (MAO) for a bsin for an inland stream is generally considerably less than the Mean Annual Flow in the basin. Below the point where the MAF is measured, significant losses occur. These losses include water stored in billabongs, ephemeral lakes, wetlands, etc; the increased infiltration and evaporation as water is spread through the many braided and efffluent streams; the losses as natural and man-made channels take water away from the main stream and major irrigation demands.

Generally the Mean Annual Outflow is estimated by summing as many of the outflows from the system as possible. Occasionally this may be a single main stream site but more typically includes several sites on the main stream, flood runners and/or effluent streams. These values will generally be skewed by the poor quality of high flow measurements at these outflow locations due to the number of ungauged flood runners and the extent of the flood plains.

Coastal

Most of the rivers and creeks in the coastal valleys are unregulated, ie there are no major storages to control flows and therefore most water users rely on natural flows or small structures for their water supplies. The only exceptions are those with several major storages namely the Hunter and the Hawkesbury-Nepean Basins.

However, the flows in the streams in these coastal catcments may still have been affected to some extent by developments in the catchment (ie urbanisation, changes in land practices, clearing, etc) and developments in the town water supply, hydroelectric dams, and weirs.

The infrastructure presently in place along these unregulated streams typically does not have the potential to take large proportions of medium and flood flows. As in most unregulated rivers, flows are only likely to be adversely affected during relatively dry times when water is low and demand is high

So in most coastal basins practically all of the basin contributes to MAF. This means that MAF for the basin should be calculated by summing the recorded flow from all streams entering the ocean. However, as the flow at the mouths of such streams are tidal it is not possible to obtain an accurate measure of the flow. Typically gauging stations are situated some distance upstream in non-tidal areas.

Accordingly the discharge from the lowest non tidal stations are summed and this combined flow is then scaled up by the ratio of the areas.

Combined flow * ( Catchment area for Flow)

MAF = --------------------------------------------------

(Total Catchment Area)

Where a large concurrent period of record was not available the MAF at the shorter stations was adjusted using the ratio of the MAFs of the long term station for the equivalent periods of record. For example with 2 sites:

Site 1 - long term site with records from 1949 to 1999

Site 2 - shorter term site with records from 1952 to 1985

Site 2 MAF (52-85) * Site 1 MAF (45-99)

Site 2 MAF (1945-1999) = ----------------------------------------------

Site 1 MAF (1952-1985)

In the coastal regulated basins the mean annual flow is at the outlet of the management area. The MAF and MAO are equal.

Developed Yield

Regulated SWMAs

The NSW Water Reforms, which are currently being developed and implemented by the NSW Government, are aimed at improving water management within the state. By managing water in a more sustainable manner it is hoped that a better balance between the environment and consumptive use of water can be achieved.

In order to adequately address current water management in NSW the DLWC has developed monthly and more recently, daily simulation models that are capable of modelling water quantity in an integrated manner. The later models, which operate on a daily time step are known as Integrated Quantity/Quality Models (IQQMs). The Department has IQQMs for most of the major regulated SWMAs in NSW and the Barwon-Darling.

Using these hydrologic models, the NSW DLWC has begun defining the volumes of water that can be extracted from each of its regulated SWMAs with the water reform management practices in place. Further details of these practices, in particular, those associated with the MDBMC Cap and environmental flow rules are provided below (See the Note in this section).

Unfortunately, these management practices do not correspond directly to the concept of annual yields, as defined for this audit. NSW has still provided an assessment of the yields, where possible, by attempting to align it's current management practises with these concepts.

As a result of the MDBMC Cap and water reforms, no further headwater storage development or issues of licensed entitlements is proposed for the Murray-Darling Basin. For the purposes of the audit, the ultimate level of development has therefore been taken to be equivalent to the MDBMC Cap level of development. As such, NSW considers the divertible yield and developed yield to be equivalent. Furthermore, the range of environmental flow rules that have been introduced to most of the regulated SWMAs within the Murray-Darling Basin result in long-term average diversions (or yield) below the MDBC Cap levels. This yield has been taken to represent the current best estimate of sustainable yield. The sustainable yield for those regulated valleys within the basin that do not have environmental flow rules implemented has been assumed to be the MDBMC Cap yield.

Summary of Definitions

FLOW As Defined for the AUDIT NSW -Adopted
MAF max basin flow max basin flow
Divertible Yield Flow assuming all licenses are fully utilised No further growth in yield is possible due to MBDMC CAP
Developed Yield Current level of development So: Divertible = Developed = MDBMC Cap yield
Sustainable Yield Long-term viable levels Current yield in valleys with EFRs or yield under MDBMC Cap

Where available, a hydrologic model was used to estimate the various yields. The model which was developed by the DLWC, was run with MDBMC Cap or 1993/94 conditions of infrastructure development and 1993/94 management rules in place to represent the divertible and developed yield. For the valleys where environmental flow rules have been implemented, the model was run using an estimate of current development conditions and management rules to determine the sustainable yield. The yield was taken to be the average annual diversion over the full period of record (generally about 100 years). This annual diversion includes both on-allocation and off-allocation use. It should be noted that this yield might change as models are updated and further climatic input becomes available.

NOTE - ADDITIONAL BACKGROUND AND SUPPORTING COMMENTS ON THE METHOD USED TO DEFINE THE DEVELOPED, DIVERTIBLE AND SUSTAINABLE YIELD

Current Management in NSW Regulated Rivers

In response to issues raised by the report "An Audit of Water Use in the Murray-Darling Basin" published in 1995, The Ministerial Council decided to introduce a Cap on diversions of water from the Basin. The Cap is defined as the volume of water that would have been diverted under 1993/94 levels of development and management rules.

As part of its role in managing the Cap in NSW, the NSW Department of Land and Water Conservation has developed a set of Cap management rules. These rules include limiting the total amount of water available in a valley in any given year by restricting the level of on-allocation and/or off-allocation access and/or the introduction of carryover using a Continuous Accounting allocation system. The NSW Department of Land and Water Conservation uses these rules where necessary to help ensure Cap compliance across the State.

When introduced in 1995, the Cap was seen as a necessary first step in the evolution of a more sophisticated method of land and water management that preserves the sustainability of both the environment and the communities that depend upon the water within the Murray-Darling Basin.

The Cap remains as a permanent feature of water management in the Basin. However, the NSW government is also well along the path of developing what it considers to be more sophisticated methods of management that aim at overall sustainability.

As part of this process, the NSW Government facilitated the establishment of community based River Management Committees (RMC's) for most of the regulated SWMAs across the State and the Barwon-Darling. These committees were charged with the task of recommending environmental flow objectives and associated management rules. A comprehensive set of Environmental Flow Rules (EFRs) were introduced in the Gwydir, Namoi, Macquarie, Lachlan, Murrumbidgee, Hunter and Barwon-Darling River systems for the first time in 1998/99.

In the short term, as part of its broader role each of the committees will monitor the impacts of these rules on the environment, the social and economic fabric of a valley and subsequently recommend any appropriate flow modifications. Following five years of experience in the development of flow rules, the Government will establish long term river flow objectives for each regulated valley in NSW, which will be referred to as River Management Plans (RMP's).

The EFR's together with current management rules are expected to result in long term average diversions that are below Cap, in all basins except the Barwon-Darling. The Hunter River is not subject to the MDBMC Cap. The collective impact of the rules will not exceed 10% of the long-term average water diversions under the benchmark level of development (that is, 1993/94 as required for the MDBMC cap) in any of the regulated SWMAs and the Barwon-Darling. The ability of these rules to bring long term diversions to below 1993/94 levels is based upon the assumption that future infrastructure development remains at current levels. Consequently, the NSW Department of Land and Water Conservation and the RMC's will review these rules in the light of any identified changes to infrastructure development, to ensure that the benefits of the environmental flow rules are protected.

Unregulated SWMAs

In mid 1997, the Government announced a series of water reforms which included the release of a discussion paper A Stressed Rivers Approach to the Management of Water Use in Unregulated Streams.

The stressed rivers approach recognises that environmental circumstances and also economic, social and equity factors vary significantly between catchments even in the same basin. Common rules and actions across all streams could result in either unnecessary hardship in some catchments or, conversely, inadequate environmental protection in others. On the other hand, the resources and time needed to evaluate each stream individually and develop appropriate management strategies would be enormous.

The stressed rivers approach, therefore established a consistent and transparent rationale for the future management of all unregulated streams while allowing for different priorities and policies depending on the circumstances of each catchment.

The critical period assessment method only focuses on the status of rivers in drought periods and the management strategies and actions required to address sustainability at that flow range, thereby ignoring the importance of floods and high flows to ecological sustainability. However, NSW's series of performance measures, strategies and management actions are designed to cover the full flow range within rivers. As a consequence of adopting these sustainability management strategies the total flow regime within rivers is to beprotected and the concept of critical period based performance measures has become redundant in NSW. Determination of yield and usage figures for a defined critical period is difficult for NSW to produce due to lack of the appropriate modelling tools and to a lack of current metering and/or water usage data. Therefore the developed yield has not been calculated for the unregulated basins in NSW.

Please refer to the Stressed Rivers Report(s) on the NSW Department of Land and Water Conservation's website www.dlwc.nsw.gov.au for further information on management practices in these unregulated SWMA's.

Divertible Yield

Regulated SWMAs

NSW has made its assessment of the divertible yield on the basis that it is equivalent to the developed yield, both of which are limited to the level of diversions available under the MDBMC Cap.

In the Murray-Darling Basin no further public storage development is proposed. Please refer to the comments for made for the 'Developed Yield' for a full explanation of the methods used to derive the divertible yield.

Unregulated SWMAs

NSW is introducing volumetric licenses for the management of unregulated SWMAs. The first stage is to determine the total volume that must remain in the river at various locations so that, access by existing users downstream will not be reduced below a reasonable limit, and protect downstream river health. The divertible volume that can be extracted upstream of each location is the difference between the natural flow and the total flow that must remain in the river. This divertible volume will be determined for three flow access categories. This approach is illustrated at Figure 2.

This information is not available. Divertible yields will not be calculated for the unregulated basins in NSW.

Please refer to the Stressed Rivers Report(s) on the NSW Department of Land and Water Conservation's website www.dlwc.nsw.gov.au for further information.

Classes of Daily Flow Share

Graph of Classes of Daily Flow Share

Environmental Flow Requirements

Regulated SWMAs

The environmental flow requirement at each reporting location in the river is the total flow in the river at that location for current Water Reform management and infrastructure conditions.

In setting the environmental flow requirements for regulated rivers in the NSW Water Reform, it has been recognised that the flow at each location in a SWMA is used to satisfy both downstream diversions as well as environmental needs. In addition, in setting environmental flows the whole flow regime over the full length of the river have been considered, and not confined to the low flow regime. Consequently the management rules that been adopted in each SWMA as part of the Water Reform process, are the result of balancing the environmental and diversion needs of each SWMA at various location in the SWMA below the dam(s). This balance has regard to the need to provide additional water for the environment, as well as limiting the reduction in diversion by existing users.

Unregulated SWMAs

The approach of recognising that the flow required at any location in a river services both downstream diversions and environmental needs has also been applied in unregulated rivers.

The environmental flow requirement at each reporting location in the river is the total flow in the river at that location for current Water Reform management conditions.

Sustainable Yield

Regulated SWMAs

Where available, a hydrologic model was used to estimate the sustainable yield. The model, developed by the DLWC, was run with current levels of infrustructure and current Water Reform (MDBMC Cap plus Environmental Flow Rules) management rules in place. The sustainable yield was determined to be the average annual diversion over the full period of record for the climatic input data (generally about 100 years). This annual diversion includes both on-allocation and off-allocation use. It should be noted that this yield may change as models are updated.

The understanding of the links between flow and sustainability of river ecological systems is still developing, and it is recognised that ecological sustainability can be affected by other factors than quantity and timing of flow. Therefore, the sustainable yield provided cannot at this stage be considered as the amount of water that can be diverted from rivers in perpetuity. The NSW Water Reform initiatives recognise this fact and current management rules for water sharing in each valley only apply to the 2001/2002-water year. At that time government and SWMA community groups, in the light of environmental conditions and performance of the current rules, will reassess the management rules.

Unregulated SWMAs

NSW is introducing volumetric licenses for the management of unregulated SWMAs and is currently collecting a wide range of data in unregulated SWMAs.

The sustainable yield concept, ie the amount of water that can be diverted from rivers in perpetuity, is recognised in NSW. However NSW's current management practices views the sustainable yield as an allowable daily extraction volume as opposed to an annual yield figure. As well, future reviews of the performance of the management rules to be adopted in each SWMA plus additional knowledge at that time may result in changes to the rules and hence changes to the "Sustainable Yield".

NSW has taken the approach that it is better to await the availability of data on the unregulated basins based on reliable and realistic analysis than to divert limited resources from this process to provide data based on unreliable information. Accordingly the Sustainable Yield has not been calculated for the unregulated SWMAs in NSW.

Please refer to the NSW Department of Land and Water Conservation's website www.dlwc.nsw.gov.au for further information.

Categorisation

Regulated SWMA

Each of the regulated SWMAs in the Murray Darling Basin has been categorised as category 4 basins. The Murray Darling Basin as a whole is considered overdeveloped and the category of the individual SWMAs should not be considered outside of this basin framework. The regulated SWMAs in the coastal basins have not been categorised as the development rules for these coastal regulated areas are currently under review.

Unregulated SWMAs

NSW is introducing volumetric licenses for the management of unregulated SWMAs and is currently collecting a wide range of data in these areas.

Each of the AWRC basins has been divided into a series of sub-catchments as shown in Figure 2. These some 650+ sub catchments are the new management units for the DLWC. Assessments of hydrological, environmental, conservation values and future risk have been combined for each of these sub-catchments to obtain an overall stress classification. Where this data has been available the Please refer to the NSW Department of Land and Water Conservation's website www.dlwc.nsw.gov.au for further information about the the stressed Streams Assessments for individual basins and sub catchments.

NSW Stressed Streams Sub Catchments

Map of NSW Stressed Streams Sub-Catchments

However an attempt was made to obtain a categorisation for the use in each SWMA based on the work done for the stressed streams. A variable P was determined for the total catchment on the basis of the combined stress classsification results from the stressed streams analysis

Total area of sub-catchments with high combined stress

P = Total area of classsified sub-catchments in basin

Categorisation was on the basis that:

Category 1 applies for 0% <= P < 30%

Category 2 for 30% <= P < 70%

Category 3 for 70% <= P <100%

Category 4 for P = 100%

Management Goals and Objectives

As part of the NSW Water Reform, water quality and flow management goals and objectives have been developed under the following principles:

Objectives

In developing and applying new water management rules as part of the Water Reform agenda recognition has been taken of the need to balance environmental, social and economic need in the use of water.

Water management committees in developing their water management plans will use the following objectives as guidelines.

1. Interim River flow objectives are to:

2. Water quality values used to maintain water quality are to protect:

3. Social objectives are broadly to:

4. Economic objectives are broadly to:

Goals

The goals of the NSW Water Reforms are:

Goal 1 - To better share the available water

Goal 2 - To enhance support to the rural water sector

Goal 3 - To reshape how water management is delivered in NSW

The Water Reform strategy is being implemented through a series of programs to address each goal

Goal 1 - Better Water Sharing

Program 1 - Sustainable outcomes for regulated rivers

The regulated rivers and the Barwon Darling management committees to prepare annual flow management plans, setting out the flow rules and operational procedures for the year. The committees report annually to the Minister for Land and Water Conservation, and the Minister for the Environment.

Revised water sharing arrangements/rules have been adopted for each regulated river in NSW, which commenced in 1998/99 and apply initially until 2001/02. These rules were designed to achieve adjustments in the flow regime, which will deliver environmental improvements or rehabilitation. The rules were the result of a whole of government assessment, with review and modification by community-based river management committees.

NSW remains committed to the Murray-Darling Basin cap.

The committees are to prepare water quality plans closely linked to the river flow rules over the initial five-year term of resource security.

The committees are to develop locally agreed water quality strategies for implementation from 2000.

The committees are to progressively integrate flow rules, monitoring, water quality plans, and socio-economic studies into a comprehensive management plan for their river valley by 2003.

The Water management plans are then to progressively incorporate other supporting plans e.g. for licensing, compliance, and operations.

The water management plan development phase will be used to more clearly define the status of water management plans and their relationship to other regional natural resource management strategies eg. Regional Natural Resource and Environmental Management Guidelines.

Program 2 - Establishing environmental objectives

For regulated and unregulated rivers, the interim water quality and river flow objectives will form the basis for the planning processes for the water management committees.

These interim environmental objectives will become finalised throughout the water plan development phase and then formalised by the Government adopting either Healthy River Commission's recommendations or a water management plan.

By the end of 1999, the Healthy Rivers Commission will have conducted and reported on its inquiries into the Bega, Hunter, Shoalhaven, Clarence, Woronora and Tweed Rivers, in addition to the Williams and Hawkesbury-Nepean Rivers.

Auditing of water management plans to meet river flow and water quality objectives will occur regularly by a process coordinated by the EPA

Program 3 - Sustainable outcomes for unregulated rivers

Catchment-based reports on the State's stressed and high conservation unregulated rivers have been completed. These reports will be reviewed and used by unregulated river management committees as a basis for river management planning.

The unregulated river management plans will provide for long term sustainability as well as a defined period of resource security for river users. The plans will cover ecological needs, broadly define access conditions and the local rules for trading. They will progressively integrate flow rules, monitoring and water quality plans and socio-economic studies.

Management plans for the most highly stressed and some high conservation value unregulated rivers will be prepared by 2001.

Plans for other stressed and high conservation unregulated rivers will be finalised by 2003. It is expected that, by 2005, all major unregulated rivers in the State will have management plans in place.

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Goal 2 - Enhancing Support to the Rural Sector

Program 4 - Providing investment confidence (Check numbering)

The implementation and management of the first term of resource security for regulated rivers and the Barwon-Darling will continue to end of 2000/2001-water year.

For all other water sources the water planning process will provide an initial 5-year period of resource security. Within this period the flow/extraction rules can only be changed by the consensus decision of the water management committee, and within the context of river flow and water quality objectives.

For licensed water users, necessary legislative and other amendments will be prepared to make fundamental changes to the Water Act. If there is support for the concept of separating water access and use rights then this will be incorporated. To enable informed decision-making a trial separation will be carried out in one or more SWMAs.

The term of water licences and their review period. Draft legislation for new licence terms and the review of licence conditions was issued for public comment in early 2000.

Based on the Farm Dams Policy, the harvestable right has been determined as well as its relationship to the Murray-Darling cap.

To address the issue of riparian rights, it is proposed to analyse the responses to the Water Sharing discussion paper, and prepare a policy options paper for the Water Advisory Council (WAC) in 1999. The objective of the Farm Dams Policy is to modify the 7 megalitre dam criterion, but further action will be required on the river pumping component.

To address the issue of floodplain harvesting, it is proposed to analyse the responses to the Water Sharing discussion paper a policy options paper will be released publicly, after consideration by WAC. The paper will identify the extent of floodplain harvesting including use of channels and billabongs, and where and why it is a particular issue. By the end of 2000 state-wide principles for management of floodplain harvesting will be in place and water management committees will advise on the local application of these principles.

To address the issue of sleepers, dozers and ghosts, as well as analysing the responses to the Water Sharing discussion paper it is proposed to:

for stressed unregulated rivers - consider sleepers and dozers in the context of volumetric conversions and constraining factors such as the Murray-Darling Basin cap and reliability impacts on regulated river licences

introduce or extend trading in groundwater and unregulated systems, once primary allocations are confirmed.

Volumetric conversions will be undertaken where economically justified for area-based unregulated licences. The conversion methodology and process for conversions are outlined in a separate document, available from all DLWC offices

The recommendations emanating from the current DLWC consultancy on water trading will be reviewed and an implementation plan for accepted recommendations developed in 1999. Opportunities for intervalley and interstate trading will be actively considered, within appropriate environmental, social and economic constraints.

An electronic Water Trading Information System will be developed in conjunction with the MDBC.

Program 5 - Providing government support

In 1999 final agreements will be reached on the details of cost sharing and implementation of the Land and Water Management Plans (LWMPs) and other investment activities for Coleambally, Murrumbidgee, Western Murray Irrigation, Jemalong and Hay Irrigation Areas.

In DLWC's Country Towns Water Supply and Sewerage program:

$590 million will be spent over the next 10 years on backlog works

$150 million will be spent over the next 10 years on small town sewerage

the Water Demand Management Manual will be published by mid 1999

integrated water, sewerage and stormwater strategies will be prepared for two pilot projects

the Water and Sewerage Infrastructure Delivery Options report will be finalised in early 1999,

annual reports will be issued on water supply and sewerage performance comparisons.

There will be a continuation of the Government's $60 million Stormwater Management Program containing two key initiatives aimed at improving urban stormwater management practices. The Program, with funding for three years from 1998, calls for local councils to prepare catchment-based stormwater management plans and provides a grant program that encourages partnerships between councils and the private sector to implement innovative, cost-effective stormwater management technologies.

There will be continued implementation of the five year (1998 to 2003), $33.5 million Structural Adjustment Program, including $25.5 million for the Irrigated Agriculture Water Use Efficiency Program (for areas outside LWMPs or not previously subject to irrigation funding grants).

The NSW Estuary Management Program will continue to provide subsidies for committees to prepare plans for the sustainable management of estuaries. These plans will need to also address how the interim water quality and river flow objectives can be met.

Regional strategies for natural resource and environment management will be developed in 1999. These strategies will be based on the regions used to establish the "one stop shop" community grants program which has operated since 1993 and will incorporate Salt Action, Rivercare and National Heritage Trust grants.

Existing natural resource management priorities will be taken into consideration where there are requests for NSW Government funds to be used to match external grants.

Program 6 - Ensuring balanced cost sharing

NSW will continue to strive to comply with the COAG Strategic Water Reform Framework's goals and timeframes, including progression towards, and achievement of specific objectives relating to water pricing, by 2001. This includes adopting consumption based pricing principles, adopting full cost recovery principles, removal of (or making transparent) residual subsidies, disclosure of community service obligations, and achieving a positive real rate of return on assets.

Bulk rural water prices in NSW continue to be set by the Independent Pricing and Regulatory Tribunal (IPART).

Bulk rural water prices set by the 1998 IPART determination will be implemented in 1998/99 and 1999/2000. For both surface and groundwater the new pricing structure reduces cross subsidies, reduces government subsidy and commences a path to recovering IPART's determined efficient level of costs. During those two years the government share of costs (including subsidy) will still amount to over 50% of total bulk rural water costs.

DLWC will implement a suite of initiatives to address all of the recommendations contained in the 1998 IPART determination. This will include a program of cost minimisation, greater customer consultation, better cost and performance information, clearer explanations of resource management costs and more detailed pricing policy assessment. Pricing structures will be reassessed to ensure that costs better reflect the security of supply, that wholesale and industry charges are appropriate and that differential charges for unregulated water are appropriate.

DLWC will prepare annual compliance reports for IPART to clarify cost information, approaches to cost recovery definitions (including cost sharing between user groups, and the treatment of capital costs) and to provide performance monitoring information.

Future investment in infrastructure will be based on economically viable and environmentally sustainable propositions for the State. There will be prior agreement to cost and benefit sharing arrangements for any public and private investment partnerships.

State Water will establish customer committees in early 1999. One of the roles of the committees will be to review total current and future costs of rural bulk water, asset management plans, proposed prices and tariff structures, and to ensure that efficient service levels are negotiated with the users receiving those services annually.

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Goal 3 - Reshaping How Water is Managed

Program 7 - Enhanced community/government partnerships

The existing water management committees will be supported to improve decision-making, with membership being reviewed 5 years after appointment.

Further unregulated river management committees will be set up for the Lachlan, Macquarie, Manning/Karuah, Central Coast and Murray in 1999.

Additional committees will be set up for: Shoalhaven in 1999; Cooks River/Georges River/Botany Bay, Port Hacking River/Woronora River and Urban Streams in 2000; and the Sydney Northern Beaches in 2001.

Continued support for committees will be by way of: Executive Officers; necessary information and data -including biophysical, socio-economic and operational; training; and financial resources for sitting fees, travel and administration costs.

The Support Package documentation for committees will be reviewed and upgraded in 1999, and then on a yearly basis to ensure that committees have up to date information when developing their water management plans.

WAC will continue to assist in major policy development and will review water management plans for quality and consistency, prior to endorsement by Government.

All government agencies involved in the implementation of the water reforms will continue to cooperate to provide on-going whole-of-government solutions and approaches. This will occur via meetings of CEOs of water-related agencies and other interdepartmental coordination mechanisms.

Improved and more effective community consultation mechanisms will be developed, including Aboriginal consultation protocols and programs for people with non-English speaking backgrounds.

Program 8 - Creating efficiencies in government delivery

The management of water extractions by the large metropolitan water corporations will be licensed, like that of other water users. A licence was issued to Hunter Water Corporation in November 1998 and an interim licence will soon be issued to Sydney Water Corporation. These licences will regulate the Corporations' access to bulk water, and establish a range of monitoring and reporting arrangements to ensure compliance.

The water corporation licences will be reviewed initially after 6 months and then every five years. A final licence for Sydney Water will be issued following completion of Healthy Rivers Commission studies into a number of rivers in the Sydney Water area.

DLWC has separated operational water activities into State Water, as a business arm of the Department. By focusing on its core activities, State Water will provide a high level of service delivery to its customers at minimum cost. It will deliver water within clearly defined parameters as to timeliness, price, quantity, quality and environmental criteria and maintain its assets to ensure safety and reliability.

In 1999 State Water will:

establish customer service committees for each regulated system

improve customer management processes to provide timely and accurate water delivery information

implement a customer enquiry plan

develop performance benchmarks for water delivery and asset management in consultation with the customer service committees

complete a major structural safety audit of all dams and weirs operated by State Water, and

develop an asset management system as a basis for costing and priority setting for future maintenance and refurbishment work.

State Water will satisfy competitive neutrality principles by adopting Treasury's requirements for full transparency in costing and full commercial accounting by the end of 2000. This means State Water will effectively operate as a commercial entity with no competitive advantage over the private sector arising from its public ownership.

Program 9 - Improved management processes

The main pieces of NSW water legislation, in particular the Water Act 1912, the Water Administration Act 1986 and the Rivers and Foreshores Improvement Act 1948 will be revised. A Bill that includes all aspects of water management currently covered by these three statutes was released for comment in early 2000. This will be the most fundamental reform of water management legislation since early this century. It will provide a legislative framework for water management that is consistent with contemporary policy directions, including sustainable management and natural resource planning.

The regulatory framework for water management will be developed to allow more efficient processing of licence applications, renewals and queries. DLWC will analyse the responses to the Water Sharing discussion paper and prepare policy papers on regulatory issues relating to the water licence amnesty, riparian water pumping, floodplain harvesting, volumetric accounting (ie. carryover and continuous accounting) and the management of urban streams.

DLWC will develop and implement a comprehensive compliance management strategy by the end of 1999. DLWC's compliance strategy will be aimed at achieving water user compliance with their licence conditions and it will form part of a broader quality management strategy. It will be regionally focussed and involve education strategies, self-assessment, measuring and audit, and prosecution policies.

The administrative framework supporting DLWC's water licensing functions will be significantly improved by:

the development of licensing procedures manuals by the end of 1999, which will ensure streamlining and State-wide consistency

the linking of the Licence Administration System (LAS), to the financial reporting system to improve the efficiency of billing for water use

the upgrading of LAS to allow more extensive and user friendly queries on an area and sub-area basis, and

the linking of LAS to the Land Titles Office Cadastral Database, significantly reducing the time and effort required to process licence applications and solicitors' inquiries.

Mechanisms to better monitor water usage, including metering, will be improved. This will involve:

the implementation of monitoring programs on unregulated rivers and groundwater systems, starting with the most stressed systems and based on the outcomes of metering trials already undertaken

the implementation in 1999, of specific water extraction monitoring programs for the Hawkesbury-Nepean, Bega and Williams Rivers, and

detailed consultation with water users concerning proposed metering programs.

Program 10 - Other major initiatives

In 1999 the Independent Advisory Committee on Socio-Economic Analysis (IACSEA) will develop a set of principles to guide water management committees in their consideration of regional social and economic objectives.

Community Water Profiles will be prepared (based on the Macquarie pilot project) by water management committees to support their determinations, assist them in prioritising detailed impact assessment studies and provide a baseline from which changes in water user groups can be assessed in the future. Preliminary Community Water Profiles for the regulated river management committees will be prepared in early 1999 and updated over time. Other Community Water Profiles will be developed as other committees' form.

Processes will be put in place to ensure that water management committees identify social and economic impacts in the course of developing options for management rules. IACSEA will continue to provide ongoing advice to water management committees on proposed analyses to ensure that they are consistent with established principles.

DLWC has commenced two programs to monitor the effect of the new environmental flow rules. These programs will improve the base environmental data DLWC and community groups need to make resource planning decisions:

The Integrated Monitoring of Environmental Flows Program (IMEF) will encompass biological, physical and chemical parameters. The initial components of the monitoring program started in October 1998 and the program will be fully operational by June 1999. Similar monitoring programs for the Murray and Border River systems are currently being discussed through the MDBC and the Border Rivers Commission, and

State of the Rivers and Estuaries Reports will be completed for each catchment across the State every 5 years as part of a rolling program. These will provide an initial benchmark for each region and thereafter an environmental report cards. Reports for the Murrumbidgee and Lachlan have been completed. Reports for the Murray, North-West (Namoi, Border Rivers and Gwydir) and Hunter, Karuah and Manning, the Far North Coast, Far West and Far South Coast will be completed in 1999.

Recognising the need for a consistent approach to water monitoring and to avoid duplication of government effort, the Government established the State Water Monitoring Co-ordination Committee, which is chaired by the EPA. The Committee is developing a state-wide strategy, which will be finalised in 1999.

The NSW Water Conservation Strategy, which will include a set of recommendations on how Government can optimise, co-ordinate and strengthen existing water efficiency programs, will be released in early 1999. An implementation timetable will be developed for accepted recommendations and various initiatives commenced in 1999.

The NSW Weir Review Committee will complete guidelines and criteria for reviewing weirs, new weir proposals as well as procedures for robust environmental assessments of the impacts of weirs by the middle of 1999. These guidelines will provide a basis for a longer-term strategy in managing weirs. As well, the river management committees will be asked to identify weirs of concern for review. A weir approval process will be developed that will ensure environmental issues are addressed. Removal of unnecessary weirs will be one option.

Full details of the Water Reform strategy, specific initiatives and progress are at the Department of Land & Water Conservation web site, www.dlwc.nsw.gov.au/

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Groundwater Methodology

Definition of Groundwater Management Unit Boundaries

Thirty Groundwater Management Areas were defined in NSW in during the period 1980 to 1990. A description of the system of groundwater management areas and their subdivision into zones, with a map of each of them was published in Ross (1990). Of these, 22 were in alluvial aquifers, and 21 of them have been included in the list of NSW Groundwater Management Units for the Audit. The one exception is the Border Rivers Alluvium, which straddles the NSW/Queensland border. It has been included with the Queensland part of this alluvial aquifer system for the purposes of the Audit, because the entire system of aquifers in the alluvial deposits of the Dumaresq-MacIntyre catchment is administered by a single entity, the Border Rivers Commission. In the smaller of these GMUs the boundary is defined by the limit of the alluvial deposits, but in the larger ones this was not feasible. In particular, the alluvial GMUs in the Murray Basin (Lower Murray, Lower Murrumbidgee and Lower Lachlan Alluvium GMUs), the Lower Namoi and the Gwydir Alluvial GMUs all occupy part of a much larger body of unconsolidated deposits. The GMUs have been confined, in general, to those parts of the deposits in which water of low salinity is available. Such a boundary is not feasible on a purely physical basis, and the borders were selected as administrative boundaries, which would completely enclose the low salinity aquifers but also some of the more saline parts. This was an appropriate action at the time, but with increasing focus on groundwater management in these areas the boundaries are not always in optimum locations. Consequently, changes to some of the boundaries are either contemplated, or operating in an informal or de facto way. For the purposes of the Audit, the original definitions from 1990 have been adopted.

Groundwater Management Areas had also been defined as described by Ross (1990) in four aquifer systems in sedimentary rock sequences, and four in fractured rock areas. The Great Artesian Basin was defined as one of them, but for the Audit has been subdivided into a number of smaller GMUs according to the boundaries established by the Great Artesian Basin Consultative Council. Some of these are entirely within NSW, and some cross the NSW/Queensland border. The Queensland Department of Natural Resources has prepared material for these GMUs, in cooperation with the GAB Consultative Council. The other sedimentary rock aquifer systems defined by Ross (1990) are the Sydney, Gunnedah and Oxley Basins. All were found to be too large for the detailed management procedures becoming necessary, and smaller GMUs have been established within their areas (see below).

The four fractured rock aquifer Groundwater Management Areas described in the 1990 report were the Orange Basalt, the Young Granite, the Inverell Basalt and the Alstonville Basalt. All were selected as excisions from a larger rock mass, in areas where relatively intense groundwater use was developing or expected to develop.

During recent years, as action on the NSW Water Reforms led to an increasing focus on groundwater management in many areas of the State, new Groundwater Management Areas have been initiated, and more are proposed. The process was boosted by the need, as part of the Water Reform process, to identify aquifers at risk of degradation for various reasons and to formulate groundwater management plans for these areas based on a concept of sustainable yield with a suitable allowance for environmental needs. The risk assessment was reported in DLWC (1998). All aquifer systems defined as being at high or medium risk in that publication and which had any record of groundwater use, was incorporated into the Audit as GMUs. Twelve areas, which had not already been defined and included the 1990 publication, fulfilled this condition. A small number, from which there was no record of any groundwater use but where the aquifer was deemed to be at risk from land use or other factors, were not included.

All areas remaining outside the adopted GMUs, of which there were 41, have been classified as unincorporated areas. There are 8 of them, including the four sedimentary rock aquifers referred to above, the remaining fractured rock areas of the New England and Lachlan Fold Belts and the Olary Fractured Rock Provinces, and the remaining area of the Murray Basin Province.

Groundwater Abstraction

Information about usage is a crucial part of the management of any water resource, but it is widely lacking for the GMUs in NSW. A system of annual reporting of water pumped based on a card to be filled in and returned by licensees, was subject to a number of difficulties and was discontinued several years ago in favour of periodic visits by metering inspectors. This system should produce accurate results where it is implemented but it is a costly process. The financial and personnel resources available for its application, and the cooperation of users, is jointly sufficient only in the more stressed areas for the system to work. Consequently, there is a dearth of abstraction information in most of the GMUs, and estimates based on a percentage of allocation and/or on information and impressions gained by regional staff have been used to derive the volumes recorded for many of them. Usage information, where collected, is referred to the type of usage authorised by the licence. That is, it is classified as being for irrigation, mining, industrial, commercial or municipal use. No subdivision according to crop types is made in relation to water used for irrigation.

Groundwater Allocation

The entitlement to a certain volume of water per year is recorded as part of the licensing procedure. It is generally recorded in, and available from, the DLWC database. Recording of the data tends to lag behind the issue of licences, however, so the database can be out of date. Another issue is that of multiple bores with a joint allocation, a situation which has become common in recent years where several bores share an allocation which has been made for a single property. Complicated, and not always successful, arrangements are necessary in order to prevent double counting, or loss, of some allocations.

The allocation information is in terms of the volume of water authorised for a particular purpose (irrigation, industrial, municipal etc). No information is collected or recorded for the crop type being irrigated by bores with an irrigation allocation.

Selection of Key Monitoring and Major Abstraction Bores

The density of observation bores in GMUs is highly variable. Where there is a large number of such bores, bores which have been referenced in a status report for the GMU or used as calibration points for numerical modelling studies have been selected as key bores. Where there are few bores in a GMU, they have all been used as key bores. For some recently implemented GMUs, where monitoring bores have recently been installed, the data set is too small for a reasonable assessment of the water level trends, so key bores cannot be defined. In these cases, however, there are usually very few observation bores, and it is reasonable to use them all as key bores.

Identification of abstraction bores is not easy because pumping rates are not recorded on the DLWC database. A selection has been made on the basis of annual abstraction, based on a mixture of data extracted from the DLWC database and on local knowledge.

Groundwater Level Change Assessment

Periodic groundwater level measurements in DLWC bores began in about 1970, but one bore reported in the Audit database (from Hunter Water Corporation) has a data record commencing in 1950. Some bores have been abandoned in the meantime, and only those still current at 1998 have been counted. Most of the records are based on monthly, or more recently quarterly, manual readings, but continuous data recording devices are also being used in a number of them. A few reported in the Audit database have been included from surveys conducted in the late 1980s for study of the water level rises in fractured rock aquifers resulting from clearance of native vegetation. There are few readings for these bores. The readings including an initial level from date of construction and licensing, a single reading in the late 1980s from the dryland salinity survey and two or three readings from the late 1990s when the bores were measured again.

Water levels are declining in parts of some of the more intensely used alluvial aquifers. Water level data from fractured rock and sedimentary rock aquifers have not been collected on a regular basis except in a few localities, and it is not possible to generalise from these. Water levels however, are known to be rising in many of the fractured rock aquifers from the dryland salinity surveys referred to above. In large areas of the State, mainly in fractured rock aquifers in unincorporated areas, surveys were conducted during the late 1980s to compare initial water levels in DLWC records, with the water level at that date. These surveys found that water levels, since the time of construction, had increased at an average of up to about a metre per year. Most of the areas in which these rising trends are apparent are in the Unincorporated Areas rather than in the GMUs.

Water levels are also rising in some of the major irrigation areas, generally in the Murray Basin Province, due to use of surface water diverted from rivers. Water levels in these areas have been measured by the DLWC at 6 monthly intervals for many years, but these areas are now the responsibility of the privatised irrigation companies. Many, but not all, are in the Unincorporated part of the Murray Basin Province. There are several thousand of them, and data is recorded and stored locally. They have not been included in the Audit. The rising groundwater level trends attributed to irrigation from surface water diversions do not occur in areas where groundwater is also being used as a source of irrigation water, such as the Namoi and Gwydir Valleys.

Groundwater Salinity Determination

The salinity characterisation for each GMU has been made on the basis of water salinity data available from bores in that GMU. The data comes from both licensed private bores for which a water analysis has been provided, or from DLWC bores from which a sample has been analysed. Data of this nature is available on a broad basis, although there are some problems with recording arrangements in recent years. There are practically no sequential salinity data available. This is one of the more notable deficiencies in the database.

Sustainable Yield

One of the most basic pieces of data required for sensible management of a resource is the quantity of input to a system or "recharge". The "sustainable yield" of an aquifer is almost always considerably less than recharge because of the provision for the environmental needs. Nevertheless, any sustainable yield study will always involve the determination of recharge as a first necessary step.

The following working definition has been adopted:

"SUSTAINABLE YIELD IS THAT PROPORTION OF THE LONG TERM AVERAGE ANNUAL RECHARGE WHICH CAN BE EXTRACTED EACH YEAR WITHOUT CAUSING UNACCEPTABLE IMPACTS ON THE ENVIRONMENT OR OTHER GROUNDWATER USERS"

The actual "proportion" is not specified in this definition. This proportion will change according to each situation and is assigned differently to each aquifer system. An interim sustainable yield figure has been derived for NSW aquifers by applying a "sustainability factor" to estimated recharge. These "sustainability factors" are a proportion of long term annual average recharge. An arbitrary default factor of 70% (ie 30% of recharge is reserved for environmental needs) has been adopted for most cases to date, but as better understanding of groundwater systems is developed, the sustainable yields can be adjusted accordingly. The initial figures are intended to be conservative while bearing in mind that it is most often easier to subsequently adjust Sustainable yield values upward rather than downward. "Sustainability factors" offer protection to the integrity of the groundwater system itself and ultimately all groundwater users including the environment and ensure that neither temporary nor permanent damage to the aquifer system results from overuse.

Sustainable yield values can - and indeed will - change over time as our technical understanding of the dynamics of individual groundwater systems is enhanced as a result of more rigorous investigation and in response to changes in natural and socio-economic realities. In short, this is a commencement of a continuous process of periodic "review and adjustment" of sustainable yield estimates. It follows therefore that a set of sustainable yield figures will reflect a level of understanding that exists at a point in time. Groundwater management committees may change the sustainable yield factor to suit local conditions.

High levels of accuracy in determining sustainable yield require a degree of rigorous study that would take years if not decades to achieve. As many NSW systems are either over-allocated or nearly so, it is not practical nor is it in the community's best interests to wait those decades before adopting allocation ceilings that are technically highly accurate. In short, at this stage a very high degree of accuracy is not required to commence management consistent with the philosophy of sustainability. Nevertheless, the approach applied has generated a set of figures that have been produced as a synthesis of knowledge accumulated to the present and have been adjusted according to good hydrogeological common sense and an understanding of local issues. Additionally, the approach has been conservative in the interest of resource protection but tempered with compromise recognising the need to preserve current development and acknowledging the importance of encouraging continued development where appropriate to do so.

Where rigorous numerical models have been developed and have resulted in the generation of acceptable recharge figures for an aquifer system, these values have been adopted as acceptable for use in sustainable yield determinations. In some cases systems that are similar to a modelled system have had recharge determined empirically using the modelled system as a reference.

Most systems however, have not been modelled. In those cases, inputs (or recharge) to the system have generally been kept to rainfall and river components of recharge. "Throughflow" and "underflow" have in most cases been omitted from calculations in the interest of both simplicity and conservatism. Likewise, irrigation "returns" have not been considered even though in some situations, a certain proportion of irrigated water might be expected to access the underlying aquifer.

Two equations were used to estimate recharge. Both have a limited number of terms and allow recharge values to be assigned respectively to:

Rainfall recharge was calculated according to assessed rainfall, area and assumed proportion of rainfall accessing the aquifer. River recharge was estimated using an equation, which is a modified form of the "Darcy" equation that is used in the assessment of river recharge in the "Modflow" software package that models groundwater flow. The result is a "theoretical" contribution of the river to the recharge. An additional factor was applied to this result as an "adjustment" factor intended to reduce the theoretical river recharge and is set as a) the fraction of the year and/or b) fraction of river reach - that is considered as a "loosing stream". In this way an actual river recharge component is produced.

There is a strong subjective character to the results achieved by the above method which has been applied to all GMUs across NSW, but they have been made with common sense and with hydrogeological principles in mind. They are therefore valid within the needs of the present situation.

Categorisation

Categorisation of each GMU has been made for both allocation and abstraction, according to the standard method adopted for the audit. Sustainable yield was determined in accordance with the method described above, and is of variable reliability. Allocation volumes were obtained from the DLWC database, supplemented in many cases by information from regional staff. Usage data were provided by regional staff where metering is being undertaken systematically, supplemented in some cases by data from regional information. In other areas (i.e. most GMUs) the usage volume was estimated, generally in terms of a proportion of allocation. The usage data are clearly the least accurate figures in the categorisation.

The total abstraction for the 41 GMUs described here (which excludes the Border Rivers Alluvium and the Great Artesian Basin) is 863000 ML/y. The corresponding values for allocation and sustainable yield are 2382000 ML/y and 1897000 ML/y respectively. That is, on a state-wide basis, that part of the State that is incorporated into GMUs is classed as Category2 for abstraction and category 4 for allocation.

Management Goals and Objectives

The management goals and objectives for groundwater management in NSW are set out in the document "The NSW State Groundwater Policy Framework Document (DLWC 1997). They can be summarised as follows.

It is the policy of the NSW Government to encourage the ecologically sustainable management of the State's groundwater resources so as to:

These policy objectives will be achieved through the application of the following management principles:

Groundwater

Assessment of Joint Groundwater and Surface Water Use

During the late 1980s and early 1990s, conjunctive use of surface water and groundwater was encouraged in NSW by the issuing of licences which provided for a varying entitlement to groundwater, depending on surface water availability in any year. Licensees holding such a licence in addition to a surface water licence could, if they chose, increase their groundwater withdrawals in years when less than 100% of their entitlement to surface water was available because of low surface water resources. Arrangements varied between GMUs but in general the holder of a conjunctive licence could make up a large part of any surface water shortfall. It was useful while groundwater sources were substantially under-utilised, but became unworkable as sustainable groundwater yields were approached or exceeded. The increased groundwater use caused by such licences coincided with periods of maximum withdrawal by groundwater-only users and placed a severe strain on aquifers. Interference effects between pumping bores during irrigation periods became excessive.

Issue of conjunctive use licences has been discontinued. The conjunctive nature of surface and groundwater resources has been addressed by the development of aquifer sustainable yield estimates, which take account of river recharge. The aim of groundwater management in the GMUs is now to limit withdrawals to the sustainable yield. Some of the sustainable yield is derived from river recharge (or river losses), but withdrawals at rates which exceed sustainable yield and which would induce additional river losses will be progressively eliminated.

Development Potential

Development potential within NSW involving additional use of resources will be confined to the NSW coast. This cannot be quantified until such time as flow management plans are developed for each of the coastal SWMAs. As this information is obtained it will be added to The DLWC website www.dlwc.nsw.gov.au

The potential for further development of groundwater resources is in general limited to some of the smaller inland river tributary valleys, some of the coastal sand and alluvial aquifer systems, and the wider areas of the unincorporated areas. Maximum withdrawal rates for individual bores are relatively low in all these cases, with maximum indicative pumping rates of no more than about 1 ML/d in most cases and in most cases less than this. There are some exceptions, such as the Oxley Basin unincorporated area, and small parts of some of the other unincorporated areas, where there is a limited potential within sustainable yield limits for the development of bores higher rate bores. Allocation in all areas where high pumping rates are available from the most productive unconsolidated alluvial aquifer systems have reached, exceeded, or are approaching, the estimated sustainable yield from those aquifers.

For the GMUs with abstraction or allocation assessed as being Category 4, the potential for development was regarded as nil. These include most of the high yielding aquifers with the higher level of sustainable yields, and consequently a large proportion of the most useable of the State's groundwater resources. For other GMUs, the potential for future development was taken as the difference between the current level of allocation and the sustainable estimated yield.

Demand for Water

Demand in the NSW portion of the Murray-Darling basin will remain static while ever the MDB Ministerial Council cap on water use is in place and the NSW government maintains its current approach to environmental flow management. There may be some change in the annual pattern of demand as users optimise their water use and management within the water sharing and cap bounds.

Some urban schemes within the NSW portion of the Murray-Darling basin may have increasing trends in demand due to population and industrial growth. This increased demand will be at the expense of reduced supply to low security users in that SWMA, so that total water use in the basin remains within cap limits.

Constraints to Development

There is no surface water development potential within the NSW portion of the Murray-Darling basin while ever the Murray-Darling Basin Ministerial Council (MDBMC) cap on water use is in place and the NSW government maintains its current approach to environmental flow management. Surface water development can only take place via transfer of entitlements to higher value use and by improvements in water use efficiency.

Identification of the surface water development potential on the NSW coast is not possible until such time as flow management plans are developed for each of the coastal SWMAs.

The main constraint to development of groundwater resources is the extent to which they have already been developed. Allocations in the more productive aquifers have already reached or exceeded the latest estimate of sustainable yield. Further development will either cause water levels to fall to depths from which pumping is uneconomic or impossible, or induce entry of saline groundwater from adjoining areas, or both. Constraints to development of other areas are mainly the uncertainty about sustainable yield and the limit to the magnitude of individual bore supplies imposed by the physical characteristics of the aquifer formation.

Cost of Water

DLWC has realigned its bulk water management functions to meet the strategic directions established by COAG. Under the current framework, DLWC undertakes the regulatory activities of licensing administration and compliance monitoring and resource management.

Operational activities are the responsibility of State Water, the commercial business unit with a discreet organisational structure and clearly delineated resourcing arrangements. State Water's funding and financial arrangements are also clearly identified within DLWC's accounting system.

State wide resource stewardship and allocative functions, together with regulatory, policy formulation and standard setting functions are undertaken within DLWC on a divisional basis.

Resource management policy implementation, monitoring standards and reporting are regional responsibilities.

DLWC is at various stages of completion of a range of bulk water initiatives directed at improving customer service, achieving cost reductions, enhancing financial information and developing legislation for a new Water Management Act. Despite the planned achievement of significant reductions in operating costs and identification of long term service levels for users on unregulated rivers and groundwater systems, a continuation of real increases in prices over the medium term will be required. This process will be driven by the finalisation of a total asset management planning system, recognition of greater levels of resource management activities and accounting for a return on capital.

The total cost of bulk water services in 1998/99 was $81.3M. These services were funded from water charge receipts, hydro_power and other income and the government's contribution. There is a deficit which represents the variance between actual bulk water income receipts and the user/government share of bulk water costs.

A summary of actual bulk water price related costs for 1998/99 (excluding licensing costs) is shown in Table 3. All price related resource management and operating costs in the Rivers and Groundwater Program are included in the figures shown.

Actual Bulk Water Price Related Costs 1998/99

Actual Bulk Water Price Related Costs 1998/99 (a)

Valley/Area

 Regulated Rivers Unregulated Rivers
Groundwater
Areas
 River Valleys & Groundwater Areas
Actual Running Costs $000 Asset Annuity (b) $000 Total Coast $000 Actual Costs
$000		 Actual Costs $000 Total Costs $000
Border 2,503 431 2,934 136 181 3,251
Gwydir 3,187 709 3,896 126 300 4,322
Namoi 3,839 593 4,432 654 961 6,047
Peel 839 152 991 18 175 1,184
Lachlan 5,521 968 6,489 431 406 7,326
Macquarie 4,115 926 5,041 556 660 6,257
Far West (c) 3,068 542 3,610 1,766 999 6,375
Murray 11,009 3,065 14,074 270 907 15,251
Murrumbidgee 8,941 1,978 10,919 863 1,117 12,899
North Coast 579 53 632 3,184 404 4,220
Hunter 4,118 412 4,530 1,140 556 6,226
South Coast 775 100 875 6,156 873 7,904
Total 48,494 9,929 58,423 15,300 7,539 81,262

(a) All figures expressed in 1998/99 dollars.

(b) Includes State Water and MDBC renewals annuities as per July 1998 determination.

(c) Far West includes Lower Murray. Far West Unregulated Rivers include a renewals annuity of $224,000.

Forecast Use

Surface Water

Information on forecast use in NSW has been provided for the Murray-Darling basin and the coast. In both cases the full details of use cannot be provided at this stage. Forecast use data can only be provided when flow management plans are developed for each of the unregulated SWMAs. As this information is obtained it will be added to the DLWC website www.dlwc.nsw.gov.au

Within the NSW portion of the Murray-Darling basin the use in 2020 and 2050 will remain static at current levels. Even though the actual use in the unregulated valleys of the Murray Darling basin cannot be provided until volumetric conversion of licenses and flow management plans are completed, the management rules adopted will ensure that NSW total use within the basin does not increase above the MDBMC cap.

Groundwater

For GMUs with an allocation or abstraction level of Category 3 or 4, the forecast use at 2020 was taken to be equal to the estimated sustainable yield. These include most of the high yielding aquifers with the higher level of sustainable yields, and consequently a large proportion of the most useable of the State's groundwater resources. For other GMUs, an arbitrary assessment of the rate of increase in use was made, on the basis of local conditions as much as possible.

Data and Information Gaps

Surface Water

The Department of Land and Water Conservation undertakes extensive monitoring and data collection of the States water resources. These activities include monitoring of surface and groundwater resources (quantity and quality), water diversions and usage and biological monitoring. In addition it maintains registrars of information on structures on watercourses used for water storage and diversion.

The data is collected to meet the objectives of the states Water Reform Programs and to satisfy the needs of other stakeholders including industry, local government and the community. Data use includes surface and groundwater assessments, river operations and flood warning, water quality and river health auditing.

A review of the Departments surface water monitoring network has recently been undertaken. This showed that 90% of current surface water sites (700 sites statewide) are currently meeting water reform or stakeholder objectives. Of these 700 sites, approximately 350 sites are on unregulated watercourses in coastal and inland catchments. It is anticipated, that in the medium term, additional surface water monitoring sites will be established in unregulated stressed coastal catchments to support Water Reform objectives. These reforms include water trading and water and environmental assessments to improve water use efficiency and environmental sustainability.

Water resource system models are the main management decision tools, which in future will need to be linked to improved economic, financial, social and environmental response models. Obviously good data and information are fundamental to the accuracy and validity of these tools. Some of the gaps in this area are:

Australian Bureau of Agriculture and Resource Economics (ABARE) data does not match the Surface Water Management Area boundaries.

Links between environmental health and river flows that are representative of regional ecological populations.

Financial data (cash flow, equity etc) for representative water user units in SWMAs or groups of SWMAs.

Representative user risk management decision criteria in SWMAs or groups of SWMAs.

Reliable and cost effective methods of obtaining information on water use, crop types and irrigated areas for unregulated rivers, and GMUs which are not metered,.

Water resource system models for unregulated rivers and accuracy of those models where they are not supported by stream flow data.

Operational decision tools for unregulated rivers.

Environmental flow performance measures.

Interrelationships between surface water and groundwater, i.e. impacts on stream flow losses.

Forestry impacts on stream flow.

Cumulative impacts of farm dams on the hydrology of rivers and basins.

Environmental impacts of flow pulsing in regulated rivers to mimic natural flow patterns in regulated rivers.

Ecological value of small streams in providing colonisation and food supply to main stream ecology.

Level of management uncertainty derived from models based on long term climatic data but calibrated with short water system management data.

The collection and storage of time series salinity data

Establishment of effective groundwater data systems that address quality control, accessibility and timeliness

Groundwater

The main data deficiencies in relation to groundwater management are reliable usage data, except in the few areas where abstractions are completely metered and fully recorded, and there is long term sequential salinity data. Water level monitoring data are available for most of the long established alluvial aquifer GMUs, but in many of the more recently defined areas the length of record is very short. There are little or no water level monitoring data for quite a few of the GMUs. An issue for management will be to determine which GMUs are likely to be subject to sufficient demand to warrant implementation of monitoring, requiring the installation of a costly observation bore network.

Information gaps, as opposed to data gaps, are most apparent in the derivation of sustainable yield estimates. Sustainable yield estimates are extraordinarily complex value to derive This estimate is crucial in formulating any groundwater management plan that has an objective of long term sustainable use of an aquifer. There are two parts to the estimate, namely the long term average annual recharge, and the proportion of that recharge which can be used without adverse impact on dependent ecosystems. For the broad scale, preliminary estimates derived for most of the NSW GMUs, a large part of the recharge (an in many cases the entire recharge) is attributed to infiltration of rainfall, and an adopted percentage of average annual rainfall is used. This takes no account of variations in the rainfall/runoff/infiltration characteristics of the GMU, and is selected on a somewhat arbitrary basis with minimal evidential backup. A more rigorous approach is to apply numerical modeling techniques, which can take account of variations in a variety of parameters across the GMU. But even here there are major problems, because such models require real data about the physical attributes of the aquifer and, perhaps more importantly, real usage data, if realistic values sustainable yield are to be derived.

The second aspect of sustainable yield for which an estimate is needed is the proportion of recharge that is required for maintenance of dependent ecosystems. The apportionment made for this requirement is, to date, essentially quite arbitrary.

Data Management

Surface Water

The major trend in data mangement requirements relates primarily to the data access and data delivery.

There is now the perception among managers that they must have the "latest", "real-time" data. This is pushing the development and implementation of "real-time" data collection and data delivery systems.

This also creates a set of data management issues related to the handling and storage of real time data as well as integration of real-time data as opposed to the traditionally collected "assessment" data.

The LAN/WAN systems and the Inter/Intra-net are also now seen as a major data delivery systems, typically via a spatial interface. This has increased the already important links between water resources data and spatial/GIS systems. It has also increased the need for more flexible data storage facilities with data access transparency to a wide range of external applications and systems.

Additionally there has also been the need to develop a range of other data dissemination options including voice, e-mail, fax-back, etc. All these requirements impact on the data storage and data management.

Technology itself, or rather its rate of change, is also impacting on data management requirements

Groundwater

Under current arrangements, a corporate database is maintained in Sydney, but data entry is essentially the responsibility of the Regions. Deficiencies in the system can be brought to the attention of the database management group, and modifications made where needed. Consequently, there are electronic data management systems in place within DLWC which would, if used to their potential by the Regions, give access to timely and comprehensive management data. This is subject, in reality, to the proviso that sufficient resources for data collection and timely data entry are made available by (or to) the Regions. The exception is access to groundwater quality data, which is currently, inhibited by deficiencies in the corporate database itself.

In a small number of GMUs with Category 4 allocation status, Regional staff has implemented local arrangements to overcome some of the deficiencies so that there is a reasonably comprehensive locally operated data set available to them for management purposes. In most cases though, the data gaps are quite significant. The impact of this situation is variable. The lack of data, In some areas, is not an immediate concern as abstraction is well within estimated sustainable limits. In other areas the lack of data is, or will soon be, a real impediment to proper management of groundwater resources.

Future Research and Development

There are a number of issues that will effect NSW's ability to achieve sustainable management of its water resources. The following are some of the important issues:

References

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