BURNETT REGION Prepared by
LEAST COST Institute for Sustainable Futures
PLANNING STUDY
For FINAL DRAFT REPORT QUEENSLAND GOVERNMENT ENVIRONMENTAL PROTECTION AGENCY
Institute for Sustainable Futures UTS March, 2002
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FINAL DRAFT REPORT
TABLE OF CONTENTS
EXECUTIVE SUMMARY...... V
1. INTRODUCTION ...... 1
2. STUDY BACKGROUND ...... 2
2.1 HISTORY ...... 2 2.2 RECENT STUDIES ...... 3 2.3 LEAST COST PLANNING ...... 3 2.4 PREVIOUS REPORTS ...... 4 2.5 WATER INDUSTRY REFORM ...... 4 2.6 OTHER RELEVANT SCHEMES /I NITIATIVES ...... 5 3. STUDY METHODOLOGY...... 7
3.1 OVERVIEW ...... 7 3.2 THE BURNETT REGION LCP STUDY METHODOLOGY ...... 9 4. REGIONAL OVERVIEW...... 11
4.1 THE BURNETT REGION ...... 11 4.2 CLIMATE ...... 11 4.3 POPULATION ...... 12 4.4 WATER USE ...... 12 4.5 PROJECTED FUTURE WATER DEMAND ...... 13 4.6 REGIONAL ECONOMY ...... 13 5. WATER SUPPLY ...... 16
5.1 OVERVIEW ...... 16 5.2 CLASSES OF SUPPLY ...... 16 5.3 SURFACE /G ROUNDWATER REGULATED SUPPLIES ...... 17 5.4 UNREGULATED WATER SUPPLIES ...... 19 6. WATER USE...... 20
6.1 OVERVIEW ...... 20 6.2 HISTORIC WATER DEMAND ...... 20 6.3 FUTURE DEMAND ...... 22 6.4 DISAGGREGATED WATER USE ...... 23 7. TOWN/URBAN...... 24
7.1 POPULATION & WATER USE ...... 24 7.2 POTENTIAL WATER SAVINGS & COSTS ...... 25 8. INDUSTRY ...... 27
8.1 WATER USE ...... 27 8.2 PROPOSED ADDITIONAL FUTURE WATER USE ...... 28 8.3 EFFICIENCY AND POTENTIAL WATER SAVINGS ...... 29 9. AGRICULTURE...... 30
9.1 OVERVIEW ...... 30 9.2 SUGAR CANE ...... 30 9.2.1 Area...... 30 9.2.2 Water Use...... 32 9.2.3 Irrigation Methods ...... 33 9.2.4 Water Use Efficiency ...... 34 9.2.5 Water Efficiency Considerations ...... 38
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9.2.6 Water Efficiency Options...... 39 9.2.7 Option Costs...... 41 9.3 HORTICULTURE ...... 43 9.3.1 Area & Water Use ...... 43 9.3.2 Irrigation Methods & Efficiency...... 46 9.3.3 Water Efficiency Considerations ...... 48 9.3.4 Water Efficiency Options...... 49 9.3.5 Option Costs...... 50 9.4 FIELD AND FODDER CROPS ...... 51 9.4.1 Area & Water Use ...... 51 9.4.2 Irrigation Methods & Efficiency...... 53 9.4.3 Water Efficiency Considerations ...... 54 9.4.4 Water Efficiency Options...... 57 9.4.5 Option Costs...... 57 9.5 STOCK & DOMESTIC ...... 59 9.5.1 Water Use & Efficiency...... 59 9.5.2 Option Costs...... 60 9.6 DISTRIBUTION LOSSES ...... 61 9.6.1 Water Use & Efficiencies ...... 61 9.6.2 Potential Water Savings & Options...... 65 9.6.3 Option Costs...... 67 9.7 REGULATED RIVER SYSTEM LOSSES ...... 67 10. OTHER SECTORS ...... 70
10.1 BACKGROUND ...... 70 10.2 THE PARADISE DAM ...... 70 10.3 DEMAND MANAGEMENT /E FFICIENCY MEASURES ...... 71 11. ALTERNATIVE SUPPLY & REUSE OPTIONS ...... 73
11.1 OVERVIEW ...... 73 11.2 SMALL SUPPLY OPTIONS ...... 73 11.3 OTHER ALTERNATIVE SUPPLY & REUSE OPTIONS ...... 74 11.3.1 Rainwater Tanks...... 74 11.3.2 Desalination ...... 75 11.3.3 Reclaimed Wastewater ...... 76 11.3.4 Greywater Reuse ...... 77 11.3.5 Urban Stormwater Harvesting ...... 78 11.3.6 On-Farm Storages...... 78 12. OPTIONS REVIEW...... 79
12.1 ORIGINAL PROPOSED SUPPLY OPTIONS ...... 79 12.2 DEMAND MANAGEMENT /E FFICIENCY OPTIONS ...... 80 12.3 ALTERNATIVE SUPPLY & REUSE OPTIONS ...... 81 12.4 ALTERNATIVE HYBRID OPTION ...... 82 12.5 SUMMARY OF HYBRID OPTION DETAILS ...... 83 13. IMPLEMENTATION ...... 86
14. RECOMMENDATIONS...... 87
15. REFERENCES ...... 88
APPENDICES A – Regional Rainfall Data B – Surface & Groundwater Supply Information C – DNR Water Use & Projections Information D – Demand Sectors Information
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E – Distribution Losses Information
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ABBREVIATIONS a annum ABS Australian Bureau of Statistics BIA Bundaberg Irrigation Area BSES Bureau of Sugar Experiment Stations COAG Council of Australian Governments DNR Department of Natural Resources h hectares kgDM kilograms of dry mass kgDM/ha/a kilograms of dry mass per hectare per annum ML/ha/a megalitres per hectare per annum LCP Least Cost Planning LGA Local Government Area m million m2 metres squared ML megalitre ML/km/d megalitres per kilometer per day ML/a megalitre per annum ML/ha megalitres per ha ML/ha/a megalitres per hectare per annum NPV net present value RWUEI Rural Water Use Efficiency Initiative SKM Sinclair Knight Merz t tonne t/a tonnes per annum WAMP Water Allocation Management Plan WBW Wide Bay Water
GLOSSARY
End use The particular uses to which a customer puts water Paradise Dam Burnett River (Paradise) Dam The Study The Burnett Region Least Cost Planning Study
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EXECUTIVE SUMMARY
The aim of the Burnett Region Least Cost Planning (LCP) Study is to develop a framework for meeting water related needs on a whole of catchment basis (irrigated agriculture, town water supplies, industry and environmental needs). The use of an LCP approach involves considering a range of options including investment in supply augmentation, recycling and water efficiency. Therefore allowing the development of an integrated ‘triple bottom line’ solution, which provides the services that water users require at the minimum economic, environmental and social cost.
This document provides the findings of the Study and includes details on the background of the Study, studies already undertaken, regional physical and economic details, methodology used, current water supply and projected water demand. It then considers possible water demand/management efficiency measures possible (under various end-use sectors) and alternative reuse and smaller supply options other then the currently proposed Paradise Dam. Using these costed options a Hybrid Option has been developed, which achieves the requirements of the Paradise Dam but with significant additional financial, social and environmental benefits.
The Study has been conducted in such as way as to provide a framework for considering LCP principles within other areas of Queensland. The Burnett Region has specifically been chosen as a pilot study to examine LCP principles due to the a wide range of complex water related issues that apply to this region.
Irrigated agriculture in the Burnett Region, notably the sugar cane industry, has experienced reduced water allocation over recent years due to below average rainfall and reduced volume in storages. This has led to concerns over reduced cane yield and the associated impact on the economic performance of the region. In order to alleviate these problems and cater for high projected future water demand (mainly associated with expansion of irrigated agriculture but also including increased population demand) there is a proposal for the construction of the 300,000 ML Burnett (Paradise) Dam and four other smaller weir structures/modifications. The dam alone will provide a high security yield of 20,000 ML/a for urban/industrial use and lower security yield of 124,000 ML/a for irrigation use in the Lower Burnett Region at an estimated present value cost of $183 m (capital and operation).
As an alternative to the Paradise Dam Option, potential efficiency improvements have been identified and grouped into options and combinations of options to reduce the unit cost of providing the identified service. In the case of town water demand, the service is the provision of end-uses such as showers, lawn and garden watering and toilet use. The options include programs of retrofitting water efficient fixtures that can provide these services at increased efficiency levels, thus allowing for growth in the number of customers being supplied by the same quantity of water being supplied from the current system. In the case of the sugar cane industry, the service has been taken as increased cane yield, because of the constraint imposed on the system by reduced water allocation. In the sugar cane program efficient irrigation systems have been proposed that reduce wastage associated with evaporation and runoff thus reducing the quantity of water required to provide the same cane yield. Hence combinations of options have been modelled that provide increased cane yield, at the lowest unit cost ($/t/a).
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In order to determine the current and future water requirements of the Region it has been necessary to ascertain the drivers behind the water demand and to critically review the projected water demand identified by previous reports. In doing so it has been found that considerable water savings can be achieved and increased crop yield attained through a combination of programs and alternative supply options ultimately attaining the goals of the future water demand without necessarily supplying the quantity of water previously identified.
A summary of the key requirements and benefits of the Paradise Dam Option together with the alternative Hybrid Option developed are provided in Table 1.
Table 1 – Comparison of Hybrid Option & Paradise Dam Option Hybrid Option Paradise Dam Option Present value cost - $184 m Present Value Cost - $183 m Water Saved/Supplied – 118,920 ML/a Water Supplied – 144,000 ML/a - 5,620 ML/a urban/industrial use - 20,000 ML/a urban/industrial use - 113,300 ML/a - 124,000 ML/a irrigation use Urban Sector Urban Sector - 5,620 ML/a water saved & reduction in current - 20,000 ML/a to cater for 2050 population demand by 35% enabling saved water to cater for future 2050 population with less water requirements. - As current supply will be able to cater for future - Additional flows are likely to lead to the need for demand, savings will be obtained in augmentation of water/sewage treatment plants augmentation in the water/sewage treatment plants. future. Sugar Cane Industry Sugar Cane Industry - 44,395 ML/a of water saved & supplied for existing - 80,000 ML/a of water supplied for existing irrigated irrigated area area - 621,026 t/a of additional cane produced - 587,996 t/a of additional cane produced - $17.1 m/a additional cane value - $16.2 m/a additional cane value - Increased cane yield sufficient for B2K+ project - Increased cane yield sufficient for B2K+ project Horticulture Horticulture - 68,905 ML/a of water saved/supplied used for new - 42,000 ML/a of water for new area areas - 24,755 ML/a used for Lower Burnett - 44,150 ML/a used for Upper Burnett - 9,670 ha of new horticultural land irrigated in - 14,000 ha of new horticultural land irrigated in Lower Burnett Lower Burnett - 6,650 ha of new horticultural land irrigated in Upper Burnett - 36,417 t/a of extra crop yield from existing areas - 490,173 t/a of crop yield from both new areas - 322,000 t/a of new crop yield - $ 960 m/a additional crop value - $593.8 m/a additional crop value
Hence for the same cost, the Hybrid Option can achieve all the requirements of the Paradise Dam Option and provide additional benefits such as:
• no requirement for augmentation of water/sewage treatment works; • reuse of current and future effluent from wastewater treatment plants for irrigated agriculture; • an additional 33,030 t/a of cane worth $1 m (over and above the 588,000 t/a, $16m achieved by both options) providing higher security of cane yield for the proposed B2K+ project; • additional 204,590 t/a of horticultural crops in both Lower & Upper Burnett worth an additional $366 m per year increasing economic return in Lower & Upper Burnett (over and above the 322,000 t/a, $594 m/a achieved by both options);
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• greater yield from existing and new land due to better management practices; • reduced losses associated with distribution and potential wastage of new supplies; • improved efficiency of field and fodder crops and stock watering; • increased technical ability of the irrigators in the Region and provision of a forum for shared learning and trialing of pilot studies on a commercial scale; • raised awareness of the importance of water efficiency and true value of water in line with COAG requirements; • complementing and building on the RWUEI enabling extension and expansion of the current 4 year program by another 4 years; • significantly increased employment during the 4 year implementation phase (and after) compared to the Paradise Dam Option due to the labour intensive nature of the programs proposed; and • significantly reduced risk associated with the provision of water services as the individual programs can be implemented over a period of time depending on the changing requirements of each end use sector.
A summary of the proposed Hybrid Option is provided in Tables 2 and 3.
The smaller weir modifications with a capital cost of $32.5 m and yield of 51,995 ML/a for irrigation and 200 ML/a for urban/industrial use, which have been used in the Hybrid Option, were originally identified to complement the Paradise Dam Option. Although not specifically identified the additional water is likely to be required for uses such as expansion of the irrigated area in the Upper Burnett Region (already provided for under the Hybrid Option) and 14,000 ML/a as part of the BIA Groundwater Rescue Project. If the Degilbo Creek Dam with a capital cost of $52.8 m and yield of 43,000 ML/a for irrigated agriculture and 20,000 ML/a for urban/industrial use was adopted to compliment the Hybrid Option at a later date the following additional advantages could be obtained:
• 20,000 ML/a for future high security use such as additional population growth and industrial development (value-adding industry such as tomato/avocado paste factories) in the future to assist in the economic growth of the region. • 14,000 ML/a for the BIA Groundwater Rescue Project • 29,200 ML/a for other irrigation requirements in the Lower Burnett such as further extension of the sugar cane or horticultural irrigated areas.
The proposed Hybrid Option addresses the requirements of the region similar to the Paradise Dam Option but provides significant economic, social and environmental benefits. In addition, the Hybrid Option allows the Government to implement the proposed program in stages and to assess the water requirements of the region over a period of time, thus minimising the risk of the Government incurring significant capital expenditure for projected water requirements that may not eventually be required.
The implementation strategy for the Hybrid Option has not been described in this Report. However, a separate document has been prepared which summarises one possible approach to the implementation of the proposed Hybrid Option, should this option be actively considered as a viable alternative to the Paradise Dam Option. This implementation strategy, of necessity, would require the involvement and input from a range of government and non- government stakeholders.
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Table 2 – Summary of Hybrid Option Details Sector/ Water Potential Option Unit Crop Crop User Used Water Cost Cost Yield Value ML/a Saved $ m $/ Increase $m/a ML/a ML t/a Town/ 16,000 5,420 5.6 1,033 - - Water saved used to provide Urban water for growing pop using lower consumption due to demand management. 200 4 4 - - Jones Weir water used in UB Industry 25,800 - - - - - No savings identified Agriculture Sugar Cane 100,000 214,395 58.2 4,044 366,026 10.1 Water saved used more efficiently on existing area using BP to produce higher crop yields. 30,000 32.5 1,083 255,000 7 300 (50) ML on-farm storage units producing water yield of 30,000 ML used on existing areas using BP to increase crop yield. Horticulture 43,300 34,174 28.6 6,848 36,417 66.4 Water saved with concurrent increased yield in both LB & UB due to BP. 3 30,680 56.0 Water saved used on new horticultural area in LB (650 ha) & UB (378 ha) in proportions saved to increase crop yields using BP. 15,295 5.2 340 167,289 308.5 Walla Weir water used to irrigate new area of LB using BP 2,645 5.6 2,117 28,930 53.3 Reclaimed wastewater discharged to BIA system & used to grow new area of LB using BP 36,700 27.3 744 182,395 327.8 Eidsvold, Barllil & Jones Weirs water used to grow new area in UB (5,527 ha) using BP Field & 22,800 34,560 7.4 1,620 - - Water saved/increase in yield Fodder (not quantified) due to BP 3 22,663 40.7 Water saved used to irrigate new horticultural area in UB (687 ha) Stock & 2,100 3380 0.25 Water saved Domestic 3 669 1,889 3.4 Water saved used to irrigate new horticultural area in UB (57 ha) Distribution 1124,000 35,150 13.1 2,542 - - Water saved Losses 3 56,328 103.9 Water saved used to irrigate new horticultural area (2,012 ha) in LB using BP. Total 210,000 118,920 183.8 1,548 977 1 – Water not used but transported, 2 – Water not actually saved due to current low allocations but more effectively used on same crop to produce increased yield, 3 – Where possible water saved used to grow horticultural crops in the LB or UB depending on proximity of the water to LB/UB. BP – Best/better practice, LB – Lower Burnett, UB – Upper Burnett 4 - cost covered in horticultural section
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Table 3 – Hybrid Option Program Details Sector/User Program Details Name Town/Urban WaterWise Burnett Apply COAG pricing policy. Towns Program Carry out education & assistance program covering residential population (including outdoor use). Conduct assessment and retrofitting program (showerheads, tap flow regulators, toilet flush reduction, leakage repair) worth $100 per house on 80% of houses. Audit and retrofitting program for 50% of commercial, institutional, industrial customers. Leakage detection and remedial works on distribution system. Industry WaterWise Burnett No program to be developed under this Study but recommend audits Industry Program should be considered. Agriculture Sugar Cane WaterWise Burnett Convert 15% of winch & furrow irrigated land to trickle & 10% to Sugar Industry alternate row trickle. Program Convert 50% of existing furrow irrigated land, 50% of winch & 100% of trickle to best practice. Convert 15% of winch & furrow irrigated land to close row cropping with trickle irrigation. Employ 4 full time and 1 part time extension officers for 4 years (including equipment). Provide technical equipment to farmers participating. Construct 300 (50 ML) on-farm storage on farms & employ 1 full time storage specialist. Horticulture WaterWise Burnett Convert 75% of area not using micro/drip irrigation to micro/drip Horticulture irrigation systems. Industry Program Convert 75% of farmers not currently using moisture/technical equipment to better management practice and provide moisture/technical equipment. . Employ 6 full time extension officers for 4 years including equipment. Field & WaterWise Burnett Provide moisture/technical equipment for all farmers participating. Fodder Field & Fodder Employ 7 full time extension officers to collect information on Industry Program industry and provide assistance in principles of Best practice irrigation techniques. Stock & Employ 1 full time extension officer to identify stock farmers and Domestic potential water savings, investigate efficient systems and provide assistance to farmers in implementing efficiency measures. Officer to work closely with other officers. Distribution WaterWise Burnett Conduct pipeline leakage test and remedial works. Losses SunWater Program Reline all 19km of leaking Woogarra Main Channel with impervious lining. Assume operational management improvements made. Other Alternative WaterWise Burnett Modifications to existing WWTPs and provision of reticulated system Supply & Government to Woongarra Channel to enable reuse of wastewater Reuse Program Construction/modification of Eidsvold. Walla, Barillil and Jones Weirs to provide additional water supply to more efficient system.
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1. INTRODUCTION
At the end of October 2001, the Sustainable Industries Division of the Queensland Government’s Environmental Protection Agency (EPA) commissioned the Institute for Sustainable Futures, in collaboration with Wide Bay Water, to carry out ‘The Burnett Region Least Cost Planning Study’. The aim of the Study is to develop a framework for meeting water related needs on a whole of catchment basis and therefore examines a wide variety of end users such as irrigated agriculture, town water, industry and the environment. The use of a least cost planning (LCP) approach requires consideration of a range of potential options including investment in supply augmentation, water recycling and water efficiency. This approach allows the development of an integrated ‘triple bottom line’ solution, which provides the services that water users require at the minimum economic, environmental and social cost.
Although the Study focuses on the Burnett Region, it has been conducted in such a way as to provide a model for other areas in Queensland. The Burnett Region has therefore been used as a case study to examine LCP principles and possible solutions for an entire catchment and to develop basic strategies that can be used to assist in the development of water demand/supply solutions in other areas within Queensland. The Study attempts to explore the driver behind the requirement for water and to identify the least cost and potentially most risk averse solutions available.
This document details the findings of the Study. It also provides the Study background, methodology, regional context and summarises the information gathered from studies already conducted in the area. It identifies current and future water demand, explores possible demand/supply side options and associated costs, reviews the options considered and details possible implementation strategies together with appropriate timing of implementation. The overall structure of this document is briefly outlined below:
• Executive Summary • Section 1 – Introduction • Section 2 – Study Background • Section 3 – Methodology • Section 4 – Regional Overview • Section 5 – Water Supply • Section 6 – Water Use • Section 7 – Town/Urban Sector • Section 8 – Industry Sector • Section 9 – Agricultural Sector • Section 10 – Other Sectors • Section 11 – Supply Options • Section 12 – Options Review • Section 13 – Implementation • Section 14 – Recommendations • Section 15 – References • Appendices
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2. STUDY BACKGROUND
2.1 History
The Burnett region is currently experiencing lower economic growth than other parts of the Queensland economy. This is mainly due to its reliance on traditional rural industries including those commodities experiencing declining world prices and reduced protection. Unemployment rates are among the highest in Australia, employment growth is low and incomes are generally only 70-80% of the Queensland average (SKM 2001).
Agriculture dominates the Burnett Regional economy. In 1995/96 agricultural activity accounted for approximately half of the region’s business turnover (SKM 1998) and in 1996/97 irrigated agriculture accounted for over 66% of the value of all agricultural production in the region. Sugar cane is the predominant irrigated crop, representing 28% of all agricultural production value (SKM 2001) and is therefore extremely important to the Burnett economy.
Over the last 10 years much of Queensland has been severely drought affected and many of the State’s water supply schemes have been fully committed. In 1996, the Government proposed the development of additional water infrastructure and established a Water Infrastructure Task Force (WITF) to consult communities concerning their future water needs and develop a program of priority projects for investigation and development (DNR 2001).
Due to the extended dry periods in the Burnett region, water allocations have been restricted over recent years. Water supplies in Central Burnett failed for two consecutive years resulting in complete crop losses. From their recent experiences communities perceive the provision of assured water supplies as critical to the social and economic stability of the region. Therefore when the WITF was set up the Burnett community established a number of local water development groups, which coordinated with other community groups and local governments throughout the Burnett to make a submission to the WITF (DNR 2001). Hence, as part of the WITF process a number of possible water supply opportunities were identified including the currently proposed Burnett River (Paradise) Dam.
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2.2 Recent Studies
Numerous studies have been conducted over the last few years in order to identify the most appropriate water supply solutions for the Burnett region. Some of the studies have projected bulk water demand to double by 2025 (Kinhill 1999), which has triggered further urgency for the implementation of water supply options such as the Paradise Dam. This increased demand has been projected on the basis of:
• significant population increase in the Lower Burnett; • a need for current water allocations to be provided with greater certainty; • development of new sugar cane and horticultural production areas; and • interest from new industries planning to establish operations in the region mainly related to the agricultural industry.
To date although various studies have been carried out to consider supply side, water use efficiency, demand management and wastewater reuse options to fulfill future water demand requirements, these studies have not been considered together within a Least Cost Planning framework for the whole catchment. Neither have they considered what the water is really required for (i.e. increased crop yield and higher economic returns from the land cultivated and whether there is an alternative solution other than supply of additional water to achieve the same goal. This Study is therefore designed to fill that gap, critically review the existing information, projected trends provided in the various reports already conducted for the Burnett region and determine the real water demand and possible alternative solutions to supply side options using LCP principles.
2.3 Least Cost Planning
Least Cost Planning (LCP), also referred to as integrated resource planning, is a process whereby a water supplier determines a range of options, which at lowest cost provide their customers with the water-related services that they require, rather than with the water itself. This process recognises that customers do not necessarily want more water but want the services that water provides, such as productive crops, aesthetically pleasing landscapes, sanitation and clean clothes. There is thus scope for satisfying demand for these water-related services by improving efficiency of water-using products, landscapes and irrigation processes. These options can be compared with supply options, including augmentation of the water supply systems and effluent reuse schemes to determine the most appropriate strategy for the supply of water services to meet the communities needs.
This Study uses the principles of LCP to identify water supply and demand options for water resources in the region and to develop demand/supply programs and action plans to maximise sustainability of those resources. Thus enabling the water suppliers in the region to meet their supply requirements and the needs of customers with minimum water use and at least cost to both the suppliers and the customers.
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2.4 Previous Reports
In order to concentrate on the principles of LCP and to maximise the work already conducted in the Burnett Region this Study has used information gained from the various studies already conducted. The key documents from which data and information have been extracted for the Study are as follows:
• Barraclough & Co. – Audit of Water & Irrigation Use Efficiencies on Farms within the Queensland Horticultural Industry – Final Report – November 1999. • CARE – The Economic Impact of Additional Irrigation Supplies in the Burnett Catchment – June 2000 • DNR - Draft Water Allocation Management Plan – June 2000 • DNR – Burnett River Catchment Appraisal Study – Technical Report – June 2001 • Kinhill – Alternative Sources of Water Supply for the Burnett River Catchment – Final Report - 1999 • SKM - Burnett River Catchment Study - Catchment Overview – June 1998 • SKM - The Efficiency of Water Use in the Burnett Region – Final Report – March 2000
The full list of references are provided in Section 14. Where these studies have appeared incomplete, limited additional information has been collected where necessary. In addition where these studies have made assumptions on projections of demand these have been reviewed to obtain a realistic ‘business as usual’ projection upon which the LCP principles have been based.
2.5 Water Industry Reform
A key consideration in the preparation of this Study has been the direction of water industry reform at the National and State level. Although the Queensland Government is driving towards water reform it is generally acknowledge that there are areas of reform that can be improved. This can be beneficial in some respects in that Queensland can benefit from learning from other States at a detailed level. However, it can also hinder the progress of particular programs such as water saving initiatives because the basic frameworks such as universal metering, user pays principles and tradeable water entitlements may not be fully operational, or in the case of two part tariffs set at a level which does not generate the desired water savings.
To make best use of the nation’s increasingly scarce resources and halt the degradation associated with inappropriate water use and inefficient management, the Council of Australian Governments (COAG) endorsed a framework for reform of the Australian water industry in 1994. For rural areas the reforms mainly consisted of:
• pricing reform for rural surface water based on a ‘user pays’ system with full cost recovery, reduction/elimination of cross-subsidies and transparency of remaining subsidies; • tradeable or transferable water entitlements; • infrastructure investment and institutional reform; and • environmental allocation for stressed rivers.
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These reforms are a formal requirement of the national competition policy reforms and as such each State/Territory must implement them to be eligible for the second and third tranches of payment to be made by the Commonwealth under the national competition policy agreements (IC 1998).
The Water Act 2000 specifically incorporates provisions addressing a number of the reforms identified in the COAG framework including;
• water allocation and management planning to balance the needs of the environment and water users; • establishing transferable water entitlements (TWE); • private sector development and operation of water infrastructure; • regulation of water services providers to ensure the maintenance of safe and reliable water services and to protect the interests of customers and the environment; and • governance arrangements for water authorities such as water boards that provide accountability mechanisms (DNR 2001).
Under the new legislation catchment based Water Resource Plans (WRP) are developed through the development of Water Allocation and Management Plans (WAMPs). These WAMPs define total water resources, current levels of commitment, current condition and utilisations, predicted condition and utilisation and allocation opportunities. From this the WRP provides a statement of outcomes, management strategies, environmental flow objectives, water allocation security objectives, monitoring and reporting requirements and an implementation schedule. The Burnett WRP was approved in December 2000 and will be implemented progressively throughout the region via the Resource Operations Planning (ROP) process, which is set out in the Water Act 2000 (DNR 2001).
Progress is being made in the structural reform of the Queensland water industry, however it is by no means complete and this will therefore have timing implications on the strategies developed as part of this Study.
2.6 Other Relevant Schemes/Initiatives
Various Government schemes and initiatives have been set up over the last few years on a State and regional basis to assist in water efficiency, groundwater protection and future supply. In addition projects driving water demand have also been identified. In determining the most appropriate water supply/efficiency options and strategies for the region under this LCP Study, it has been necessary to consider the existing schemes/initiatives already targeted or under way. This is in order to complement these schemes/initiatives taking into consideration the implications of planned projects and determining future water demand based on realistic figures. Some of the key schemes/initiatives and projects considered in this Study include:
• Rural Water Use Efficiency Initiative – A four year $41 million Queensland based project currently covering sugar, horticultural, cotton, dairy and lucerne industries aimed at increasing the efficiency of water use in irrigation practices primarily through the use of education, advice and loan schemes.
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• BIA Groundwater Rescue Project – A project designed to control saltwater intrusion into coastal aquifers by replacing some of the existing groundwater allocations in threatened areas with 14,000 ML/a of surface waters. • Burnett River (Paradise) Dam Project – A $180 million proposal to build a 300,000 ML capacity dam on the Burnett River (AMTD 131.2) to increase supply of surface water to meet future demand in the Lower Burnett. • The Bundaberg 2000 Plus (B2K+) Project - A proposed paper pulp mill which will use bagasse (waste plant matter from sugar cane), thus increasing the incentive to increase the production of sugar cane in the region to at least 3.6 million tonnes annually.
Each of these issues is discussed in more detail in the relevant Sections of this report.
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3. STUDY METHODOLOGY
3.1 Overview
The methodology used for LCP studies can vary considerably depending on the purpose of the study, the size of the area being considered, available data to be reviewed, the number of end users being considered and the complexity of the water issues concerned.
In the case of the Burnett Region, this Study is one of the first to consider LCP principles on a whole of catchment basis, which involves such a wide range of end uses and such complex issues relating to water use and projected demand. As such, a detailed analysis and modelling exercise was considered inappropriate and a more strategic overview approach used instead, in order to provide a basic model that could be used for other areas in Queensland when required. This model could then be considered in more detail when detailed data was available or less end users involved in the specific areas being considered.
The Burnett Region is very appropriate to choose as a case study to provide this basic model, due to its geographic size, number of end users and complexity of water issues.
An overview of the methodology that can be used when considering LCP studies is provided in Figure 3.1.
This basic methodology has been followed by this Study. However, as discussed above, the Burnett Region LCP Study is fairly complex and additional issues have been considered at various stages. An important issue that has come to light during the Burnett Study is consideration of the real driver behind the water required. It should be noted that this driver can often be masked and sometimes takes considerable investigation to bring to the surface. This driver can often affect the real projected water demand required.
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Figure 3.1 – General LCP Methodology
GATHER INFORMATION & WATER USE DATA, REVIEW & IDENTIFY DATA GAPS
IDENTIFY WATER USERS, SUPPLY & CURRENT/FUTURE DEMAND
IDENTIFY DRIVER BEHIND CONVENTIONAL SUPPLY OPTION PROPOSED OR IDENTIFIED PROBLEM TO BE RESOLVED
SPLIT WATER USERS BY SECTOR & CONSIDER WATER USE CHARACTERISTICS SEPERATELY
OPTIONS GENERATION
IDENTIFY POTENTIAL IDENTIFY ALTERNATIVE IDENTIFY PROPOSED WATER DEMAND SUPPLY OPTIONS POSSIBLE CONVENTIONAL SUPPLY MANAGEMENT/EFFICIENCY OPTION PROPOSED OPTIONS & POTENTIAL BENEFITS POSSIBLE
MODEL & COMBINE OPTIONS TO OBTAIN DESIRED OUTCOME INCLUDING LOW UNIT COST & HIGH BENEFITS
COMPARE HYBRID OPTION WITH ORIGINAL CONVENTIONAL SUPPLY OPTION & REVISE AS NECESSARY
CONSIDER PROGRAM DETAILS AND IMPLEMENTATION STRATEGY NECESSARY
IDENTIFY ANY ADDITIONAL ISSUES TO BE CONSIDERED
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3.2 The Burnett Region LCP Study Methodology
The basic methodology identified in Figure 3.1 was used for the Burnett Region LCP. The detailed methodology was as follows:
• Information Gathering - A large number of studies have already been carried out on the Burnett Region relating to water use and efficiency issues. These studies together with other documents relating to irrigation issues etc. were collected and reviewed. Where inconsistencies or data gaps appeared these were identified for further action/assessment. In addition investigation on existing water efficiency schemes was investigated in order to compliment were appropriate.
• Water Use - Current water supply systems and structures were identified and historical water use and projected water demand collated.
• Identify Driver - The driver behind the projected water demand and reason for the proposed conventional supply side option proposed (Paradise Dam) was then identified and the water demand projections reviewed accordingly.
• Water Use Sectors - Water users were disaggregated into separate sectors of town/urban, industry, agriculture and other and individual end users identified within each sector. Then for each individual sector and end user, where considered appropriate, a detailed review was conducted of current water use and projected demand. In the case of the agricultural industry detailed assessment of current irrigated areas, irrigation methods, factors affecting water use efficiency, transmission losses etc. was conducted due to the large proportion of water used by this particular sector. In addition due to the particular driver behind the Paradise Dam, crop yield and value was also investigated in order to identify alternative potential options that provided the crop yield required but with less water.
• Options Generation - The potential options were split into three main groups consisting of the Paradise Dam, demand management/efficiency measures and alternative supply options. A series of options were developed under the later two categories in order to compare costs, water savings and potential crop yield increases against the Paradise Dam Option. Where possible both capital and operational costs were included.
• Modelling - Issues relating to water saved, option costs, potential yield increases and value were then modelled and combinations of options identified that maximised crop yield and value, maximised water saved but minimised option costs. A preferred combined option was created including demand management/efficiency measures, alternative supply and reuse and identified as the Hybrid Option.
• Option Comparison - Having identified the preferred Hybrid Option, this was compared against the Paradise Dam to ensure that the objectives of the Dam were provided by the Hybrid Option. In addition other potential benefits which could be obtained by adopting the Hybrid Option instead of the Paradise Dam Option were also identified.
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• Program & Implementation Details - Having identified the Hybrid Option basic program details identified and costed during the options review process such as infrastructure modifications, education, pricing policy modifications and use of extension officers etc. were summarised. These program details are important when considering the implementation strategy required. In the Burnett Region LCP Study the implementation issues have not been included in the main report but have been discussed in a separate document.
• Additional Issues - At various stages of the Study additional issues were identified that need consideration. These issues were summarised and identified as recommendations for potential further action.
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4. REGIONAL OVERVIEW
4.1 The Burnett Region
The Study area, which is shown in Figure 4.1, is approximately 38,380 km2 and comprises all or part of the Burnett, Kolan, Elliot, Gregory and Isis River catchments. The Study area encompasses all or part of the Local Government Areas (LGA) of the City of Bundaberg and the Shires of Burnett, Eidsvold, Gayndah, Monto, Mundubbera, Murgon, Perry, Kolan, Isis, Chinchilla, Biggenden, Kilkivan, Wondai, Kingaroy and Nanango. As can be seen in Figure 4.1, the area can be split into four main areas of the North, Central, South and Lower Burnett Regions. (DNR 2001).
The Study area is bounded by the Dawes Range to the north, Auburn Ranges to the west and Great Dividing Range to the south-west. To the east the area is separated from the adjacent coastal river basins by the Cooyar, Brisbane, Coast and Woowoonga Ranges. The Burnett Range separates the Burnett River from the Kolan River in the north-east. The catchment slopes from west to east and the tributary streams flow into the Burnett River, which drains to the sea through the gap between Mt Woowoonga and Mt Perry (DNR 2001).
4.2 Climate
The climate of the Burnett catchment is transitional between the tropical weather patterns (summer monsoons and cyclones) of the north and the temperate weather patterns (fronts and depressions that bring winter/spring rains) of the south. As a result, rainfall is relatively low, unreliable and less seasonal. Average annual rainfall varies from 706 mm inland to 1,128 mm along the coast. Along the hilly eastern rim and the coast, rainfall exceeds 900 mm, however, the bulk of the catchment receives less than 800 mm. Rainfall is extremely variable and is characterised by frequent drought. On average, a major drought (long dry period of 12 months or more) occurs every 5 years and extended drought (24 months or more) occurs every 11-12 years.
The drier inland areas such as Gayndah (2,020 mm) have slightly higher mean annual evaporation rates than coastal Bundaberg (1,823 mm), although Kingaroy has the lowest mean annual evaporation rate at approx. 1,601 mm. Peak evaporation occurs between November and February and the lowest evaporation is recorded around June (DNR 2001, SKM 1998).
Figure 4.2 shows the weighted average rainfall over the whole catchment over the last 11 years together with the long term weighted average rainfall, indicating the shortfall currently being experienced. Additional rainfall data for individual regions is provided in Appendix A. It should be noted that over the last 11 years water has been 13.5% below the long term weighted average and 6 of the last 8 years have been below the long term weighted average.
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Figure 4.2 – Burnett Regional Weighted Average Rainfall
1000 Recorded Historic Average 900
800
700
600
500
400
300
200
100
0 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 Year Area based weighted average (Historical trends based on over 100years of records).
4.3 Population
In the 1996 census year the Study area population was 122,933 with an average growth rate of over 2% per annum since 1988. Approximately 60% of the Study area’s population lives within the Burnett Shire and Bundaberg City. Two areas of strong population growth are Bundaberg (and the surrounding three shires of Burnett, Kolan and Isis) and the Kingaroy/Nanango area. In the remainder of the catchment there is generally a zero or negative population growth (DNR 2001). The 1996 population figures for each sub region are as follows:
• North Burnett – 2, 921 • Central Burnett – 17,113 • South Burnett - 28,251 • Lower Burnett - 74,648
The population figures for the region vary according to different reports. The figures identified above have been abstracted from DNR (DNR 2001) and are consistent with the more extensive catchment being considered under this Study.
Many of the key studies already carried out in the Burnett area identify that the population is forecast to grow to 156,750 by 2011 and 186,500 by 2050. These include negative growth in areas such as Murgon and Monto to over 5% for the Burnett Shire. A review of these population projections and ultimate water use is provided in Section 7.
4.4 Water Use
According to SKM (2000) overall water use in the Burnett region (1997/98), obtained from both surface and groundwater supplies, was in the order of 210,000 ML. This water use figure can be split into major demand groups as shown in Figure 4.3. As shown water use associated with the agricultural industry is the major user, with the sugar cane industry being particularly high. The amount of water used for sugar cane production in any given year varies depending on the quantity of water available within storages and annual rainfall. Hence the overall water use within the region can vary significantly between years. The 1997/98 period is considered a low use year.
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Figure 4.3 – Water Use 1997/98 7 % 1 %
1 2 % Sugarcane H orticulture 4 8 % Field and Fodder Crops 1 1 % Indu stry Town W ater Stock and Domestic 2 1 %
Source – SKM 2000 Note: Based on DNR water usage records and using Barracloughs (1999) average usage data for horticulture and Sinclair Knight Merz (1998) estimate for unregulated water use.
4.5 Projected Future Water Demand
Water restrictions are currently being experienced in the region due to below average rainfall and low storage volumes in existing structures. Several recent studies have projected water demand in the Burnett Region to rise significantly and even to double by 2025. This increase rise in demand is expected to be mainly attributable to those irrigators currently experiencing restrictions on existing land requiring their full allocation and demand to expand irrigated agriculture, especially in the sugar cane and horticultural industries. In addition, to a lesser extent, reasons put forward for demand to rise include population growth, necessity for groundwater rescue (to reduce salinity problems), industry and rural water supply schemes. In order to fulfill these anticipated future water demand requirements and to alleviate current water restrictions the Burnett (Paradise) Dam and four smaller weir structures/modifications are currently being investigated. These supply structures will provide approximately 170,000 ML/a of additional yield (99.7% WSI).
4.6 Regional Economy
The Burnett Region is currently experiencing lower economic growth than other parts of the Queensland economy. This is mainly due to its reliance on traditional rural industries including those commodities experiencing declining world prices and reduced protection. Unemployment rates are among the highest in Australia, employment growth is low and incomes are generally only 70-80% of the Queensland average (SKM 2001).
The economy of the region is heavily dependent on primary industry with the majority of the top 20 industries, mainly relating to agriculture, being primary production or related processing. This indicates that Burnett is a natural resource dependent region relying on commodity markets and seasonal conditions. The top ranking industry assessed was sugar cane, which in 1996 was 26 times more important to the economy of the region, when considering employment, than in the rest of Australia (CARE 2000).
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Figure 4.4 provides a general overview of the regional economy with respect to gross regional product, employment and exports for individual sectors. This shows a large contribution of primary industry to the economy that flows into a large part of manufacturing that is agriculture related. Primary production and processed primary products comprise the bulk of exports. The utilities activity is boosted by coal mining and electricity generation, which also contributes to exports from the region. Services contribute only a small amount to the region exports but are extremely important to employment (DNR 2001).
Figure 4.4 – Burnett Region Economy 1996 - 1997
7 0 %
G ross Regional Product 6 1 % Em ploym ent 6 0 % 5 8 % E xpo rts
5 0 %
4 4 %
4 0 %
3 0 %
2 1 % 2 0 % 2 0 % 1 6 % 1 3 % 1 2 % 1 1 % 1 0 % 9 % 8 % 6 % 6 % 3 % 4 % 1 % 1 % 0 % 0 % A g Forestry M in in g M anufacturing U tilitie s B u ild in g S ervices F ish in g Source – CARE 2000
A summary of the economy of the individual sub-regions is as follows:
• North Burnett is heavily dependent on agriculture with the main manufacturing activities also being agriculture based. The service industries are significant but are mainly focused on providing basic services to local residents. • Central Burnett is dominated by agricultural production with the largest dependence on agriculture within the region. A small amount of manufacturing and services are targeted at the local population. • South Burnett has a greater diversity than the other regions through the significant mining and utilities that operate in the region. In addition, there is a diversified agriculture that supports a number of value-adding trading and manufacturing operations. • Lower Burnett comprises approximately 60% of the Burnett economy. Mining and utilities are less important than in the total catchment but services contribute more and manufacturing provides a dominant source of export, which is predominantly related to the sugar industry. Tourism is becoming increasingly important in Lower Burnett, which may lead to more diversification of the economy (CARE 2000).
Agriculture dominates the economy of the region, which has shown little growth in industry and low diversification of economic activities. In 1995/96 agricultural activity accounted for approximately half of the region’s business turnover (SKM 1998). In 1996/97, the total agricultural production value was $508.5 million (ABS Agstats 96-97). Irrigated agriculture accounted for over 66% of the value of all agricultural production in the region ($337 million as products exit the farm gate) in the same period with cane sugar being the predominant product representing 28% and 48% (DNR 2001) of all agricultural and irrigated agricultural production value respectively (CARE 2000, SKM 2001).
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Agricultural production in the region covers an area of approximately 3.13 million ha. Irrigated agriculture, although representing a high proportion of total agricultural value, only covers 2.7% of the area. Sugar cane is only grown in Lower Burnett but there is considerable diversity within the irrigated agriculture of the whole Burnett region with vegetables, citrus and dairy products also being important.
Many of the agricultural industries in the region do not support value adding (e.g tomato paste factories) to a substantial degree and thus effectively lose out on the value chain by receiving the farm gate price of only approximately 10% of final price paid by consumers. Thus indicating that substantial economic benefits could be derived from pursuit of value adding to agricultural production in the region. The overall direct and flow-on effects of agricultural production in the region in 1996/97 amounted to approximately 26% of the Gross Regional Product of the Burnett economy (CARE 2000). Some potential and planned future industrial growth in the region includes expansion of the Tarong Power Station, a chicory farm at Childers and the B2K+ Project in Lower Burnett. Tourism is also on the increase, which will assist economic diversification.
It has been highlighted (CARE 2000) that diversification into value adding industries is required to improve the economy of the region and that without this diversification any water supply scheme implemented will only have limited economic benefit within the region itself.
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5. WATER SUPPLY
5.1 Overview
Water required in the region for the town/urban, industrial and agricultural sectors is drawn from both surface and groundwater reserves. The major streams, locations of existing storage structures and groundwater reserves in the Burnett Region are identified in Figure 5.1. Water is supplied to these sectors by both regulated and unregulated systems. Figure 5.2 identifies the 660 km of regulated river within the catchment and the remaining unregulated sections, together with the four irrigation projects and one irrigation area in the region. These irrigation projects/area are listed below:
• North Burnett - Three Moon Creek Irrigation Project • Central Burnett - Upper Burnett River Irrigation Project • Central Burnett - Boyne River Irrigation Project • South Burnett - Barker/Barambah Irrigation Project • Lower Burnett - Bundaberg Irrigation Area (BIA)
The water supplied from these resources is provided directly or indirectly by:
• The Dept. of Natural Resources (DNR). • SunWater on behalf of DNR. • Water Boards (Avondale, Merlwood, Mulgildie, Proston and Woodmillar). • Local Authorities/Town Water Supplies.
5.2 Classes of Supply
Classes of supply can be split into regulated and unregulated water.
Regulated supply of both surface water and groundwater is by far the largest proportion of water used in the region. Regulated supply includes:
• Irrigation under volumetric entitlements with licences for nominal allocation issued by SunWater (on behalf of DNR) for surface waters and DNR for groundwaters. • Use by Water Boards (primarily for stock and domeistic use) constituted under the Water Resources Act with entitlements regulated by DNR. • Urban use regulated by local authorities under agreements with DNR. • Dedicated industrial use under licence from DNR (DNR 2001).
Unregulated use includes:
• Riparian pumping - Extraction from unregulated sections of streams under licences issued by DNR. Under these licences water can be taken from streams wherever flow is sufficient to permit pumping. The licence is issued with conditions, which limit the capacity of the pump and/or the size of the irrigation area supplied under the licence. The volume of water supplied under this form of licence is relatively small compared with regulated supplies.
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• Water harvesting – Under these licences water can be taken from a watercourse when streamflow is above a minimum threshold. The maximum pump capacity is usually also a condition of the licence. Periods when water can be taken are determined by DNR after assessing hydrographic data. Pumping for water harvesting purposes must cease when stream flows fall below predetermined rates at nominated sites and is prohibited whenever regulated releases are made from storages. • Stock and domestic use – Licences and permits issued to riparian landholders by DNR. • Unlicenced groundwater use – Licences are not required to drill or pump from aquifers that have not been proclaimed for management purposes. This applies to all areas other than the Bundaberg, Three Moon Creek and Cattle Creek DGAs. The number of unlicenced bores and volume extracted is unknown.
5.3 Surface/Groundwater Regulated Supplies
The main existing surface water storage structures relating to each sub-area are shown in Table 5.1.
Table 5.1 – Storage Structures within the Burnett Region Area Stream Storage Structure North Burnett Three Moon Cania Dam*, Creek Youlambie, Monto, Bazely, Avis & Mulgildie Weirs Monal Creek Mungungo Weir Central Burnett Nogo River Wuruma Dam* Burnett River John Goleby*, Jones* & Claude Wharton* Weirs South Burnett - Boyne Catchment Boyne River Boondooma Dam* Stuart River Gordonbrook Dam & Proston Weir - Barambah Catchment Barker Creek Bjelke-Peterson Dam* & Nanango Weir Barambah Creek Joe Sippel, Silverleaf & Murgon Weirs Lower Burnett Burnett River Ben Anderson Barrage*, Walla* & Bingera Weirs Kolan River Fred Haigh Dam*, Bucca Weir* & Kolan Barrage* (DNR 25 p5-4) * - Identified as major water storages in DNR 7
Total storage capacity of the ‘major dams and weirs’ within the study area, as reported in the DNR Annual Statistics 1999/2000, is in the order of 1,248,420 ML (DNR 2001), with actual usable storage for distribution from these structures being approximately 1,216,983 ML/a. Over recent years the usable storage has been reduced due to a combination of unsustainable demand and less than average rainfall. This translates to major structures such as the Fred Haigh Dam, in Lower Burnett, which has a maximum usable storage capacity of 557,610 ML only having a usable storage of 16 to 21% between July 1999 and June 2000 (DNR 2000).
Nominal supply available from these structures is over 300,000 ML/a of which approximately 60% is from the Burnett catchment and the remaining 40% from the Kolan catchment (SKM H p55). Nominal allocation figures vary slightly between years but are generally based on the total water available if all allocations, entitlements, licences and agreements etc were used. As identified above many of the dams in the area are considerably below capacity, therefore the DNR set announced allocations which are the percentage of nominal allocation available to farmers, with supplies to the urban sector being given priority. These announced allocations are set at the beginning of the year (in July) based on the amount of water in storage, then reviewed upwards as inflows occur (DNR 2001).
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Current nominal allocations from regulated surface and groundwater supplies are summarised in Table 5.2 for different end-users. Surface water nominal allocations are currently approximately 303,171 ML/a and groundwater allocations are approximately 90,714 ML/a.
Table 5.2 – Burnett Region Nominal Allocations Area Nominal Allocations (ML/a) Irrigation Industrial Urban Stock & Water Total Domestic Board North Burnett (SW) 1,484 125 15,414 (GW) 13,155 580 70 Upper Burnett (SW) 26,119 1,670 85 80 27,954 Central Burnett 75,246 Boyne (SW) 12,734 29,270 176 500 Barker-Barambah (SW) 30,257 127 2,000 182 Lower Burnett (SW) 186,822 20 7,020 4,500 275,271 (GW) 65,458 11,451 Total 336,029 29,542 22,721 261 5,332 393,885 Source – DNR 2001 SW – Surface water, GW - Groundwater
Table 5.3 summarises the announced allocations as a percentage of the nominal allocation at the start and end of each year since announced allocations were introduced in 1992. As shown water availability can vary considerably throughout the year and in some locations such as the BIA have been far below nominal allocations for some time.
Table 5.3 - % of Nominal Allocations Available Over Recent Years Regulated Supply Announced Allocation (Start/Finish of Year) (% of Nominal Allocation) 92/93 93/94 94/95 95/96 96/97 97/98 98/99 99/00 Three Moon Creek 100 100 100 100 100 100 90/90 80 Irrigation Project Upper Burnett 100 80 60 0/100 100 100 62/90 17-30 Irrigation Project Boyne River 100 50 0 0/100 100 100 100 100 Irrigation Project Barker-Barambah 150 125 80 100 100 100 100 100 Irrigation Project Bundaberg 170 120 110 80/95 50/75 15/38 15/30-60 20-30 Irrigation Area Source – DNR Bundeberg, 1999 (DNR 25 p5-6) Announced allocations for BIA since 95/96 split into Kolan/Burnett catchment as no transfers between two catchments have occurred since that time.
Deliveries across the catchment between 1990 and 1998 for surface and groundwater were well below nominal allocation levels, being on average only 245,000 ML/a compared with an average nominal allocation of 329,000 ML/a (SKM 6 p14).
As indicated above, groundwater also plays an important part in the supply of water to the region. The estimated long term yield for the region is 108,900 ML/a. However, the Bundaberg (Elliott-Fairymead), Three Moon Creek and Cattle Creek aquifers, which can be seen on Figure 5.1, are the only resources that have been constituted as Declared Groundwater Areas (DGAs) for management purposes (DNR 2001) with annual allocation from these DGAs being 90,714 ML/a.
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Over the years the demand for water in the Lower Burnett region, primarily associated with irrigation, has meant over-exploitation of the groundwater aquifers, which has lead to saline water intrusion. The DGAs were set up in the 1970s to attempt to resolve the issue, however salinity problems persisted. Management by announced allocation was also set up but this dramatically reduced the quantity of irrigation water available to farmers in Lower Burnett. Groundwater use has been limited to approx. 50% of allocation in recent years to attempt to further reduce salinity problems. Investigation is now underway by DNR into the replacement of 14,000 ML/a groundwater allocation with surface water as part of the BIA Groundwater Rescue Project to attempt to resolve the salinity problems and provide more water to irrigators (SKM 1998). The required 14,000 ML/a has been highlighted as a required proportion of the Paradise Dam supply option.
5.4 Unregulated Water Supplies
Diversions from unregulated surface water supplies are not currently metered except in some water project areas. A basin-wide hydrological model was used under the Burnett Basin WAMP process to identify potential mean annual diversions for the current capacity of private water infrastructure development within the Burnett region. The results of these findings are shown in Table 5.4. It should be noted that these diversions are only an estimate. Actual diversions may vary significantly between years depending on how, where and when stream flows occur.
Table 5.4 – Potential Mean Annual Surface Water Diversion of Unregulated Supplies Area Unregulated Supplies (ML/a) Irrigation Stock & Domestic Water Harvesting 1 Total North Burnett 107 524 631 Central Burnett 5,227 182 1,876 7,285 South Burnett 10,086 230 2,036 12,352 Lower Burnett 19,555 145 465 20,165 Total 34,975 1,081 4,377 40,433 Source – DNR 2001 Based on current capacity of private water infrastructure 1 – Includes water harvesting of unregulated supplies within regulated sections.
For groundwater, licences are not required to drill or pump from aquifers that are not DGAs. This applies to all areas other than Bundaberg, Three Moon Creek and Cattle Creek aquifers. The number of boreholes and the volume of water extracted is unknown.
A brief description of the surface and groundwater supplies identified by DNR (2001) is provided in Appendix B.
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6. WATER USE
6.1 Overview According to SKM (2000) overall water use in the Burnett Region in 1997/98, obtained from both surface and groundwater supplies, was in the order of 210,000 ML, which can be split into major demand groups as shown in Figure 6.1. SKM also identified, that water use can vary considerably between years depending on available water in storage and rainfall and that 1997/98 was a fairly low water use year compared to some others in the 1986 to 1998 period. Figure 6.1 does illustrate however, that irrigated agriculture is the primary water user in the area and that industry, town/urban and stock and domestic water users currently together represent a significantly smaller proportion of water demand in the area then irrigation. Sugar cane is by far the biggest water user in the region and when more water is available in certain years, uses this accordingly, thus representing an even higher proportion then then that shown in Figure 6.1.
Figure 6.1 – Water Use 1997/98
7 % 1 %
1 2 % Sugarcane H orticultu re 4 8 % Field and Fodder C rops 1 1 % In d u stry Town W ater Stock and D om estic 2 1 %
(Source - SKM 2000)
6.2 Historic Water Demand
In order to gain a better understanding of the current water use in the area and realistic potential water use in the future it has been necessary to review available SKM and DNR water use figures (SKM 1998, DNR 2001) and identify the historical trend of water use in the region.
Figure 6.2 summarises the water use of irrigation, industry, urban, stock & domestic and water board water users between the years 1986 and 1999. The nominal allocation figure used is based on current allocations (surface & groundwater) and has been projected back to 1986 in the absence of available data.
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Figure 6.2 – Regulated Surface & Ground Water Use 1986 to 1999
450000
400000 Irrigation 350000 Industry 300000 Urban 250000 Stock & Domestic 200000 Water Board Other 150000 Total 100000 Nominal Allocation 50000
0 1986/87 1987/88 1988/89 1989/90 1990/91 1991/92 1992/93 1993/94 1994/95 1995/96 1996/97 1997/98 1998/99 Years
Source Data - DNR 2001
As can be seen the water use in the area varies considerably between years but is dominated by irrigation. The significant variations in water use each year correlate to water availability in existing storage structures (announced allocated water) and rainfall. In high rain years less supplementary irrigation is required therefore demand drops. However, similarly when storages cannot provide water due to insufficient water, announced allocations are smaller and demand is forced to drop. Between 1986 and 1995 there appears to be a strong increase in water demand mainly associated with irrigation. However, in more recent years since 1995 this demand has dropped significantly which can mainly be attributed to the low volumes of water in existing storages which have not been able to provide adequate water to meet demand.
The water use figures used in Figure 6.2 are provided in tabular form in Table C1 in Appendix C. These figures include regulated surface and groundwater use and water harvesting which is mostly undertaken along regulated river sections. However they do not include unregulated water use. Unregulated surface water use for stock and domestic and irrigation use is in the order of 1,000 ML/a and 35,000 ML/a respectively (refer to Table 5.4). Unregulated groundwater use is not measured and as such volumes are unknown. This unregulated groundwater use occurs anywhere outside the DGAs of Bundaberg, Three Moon Creek and Cattle Creek.
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6.3 Future Demand
Various studies have attempted to predict future water demand in the region based on current demand, identified needs submitted to the Water Infrastructure Task Force (WITF), surveys and unconstrained potential of the soil in the region. Projections of water demand for sectors such as town/urban can be predicted with some level of certainty using past experience. However, irrigated agriculture and associated industries are far more unpredictable as they are affected by many factors, such as local and foreign market forces. As such, the projected water demand in the region varies significantly between studies depending on the assumptions used.
Figures 6.3 & 6.4 illustrate the future water demand projected by DNR (2001) for identified water requirements and unconstrained development of irrigable land. A summary of the DNR findings used to obtain these projections are provided in Appendix C (Table C2). For full details refer to DNR (2001) Report. It should be noted that the time scale for these projections has not been clearly defined by DNR. Some of the identified water demand requirements, which are part of the projected demand case in Figure 6.3, are needed within a 10 year rather than the 20 year period indicated. Hence this may mean the water identified is required within a tighter timeframe then shown. Much of the water required is to make up for the deficiencies in the storage volumes currently being experienced. In Figure 6.3 much of the identified water required assumes high application rates for irrigation, which may not be necessary if higher application efficiency was adopted. In Figure 6.4 the unconstrained scenario cannot be achieved due to catchment water constraints.
Figure 6.3 – Projected Water Use Based on Identified Requirements
600000 500000 400000 Total Water Use 300000 (Identified) 200000 100000 0 1986/87 1990/91 1994/95 1998/99 2002/03 2006/07 2010/11 2014/15 2018/19 Years
Figure 6.4 – Projected Water Use Based on Unconstrained Development of Irrigable Land
1200000 1000000 800000 Total Water Use 600000 (Unconstrained 400000 Irrigation) 200000 0 1986/87 1990/91 1994/95 1998/99 2002/03 2006/07 2010/11 2014/15 2018/19 Years
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6.4 Disaggregated Water Use
Water demand in the region can be disaggregated into various sectors as illustrated in Figure 6.5. Disaggregated demand split in this way can be useful in understanding overall water demand within the region, future water demand, potential losses from the system (such as town reticulation or irrigation distribution channels) and defining areas where demand management/water efficiency measures may potentially reap the greatest water savings.
Figure 6.5 – Disaggregated Water Use by Sector
WATER - Surface - Groundwater
TOWN/URBAN INDUSTR Y AGRICULTURE OTHER - Residential - Major Bulk Users - Sugar Cane - Environmental Flows - Commercial (e.g. Tarong Power - Horticulture - Minor Industrial Station) - Field & Fodder - Institutional - Stock & Domestic - Unaccounted for - Losses (transmission/ (leakage/unmetered/ pipelines/channels) illegal use etc)
The current water use and potential to reduce water demand through demand management/efficiency measures for each of these individual sectors is considered in Sections 7 to 10. Various options have been identified in each of these sections. These options and the associated costs are then summarised in Section 12 and assessed, together with supply options identified in Section 11, to find the most socially, environmentally and economically suitable solution to the regions requirements.
Although irrigated agriculture is the largest consumer of water in the Region and is likely to have the greatest potential for water efficiency savings, this Study is designed to provide an overview of LCP principles available and thus although town/urban and industry sectors are considerably smaller they are still important in providing potential savings. When considering the principles of LCP a key issue is understanding that every water end use must be considered and that every mega litre of water saved means one less mega litre needs to be supplied.
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7. TOWN/URBAN
7.1 Population & Water Use
In the 1996 census year the Study area population was 122,933 with a growth rate of over 2% per annum since 1988. In the order of 60% of the catchment’s population lives within the Burnett Shire and Bundaberg City. Two areas of strong population growth are Bundaberg (and the surrounding three shires of Burnett, Kolan and Isis) and the Kingaroy/Nanango area. In the remainder of the catchment there is generally a zero or negative population growth (DNR 2001). Table 7.1 provides a breakdown of the population spread for each area over the last three census years.
Table 7.1 – Population Breakdown Local Government Area 1986 1991 1996 North Burnett Monto 3269 3138 2921 Central Burnett Eidsvold 1240 1052 965 Chinchilla 2 5884 5913 5600 Mundubbera 2347 2337 2436 Gayndah 2932 2928 2872 Perry 332 386 371 Kilkivan 2 2765 2944 3232 Biggenden 1603 1643 1637 Sub total 17103 17203 17113 South Burnett Wondai 2 3940 4059 4106 Kingaroy 10212 10863 11442 Murgon 4728 4663 4627 Nanango 2 5536 7052 8076 Sub total 24416 26637 28251 Lower Burnett Bundaberg 37994 41790 43538 Burnett 1,2 12608 15619 20964 Kolan 2699 3098 4347 Isis 4065 4730 5799 Sub total 57366 65237 74648 Total 102154 112215 122933 Source – Dept of Local Government and Planning – Recent Population and Housing Trends in Queensland, 1997 1 - Burnett Shire is a combination of Gooburrum and Woongarra Shires 2 - Denotes Shires which are only partly within the Study area
Many of the key studies already carried out in the Burnett area identify that the population is forecast to grow to 156,750 by 2011 and 186,500 by 2050. These include a net reduction in areas such as Murgon and Monto to over 5% annual growth for the Burnett Shire. No allowances in the figures appear to have been made for current or projected tourists. The tourist industry appears to be fairly strong in the region, especially in Bundaberg where a number of hotels are situated together with a small local airport.
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Urban/town water use, which includes residential, commercial, industrial, institutional and unaccounted for water (leakage, unmetered, illegal use etc.) is estimated to be approx. 7% of the Burnett Region total water usage (SKM 2000). From 1997/98 DNR records, surface water usage was approx. 8,813 ML and groundwater usage 6,797 ML. Therefore total use was approx. 15,610 ML. In addition, from DNR investigations, it appears approx. 75% of the population is supplied by some form of reticulated supply (DNR 2001).
No specific data is currently available on the breakdown of end users or their demand therefore industry accepted general figures will be used to assist in the assessment of possible water savings. Based on the figures identified above and using additional assumptions indicated the estimated number of customers together with their current demand is provided in Table 7.2.
Table 7.2 – Estimated Number of Customers and Associated Current Water Demand Sector User Estimated Estimated Assumptions No. of Current Customers Demand (ML/a) Residential 30, 700 11,200 Approx. 3 persons per connection 75% of region population on reticulated supply (92,200) Approx. water demand of 365 kL/connection/a Commercial, 1,500 2,400 15% of total water use for town/urban sector Institutional, 20:1 ratio of residential connections to CII Industrial (CII) Reticulated - 2,400 15% of total water use for town/urban sector Losses Total 16,000 Rounded region demand figure
7.2 Potential Water Savings & Costs
Bundaberg represents approximately 35% of the region’s population and currently has a universal metering system with a tariff structure allowing 600 kL/hh/a as a base allocation with an excess charge for additional use. This allowance is high and the tariff structure does not facilitate water efficiency. Hence there is substantial scope for water savings in this area alone through demand management with an initial emphasis on pricing reform consistent with the Council of Australian Governments (COAG) requirements. When combined with a community education and assistance program (including outdoor usage issues) this can provide a significant demand reduction in the order of 25%, based on experience from other regional areas in Australia (White, 1998).
Further investment in a water efficiency program could then be undertaken, which could reduce demand by an additional 10 to 20%, with a combination of residential appliance retrofitting, leakage reduction and a business program targeting commercial and town water supplied industrial customers. In the coastal areas, especially Bundaberg, there is likely to be significant potential savings associated with the hospitality sector.
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Assumed costs associated with these programs are as follows:
• Pricing reform costs have not been considered as these reforms are required to be implemented in the near future and due to the low cost of such reforms commercial, institutional and industrial (CII) users will also be influenced by volume based charging for wastewater were that to be introduced. • Education and assistance programs involving various forms of media $0.25m. • Retrofitting of showerheads, flow regulators on taps, toilet flush reduction and leakage repair by plumber inspection, $100 per connection. Assuming 80% of households take up offer. • Cost of $2,500 per CII connection for assessment and retrofitting of 50% of industries. • Cost of a leakage detection program and associated remedial works, $1m.
Using these assumptions and the previously identified figures, estimates of savings and costs are shown in Table 7.3. The sector breakdown and customer numbers used from Table 7.2, are estimates only and will be reviewed if further information becomes available.
Table 7.3 – Potential Water Savings and Associated Program Costs Sector User Program Element Estimated Estimated Unit Cost Water Program Cost ($/ML) Savings ($ m) (ML/a) Residential Pricing reform 2,800 - Education Assessments & 1,260 2.7 retrofitting Sub Total 4,060 2.7 665 CII Pricing Reform - Assessments & 360 1.88 5,208 retrofitting Leakage Detection & remedial 1,000 1 1,000 works Total 5,420 5.6 1,033
From the results a combined program as suggested could potentially provide savings of 5,420 ML at an overall cost of $5.6m. This produces substantial savings of around one third of the current usage for a unit cost of only $1,033/ML.
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8. INDUSTRY
8.1 Water Use Only a limited number of major industrial operations are supplied separately from the urban industrial sector which includes commercial, institutional and light industrial water demand supplied under the urban reticulation system. According to SKM (2000) water demand for the industrial sector supplied separately to town water supplies in 1997 was in the order of 25,800 ML/a, representing 12% of water usage.
The key industrial water users in the region are:
• Tarong Power Station in South Burnett • South Burnett Meat Works • Bingera, Fairymead, Millaquin and Isis sugar mills
The current and proposed water usage in the Burnett Region is identified below.
North Burnett - Only 30 ML/a is allocated for industrial purposes. Several industrial proposals have been suggested including mining of ilmenite and coal but identification of water demands for these proposals have not been qualified.
Central Burnett - There are no specific allocations for existing industrial sites or proposals requiring additional diversions from surface water supplies but a proposal for an ilmenite mine at Mt Goondicum is likely to draw water from an artesian bore.
South Burnett - Tarong Power Station and associated coal mine is the major industrial activity within the Burnett Region. The power station is supplied from Boondooma Dam via Tarong pipeline. The current allocation is 29,270 ML/a. Use has ranged from 21 050 ML/a to 31 280 ML/a of which approximately 5,100 ML is released annually into Meandu Creek as effluent. An additional pipeline to provide contingency supplies has been constructed from Wivenhoe Dam.
An expansion of the power station to be commissioned in 2003 has been approved and construction is currently under way. It is understood that Tarong North will require 8,000 ML/a of which 6,000 ML/a is to come from recycling, leaving a demand for an additional 2,000 ML/a.
In addition to the Tarong Power Station, South Burnett Meat Works currently uses 580 ML/a. No expansion of the abattoir is currently envisaged. The abattoir has achieved 24% water savings over the last two years and now operates at half of the industry standard for water consumption.
Lower Burnett – The current industrial users include the Bingera, Fairymead, Millaquin and Isis sugar mills. Total consumption of the four mills is estimated to be 625 ML/a.. The sugar mills import water in the harvested cane and only marginal savings in water consumption are possible with modifications to the process chain. (pers. comm.).
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8.2 Proposed Additional Future Water Use
The development of new industries is unpredictable and arises as opportunities present or as a result of specific government initiatives to create employment and diversify the economy. Should additional water be provided, these might include value-added horticultural operations such as tomato paste, avocado paste, sweet corn and citrus processing plants.
A chicory processing plant has been proposed for Childers. The processing plant would require 2,500 ML/a for its operation (pers. comm.) and up to a further 11,500 ML/a for irrigation requirements to grow the crop in the district (SKM, 2001).
A major new industrial proposal identified for the region is the Bundaberg 2000+ (B2K+) Project. The industrial development is centred on a new paper pulp mill using bagasse (waste plant matter from sugar cane) and plantation woodchips as fibre sources. The project proponent, Bundaberg Project 2000 Pty Ltd (a wholly owned subsidiary of Multiplex Constructions Pty Ltd) released an EIS for the proposal in January 2001. However, no firm decisions are known to have been made on whether the proposal will go ahead. The project would involve a total capital expenditure of $1 billion and was originally proposed to be commissioned by mid 2004.
The B2K+ project is designed to use state-the-art technology to achieve a zero process effluent capability in the pulp mill. Maximum re-use of effluent and utilisation of captured stormwater and excess water from the sugar mill achieve this. It is proposed to use 3,000 ML/a of secondary treated effluent from Bundaberg City Council sewage treatment plants, which is currently discharged into the Burnett River to supplement industrial process water requirements.
The EIS states that financial viability of the Project is dependent on producing a nominal 185,000 t/a of pulp from bagasse and 180,000 t/a of pulp from woodchips. To achieve this production output the mill requires a nominal supply of 1.12 million t/a of bagasse from Bundaberg Sugar mills. Upgrading of the sugar milling operations will address this processing requirement. The minimum sustained sugar cane crop in the Bundaberg district to ensure viability of B2K+ is 3.6 million t/a. However, there are significant variations in annual cane crop production. The average cane production for the past 10 years from the Bundaberg district (which does not include the Isis Mill area) has been 3.0 million t, with the 3.6 million- t target being met in only one year. The average crop has been 3.3 million t over the last 5 years, which does not meet requirements. A study undertaken by RR Consultancy (2000) investigated the long term additional water required to meet the 3.6 million t sugar cane requirement but concluded that the target would be difficult to reach on a secure basis and would require in the order of 114,000 ML of additional water.
It is not known whether either of these particular projects will go ahead in the future. The B2K+ project has been proposed as a major driver for the Paradise Dam Option. An alternative to the Paradise Dam Option has been considered for the sugar industry in Section 9.2, which is believed to be capable of achieving the required increased cane yield for the B2K+ project.
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Using SKM (2000) figures current demand is in the order of 25,800 ML/a depending on the use by Tarong Power Station. This is likely to rise to around 30,000 Ml/a in future if the additional requirements of the Tarong extension and chicory plant are considered. An additional 11,500 Ml/a would be required specifically to irrigate the new chicory crop.
8.3 Efficiency and Potential Water Savings
The current SKM (2000) water demand estimate for this sector is 25,800 ML/a. However, due to the limited number of industrial water users it would be advantageous to consider an auditing program to investigate if potential savings are feasible. The three main water users identified in Section 8.1 may already be close to best practice efficiency of water use, and may have had some assistance or monitoring to develop these efficient systems. Therefore for this Study no allowance will be made for water savings or costs. However, it is recommended that these industries are investigated further and an audit conducted to determine if additional savings can be achieved.
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9. AGRICULTURE
9.1 Overview
Agricultural water use in the region can be disaggregated into the following users:
• sugar cane irrigation; • horticultural irrigation; • field & fodder irrigation; • stock & domestic watering; and • irrigation supply losses before the farm gate.
The water use and potential savings through efficiency measures for each of these users is considered in the following sections. In addition potential crop yield increases have also been considered together with their potential value. These issues have been addressed because the main purpose of the water being supplied by the Paradise Dam and the other more minor structures is primarily to increase sugar yield and to expand the area under horticultural irrigation. Therefore in order to compare demand management/efficiency options effectively against supply side options, crop yield increases and associated value as well as relative unit cost of options must be taken into consideration. These issues are considered in depth in Section 12 following identification of supply side options in Section 11.
Many of the main principles behind water efficiency in the agricultural industry are summarised in section 9.1, the sugar industry. These principles are then used for the other irrigation industries in the subsequent sections.
In each of the irrigated industries, the following issues have been considered:
• current area irrigated; • current water used; • irrigation methods • water use efficiency and potential water savings available; • water efficiency considerations; and • water efficiency options and costs.
9.2 Sugar Cane 9.2.1 Area
Sugar cane is only grown in the Lower Burnett region, in the Bundaberg Irrigation Area (BIA), close to the 4 sugar mills of Bingera, Fairymead, Millaquin and Isis. The BIA is dominated by sugar cane production. Assigned and harvested sugar cane areas, as reported in the CANEGROWERS Annual Reports, vary each year. Over recent years there has been a gradual rise in the assigned area but the actual harvested area has not increased at the same rate. Using available data from only 3 of the 4 mills (Isis Mill missing) this is illustrated in Figure 9.1.
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Figure 9.1 – Assigned & Harvested Areas (1986 to 1999)
60000
50000
40000 Area Assigned (Ha) 30000 Area Harvested (Ha) 20000
10000
0
6 8 0 1 3 6 8 8 87 8 89 9 9 92 9 94 95 9 97 9 99 Years
(Data source – RR Consultancy)
A snap shot of the sugar cane areas harvested and yields obtained in 1997 is provided in Table 9.1 below.
Table 9.1– Cane Areas Harvested (1997) Mill Area Area Harvested Cane Yield Sugar Yield (ha) (t) (t) Bingera 12,386 1,050,396 157,282 Fairymead 13,697 1,303,808 191,321 Millaquin 11,119 1,046,603 155,101 Isis 12,013 1,103,355 164,059 Total 49,215 4,504,162 667,763 (Source – SKM 1998, RR Consultancy)
According to SKM (2000) and RRC (2000), over the same period there has been a growing trend for sugar cane farmers to use mixed cropping of horticultural crops to supplement incomes, which has led to a small proportion of the assigned areas being used for horticultural crops instead of sugar cane. Actual figures for the area under horticulture and the area assigned to sugar cane, now being used for horticulture, are not fully recorded and are thus difficult to ascertain. The areas lost to horticultural crops, left fallow or which are unused or abandoned due to shortage of water in the area vary each year. Horticultural crops grown in the BIA in 1997 covered just over 5,000 ha according to a recent study (Barraclough 1999), which currently represents only a small area (approx. 10%) compared to that of harvested sugar cane.
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9.2.2 Water Use
Water used for sugar cane in 1997/98 is believed to be 48% (100,000 ML) of total water use within the region, according to SKM (SKM 2000) investigations. As indicated in Section 6.2, in other years when announced allocations are higher and closer to nominal allocations water demand can increase substantially. Many of the dams in the area are currently considerably below capacity. Therefore the announced allocations (which are the percentage of nominal allocation available to farmers with supplies to the urban sector being given priority) are substantially below nominal allocations. Hence under the current situation where announced allocations are only approx. 50% of nominal allocations, sugar cane water demand increases substantially when water becomes available because nominal allocation represents the approx. water required for optimal growth. During periods of low announced allocations cane yield and profitability can be significantly reduced.
The actual water used on sugar cane alone is difficult to ascertain due to the complications associated with the mixed cropping, regulated and unregulated water supplies and on-site storage etc. Water is generally only measured, if at all, at the farm gate and thus those farms that use mixed cropping can complicate the water use data. In addition, due to the scarcity of water and subsequent reduced allocations to farmers in the region it is now often found that water allocated to these mixed crop sugar cane farmers is given to the horticultural crops as a priority and the sugar cane as a secondary exercise due to the relatively high return on horticultural crops compared to sugar cane. This therefore compounds the problems associated with data obtained for water use, tonnes of sugar cane harvested per hectare or per ML of water, and cane yield obtained each year. The Bureau of Sugar Experiment Stations (BSES) collate such figures each year. In order to isolate sugar cane statistics BSES attempt to remove the results of those farmers currently using mixed cropping.
Annual crop water use varies from region to region throughout Queensland due to climatic variations. In the BIA, annual crop water use is in the order of 1,360 mm (13.6 ML/ha/a), which comprises of effective rainfall and supplementary irrigation. In the BIA, the effective rainfall, which is defined as the proportion of total rainfall stored within the rooting depth of soil and which is potentially available for cane growth, is in the order of 580 mm. This means that the missing 780 mm of water required per annum should be made up by irrigation (BSES 1998).
The BIA was designed to provide 6 ML/ha/a for 75% of the 1970 assigned area with 25% of the area in rotation. Due to changes in agricultural practices and crop types around this time the allocation dropped to 4.5 ML/ha/a when little rotation was actually implemented. From 1970 to approximately 1995 announced allocations averaged only 3.6 ML/ha/a. Over the last 5 years these allocations have only been around 2.2 ML/ha/a. This is due to below average rainfall, subsequent reduced storage volumes and increased supply to more assigned areas including the 19,000 ha Isis area, which was not previously supplied with irrigation water. As such the 2.2 ML/ha/a is well below the 7.8 ML/ha/a required for optimum production.
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However, cane yield has increased, despite the water scarcity over the last few years. The relationship between yield and water use is often described by the Cane Water Index (CWI) identified below:
CWI (Tonnes/ML) = Productivity (t/ha) Total water use (irrigation plus effective rainfall in ML/ha)
The relationship in recent years between CWI, rainfall and irrigation use is illustrated in Figure 9.2. The increase in CWI can be generally attributed to extension advice from BSES and others, improved management practices, new cane varieties, improved practices such as trash blanketing and improved water efficiency due to restricted water availability.
Figure 9.2 – Relationship between CWI, Rainfall, Effective Rainfall & Irrigation (1989 to 1999)
1 0 1 8 0 0
9 1 6 0 0
8 1 4 0 0 7 1 2 0 0 6 1 0 0 0 5 8 0 0 4 6 0 0 3 CWI (tonnes cane/ML) (tonnes CWI 2 4 0 0 (mm) irrigation Rainfall,
1 2 0 0
0 0 89 90 91 92 93 94 95 96 97 98 99 R ain fall Effective rainfall Irrig a tio n C W I (Source – DNR 2001)
9.2.3 Irrigation Methods
The main irrigation methods used for sugar cane production in the Burnett Region are as follows:
• Furrow – Originally the main irrigation method used in the BIA until the 1960s due to the simple and cheap on-farm infrastructure required. The system basically comprises mains pipelines connected to the water supply point; header pipes of flexible, lay-flat or gated aluminium pipe; evenly spaced furrows fed from outlet points along the header pipe; and in more efficient systems a tail water return system to capture and return runoff to the header system. • Overhead (winch) – In the 1970s and 80s overhead methods replaced many of the furrow systems in the area especially where terrain or soil type constraints provided difficulties. Lateral move irrigators are used to a small extent but the main systems used are large capacity spray guns, locally known as water winches, which comprise a mobile spray gun with a spray radius of around 30 to 50 m, a cleared track along which the gun is towed, a hard or soft hose water supply pipeline to feed the gun, and a winching device.
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• Drip/Trickle – Trickle represents only a small proportion of the overall irrigation systems used in the region, however, over the last 5 years there has been an increased movement towards this system mainly due to the growing trend towards mixed cropping. These relatively expensive systems comprise of a booster pump and filtration unit, a network of fixed or floating header pipes, small diameter tapes laid along the crop line either above or below ground which feed water directly to the root zone, and a collector pipework network returning water to the filter and pump system.
According to Tilley & Chapman (1999) in their recent review conducted for the Rural Water Use Efficiency Initiative (RWUEI) the irrigation methods used in the BIA are as identified in Table 9.2, with 96 to 97% of growers using irrigation.
Table 9.2 – Irrigation Systems Used for Sugar Cane in the Burnett Region District Irrigation Method (%)* Furrow Drip/Trickle Overhead Winch Lateral Move Bundaberg (Millaquin, 25 5 70 Bingera & Fairymead) Childers (Isis) 20 5 70 5 * - Based on areas irrigated. (Source – Tilley & Chapman)
A further breakdown of irrigation methods used as a percentage of the irrigated area within each mill area (1998) is identified below in Table 9.3.
Table 9.3– Irrigation Systems Used in Each Mill Area Irrigation Method Mill Area Trickle (%) Overhead (%) Furrow (%) Millaquin 19 31 50 Isis 9 87 4 Bingera 1 77 22 Fairymead 5 54 41 (Source – SKM 2000) Millaquin yearly info, Bingera fairly good, Fairymead no info so collected by Cane Assignment Officers (cane farms only)
9.2.4 Water Use Efficiency
Water input at the farm gate can be lost at various points within the on-farm system thus affecting the water use efficiency. ‘Farm Application Efficiency’ can therefore be used to determine the water lost within the on-farm system. This lost water can potentially be saved through efficiency measures and reapplied on the same crops or used to expand irrigated areas. The term ‘Farm Application Efficiency’ has been taken from SKM (2000) and is defined as shown below:
Farm Application Efficiency = Irrigation water available to crop (ML/a) Volume of water received at the farm gate (ML/a)
This definition is based on the concepts put forward by the Land and Water Resources Research and Development Corporation (LWRRDC) (Barrett Purcell et al 1999) but does not exactly follow the definitions they provided.
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It is impossible to obtain 100% farm application efficiency such that all water supplied to the farm gate is used beneficially by the crop irrigated. This is due to the fact that in practice various irrigation systems have varying levels of application and transmission efficiency, there are variations in soil type which can lead to runoff or deep drainage if not irrigated effectively, variations in management practices which determine when and how to irrigate, and other issues such as the requirement for leaching of soils in order to reduce the build up of salts within the soil caused by irrigation.
These variations in farm application efficiency mean that water actually available to the crop root zone for growth varies, subsequently affecting crop yield. A simplified diagram based on Barrett Purcell (Barrett Purcell et al) of the points at which farm gate water can be lost to the system is provided in Figure 9.3. It should be noted that distribution losses before the farm gate can often be significant. These losses are discussed in Section 9.5.
Figure 9.3 – On-Farm Water Losses
TOTAL WATER INPUT FARM GATE DELIVERED WATER
RAINFALL STORAGE LOSSES - evaporation - seepage ON-FARM STORAGE - leakage - operational losses Tailwater return
TRANSMISSION LOSSES - evaporation - seepage - operational losses TRANSMISSION - leakage
WATER APPLIED APPLICATION LOSSES - off-target - deep drainage - evaporation WATER RETAINED IN - surface run-off SOIL AS PLANT AVAILABLE WATER
WATER CONSUMED BY AFFECTED BY CROP - management - climate - soil type - crop variety CROP YIELD - pests & disease
The main purpose of irrigation is to supply additional water were rainfall alone is insufficient to produce a viable crop yield. Irrigation water is therefore used to ‘top up’ the soil water to minimise plant stress, which can lead to crop death if the water level drops below the wilting point. Figure 9.4 illustrates the different types of soil water.
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Figure 9.4 – Different Types of Soil Water
Water Applied Irrigation & Rainfall
Soil in Root Zone Runoff Gravitational Water
Full Point Readily Available Water
Refill point Plant Available Water Permanent Wilting Point
Air Dry Zero Moisture
Water below Root Zone Deep Drainage
(Source – BSES 1998)
The farm application efficiency for various irrigation systems used in the region has been identified by SKM (SKM 2000). These farm application efficiencies are provided in Table 9.4.
Table 9.4 – Attainable Farm Application Efficiencies Irrigation Type Description Farm Application Efficiency (%) Furrow Irrigation Free-draining furrows 65-70% Blocked-end furrows 70-75% Surge-flow (initial pulse application) 70-75% Best practice tailwater recovery & reuse (BPF) 85-90% Overhead Irrigation Water winch 60-70% Hand-move, side roll, wheel line 65-75% Solid set 70-80% Centre pivot, linear move 75-85% Micro-systems Drip irrigation, mini-sprinklers >90% (Source – SKM 2000 from Utah Uni discussions and SKM expert)
To achieve maximum farm application efficiency the irrigation system needs to concentrate the limited water resource around the root zone of the plant thus minimising runoff, evaporation, deep drainage and other losses. Timing of application to the plant is also important as there is a fine balance between soil water ‘top up’ and surface runoff or deep drainage. Micro-systems such as drip/trickle irrigation can achieve the highest farm application efficiency rates on a wide variety of soil types when the systems are managed correctly. Systems such as furrow irrigation can achieve increased levels of efficiency when tail waters are returned or the cross-section and/or length of furrows together with application rate are modified to suit individual soil types. Similarly winch irrigation efficiency can be improved with better management techniques and application in low winds. Improvement in equipment efficiency, management techniques and the use of scheduling can lead to ‘best practice’ management and achievement of maximum on-farm water use/farm application efficiency.
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A feel for irrigation efficiency within the region can be gained by considering the irrigation method against CWI for the BIA as shown in Figure 9.5. As shown there is wide variability in the tonnes of cane achieved per ML of water for both overhead and furrow irrigation methods but far less variation for trickle irrigation. In addition trickle irrigation provides a higher average level of CWI compared to the other methods. This implies that a move towards trickle irrigation could potentially provide more tonnes of sugar cane per ML of water supplied to the farm gate thus providing greater return for farmers through increased crop yields and reduced water bills. The higher capital costs associated with trickle irrigation need to be taken into consideration.
Figure 9.5 – CWI against Irrigation Type for the BIA
C W I v s Irrigation Type 1 6 .0
1 4 .0
1 2 .0
1 0 .0 1 0 .0 8 . 8 9 . 1 8 . 0
6 . 0 M ax im um
CWI (tonne cane/ML) (tonne CWI 4 . 0 A vera ge 2 . 0 M inim um 0 . 0 Overhead Furrow Trickle
(Source – DNR 2001)
Water use variations can also be illustrated by considering crop yield against total water use for a group of farmers. Appendix D identifies the crop yield against total water used (rain and irrigation) for the Millaquin area in 1997/98 for the three main methods of irrigation. As indicated trickle irrigation is much more tightly distributed around the trend line then the other forms of irrigation method which scatter widely indicating a wider variation in water use for the same crop yield. These variations can be attributed to factors such as different irrigation methods, water efficiency, management techniques, soil type and crop varieties but illustrate that a move towards bringing those less water efficient farmers in line with ‘better practice’ farmers (i.e. tightening the distribution) could potentially lead to an increase in water efficiency and thus reduction in water demand. This would enable the water saved to be used to increase crop yield more effectively.
Trickle irrigation appears to provide the greatest potential for maximum farm application efficiency when managed correctly. Using recent SKM modelling results (SKM 2000) potential water savings can be calculated under the current limited irrigated water supply (2.28 ML/a) which is approx 50% of nominal allocation. Table 9.5 provides the assumptions used and identifies the attainable efficiencies according to various soil types and the proportion of soil types within the area. The areas used are from 1998 figures, which are very similar to the 1997 figures identified earlier. The scenario considered assumes that all irrigation is converted to trickle irrigation. The model effectively calculates the current water losses due to low application efficiencies associated with the proportion of inefficient systems used and then recalculates the smaller losses achieved when higher efficiencies are obtained through transfer to trickle irrigation. As can be seen from Table 9.5, a saving of 26,300 ML/a can be achieved, representing 26% of current sugar cane water use.
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Table 9.5 – Potential Water Savings for Sugar Cane Assuming 100% Trickle Adoption Irrigation Efficiencies for Various Soil Irrigation Future Losses Possible Method Types Water Use Adoption (ML/a) Savings (ML/ha/a) Rates (ML/a) Heavy Medium Light Current Future Trickle 95 90 90 2.28 100 Overhead 70 65 65 2.28 0 36,170 9,870 26,300 Furrow 75 70 60 2.28 0 (Source – SKM 2000)
9.2.5 Water Efficiency Considerations
Due to the shortage of water in the area, considerable discussion and investigation has already concentrated on the various issues related to water efficiency. From these investigations and programs, such as the RWUEI, it has become evident that irrigation is a complex technical and managerial task and that the efficiency of water use can vary considerably due to a number of factors.
It is now becoming apparent that investment in improved irrigation methods alone, such as trickle irrigation, is insufficient and that other factors should be considered, including:
• a full understanding of the type of soil each farmer has and the most suitable irrigation system for that soil; • the achievable ‘best practice’ water use for the combination of soil and irrigation system; • management techniques; • weather and soil moisture monitoring; • irrigation scheduling; • plant growth cycles; • cane varieties; and • sugar yield compared to cane yield and potential yield increases due to water stress etc.
It is therefore essential that any options considered and program developed for the sugar cane industry (and for that matter the other agricultural industries being considered) should consist of multiple components including:
• improved irrigation systems; • financial assistance; • improved management; • education and awareness; and • research.
Hence, extension and expansion of the RWUEI, which attempts to cover these issues, is vital in order to complement any infrastructure developments. The farming community and industry appear to be working well together in this particular program and hence extension and development of this program would be more beneficial then devising a new scheme.
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Other issues that need to be considered in a program include:
• In order for a program to work, water savings alone will not be sufficient. A combination of water savings and increased cane yield are required. Farmers are unlikely to be willing to change or participate in a program concentrating solely on water saving and are likely to use the water saved to make up for the allocation deficit experienced in recent years. Identification of increased cane yield potential from water saved and the chance to use new technology at a reduced cost is likely to achieve a better participation rate and meet long term goals. • It has been known for many years that farming methods such as close row or multi row cropping can significantly increase yield with little or no extra water use. Trials of these farming methods have and are currently being conducted and show yield increases of as much as 50% with efficient irrigation systems such as trickle irrigation (RR Consultancy, 2000). One of the primary reasons this form of farming method has not been adopted extensively commercially is due to the lack of modified farming equipment required to deal with the unconventional row width. With widespread adoption of this farming technique and financial assistance with equipment modification in the form of large-scale subsidised co-operative contractors, this technology could revolutionise the sugar industry. • Investment in on-farm storage to assist in capturing runoff and seepage from rainfall and irrigation plus out of allocation water essentially lost from the system could be extremely beneficial. On-farm storage would enable farmers to manage and schedule irrigation more effectively and supplement their allocation, providing a buffer for the system and ultimately increasing overall storage in the whole catchment. • The integration of water monitoring techniques and increased management to achieve a better appreciation of the real quantity of water used on farms, how much is available for plant growth and where water is being lost will be of enormous benefit and enable farmers to modify systems to achieve maximum efficiencies and come in line with best practice principles. • The combination of various options will minimise the risk of money invested being wasted on an option that does not achieve the anticipated outcome of water savings and thus potential increased cane yield. It will also enable various large scale pilot studies to be implemented thus providing a basis for further research and validation of research already/currently being undertaken.
9.2.6 Water Efficiency Options
From initial costing investigations, full conversion to trickle irrigation alone would be relatively expensive and would not provide for the comprehensive packeage of options identified. It is therefore recommended that a cheaper combined program should be developed to test the various options proposed under this Study.
The individual options upon which the combination options have been based are summarised in Table 9.6.
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Table 9.6 - Sugar Cane Water Efficiency Options Option Area Water Option Description No. Applied Efficiency to (%) Gains on Area Converted (%)* 1 95 25 Convert all areas currently irrigated using winch (70%) & furrow (25%) to trickle irrigation with application efficiency in the order of 90 to 95%. 2 25 15 Convert all existing standard furrow area (25%) to best practice furrow with application efficiency of approx. 75%. 3 70 5 Convert all existing winch area (70%) to best practice winch with application efficiency of 75%. 4 5 5 Convert all existing trickle area (5%) to best practice trickle, assuming efficiency in the order of 90 to 95%. 5 95 25 Conversion as in Option 1 but with adoption of 100% close row cropping with alternate row trickle irrigation. 6 95 25 Conversion as in Option 1 but with reduced costs associated with alternate row trickle irrigation. * - Percentage increase compared to existing.
All options considered include:
• An allowance for an expanded team of extension officers based on the existing RWUEI. Assuming 100% conversion of all irrigated land, a maximum of 5 full time equivalent officers have been dedicated to the sugar industry, together with equipment, to work on the scheme for 4 years. The number of officers in each option therefore depends on the proportion of area converted. • An allowance for farmers to buy soil moisture measuring equipment and water meters has also been provided together with the cost of the new irrigation equipment.
Option 6 allows for costs associated with modified farming equipment to deal with altered row widths.
Some options are mutually exclusive but can be used to indicate the potential savings and costs associated with 100% adoption. Some options are also partially implemented already therefore 100% conversion would not be required/necessary. Following assessment of these options, combined Options 7, 8 and 9 have been considered which include the various elements of the other options. Options 7, 8 and 9 are as shown in Table 9.7. The percentage area conversion refers to the proportion of area under a particular system converted to an alternative system (e.g. 100% conversion from trickle irrigation to best practice trickle irrigation means that all the area currently under trickle irrigation has been converted).
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Table 9.7 – Combined Options 7, 8 & 9 Option 7 Option 8 Option 9 Description 5 10 15 % area under winch and furrow converted to trickle 50 50 50 % area under standard furrow converted to best practice furrow 50 50 50 % area under winch converted to best practice winch 100 100 100 % area under trickle converted to best practice trickle 5 10 15 % area under existing winch and furrow converted to close row cropping 5 10 10 % area under existing winch and furrow converted to alternate row trickle 65 80 90 Total % of sugar cane area converted 3 4 4 Number of full time extension officers required 1 Number of part time extension officers required
An additional option, Option 10, concerning on-farm storage has also been considered. Although strictly a supply side option this option has been included in this section because it would be used exclusively for sugar irrigation. This option includes the construction of 300 (50 ML) on-farm storages capable of supplying 30,000 ML/a through collection of runoff, off allocation supplies, rainwater and tail water return etc. In addition to the capital cost, an allowance for a storage specialist to assist in advice and design for a four year period has also been considered.
9.2.7 Option Costs
Table 9.8 identifies the water saved, option cost and unit cost of each ML of water saved under each option. In addition the increased crop yield, associated value and marginal cost of increased crop yield of each option has also been considered. This is in order to compare the options with the supply side options identified in Section 11. Option cost assumptions and crop yield assumptions are provided in Appendix D.
Table 9.8 - Option Costs and Potential Cane Yield Increases Option Area Potential Present Unit Potential Sugar Potential Marginal No. Applied Water value Cost Increase Cane Gross Cost of to (%) Savings cost of ($/ML/a) in Sugar Yield Value to Option (ML/a) Option Cane Increase Farmers ($/t/a) ($m) Yield (%) (t/a) ** ($m) 1 95 26,300 122.5 4,657 11 496,530 13.7 247 2 25 3,750 8.9 2,374 0.75 31,875 0.9 279 3 70 3,500 4.3 1,216 0.7 29,750 0.8 143 4 5 250 0.3 1,216 0.05 2,125 0.06 143 5 95 26,300 169.2 6,434 33 1,448,213 39.9 117 6 95 26,300 75.8 2,883 10 413,775 11.4 183 7 65 7,820 25.3 3,230 3 150,863 4.2 167 8*** 80 11,765 43.6 3,709 6 268,789 7.4 162 9*** 90 14,395 58.2 4,044 8 366,026 10.1 159 10*** 35 *30,000 32.5 1,083 255,000 7 126 * Water provided not saved, ** Potential Gross Value to Farmers of Increase in Sugar Cane Yield ($m), *** Combination options
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Option 9 saves a significant amount of water and has the lowest marginal cost, in relation to crop yield increases, of the three combined options considered. Option 10 can provide a substantial quantity of new water that can be used on existing land to provide significant yield increases at a very low marginal cost. Therefore Options 9 and 10 are considered to be the preferred options for this sector and will be reviewed further in Section 12 as part of the whole catchment program.
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9.3 Horticulture 9.3.1 Area & Water Use
A wide range of horticultural crops are grown in the Burnett Region with the majority being produced in the BIA, located within the Lower Burnett. Detailed data on the breakdown of areas and water used for the horticultural industry in the region are generally difficult to obtain due to the diverse types of crops grown and the large ABS statistical areas for which information is gathered. Many of the references investigated for this Study provided conflicting information. However, as part of the RWUEI, Barraclough (1999) recently collected data as part of an audit to provide an overall picture of the horticultural industry for Queensland (1997 figures) by collecting information on a regional basis. The results of this audit have been used extensively in this Study.
Under the audit the areas for the Burnett Region were split into the Lower and Upper Burnett, where the Lower Burnett basically covers the BIA and the Upper Burnett covers the rest of the Burnett Region. The areas irrigated and number of growers in each area have been obtained by Barraclough (1999) from a combination of ABS statistics and grower surveys. These figures are provided below:
• Lower Burnett – 5,285 ha with 860 growers • Upper Burnett – 3,656 ha with 145 growers
An indication of the types of horticultural crops grown and water used for those particular crops both in the Upper and Lower Burnett regions are provided in Table 9.9. (Barraclough 1999).
Table 9.9 – Horticultural Areas and Water Use in the Burnett Region (1997) Crop Lower Burnett Upper Burnett Area Irrigated Total Area Irrigated Total (ha) Water Use Water Use (ha) Water Use Water Use (ML/ha/a) (ML) (ML/ha/a) (ML) Avocado 495 4.3 2,124 42 5.5 229 Banana 76 5.0 381 0 0 0 Grape 29 3.0 88 292 2.0 578 Mango 433 4.0 1,717 80 3.2 256 Pineapple 121 0.8 97 0 0 0 Strawberry 5.5 2.9 16 0 0 0 Tomato 746 1.7 1,246 0 0 0 Citrus 322 5.2 1,656 2732 8.3 22,647 Stone Fruit 22 6.0 129 325 6.2 2,018 Exotic Fruit 98 4.8 473 0 0 0 Other Fruit 25 4 102 0 0 0 Cucurbit (Melon/Pumpkin) 963 3.4 3,227 42 2.6 107 Heavy Produce 387 2.9 1,122 1 3.2 3 Vege Cucurbit 764 2.4 1833 1.2 2.8 3 Brassica 10 5.8 58 0 0 0 Pods & Seeds 425 2.2 919 0 0 0 Solanum 334 3.5 1,162 0.3 4.1 1 Salad 12 4.2 51 0 0 0 Other 17 5 86 141 12.5 1,764 Total 5285 *15,700 3,656 27,606 (Source – Barraclough 1999), * - Figure adjusted due to slight error in Barraclough data.
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The average horticultural water use in the Burnett Region is therefore approx. 15,700 ML/a within the BIA and 27,600 ML/a outside the BIA. Hence total horticultural water consumption averages approximately 43,300 ML/a or 21% of total water use in the region.
When growers were surveyed by Barraclough and asked to rate their perceptions of both current and future water availability the growers responded as shown in Figure 9.6. These figures illustrate that the majority of growers (60% in the BIA) currently feel they have adequate or even surplus water but approx. half of those currently satisfied generally appear concerned for the future.
Figure 9.6 – Current & Projected Perception of Water Availability
100%
90%
80%
70%
60% Surplus 50% Adequate Insufficient 40%
30%
20%
10%
0% LB Current LB Projected UB Current UB Projected Regions (Source – Barraclough 1999), LB – Lower Burnett, UB – Upper Burnett
Mixed cropping is now a vital component of many sugar cane farmers’ incomes in the BIA, and in some cases is the primary source of income due to horticultural crops providing relatively high gross margins compared to sugar cane. Due to these high returns, horticultural crops often take priority over the sugar cane crops with respect to the limited irrigation water available.
Joint or mixed cropping was first adopted in the early 1980s with the expansion of tomato crops. From personal correspondence with BSES staff this expansion continued until over- supply of tomatoes led to reduced prices. Other crops were then investigated. Zucchini and other vegetables are now extensively grown in the BIA. Figure 9.7 identifies the growing trend over recent years of growing mixed crops such as trees (mainly citrus) and vegetables in the BIA. The value fluctuations associated with tomatoes may be representative of the price fluctuation and hence reflect shifts from tomatoes to other crops.
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Figure 9.7 – Horticultural Crop Value of Production Trends (1980 –1998)
V A L U E o f C RO PS Bu ndaber g Irrig ation A rea
T rees Ve g eta b les To m a t oes C a ne Bu n dabe r g C a ne T ota l 250
225
200
175
Val u e 150 in Milli on Do llars 125
100
75
50
25
0 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998
(Source – DNR 2001)
Table 9.10 identifies the comparative gross margins for selected crops. As shown tomatoes, mangoes and citrus all give very high returns per hectare grown and per ML of water used for irrigation, particularly compared to sugar.
Table 9.10 – Comparative Gross Margins for Selected Crops Crop Units Bean Rock Tomato Mango Mac’ Citrus Cotton Lucerne Sugar Melon Nut (Bale) Cane Production t/ha 7 37 50 16 4.5 40 6.9 15 89 Price $/t 1500 647 1500 1536 2000 1316 455 200 29 Income $/ha 1050 24200 75000 24092 9000 52800 3142 3000 2551 0 Variable $/ha 9040 18104 48805 13902 2660 32906 1318 1028 1474 Costs Gross $/ha 1460 6096 26195 10190 6340 19894 1824 1972 1077 Margin Water Use ML/ha/a 1.25 2.5 2.5 3.85 4.5 8 6 10 3.6 Gross $/ML 1168 2438 10478 2647 1409 2487 304 197 299 Margin (Source SKM 2000)
Table 9.9 identifies that the majority of horticultural crops use more than the 2.2 ML/ha/a announced allocation currently used by sugar cane. However, Table 9.10 illustrates that less area needs to be cultivated for horticultural crops in order to obtain the same economic returns. Therefore overall less water needs to be used in the horticultural industry compared to the sugar industry in order to gain comparable economic returns.
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Citrus trees dominate the horticultural industry in the Burnett Region and use a considerable proportion of the water used. Therefore they are seen as one of the key areas where water can be saved. Citrus covers approximately 34% of the horticultural area, predominantly in the Upper Region, but uses approximately 56% of the water. Irrigated water use for citrus varies between 8.5 ML/ha and 5.2 ML/ha between the upper and lower areas respectively, which may be due to differences in irrigation method and annual rainfall. Other high irrigation water users in the BIA, due to area or level of application required, include annual crops such as cucurbit, heavy vegetables, and tomatoes as well as mangoes and avocados. These crops alone account for 42% of the area irrigated and 26% of the water used for irrigation, which does not relate to water use efficiency but the fact that these plants require less water per hectare. Therefore these crops could also provide substantial water savings.
9.3.2 Irrigation Methods & Efficiency
Unlike the sugar cane industry there is very little information available concerning the irrigation methods and efficiencies of the horticultural industry. This is mainly due to the complexity of the industry and the large variety of crops grown. This makes calculation of current water efficiency and potential water savings available extremely difficult. Therefore, we have interpolated from best available data.
Further investigations on water use efficiency are currently being carried out as part of the RWUEI. However, little data is available because this particular program started after the sugar cane program in the Burnett Region. In addition the RWUEI has limited resources. Therefore it is unlikely that detailed data will become available from this program.
As part of the RWUEI, Barraclough (1999) attempted to identify statewide the types of equipment used for perennial and annual crops, the number of farmers using monitoring equipment and those farmers using professional advice on scheduling etc. As no specific data on these issues is available for the Burnett Region, Barraclough’s statewide figures have been used to build a picture of likely horticultural irrigation methods and efficiencies in the region. Using data collected by Barraclough it is believed that state wide the percentages provided in Table 9.11 are currently used.
Table 9.11 – State Wide Irrigation Use Irrigation Type % of Area Irrigated Annual Crops Perennial Crops Overall (%) (%) (%) Micro (drip, trickle, micro spray) 39 84 62 Low Pressure (center pivot, lateral move, boom, 47 14 31 hand shift, solid set) High Pressure (soft & hard hose winches) 11 2 6 Furrow or Flood Based 2 0 1
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Table 9.11 shows the horticultural industry generally uses the higher technology, more expensive and potentially more water efficient irrigation systems. Surprisingly, however, only approx. 37% of growers of perennial crops and 25% of annual crops statewide are thought to use monitoring technology to support irrigation scheduling. These figures are fairly low considering that although micro systems are often the most efficient, when considering water application efficiency, management and monitoring techniques are essential to obtain maximum or ‘best practice’ water efficiency or higher crop yields. Barraclough also found that while 44% of perennial and 31% of annual growers use irrigation consultant professional advice, only 7% of all growers actually calculated water efficiency.
According to DNR (DNR 2001) citrus crops in the Burnett generally use under-tree micro- spray systems whilst vegetables, grapes and other small crops use drip or micro-spray systems. A gradual transition from fixed overhead sprinklers to micro-systems has been observed in recent years but some of the less efficient overhead systems are still used. No specific data on the region is available.
From the figures identified in Table 9.9 it appears that approx. 28% of the Lower Burnett horticultural land is used for perennial crops and the remaining 72% for annual crops. In contrast 95% of horticultural land in the Upper Burnett is used for perennial crops and only 5% of the land is used for annual crops. Using the Barraclough state figures identified above this indicates that there is still scope for efficiency measures through a drive towards further use of micro irrigation systems (especially in the Lower Burnett), additional professional advice on irrigation practices, increased use of monitoring technology and scheduling and wider appreciation of the benefits of water efficiency measures and techniques for improving crop yield.
Based on the Barraclough results summarized in Table 9.9 and calculations conducted by Barraclough on the irrigation rates used by ‘better’ irrigators an estimate of the difference between average and ‘better’ irrigation rates was identified as the notional improvement possible. Better irrigators were defined as those who have application efficiencies within one standard deviation better than the mean. This notional improvement figure was then multiplied by the total crop area to derive a total water saving value for the region. A summary of the figures calculated is provided in Table 9.12. Some discrepancies appear to exist in the Barraclough figures, mainly due to rounding errors. However, the overall water opportunity identified by Barraclough is in the order of 11,000 ML/a, which represents 25% of the current horticultural water usage.
Table 9.12 – Potential Quantified Water Saving Opportunities Region Area Current Current Possible Possible Water Saving (ha) Water Use Water Use Water Use Water Use Opportunity (ML/ha) (ML) (ML/ha) (ML) (ML) Lower Burnett 5,285 3.0 15,751 2.1 11,330 4,421 Upper Burnett 3,656 7.6 27,606 5.7 20,899 6,707
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9.3.3 Water Efficiency Considerations
The 11,000 ML/a calculated is thought to be an upper limit by Barraclough and as such Barraclough and other studies have attempted to identify a ‘more realistic’ attainable water saving based on likely adoption rates of programs, industrial reference studies and realistic on-farm efficiency losses of 10 to 15%. However, under this LCP Study it has been assumed that full attainment can be achieved if the following issues are considered in the development of a water efficiency program:
• improved irrigation systems; • financial assistance; • improved management and scheduling; • education; • research; and • emphasis on both water efficiency and increased yield.
The current RWUEI, or ‘Water for Profit’ Scheme as it is known for the horticultural industry, does currently cover many of these issues and a program developed under this Study should attempt to build on the current scheme. However, in order to attain the potential water savings identified it is considered essential to increase the number of officers in any future extension of this scheme in order to provide the personal contact necessary to assist growers producing such a wide variety of crops. In addition greater assistance in funding and transferring to the more water efficient irrigation systems would also be essential in order to maximise participation and commitment of growers.
Drawing from these considerations and realising the limitations of the Barraclough figures (mainly due to the lack of information available specifically for the region on irrigation systems used, application efficiency and irrigation advice etc.) a more generic approach has been used for option assessment of the horticultural industry than compared with the sugar cane industry. Options developed have been based on the assumption that the Burnett has similar micro irrigation percentages and moisture equipment usage to that of the state average. However, more specific figures on the perennial and annual crops grown has been used to assist in identifying the areas remaining that need to be converted to attain ‘better’ practice irrigation.
Other opportunities identified by Barraclough in moving towards the ‘better’ irrigation include increased tonnage of crop yield and subsequent income. A total attainable tonnage increase of 97,000 t was identified with 52,200 t in the Lower Burnett and 44,800 t in the Upper Burnett. This assumes increasing yield from 23 to 33 t/ha in the Lower Burnett and 27 to 39 t/ha in the Upper Burnett, with aggregate crop prices of $1,844 /t and $1,797 /t respectively. These yield increases appear very high when compared with actual tonnage currently obtained 124,349 t/a (1997 figures) however no other study has attempted to identify potential yield increase for the whole horticultural industry in such detail. Therefore these figures have been used.
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It is anticipated that as irrigators become more aware of the ‘better’ irrigators methods and efficiencies that some farmers will attain more efficient water consumption, others will attain higher yield and some a combination of the two. It is unlikely that full attainment of the 11,000 ML/a water savings will be achieved or alternatively an increase of 97,000 t of crop yield with the same existing water use. A combination of water savings and increased crop yield is the most likely outcome.
It is presumed that the water savings and increased yield will be achieved with a combination of the following:
• conversion of the non micro irrigation areas to drip/micro irrigation systems which will enable more efficient water use and direct water application to the root zone; • use of moisture monitoring equipment on those areas not currently using such equipment to enable farmers to understand when to irrigate; • extension of the RWUEI and provision of additional officers for a four year period (similar to the sugar cane program) to assist farmers to understand the ‘better’ irrigators techniques and concepts of ‘best practice’.
Using these concepts, options have been developed as identified in the following section.
9.3.4 Water Efficiency Options
As already identified full attainment of ‘better practice’ could result in a water saving of 11,000 ML/a, a 97,000 t increase in overall crop yield in the region or a combination of the two. Options 1 and 2 have been considered relying on full attainment of either water or yield. Option 3 is a 50/50 split between water saved and increased yield with full adoption of new irrigation methods and monitoring techniques and Option 4 is based on Option 3 but where only 75% of the remaining non micro irrigated land is converted because a small number of farmers may not wish to convert even with substantial financial incentives. These options are identified in more detail in Table 9.13. Figure 9.8 attempts to illustrate the trade off between water use and yield gain between options 1, 2 and 3.
Table 9.13 – Water Efficiency Options Option Water Yield Description No. Saving Increase (ML/a) (t/a) 1 11,000 0 Full attainment of water savings but with no attainment in yield increase by converting all remaining non micro areas to drip/micro systems, providing moisture technology to all farmers not currently using such equipment and providing assistance through 6 RWUEI officers over a 4 year period. 2 0 97,000 As for Option 1 but with full attainment of yield increase rather than water savings 3 5,500 48,500 Combination of Options 1 & 2 so that 50% attainment in water savings with 50% attainment in yield increase 4 4,174 36,417 Combination of Options 1 & 2 so that 50% attainment in water savings and 50% attainment in crop yield increase but where only 75% uptake in transition of non micro systems to drip/micro systems, 75% of uptake to using soil moisture equipment but assuming 6 RWUEI officers still required.
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Figure 9.8 – Water Use/Yield Gain Trade-off
WATER Crop Yield AVAILABLE t/a ML/ A
MAX POTENTIAL MAX POTENTIAL WATER YIELD AVAILABLE
CURRENT CURRENT WATER AVAILABLE
100 % 50 % 0 % 0% 50% 100%
Option Option Option 1 3 2
9.3.5 Option Costs
The water saved, option cost and unit cost of each ML of water saved for each option has been identified in Table 9.14. In addition the increased crop yield, associated value and marginal cost of increased crop yield of each option has also been considered. This is in order to compare the options with the supply side options identified in Section 11. The assumptions used for costs etc. are provided in Appendix D.
Table 9.14 - Option Costs and Potential Yield Increases Option Area Farms Potential Present Unit Potential Value of Marginal No. Converted Converted Water Value Cost Increase Increased Cost of to Micro to Savings Cost of ($/ML) in Crop Crop Option System Moisture (ML/a) Option Yield Yield ($/t/a) (ha) Tech ($ m) (t/a) ($ m) 1 3,228 708 11,129 37.5 3,367 0 0 0 2 3,228 708 0 37.5 0 97,112 177 386 3 3,228 708 5,565 37.5 6,734 48,556 88.5 772 4 2,422 531 4,174 28.6 6,848 36,417 66.4 785
Option 4 is considered to be the most attainable solution of those considered. Therefore Option 4 together with the water saved will be considered further in Section 12 where it will be assessed against the supply side options.
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9.4 Field and Fodder Crops 9.4.1 Area & Water Use
According to SKM (2000) investigations, irrigated cropping is fairly widespread along the river systems in the Upper Burnett, including approx. 1,400 ha of cotton near Murgon. Fodder and irrigated cereal cropping is generally undertaken on regulated river systems and on a more opportunistic basis along the unregulated streams or by using unregulated groundwater resources. Summer fodder crops are undertaken to supply supplementary feed to cattle and to a limited extent dairy cattle are fed on irrigated pasture.
It is apparent that very little information is available on actual areas irrigated and water used in the region due to issues such as the opportunistic nature of field and fodder cropping, a history of not calculating water usage or associated yield and the use of unregulated water supplies. Thus making an estimate of water savings very difficult to establish.
According to SKM (2000) water consumption by irrigated field and fodder cropping is estimated to average approximately 22,800 ML/a (1997 figures), or 11% of total consumption in the region. This figure is only an approximation based on an estimate of 15,000 ML/a for unregulated diversions and deduction of horticultural use in regulated areas. Taking into consideration the flexible and opportunistic nature of field and fodder irrigation, actual water use is likely to vary significantly between years, depending on water availability.
Since the SKM Report was issued, additional figures on water use and areas irrigated have been collated as part of the initial RWUEI audits for the cotton & grains, dairy and lucerne industries for the whole of Queensland (Barraclough Feb 2000 & April 2000; P J Goyne et al). A summary of the findings for areas irrigated and water used from each of the audits is provided in Table 9.15.
Table 9.15 – Area & Water Use for the Cotton & Grain, Lucerne and Dairy Industries Industry/ Area Water Water Details Area w/s Use Use w/s (ha) (ML/a) (ML/ha) Cotton & - - - In this audit no specific figures were provided for the Grain Burnett Region as it only represents a small proportion of the state cotton industry. The audit highlights that cotton is often rotated with crops such as wheat & sorghum, with cotton often receiving priority irrigation in areas with limited water. This rotation of crops adds to the problem of quantifying specific areas cultivated under each crop. Lucerne In this audit, Monto & South Burnett were identified as two Monto 3,132 20,879 6.7 key areas of irrigation with South Burnett actually being the South Burnett 2,975 29,847 10 second highest water user for this industry in the state. Dairy The two area & water use figures provided are for winter & Monto 1,682 16,208 3.7 summer respectively. In the dairy audit Monto, South 1,775 5.7 Burnett and Bundaburg were identified as three main areas South Burnett 3,533 41,935 5.3 of dairy production with South Burnett, similarly to lucerne, 3,281 7.1 being the second biggest water user in the state for this Bundaberg 1,183 12,623 4.7 particular industry. 1,248 5.7 w – winter, s - summer
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The water use figures for both lucerne and dairy appear very high compared to the SKM figures. Barraclough quantified the lucerne figures by stating: “ It is important to note the ABS statistics do not separate dry land from irrigated lucerne production. Consequently these figures over represent irrigated lucerne production for hay ”.
Water sources supplying these industries were investigated using the limited number of growers surveyed in the audits. Supply was identified as shown in Table 9.16. From these limited survey results and ignoring the biased Bundaberg figure it appears a high proportion of the water used is sourced from boreholes which may be in unregulated groundwater supplies and thus not included in the DNR statistics used by SKM. For the cotton & grain industry water sources were not identified but it appears over the last few years that there has been an increase in the number of on-farm storages (mostly ring tanks) to assist in the overall reliability of supply which may be the case in Murgon. If this is the case much of this water may not be included in the DNR statistics.
Table 9.16 – Water Supplies According to Limited Grower Survey Industry/Area Regulated Unregulated Borehole Other Farmers Surveyed Lucerne - Monto 100% 26 of 189 - South Burnett 17% 83% 6 of 246 Dairy - Monto 60% 20% 20% 10 of 64 - South Burnett 33% 7% 47% 13% 15 of 441 - Bundaberg 100% 1 of 45 (Source - Barraclough Feb 2000 & April 2000) % based on no of growers surveyed.
Based on the following issues, this Study has used the original SKM figures of 22,800 ML/a for water use:
• There is uncertainty whether the areas and water use figures identified in these audits actually fall within the boundaries of the Study area as many ABS statistics cover wider areas such as Wide Bay. The audits do not geographically identify the areas being considered. • The majority of water used in these industries appears to be from boreholes in unregulated groundwater supply regions which are not controlled by DNR and thus do not appear in their annual statistics as water supplies. • There is uncertainty in the actual water used in these particular industries as water is not as carefully measured as in the sugar or horticultural industries.
By using the SKM figures a conservative approach has been taken on the amount of water used in these industries and thus a conservative figure for water savings will be obtained. However, it should be noted that if the audit figures are closer to the real water use figures then the difference between the SKM figures and audit figures, 22,800 and 121,492 ML/a respectively, could result in a further 98,692 ML of water being used from unregulated groundwater supplies or on-farm storage. This additional water used could provide a huge additional potential for water savings and thus future water use depending on the water quality.
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9.4.2 Irrigation Methods & Efficiency
From a combination of SKM (2000) research and the recent RWUEI audit information (Barraclough Feb 2000 & April 2000; P J Goyne et al), a basic understanding of the irrigation methods and efficiencies for the region has been developed. Very little specific details on irrigation methods and efficiencies are available for these particular industries compared to sugar cane and horticulture as they have not been investigated or documented to the same extent. However, using the limited information available and the limited survey results obtained by the RWUEI audits the following picture has been determined:
• Cotton & Grain – The cotton in the Murgon area is mostly grown under furrow irrigation, however, cereal and grain crops are mostly irrigated using water winches, side roll or hand move sprinkler systems. There has been a gradual move towards the slightly more efficient low pressure boom sprinklers due to replacement of the older winches. Very little information is available on the amount of moisture measuring and scheduling equipment used in the region. However, from the audit it appears that water is not generally measured or monitored and there is major potential for improvements in efficiency through greater use of management techniques and scheduling. Where storage tanks are used, a considerable amount of water is thought to be lost through leakage and evaporation. • Lucerne – According to the audit no specific information on systems was available for Monto but for South Burnett and state wide hand shift systems are the most common system used. For both regions, under 20% of growers use scheduling and state wide only 31% of growers measure and record irrigation applications as part of management practices. Of that 31% only 32% actually calculate water use per hectare. State wide only 4% of growers use irrigation advisors. • Dairy – Both Monto and Bundaberg seem to mainly use high pressure low efficiency winch systems. A third of South Burnett uses winch but the majority use handshift with smaller proportions of center pivot and solid set. State wide only 20% of growers use scheduling and only 5% use technology to support irrigation scheduling. 21% of growers measure and record irrigation applications as part of their irrigation scheduling and of that 21% only 19% actually calculate water use per hectare. 7% of those surveyed use irrigation experts.
Growers perceptions of existing and future water availability which are likely to affect their use of current water supplies are as indicated in Table 9.17. As can be seen a large proportion of the growers do not consider water availability to be of concern.
Table 9.17 – Grower Perceptions of Current & Future Water Availability Industry/Area Current (%) Future (%) Surplus Adequate Insufficient Surplus Adequate Insufficient Lucerne - Monto 0% 31% 69% 0% 38% 62% - South Burnett 17% 50% 33% 0% 50% 50% Dairy - Monto 10% 50% 40% 0% 43% 62% -South Burnett 31% 46% 23% 18% 45% 37% - Bundaberg* 100% 100% * only one grower surveyed
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9.4.3 Water Efficiency Considerations
Considering the general use of low efficiency irrigation equipment, overall perceptions that there is adequate water, minimal use of moisture management/scheduling techniques, high losses associated with on-farm storage and overall lack of water measurement, it is anticipated that farm application efficiency will be highly variable and generally inefficient within this region. Attainable farm application efficiencies for the types of irrigation systems used in the area usually range from around 60% to 85%. However, actual efficiencies, due to the issues identified, could be considerably less than these figures. It is therefore assumed that water efficiency could be improved through:
• a move towards ‘better’ irrigation practices through adoption of water management; • appreciation of the importance of water conservation and understanding of the potential yield increases through better management of resources; • use of advice from irrigation advisors or extension officers on soil types and best irrigation methods; • use of moisture monitoring techniques; • use of scheduling; and • reduction in leakages associated with storage tanks.
With adoption of these practices, ‘better’ irrigation practice could be achieved by a substantial number of growers. Based on the problems previously identified and the types of irrigation systems used in the region it could realistically be interpreted that efficiency gains of 20% could be achieved using the same equipment, representing a water saving of 4,560 ML/a based on SKM water use assumptions.
For both the sugar cane and horticultural industry it has been assumed that a drive towards drip irrigation together with management, scheduling and assistance from extension officers would provide the greatest benefits. For field and fodder crops, drip irrigation could also provide substantial water savings. However, it is not considered to be the optimal option to invest in due to the following issues:
• The current lack of detailed knowledge of the actual water used and areas irrigated adds risk to the program failing. • Field & fodder crops have relatively low gross margins compared to other crops (refer to Table 9.10) which will limit the adoption of more expensive irrigation systems even with financial assistance and reduce the financial return benefits of the program adopted. • Based on the lack of basic management techniques currently used it is unlikely that drip irrigation systems would be managed correctly and thus farm application efficiency would be low. Through an improvement in management practices on the current systems water efficiency gains can be made at a relatively low cost. • Uncertainty of the future of the industries adds risk to investing in expensive technology. 14% of dairy farmers decided to leave the industry in 2000/01 due to deregulation which caused a 25 to 30% drop in farmer revenue from milk (QLD 2001). • Uncertainty whether field and fodder cropping may diversify into horticultural mixed cropping in order to increase financial returns. If mixed cropping was adopted then less water may effectively be used on the areas irrigated and provide greater returns due to the higher gross margins of horticultural crops thus justifying expenditure on more expensive irrigation systems.
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Considering these issues it is recommended that a two staged approach may be most appropriate for the field and fodder industry. Under an initial program, covered by this Study, identify the real water used by the industry and basically gain a better understanding of water use and efficiency specifically within the Burnett Region. At the same time:
• raise awareness of water efficiency issues and better practice using existing equipment; • offer financial assistance with management equipment; • provide scheduling advice; and • to ensure greater participation highlight the benefits of increased yield through better management practices.
Much of this is currently being offered by the RWUEI but as with the other industries, due to the limited officer resources and funds, the initiative is only likely to raise awareness and effectively provide a foundation upon which a more aggressive program with additional funds can be based. Once these initial issues have been addressed, it can then be determined whether investment in higher efficiency irrigation equipment will be economically viable.
Other opportunities identified by the RWUEI audits include potential yield increases. As with the horticultural industry, the audits conducted by Barraclough for the lucerne and dairy industries, attempted to identify figures for potential yield increases by the better irrigators. Based on Barraclough’s figures, Table 5.18 identifies the potential gains for moving from average to better practice irrigators in terms of potential yield increases. As for the horticultural industry it is likely that some irrigators will save water which can be used for other purposes while others will save water which will effectively be used more efficiently on the same crops to increase crop/milk yield.
Table 9.18 – Potential Gains for Moving from Average to Better Irrigators in the Lucerne and Dairy Industries Lucerne Dairy Area ‘A’ water Difference Value ‘A/B’ water Difference in Manufacture Value* application in crop $/ha/a application milk yield $/ha/a ML/ha yield ML/ha between ‘A’ between & ‘B’ ‘A’ & ‘B’ irrigators irrigators L/ha/a kgDM/ha/a Monto 6.7 1,068 192 9.4/7.3 10,630 2,551 South 10 2,478 446 12.4/9.6 10,596 2,543 Burnett Bundaberg - - - 10.4/8.1 5,461 1,311 (Barraclough Feb 2000 & April 2000) ‘A’ – average irrigator, ‘B’- better irrigator DM – dry mass
The figures show that there are financial benefits to moving towards better irrigation techniques due to potential crop/milk yield increases. However, it appears that the financial gains per hectare and per ML of water used for lucerne are relatively small compared to the dairy and horticultural industries in general.
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9.4.4 Water Efficiency Options
Only one option has been considered for the field & fodder industry, which encompasses the following:
• Extension of the current RWUEI by providing seven full time officers to collect information on current water use, irrigation methods used, management and scheduling techniques, storage tank details, areas irrigated to provide a better understanding of the current situation and determine a baseline upon which to assess the benefits of the program. The extension officers will then assist growers in each of the industries to better understand their soil and irrigation systems and advise on how to become better irrigators through the use of moisture measuring, irrigation management and scheduling techniques. One of the extension officers will need skills in storage tanks in order to assist growers on how to best install tanks and minimise leakage and evaporation losses. The officers will be required for the full 4 years as with the other industries and each will have equipment similar to that previously outlined. One to one contact, barn talks, media and other interaction techniques will be used to impart this information as used in the current RWUEI. • Moisture testing and flow measurement equipment will be provided for all farmers. The exact number of farmers is not known but figures from the RWUEI audits indicate that there are: • 189 and 246 growers for lucerne in Monto and South Burnett respectively; • 64, 441 and 45 growers for dairy in Monto, South Burnett and Bundaberg respectively; and • no figure for the number of growers in the cotton and grain industry was identified therefore an allowance of 50 has been made. Therefore a total of 1035 growers have been provided for, which should be adequate considering a small proportion of farmers may already have equipment.
9.4.5 Option Costs
Potential water savings, option cost and unit cost of the option considered are provided in Table 19. Cost assumptions are provided in Appendix D. This option has been considered further in Section 12 where it is compared against supply options.
Table 9.19 – Option Cost and Details Option Farms Potential Water Option Present Unit Cost of Option Unit Cost No. Converted Savings Value Cost ($/ML) $/t/a (ML/a) ($ m) 1 1,035 4,560 7.4 1,620 * * - Insufficient Data
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Whilst saving the 4,560 ML, potential yield increases may occur simultaneously because the water being used by irrigators is applied to the root zone of the existing plants more effectively. The value of this potential yield increase has not been calculated. However, if the 4,560 ML of water saved were applied to a new area of either lucerne or dairy crops then the value would be as identified in Table 5.20. The figures calculated assume full use of the 4,560 ML for each area, assumes average irrigator water application and best practice irrigator yields. The values identified indicate where the greatest return could be obtained at current prices. It should be noted that if the actual water use is closer to that identified in Section 9.4.1 then considerable additional savings could similarly be applied to existing or new areas to increase crop/milk yield. These increased yields have not been quantified due to the level of uncertainty.
Table 9.20 – Value of Saved Water Each Year if Used on Additional Area Area Lucerne Dairy ‘A’ Water New Area New Crop Yield ‘A’ Water New Area New Milk Use Irrigated Yield Value Use Irrigated Milk Yield (ML/ha/a) (ha) (MkgDM) ($m) (ML/ha/a) (ha) Yield Value (ML) ($m) Monto 6.7 681 12.1 2.2 9.3 489 12.7 3.0 South 10 456 9.3 1.7 12.4 369 6.7 1.6 Burnett Bundaberg 10.4 440 5.9 1.4 ‘A’ – average irrigator, DM – dry mass
The values range from $1.4 m to $3.0 m and indicate that the crop/milk yield increases obtained each year could assist in paying back the cost of the $7.4 m program.
As discussed earlier investment in a program to convert field and fodder cropping to drip irrigation has not been considered. However, in the long term this may be a viable option after further research. One case study carried out on a lucerne grower in Tamworth (NSW Agriculture) indicated that considerable yield gains and labour savings were obtained by converting to drip irrigation. By converting a quarter of his property to drip (13 ha), at a cost of $42,000, the farmer anticipated, based on observed yield increases, that the extra yield would pay for the system in approx. three years. The drip system does not generally reduce water usage but assists in producing higher crop yields for the same water usage whilst reducing labour costs and improving crop uniformity.
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9.5 Stock & Domestic
9.5.1 Water Use & Efficiency
According to SKM (2000), stock and domestic use in 1997 was approximately 2,100 ML/a which represents 1% of total water use. This may be a conservative value as DNR identified 1,081 ML/a from unregulated use alone in their more recent report (DNR 2001).
Very little information on stock & domestic use is available from current studies and no potential water savings have been identified. From general experience it is known that stock & domestic water usage can be extremely wasteful at various stages of the supply system. Losses can occur within the on site storage and channel systems through evaporation, leakage and seepage, reticulation system through leakage, spills due to stock damage of equipment or poor management relying on timing of filling of troughs.
As no specific details are available for the Burnett Region basic assumptions have been used to obtain estimates of potential water savings. These assumptions would need to be verified by local surveys.
Assuming the more conservative SKM (2000) figure for water use is used of 2,100 ML/a, it is assumed that 90% of this water will be specifically used for stock use. Of that 90% it is anticipated that 20% could be saved through basic efficiency measures. Thus providing a water saving in the order of 380 ML/a.
Basic efficiency measures that could be adopted would include:
• Modification of existing dams (deepen/line) to minimise evaporation and seepage losses. • Checking of existing equipment for leakage. • Use of covering or fencing and other protection to minimise damage to equipment. • Improved management practices such as the use of ball floats rather than timing to fill troughs.
In order to achieve these increased efficiencies another RWUEI extension officer would be required to investigate potential losses by visiting stock and domestic water users, advise farmers of the importance of water efficiency, identify suitable potential efficiency solutions and assist farmers in the choice of efficiency measures and implementation. It is anticipated that many of the farmers may also be involved with other irrigated agricultural activities. Therefore this additional RWUEI officer would work closely with the other RWUEI officers over the four year period to identify farmers that require assistance with stock water practices.
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9.5.2 Option Costs
Assuming a total of 380 ML/a could be saved by employing one RWUEI officer at a present value cost of $254,041 (similar to the other irrigated agricultural sectors), Option 1 has been identified as the only option for this particular end-user. Table 9.21 provides the details of the option which is considered further in Section 12 with the other demand management/ efficiency options.
Table 9.21 – Stock & Domestic Option Costs Options No. Potential Water Savings Option Present Value Cost Unit Cost ML/a $ m $/ML 1 380 0.25 669
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9.6 Distribution Losses 9.6.1 Water Use & Efficiencies
Before water reaches the farm gate, water losses can occur within the distribution/reticulated supply system which links the water sources with the farm gate end users.
These distribution systems mainly take the form of open channels, pipelines, balancing storages and pumping stations. Within the Study area all such systems lie within the BIA which extends from the Fred Haigh Dam to Kolan Barrage on the Kolan River and from Walla Weir to the Ben Anderson Barrage on the Burnett River. During limited water availability water from the Fred Haigh Dam can be diverted across to the Burnett River upstream of the Walla Weir. The figure provided in Appendix E shows the main routes of the supply systems within the BIA.
Water in the BIA is mainly used for irrigation with water off-take via metered outlets from the channels/pipelines. A small quantity of water is extracted from the network for town supply. The BIA generally works as an ‘on-demand’ delivery system meaning water use causes channel levels to drop which automatically activate float controlled regulator gates thus allowing additional inflow into the system via the electronically linked pumping stations. The system is therefore automatically topped up, obviating the need for estimation of water releases by operators. Riparian irrigators supplied along the Burnett and Kolan Rivers by the on-river storages are controlled by operations staff.
Water delivered to the supply network is monitored at all input locations (upstream pumping stations) by meters situated on the delivery lines or from calibrated pump curves and operating times. Daily records of this data are kept together with rainfall, storage levels in the main balancing storages and river flows. Operators record estimated release volumes and fish way by pass volumes at each weir and generally read individual outlet meters on a quarterly basis to determine water bills.
The water provided by the system is transported via pipelines or channels which are either bench flumes, concrete/gravel/clay lined or unlined earth. Table 9.22 identifies the individual supply systems within the BIA and the proportions of open channel/closed pipeline.
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Table 9.22 – Supply System Characteristics within the BIA Channel Total Component Length (m) Length Earth Clay Gravel Rock Concrete Bench Pipeline (m) Unlined Lined Lined Cut Lined Flume Earth Earth Abbotsford M/C 3,687 ------3,654 Berrembea M/C 11,154 ------11,154 Bingera M/C – 12,060 4,173 - - - - - 1,838 Upper Bingera M/C – 30,303 ------29,635 Lower Booyan M/C 14,487 6,701 - - - - - 7,774 Childers M/C 22,920 ------22,385 Dinner Hill M/C 6,492 ------6,416 Fairymead 2,068 ------2,068 Channel Farnsfield 10,000 ------9,415 Channel Gin Gin M/C 28,204 13,739 - - 104 5,507 3,108 5,746 Gooburrum M/C 20,352 10,815 - - - 96 - 8,586 Gooburrum G1 5,117 1,537 - - - - - 3,580 Gooburrum G3 3,312 260 - - - - - 3,052 Givelda M/C 6,336 ------6,332 Isis M/C 25,414 3,085 - 8,825 - 8,097 298 3,737 Moore Park M/C 8,655 2,301 - - - - - 6,333 North Gregory 4,125 ------4,006 M/C St Agnes M/C 15,057 ------15,057 Tirroan M/C 5,454 ------5,385 Woongarra M/C - 21,680 17,881 457 - - - 690 1,003 Upper (Source – GHD 2001)
Losses from the supply system can occur through:
• evaporation, seepage and transpiration from open channels; • leaks from pipelines or associated pumping systems; • unrecoverable overflows; • pilfering from the system; and • errors in metering or recording of flows.
In addition gains to the system can be experienced through runoff, groundwater seepage and rain. Hence calculation of the losses in a distribution system can be very difficult to ascertain.
The methods often used to calculate system efficiencies and associated losses are direct estimation and water balance. The efficiency figures used for this Study have been taken from a recent study (GHD 2001) conducted by GHD on behalf of DNR which has used the water balance method. The GHD study concentrates specifically on the losses associated with the supply system run by State Water Projects (now SunWater) within the BIA.
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To assess supply system performance, two different concepts of efficiency were developed by the GHD study:
• theoretical efficiency - derived taking account of only ‘uncontrolled’ losses/gains (evaporation, seepage, local runoff and direct rainfall); and • operational efficiency - actual efficiency achieved taking into account all losses i.e. uncontrolled and operational (other losses such as un-metered use, overflows and other releases).
Theoretical and operational efficiencies are therefore as follows:
Etheory = (water available) – (uncontrolled losses) water available
Eoperation = metered use water available where: water available = (pumped or released volume) + (net loss in storage) time period.
It should be noted that in GHD’s calculations, contributions from direct rainfall and local catchment inflow (gains) have not been considered as the channel systems will generally be full or overflowing during rainfall events.
The annual operating efficiencies (E operation ) calculated by GHD, over the period 1991/92 to 1996/97 are provided in Table E1 in Appendix E. Those systems where operational efficiencies deviate substantially from the theoretical efficiencies, could potentially be targeted for investigation of efficiency improvements.
The results suggest that average operational efficiency ranges from 81.4%(in Gooburrum distribution system) to 98.3% (in Bingera distribution system, down stream of Bullyard Pumping Station). The Gooburrum system consists predominantly of open channel and has a large balancing storage (1,117 ML), while the Lower Bingera System is fully piped with only two small balancing storages. As might be expected, the pipeline systems appear to have higher theoretical and operational efficiencies than compared with the open channel systems. However, on closer inspection this is not consistent throughout the BIA. Comparatively lower average operational efficiencies were determined for the closed pipeline systems of Tirroan, McIlwraith, Bucca and North Gregory. The closed pipeline systems of Childers and Lower Bingera demonstrated the highest operational efficiencies. Close inspection of the average efficiencies across systems in Table E1 show inconsistencies in some efficiencies. Maximum efficiencies over 100% indicate contributions from rainfall to balancing storages or more likely (according to GHD) from errors in data and inaccuracies of flow metering. The average efficiencies determined for the combined BIA gave lower figures then for the individual systems which is probably due to losses resulting from transfer from the Fred Haigh Dam due to high losses in the natural Burnett River.
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The GHD study also collected and assessed data on individual years. The water balance analysis for the 1994/95 water year, which was a low rainfall year and hence a high irrigation use year, is summarised in Table E2 in Appendix E. The results show the relative proportions of inflows (volumes pumped into the systems) and estimated outflows (recorded use, evaporation and seepage). The water balance is then closed by the figure ‘additional losses/gains’ which is a composite of all the unmeasurable quantities, such as operational losses, unaccounted for inflows (e.g. direct rainfall) and data error. The volume would also include water dumped during maintenance activities although this is reported to be fairly small in the Burnett Region according to DNR (DNR 2001) investigations.
GHDs interpretation of the results from Table E2 are summarized as follows.
The results show that the systems with a high proportion of pipeline (such as Abbotsford, Tirroan, McIlwraith, Bucca, Lower Bingara, North Gregory, Farnsfield, Dinner Hill, Childers & Cordalba and Lower Woongarra) have external system losses from seepage and evaporation of less than 1%. Water delivered for use is typically 69% to over 100% of the total available water volume. The high water use estimates of around 100% and above are likely to be as a result of data inaccuracies. The ‘additional losses/gains’ balance quantities vary from an additional ‘loss’ of 31% to a ‘gain’ of 17%. Some of these calculated losses/gains will be real and some can be associated with measurement error. Variations in the water balance results for the different pipeline systems may generally be associated with balancing storage components, system operation and metering accuracy.
For the predominantly open channel systems of Gin Gin, Gooburrum, Isis and Woongarra the analysis indicates that these systems all experience greater losses than the pipeline systems due to evaporation and seepage losses. However, actual water use volumes were typically higher, ranging from 78% to 100% of the total inflow volume. Water use percentages greater than 100% corresponded to periods of significant additional gains in the systems being analysed (i.e. volumes of available water). Additional water volumes required to complete the open channel system water balance analyses typically range from a loss of 15% to a gain of 13%. The variation in water balance results for the open channels systems, according to GHD, is likely to be due to the relatively large balancing storage components of these systems.
Other data collected by GHD included seepage measurements undertaken by SunWater in July 1999 during a shut down period. SunWater conducted these tests in order to identify any particularly ‘leaky’ sections of the channel system. Three sections were tested over a two week period. The results of the tests are provided in Table 9.23. The results show that the Woongarra Main Channel has the highest seepage losses of the three earth channels assessed.
Table 9.23 – Measured In-Situ Channel Seepage Rates Channel Total Length of Total Surface Seepage Seepage Rate Length (m) Earth Area of Channel Rate (mm/d) Channel (m) (m 2) (ML/km/d) Gooburrum MC 5,510 4,600 43,293 0.088 11.2 Booyan MC 7,900 7,617 70,966 0.095 10.6 Woongarra MC 5,500 5,378 72,374 0.171 13.0
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DNR also reported field testing results (DNR 2001) for a 5.5 km and 2 km open channel section of the Woongarra channel system. These results indicated that 5.6 ML/d was being lost over the first 5.5 km of the channel with similar losses being found in a 2 km section further downstream. In addition, the Woongarra balancing storage is believed to seep significantly.
9.6.2 Potential Water Savings & Options
The calculated average operational efficiencies of the largely piped supply systems are generally high (in the order of 83% to 98%) and the estimated seepage and evaporation losses from these piped systems is low (being generally less than 1%). The inconsistency in results, due to inaccuracy of metering and other data, bring into question the actual efficiency levels achieved. It is understood that no leakage detection of the piped system has been undertaken to date. Therefore an option involving a leak detection review and investigation of other losses followed by remedial works across all piped networks is recommended.
The leakage losses found when Wide Bay Water carried out investigations into the urban water supply distribution systems for the Townships of Mackay, Logan, Charters Towers and Hervey Bay ranged from 0.7 to 4.6 ML/km/a and averaged 2.2 ML/km/a. The length of mains in the piped systems supplying the BIA is 518 km. The pressures vary from low pressure areas of 1 or 2 m up to high pressure areas in the order of 50 m, which on average is lower than urban water supply systems. However the average size of pipes and hence circumference at joints where leaks can occur is much larger for the BIA than for urban systems. Assuming a level of leakage is equivalent to the average for the urban systems identified above (2.2 ML/km/a) this would provide a potential leakage of 1,140 ML/a. This represents 0.92% of the average usage from 91/92 to 96/97 through the piped and channel distribution systems. A leak detection review and investigation of other losses followed by remedial works across all piped networks could reasonably be anticipated to save 30% of the estimated leakage. This would result in a potential water saving in the order of 350 ML/a.
The efficiencies calculated for the predominantly open channel systems (81% to 90%) are considered fairly high. Efficiencies between 75% and 80% are typically accepted as indicative of earthen supply channel systems according to DNR investigations (DNR 2001). However, as for the pipeline systems actual efficiencies may vary from the calculated results. From the results of the recent tests conducted it appears that the Woongarra Main Channel has the highest seepage rate per km. Using DNR information (DNR 2001), channel losses (total losses less 612 ML/a for evaporation) range from 2,300 ML/a (two specific sections totaling 7.5 km) to 4,800 ML/a (over the entire channel length of which approximately 19 km is unlined). Therefore if options concentrated on lining of the Woongarra Main Channel with an impervious lining in order to reduce seepage losses, savings in the range of 2,300 ML/a to 4,800 ML/a could be expected depending on the extent of channel lined.
It is reasonable to anticipate that other sections of unlined earth channels within the BIA would have similar losses as the Woongarra channel, although with a likely lower level of losses. Therefore, in order to assist in cost comparison, an additional option has been considered allowing for a further 38 km of channel to be lined with a seepage rate of half that of the Woongarra channel. The options considered are identified in Table 9.24.
Table 9.24 – Distribution Loss Options Option Water Saved Option Description
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(ML/a) 1 350 Leak detection review and investigation of other losses followed by remedial works across all piped networks 2 2,300 Lining of 5.5 and 2 km sections of earth unlined Woongarra channel identified by DNR 3 4,800 Lining of entire approx. 19 km earth unlined Woongarra channel 4 4,800 Lining of 38 km of earth unlined channel anticipated to have half the seepage losses of the Woongarra channel 5 2,650 Combination of Options 1 & 2 6 5,150 Combination of Options 1 & 3 7 9,950 Combination of Options 1, 3 & 4
Other more operational issues that need to be considered are:
• Much of the data collected for the GHD study appears to provide inconsistent results thus leading to lower confidence in the results used to calculate efficiencies and losses. According to GHD, inconsistent results would tend to suggest measurement error or a temporary fault in the system rather than a chronic problem such as a leaking pipe. Regular records are currently kept for much of the system. However, a review of methods of measurement and recording procedures should be undertaken in order to ensure that the records more accurately represent the real situation and can thus be used with greater confidence. Where calculations such as pump curves are used to determine inflows to the system the addition of flow measurement devices may prove to be more accurate. In addition, it may be advantageous to set up additional measuring points within the system to assist in calculating losses associated with a specific section. • Actual recording of volumes dumped during maintenance periods for example, would assist in water balance calculations. • A survey and review of the meters currently used within the system would be useful in identifying slow running meters. SunWater is currently running a program to replace certain meters. However, if the use of trickle irrigation and on-farm storage tanks becomes more common then under/slow reading meters may become more significant. In order to reduce this problem GHD recommend replacement of the common propeller actuated meters with more sensitive paddle actuated meters. • GHD found in their study that losses tend to occur in channel systems with an intermittent demand due to local rainfall or when demand is low and the channels are near pool level meaning seepage and evaporation losses have a relatively large effect. They determined that higher efficiencies can therefore be obtained when channels are supplying a near continuous volume near channel capacity. It was found that the BIA generally has the lowest efficiency in the September quarter (when channel saturation and water tables would have subsided during the winter months and evaporation is high) and highest in December to March (when demands and delivery volumes are higher and local catchment runoff and rainfall higher). A more even demand for the water from the distribution system will occur with the increased use of soil moisture measurement by irrigation farmers and better use of scheduling techniques ensuring land is irrigated when the soil needs water. This will assist the system to become more efficient as peak demands (normally caused by conventional timing of irrigation application) will be smoothed and a more even demand become common. In addition, with the increased use of on-farm storage, demand from the system can be further regulated during periods of low demand for irrigation application by scheduling of topping up of the on-farm storage units.
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• The gathering and ongoing use of efficiency data will enable operators to regularly determine system efficiency and associated losses. This regular monitoring will enable operations staff to identify and thus rectify a fault quickly, thereby saving water.
Many of these issues are concerned with operational issues which are primarily the responsibility of SunWater and as such have not been included in the costing for the proposed options but should be considered as part of the program for distribution losses in order to save additional losses that cannot currently be quantified.
9.6.3 Option Costs
Option costs have been based on the following assumptions:
• The cost of a leakage detection review is estimated to be approx. $80,000 with associated remedial works being in the order of $150,000 to $ 250,000 to achieve the 350 ML/a savings. Hence the cost of a combined pipeline leak detection review and remedial works is estimated to be $0.26 m (based on WBW experience). • Costs associated with lining the Woongarra channel are based on DNR figures (DNR 2001). Average channel wetted perimeter (perimeter of the open channel below the water line) equals 13.5 m and concrete lining of $50 /m 2 results in a cost of $675,000 /km. • Costs associated with lining 38 km of channel identified in Option 4 are the same as those for the Woongarra channel at $675,000 /km. • Operational improvements identified in Section 9.6.2 have not been costed.
Option costs are summarised in Table 9.25 together with potential water saved.
Table 9.25 – Option Costs Option Water Saved Option Cost Unit Cost (ML/a) ($ m) ($/ML) 1 350 0.26 743 2 2,300 5.06 2,201 3 4,800 12.83 2,672 4 4,800 25.65 5,344 5 2,650 5.32 2,008 6 5,150 13.09 2,542 7 9,950 38.74 3,893
The combined options 5 to 7 would be most beneficial in resolving water losses related to both pipelines and channels. Option 6 has been chosen as the preferred option due to the substantial water savings potentially attainable and the fact that the Woongarra Main Channel is known to have seepage problems. Option 6 costs and potential water savings will be considered further in Section 12.
9.7 Regulated River System Losses
Certain sections of the rivers and streams in the Burnett catchment are used to convey water from storages to water users. The flows within these watercourses are regulated by controlled releases from various storages. These regulated sections of river and the associated storages are discussed in Section 5 and shown on Figures 5.1 & 5.2.
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Losses from these systems can be affected by:
• surface geology of the river system; • the characteristics of the water way in terms of size, floodplains, natural/man made, extent of vegetation etc.; • variation in flows and timing relative to climatic conditions; • groundwater influences; and • antecedent conditions.
A DNR Report (Scriven, 1997) conducted for the Burnett region on transmission losses attempted to quantify losses in the Upper Burnett region. The figures calculated, which are shown in Table 9.26, are based largely on anecdotal evidence provided by system managers.
Table 9.26 – Transmission Loss Rates in the Upper Burnett Catchment System Reach Losses ML/km/d ML/km/a Three Moon Creek Cania Dam – Monto Weir 1.7 – 3.3 621 – 1205 Monto Weir – Burnett Three Moon Creek 0.48 175 River Burnett River Nogo River to Gayndah 0.12 44 Boondooma to Burnett Boyne River 0.18 66 River Barker Creek to Barambah Creek 0.30 110 Stonelands Source – DNR 2001
From investigations conducted by DNR using a direct estimation method (using key parameters such as seepage and evapotranspiration) the figures identified in Table 9.27 were established.
Table 9.27 – Summary of Direct Estimated Losses for the Burnett River Systems System Average Loss Average Loss Loss Range ML/a ML/km/a ML/km/a BIA 257 164 - 331 34,695 Upper Burnett Irrigation Project 174 93 - 197 33,060 Barker – Barambah Irrigation Project 24 21 - 27 1,918 Boyne Irrigation Project 36 13 - 42 3,060 Source – DNR 2001
The DNR Report (DNR 2001) proposed that strategies for reducing river transmission losses in order to improve efficiency were fairly limited, because these losses are dependent on natural conditions beyond control. Anecdotal evidence provided by system operators indicates that the regulated river systems are currently operated fairly efficiently, with minimum losses from overflows at the bottom ends of the regulated river sections. It is therefore unlikely that gains of greater than 5% could be achieved. General strategies that may be used to improve efficiency and gain a proportion of the losses identified could include:
• Improved management to minimise fluctuations in river flow rates, hence reducing losses. • Improved management of water ordering and deliveries to minimise overflow losses. • Construction of new storages or weirs as close as practical to the demand area to minimise transmission losses.
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However, all river flows have environmental benefits, and determining the extent to which natural flows can be affected without detriment to the environment is a complex issue. Hence considering the difficulties in identifying and achieving savings it is not proposed to allow for the potential for any savings from losses in river systems in this Study. The concept of environmental flows is discussed in more detail in relation to the Paradise Dam Option, in Section 10.
Considerable water savings could potentially be achieved through the strategies identified above. Therefore further study on the environmental affects of such strategies should be explored to eventually tap into these potential savings.
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10. OTHER SECTORS
10.1 Background
One of the key users of water in any river is the ecology of that river system. The concept of environmental flows (the assignment of some level of water within the system to maintain various ecological processes) attempts to more effectively incorporate an appreciation of ecological issues into water resource planning and management. In the past environmental flows issues have been neglected in many river systems throughout Australia leading to detrimental effects on the riverine ecology. However, it is now recognised that environmental flows are important and one of the major challenges in water resource planning today is to deliver regional social and economic benefits, by providing secure water entitlements for users (now and in the future), yet still allow for environmental flows. Thus reducing the level of compromise of the ecological sustainability of the watercourse being utilised to produce those social and economic benefits.
The Queensland Water Act, 2000, has established a requirement for Water Resource Plans (WRPs) to be developed for all catchments having significant ecological or cultural values or where abstraction can have measurable impacts. WRPs are currently the best means of determining the optimum balance between the community needs for secure water allocation and the provision of an environmental stream flow, which will sustain the physical and ecological integrity of waterways.
In Queensland, the key tool for environmental streamflow assessment is a hydraulic model, the Integrated Quantity and Quality Model (IQQM), which is used to characterise the natural flow regime (i.e. pre-development conditions), and also existing and proposed flow regimes. Appropriate environmental flow indicators are then used to measure the variation in existing or proposed flows from the natural flow regime. The different levels of flow variation in different reaches can be benchmarked by comparing with reference stream reaches in other catchments with measured impacts from different levels of water demand. Risk assessment diagrams are also used in the analysis of different development scenarios to assist in the interpretation of results. For example, a system with no water resource developments will have a 100% environmental flow and minimum environmental impact. However, there will be no allocation of water for agriculture, urban or industrial users. On the other hand, a system with 50% of the natural flow allocated to developments, is likely to exhibit significant environmental degradation.
10.2 The Paradise Dam
A WRP has been developed for the Burnett River basin (DNR, 2000), which establishes environmental flow and water security objectives for the Burnett Region. The WRP for the Burnett River basin has specified that the Mean Annual Flow (MAF) should be > 75% of the natural flow. Modelling undertaken by SKM (2001) indicates that if the Paradise Dam is constructed, the average flow will be 83% at AMTD 119km (Node 2) and 73% of the natural flow at the river mouth (Node 1). These two nodes have been identified as the two most critical nodes.
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A second key environmental flow measure is the Annual Proportional Flow Deviation parameter (APFD), which has been specified as < 2.0 for the Burnett River. The post- Paradise Dam model statistics are 2.04 at Node 2 and 2.07 at Node 1.
A third key performance indicator is the Average Recurrence Interval (ARI) for daily flows (1.5, 5 and 20 years). Modelling indicates that if the Paradise Dam is constructed, all the ARI indicators will be satisfied with the exception of the 1.5 year ARI, which will be 51% at node 1 whereas the WRP target is 69%. However, according to the SKM Supplementary Report (2001) this may be a modelling problem and the target may be achievable by refining the environmental flow release strategy. Statistics for all seven nodes indicate 86% compliance with the 44 specified environmental flow objectives for medium to high flows.
Although the resource operating plan for the Paradise Dam results in a decrease in the frequency of low flows (< 100ML/day), both the EIS and the Supplementary EIS (SKM 2001) emphasise that low flow conditions are a critical factor for survival of the lungfish and the Elseya turtle, which are two main fauna species of concern. It should be noted however, that because the Burnett River is already substantially modified and regulated, some of the low flow statistics do not conform under the existing entitlements case and at Node 1, the Paradise Dam case does not change the level of compliance. It is argued in the EIS that the excursions are not major and that they can be managed by an appropriate environmental release strategy with approximately 30% of this flow being required to operate the fishway. The overall assessment indicated that construction and operation of the Dam will result in compliance of 6 of the 9 low flow objectives compared to a compliance score of 7 for the existing case. (SKM Sup 2001).
Nevertheless, according to the assessment conducted by SKM (Sup 2001), if all the proposed Dam and weir structures proceed, the potential impact upon the lungfish is an increase in the number of disturbed reaches from 7 to 10 reaches i.e. a 26% potential decline in environmental value for this species. In addition, a total of 5 reaches where the turtle Elseya sp. occurs will be downgraded in environmental quality equating to 38% of the reaches where this environmental attribute is rated.
The proposed Paradise Dam therefore has a similar level of compliance with the WRP and the existing entitlements case. However, concerns for the lungfish and Elseya turtle are exacerbated.
10.3 Demand Management/Efficiency Measures
In the case of demand management/efficiency measures, the water saved which is then used more efficiently for the same or an alternative end use, does not affect environmental flows to the same extent as the Paradise Dam. The water extracted under the existing entitlements case is effectively merely used more efficiently, extracted and stored in on farm storages or used by an alternative end user. As such it will have less of an effect on the lungfish and the Elseya turtle.
If alternative supply or reuse elements are incorporated into an option with the demand management/efficiency measures these could potentially have more of a detrimental effect on the environmental flows then demand management/efficiency measures alone. However, such an option would still have less of an effect then the Paradise Dam which also incorporates smaller supply elements of weir modifications etc.
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A demand management/efficiency measures and/or alternative supply and reuse option has not been modelled for compliance of WRP identified objectives as it is considered that it would be very close to the existing entitlements case. Depending on the management of flow releases of such an option and the extent of uptake of identified entitlements it could even be argued that such an option could in fact have even less of a detrimental effect on the riverine ecology then the existing entitlements case due to various issues including the use of on farm storage allowing a more continuous demand of entitlements. If a combined alternative option to the Paradise Dam, as outlined in Section 12, is considered viable it may be necessary to assess flow release and management of the modified system in order to maximise compliance with the identified WRP objectives and minimise impact on the riverine ecology.
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11. ALTERNATIVE SUPPLY & REUSE OPTIONS
11.1 Overview
In addition to the demand management/efficiency measures identified in Sections 7 to 9, various alternative supply and reuse options have been considered. The main alternative sources of supply have been investigated in depth by various reports but the main reference document used in this Study has been the Kinhill Final Report (Kinhill, 1999).
Smaller supply options (weir modifications) which are proposed to be constructed in conjunction with the proposed Paradise Dam have also been considered. These smaller supply options potentially provide a significant cumulative quantity of water which can be used at various locations within the region at a fairly low capital cost. An additional option, the Degilbo Creek Dam on the Burnett River, which was one of the alternative supply options discussed in the EIS Report (SKM 2001), has also been identified as a potential option for the same reasons.
11.2 Small Supply Options
The small supply options considered in the Paradise Dam EIS Report (SKM, 2001) together with their water use reliability and development costs are identified in Table 11.1 and shown in Figure 11.1. These smaller structures are situated at various locations within the catchment, thus providing benefits to areas other than the Lower Burnett in some circumstances.
Table 11.1 – Small Supply Side Options Option Structure Development/ Water Use Water Use Cost Unit Cost No. Modification Urban/ Irrigation $ m ($/ML) Industrial (95% WSI) (99.7% ML/a WSI) ML/a 1 Eidsvold Weir (C) New Weir - 23,800 18.6 782 2 Walla Weir (L) Raising - 15,295 5.2 340 Existing Weir by 2m 3 Barllil Weir (S) New Weir - *6,000 2.8 467 4 Jones Weir (C) Raising of 200 6,900 5.9 855 Existing Weir 5 Degilbo Creek Dam New Dam 20,000 43,200 52.8 835 (C) Source – EIS Report (SKM 2001) C – Central Burnett, S – South Burnett, L – Lower Burnett, * - Yield is at WSI of 89.6% The costs identified are believed to be capital costs only. However, such structures are likely to have minimal operation & maintenance costs and as such should not alter the present value cost significantly from those costs identified.
These small supply options are considered further in Section 12 together with the preferred demand management/efficiency options.
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11.3 Other Alternative Supply & Reuse Options
Other less conventional supply/reuse water sources considered are as follows:
• Rainwater Tanks • Desalination • Reclaimed Wastewater • Greywater Reuse • Urban Stormwater Harvesting • On-Farm Storages
A brief description, potential yields, costs and unit costs are provided in the following sections.
11.3.1 Rainwater Tanks
Rainwater tanks are traditionally used as the main source of domestic supply in rural areas and small towns in Queensland. Rainwater tanks are still used extensively in many areas and often in preference to reticulated town water supply, although town water is often used as a back-up during extended dry periods. Approximately 12.6% of households are believed to use rainwater tanks in Australia (Wallington, 1999). Rainwater tanks can therefore be used as a sole supply or as a supplement to a reticulated supply thus reducing demand on the reticulated system. The critical issues affecting the use of rainwater tanks are water quality and tank yield versus cost.
Water quality can be affected by locality (proximity to roads and agricultural areas), roof catchment and material and tank materials. Bacteria, pathogens, heavy metals and pesticide levels can therefore be above accepted guidelines in some circumstances. However, several studies conducted in Australia have shown that water is generally within most accepted guidelines. In order to minimise potential pollution of drinking water, it is often recommended to use a first flush (diversion of the initial volume of water away from storage due to potentially higher pollutant concentrations) system and/or disinfection.
Key factors affecting tank yield and viability are annual/seasonal rainfall patterns and roof catchment area, which determine the likely yield performance of a tank. In Queensland rainfall typically occurs in a small number of intense storm events. In addition, tank capacity and water demand can also affect viability, which can be determined by the owner. Larger tanks can improve yield and reliability, however, there is a point of diminishing returns where a larger tank can marginally increase yield and reliability but at a significant increased cost.
According to Kinhill (1999), a tank size of approximately 20 kL appears to be the optimum in relation to cost and supply of water for the Burnett region. A 20 kL tank would yield approximately 61 kL/a in the Bundaberg and 45 to 50 kL/a in the dryer inland catchments. A 20 kL tank costs in the order of $2,750 depending on the materials used (RCC, 1997).
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Assuming 10,000 20 kL tanks were installed region wide, with 5,000 in the Bundaberg area and the remaining 5,000 in the inland areas, a total yield of 543 ML/a could be expected at a cost of $27.5 m. This translates to a unit cost of $50,691/ML, which is one order of magnitude greater then any of the main supply or efficiency measures considered. For this reason rain tanks will not be considered further in this Study. It should be noted however, that rain tanks can be financially viable in areas where no infrastructure currently exists or in new developments where economies of scale or collective rain tanks can be adopted. Hence rain tanks could be a potential option for specific areas within the region in the future.
11.3.2 Desalination
Desalination can be used to treat water from the sea, estuaries and saline groundwaters. These salt rich water sources can be treated to varying degrees to remove salt and enable the water to be used for potable, industrial and irrigation purposes. The level of treatment and quantity of water treated affects the cost of the treatment plant required. Kinhill (1999) considered a number of possible desalination options for the Burnett region. These options are identified below:
• Options 1a & 1b - Supply potable water to Bundaberg City and the Burnett Shire from seawater desalination process. • Options 2a & 2b – Supply desalinated water to Bundaberg Irrigation System. • Option 3a & 3b – Treat brackish groundwater to supply Bundaberg City and the Burnett Shire.
A summary of these options, the yield, present value and unit cost are provided in Table 11.2. Option 3a and 3b were not costed by Kinhill and will not be costed in this Study because they are considered unsustainable. These groundwater options would increase the burden on the currently over committed aquifers thus adding to the salinity problems already being experienced. It should be noted that the operation and maintenance costs have been modified for the options considered (compared to the original Kinhill figures) and brought forward (7% over 30 years) in order to allow comparison with the other options. Due to the very high operational cost of such treatment processes these options are approx. one order of magnitude greater then the other main supply and efficiency options considered. Therefore these options will not be considered further in this Study.
Table 11.2 – Summary of Desalination Options Option Water Supplied Total Option Cost Unit Cost ML/a $ m $/ML 1a 16,000 258 16,148 1b 16,000 251 15,713 2a 20,000 316 15,788 40,000 599 14,978 2b 40,000 623 15,563 100,000 1,487 14,866
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11.3.3 Reclaimed Wastewater
Approximately 60% of the current population lives in and around the Bundaberg area. This proportion is expected to grow in the future as more people move into the Bundaberg and Lower Burnett region. This will result in higher effluent discharge to receiving waters from wastewater treatment plant (WWTP), which could provide a potential pollution problem in the future. Considering the majority of the population and irrigated agriculture is located in the Lower Burnett, effluent reuse provides a logistically viable option for both potable & non- potable uses.
There are currently 6 WWTP in the Bundaberg & Lower Burnett region producing approximately 4,520 ML/a of sewage effluent. These WWTPs are expected to produce 7,550 ML/a by 2025 according to Kinhill (1999). A summary of the details of these WWTPs are provided in Table 11.3. It should be noted that the current and predicted 2025 flows do not consider demand management effects that could potentially decrease water demand and thus decrease the quantity of effluent discharged for potential reuse.
Table 11.3 – Summary of Details of WWTPs in Bundaberg and Burnett Shire Area/WWTP Treatment Process Effluent Disposal Licence 1996 2025 Effluent Flows Flows Standard ML/a ML/a BOD:SS (mg/L) Bundaberg East Bundaberg Trickle filters + continuous Discharge to 20:30 2,530 3,730 WWTP flow oxidation ditches Burnett River Millbank WWTP Trickle filters Discharge to 20:30 790 1,160 Burnett River Avoca WWTP Flows to be transferred to Discharge to 20:30 400 590 Millbank WWTP Burnett River Thabeban Continuous flow oxidation Cane lands disposal 20:30 250 400 WWTP ditch Tantitha WWTP Passveer oxidation ditch Discharge to 20:30 120 170 Burnett River Burnett Shire Bargara WWTP Trickle filters and Passveer Ocean outfall + 20:30 430 1,500 ditch small irrigation use Total 4,520 7,550 Source – Kinhill 1999 BOD – Biochemical oxygen demand, SS – suspended solids
Kinhill (1999) identified four WWTP’s (East Bundaberg, Millbank, Avoca and Bagara) that could be used to discharge treated effluent into the Woongarra Irrigation Channel. This water would be used for irrigation or potable use, considering Kalkie Water Treatment Plant extracts water from this channel for potable supply. This would require a grade 4+ polished effluent free of pathogens which could be achieved by treating the effluent with ozone and biologically activated carbon filtration. The costs of adopting all three WWTP transfer schemes are identified in Table 11.4 using current effluent discharge figures. Two options have been considered. Option 1 where all current available sewage from the four WWTP is reused and Option 2 where the effects of demand management, identified in Section 4, are taken into consideration which reduce effluent available for reuse. Both options assume infrastructure sizes that can cater for future flows.
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Table 11.4 – Costs for Reclaimed Wastewater Option WWTP Transport Means Water Total Cost Unit Cost Supplied $ m $/ML ML/a 1 East Bundaberg, 6.5 km, 450 mm dia pipe **4,150 *5.6 $1,349 Millbank/Avoca 7.0 km, 300 mm dia. Pipe & Bagara 4 km, 300 mm dia pipe 2 East Bundaberg, 6.5 km, 450 mm dia pipe **2,645 *5.6 $2,117 Millbank/Avoca 7.0 km, 300 mm dia. Pipe & Bagara 4 km, 300 mm dia pipe * - Assume operation & maintenance costs 2.5% of capital costs over 30 year period. ** - Assumes current population effluent available but sized in order to cater for future effluent.
The option of using reclaimed water is relatively cheap compared to the other alternative supply and reuse options considered. As demand management of the town/urban sector is likely to be adopted, Option 2 will therefore been considered further in Section 12 with the other supply/demand options.
It should be noted that in order to maximise the use of the reclaimed water identified, the seepage problems associated with the Woongarra channel would need to be minimised.
11.3.4 Greywater Reuse
Greywater constitutes useful water such as bathroom (excluding toilet), laundry and kitchen effluent generated in households, that could be used beneficially for outdoor water use such as gardens thereby reducing potable water demand. Current state regulations prohibit the use of greywater reuse in sewered urban areas but allow use in unsewered urban and rural areas.
In many cases greywater is stored in a tank ready for pumping on garden areas. Often this water is not treated and can represent a potential health risk due to pathogenic organisms. Treatment in the form of filtration and disinfection is generally recommended together with sub surface irrigation systems to minimise direct human contact.
According to Kinhill (1999), 20% of urban water usage could be saved using greywater reuse with a 60% reduction in wastewater discharge. The cost of installing a reuse system is in the order of $1,500 in a new residence but rises to $6,000 per new residence if full treatment, consisting of a gravel filter, sand filter and UV disinfection, and irrigation system are provided (DNR 2001). These costs would be higher if retrofitting an existing house. Assuming water usage of 0.4 ML/hh/a, this would equate to a water saving of 0.08 ML/hh/a and a unit cost of between $18,750 and $75,000 per ML without consideration of operating costs.
Considering the State Government does not currently support this form of reuse, the high costs associated with retrofitting greywater reuse systems and considering the demand reduction option proposed in Section 4 may reduce the potential water savings available, this option has not been considered further in this Study. However, the concept of greywater reuse and detailed costing should be investigated for new development as application on a larger scale systems as an alternative to traditional systems is believed to be viable and has been adopted in several new developments throughout Australia.
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11.3.5 Urban Stormwater Harvesting
Urban stormwater collected from impervious surfaces can be used beneficially for a wide range of uses and can be conducted at an on-site, local or regional level. Various methods of harvesting include rainwater tanks, detention basins/wetlands and groundwater recharge. This water can then be used for potable use, dual reticulation systems, irrigation of public parks or for industry. However, the use is dependent on the level of treatment adopted, the volume potentially harvested and availability of storage facilities.
Water quality of stormwater varies considerably and is dependent on the function of the impervious or semi-impervious area over which the stormwater travels. Stormwater from roads is often highly contaminated by heavy metals whereas water from grassed areas is more likely to contain contaminants such as sediments, ammonia and pathogenic organisms.
Trials of stormwater harvesting have been carried out in various locations around Australia and there is considerable interest in the adoption of harvesting on new developments. However, retrofitting of harvesting systems can be costly and viability can only be assessed on a site specific level.
There is very little information available on costs for stormwater harvesting. According to Kinhill (1999), if water is used for non potable domestic use the cost would be comparable with dual systems and if used for potable domestic use the cost would be comparable with conventional potable water systems. However, there are no firm figures to substantiate these statements.
Hence due to lack of detailed information on costings and site specifics this option will not be considered further in this Study. However, it is recommended that this alternative supply option is considered further in the future if detailed information on the existing Bundaberg stormwater system can be collected. Considering the Bundaberg area is expected to grow rapidly in future it is assumed new developments may be constructed. In such areas stormwater harvesting should be considered as a viable alternative to discharge to local rivers in order to minimise potential pollution and maximise the available water resource.
11.3.6 On-Farm Storages
On-farm storages have been considered for the sugar cane industry only and as such have been included in Section 9.2.6 as Option 10.
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12. OPTIONS REVIEW
12.1 Original Proposed Supply Options
To resolve the current and future predicted water shortages in the Burnett Region, the current planned solution is to construct the Burnett River (Paradise) Dam and modify/construct 4 additional weir structures. The details of these supply side options are summarised in Table 12.1.
Table 12.1 – Original Proposed Supply Side Options Structure Development/Modification Proposed Use (ML/a) Urban/Industrial Irrigation (99.7% WSI) (95% WSI) Paradise Dam New 300,000 ML Dam 20,000 124,000 Eidsvold Weir New Weir 23,800 Walla Weir Raising of Existing Weir by 2m 15,295 Barllil Weir New Weir *6,000 Jones Weir Raising of Existing Weir 200 6,900 Source – EIS (EIS) * - Yield is at WSI of 89.6%
The additional yields supplied by these structures will be used to increase allocations within the BIA. According to the original EIS document (SKM 2001), the needs that could be satisfied by the identified water, are as follows:
• 20,000 ML/a of high security water for urban and industrial water use; • 86,000 ML/a on existing cane sugar to stabilise production and support the B2K+ Project; • 14,000 ML/a for the proposed chicory plant; and • 14,000 ML/a for the Ground Water Rescue Project to achieve a sustainable supply of groundwater.
The subsequent Supplementary EIS document (SKM 2001), identifies that the water will not be distributed in any particular manner other than it be driven by market forces. Key uses identified by the Interim Report (NECG 2001), appended to the original EIS document, identify that the key water uses of the Dam are as follows:
• 20,000 ML/a of high security water for urban and industrial water use; • 80,000 ML/a for application on existing sugar cane areas; and • 42,000 ML/a for application on new horticultural areas within the BIA.
These water uses are more in line with probable demand requirements driven by market forces and the potential move to higher value horticultural crops. As such, in order to compare the objectives of the Paradise Dam with the proposed alternative ‘hybrid’ option, which will combine smaller supply options, efficiency measures and water reuse, the NECG water uses have been used as the bench mark for comparison and the key factors driving water demand.
The Paradise Dam has been considered in isolation as the 4 smaller proposed weir modifications can potentially be used as part of the alternative ‘hybrid’ option considered.
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Using current demand and efficiency figures the proposed Paradise Dam (not including the smaller weir modifications) will achieve the following outcomes:
• Present value cost $183 m. • Water supplied 144,000 ML/a of which 20,000 ML/a is of high security for urban/industrial future demand and 124,000 ML/a of lower security irrigation use. • 80,000 ML/a of water used for irrigation of the existing sugar cane area (additional application rate of 1.6 ML/ha/a) producing a crop yield increase of 13.5% of the existing 4,355,527 t/a. This is based on actual crop yield response curves (over a three year period) where additional water supplied is between the application rates of 2 to 4 ML/ha/a. • Increased cane yield is valued at $16.2 m/a. • 42,000 ML/a of water used for irrigation of new 14,000 ha horticultural area in the Lower Burnett using current crop mix and current average application rates of 3 ML/ha/a and crop yield production of 23 t/ha/a. • Increased horticultural crop yield is valued at $593.8 m (based on $1,844 /t).
It should be noted that the figures identified above use many of the same assumptions used for the efficiency options identified in Section 12.2 (cane price, horticultural crop price etc.). This is in order to provide a fair comparison between the options and remove discrepancies which may occur if other studies findings were used using alternative assumptions for costs and crop yields.
12.2 Demand Management/Efficiency Options
The preferred options identified in Sections 7 to 9 are shown in Table 12.2. This table provides a summary of the individual sectors/users assessed, water currently used, potential water savings possible through demand management/efficiency measures, program costs, and for the agricultural industry concurrent potential crop yield increases and associated values.
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Table 12.2 – Summary of Preferred Demand Management/Efficiency Options for Individual Sectors Sector/User Water Potential Option Unit Crop Potential Marginal Option Used Water Cost Cost Yield Crop Cost of No. (ML/a) Saved ($ m) ($/ML) Increase Yield Option (ML/a) t/a Value ($/t/a) ($ m) Town/Urban 16,000 5,420 5.6 1,033 - - - Only Option Industry 25,800 ------No Option
Agriculture Sugar Cane 100,000 14,395 58.2 4,044 366,026 10.1 159 Option *30,000 32.5 1,083 255,000 7 126 9 Option 10 Horticulture 43,300 4,174 28.6 6,848 36,417 66.4 785 Option 4 Field & 22,800 4,560 7.4 1,620 ** ** ** Option Fodder 1 Stock & 2,100 380 0.25 669 - - - Option Domestic 1 Distribution 1124,000 5,150 13.09 2,542 - - - Option Losses 6 Regulated ------No River Losses Option Other Environmental ------No Flows Option Total 210,000 64,079 145.64 2,273 1 – Water not actually used but transported * - Water not actually saved but supplied by on farm storage but used exclusively for sugar industry. ** - Simultaneous crop yield likely but unquantifiable.
12.3 Alternative Supply & Reuse Options
The preferred options identified in Section 11 are shown in Table 12.3. This table provides a summary of the potential water supply possible, option costs and unit costs. On farm storages are strictly categorised as an alternative supply option but have been included in the efficiency options identified in Table 12.2 in this Study because they have only been considered for the sugar cane industry.
Table 12.3 – Alternative Supply & Reuse Options Option Water Supplied (ML/a) Cost Unit Cost Option No. Urban/Industrial Irrigation $ m $/ML Eidsvold Weir 23,800 18.6 782 Option 1 Walla Weir 15,295 5.2 340 Option 2 Barllil Weir 6,000 2.8 467 Option 3 Jones Weir 200 6,900 5.9 855 Option 4 Degilbo Creek Dam 20,000 43,200 52.8 835 Option 5 Reclaimed 2,645 5.6 2,117 Option 2 Wastewater Total 20,200 97,840 90.9 929
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It should be noted that several other alternative supply options were also considered but found to be expensive compared to the preferred options identified in Table 12.3. Although the other alternative supply options have not been considered further in this particular Study they may be viable alternatives to conventional supply methods in the Burnett Region in the future, for individual locations or when considering other areas within Queensland.
12.4 Alternative Hybrid Option
In order to compare the Paradise Dam, a Hybrid Option has been considered using a combination of demand management/efficiency options and alternative supply/reuse options. A summary of the two options costs and benefits is identified in Table 12.4.
Table 12.4 – Comparison of Hybrid Option & Paradise Dam Option Hybrid Option Paradise Dam Option Present value cost - $184 m Present Value Cost - $183 m Water Saved/Supplied – 118,920 ML/a Water Supplied – 144,000 ML/a - 5,620 ML/a urban/industrial use - 20,000 ML/a urban/industrial use - 113,300 ML/a - 124,000 ML/a irrigation use Urban Sector Urban Sector - 5,620 ML/a water saved & reduction in current - 20,000 ML/a to cater for 2050 population demand by 35% enabling saved water to cater for future 2050 population with less water requirements. - As current upply will be able to cater for future - Additional flows are likely to lead to the need for demand, savings will be obtained in augmentation of water/sewage treatment plants augmentation in the water/sewage treatment plants. future. Sugar Cane Industry Sugar Cane Industry - 44,395 ML/a of water saved & supplied for existing - 80,000 ML/a of water supplied for existing irrigated irrigated area area - 621,026 t/a of additional cane produced - 587,996 t/a of additional cane produced - $17.1 m/a additional cane value - $16.2 m/a additional cane value - Increased cane yield sufficient for B2K+ project - Increased cane yield sufficient for B2K+ project Horticulture Horticulture - 68,905 ML/a of water saved/supplied used for new - 42,000 ML/a of water for new area areas - 24,755 ML/a used for Lower Burnett - 44,150 ML/a used for Upper Burnett - 9,670 ha of new horticultural land irrigated in - 14,000 ha of new horticultural land irrigated in Lower Burnett Lower Burnett - 6,650 ha of new horticultural land irrigated in Upper Burnett - 36,417 t/a of extra crop yield from existing areas - 490,173 t/a of crop yield from both new areas - 322,000 t/a of new crop yield - $ 960 m/a additional crop value - $593.8 m/a additional crop value
Hence for the same cost, the Hybrid Option can achieve all the requirements of the Dam but provide additional benefits such as:
• no requirement for augmentation of water/sewage treatment works; • reuse of current and future effluent from WWTPs for irrigated agriculture; • additional 33,030 t/a of cane worth $1 m providing higher security of cane yield for the B2K+ project;
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• an additional 204,590 t/a of horticultural crops in both Lower & Upper Burnett worth an additional $366 m per year increasing economic return in Lower & Upper Burnett (over and above the 322,000 t/a, $594 m/a achieved by both options); • greater yield from existing and new land due to better management practices; • reduced losses associated with distribution and potential wastage of new supplies; • improved efficiency of field and fodder crops and stock watering; • increased technical ability of the irrigators in the Region and provision of a forum for shared learning and trialing of pilot studies on a commercial scale; • raised awareness of the importance of water efficiency and true value of water in line with COAG requirements; • complementing and building on the RWUEI enabling extension and expansion of the current 4 year program by another 4 years; • significantly increased employment during the 4 year implementation phase (and after) compared to the Dam Option due to the labour intensive nature of the programs proposed; and • significantly reduced risk associated with the provision of water services as the individual programs can be implemented over a period of time depending on the changing requirements of each end use sector.
The only alternative supply option not considered at this time is the Degilbo Creek Dam which can supply 20,000 ML/a of secure urban/industrial water and 43,200 ML/a of water for irrigation use at a cost of $52.8 m. The original Paradise Dam Option identified in the EIS (SKM 2001) also required the use of the Eidsvold, Walla, Barillil and Jones Weirs at a cost of $32.5 m, although the purpose of these structures was not specifically identified. If the Degilbo Creek Dam was combined with the Hybrid Option at some time in the future depending on the changing requirements of the Region, the following additional benefits could be obtained:
• 20,000 ML/a for future high security use such as additional population growth and industrial development (value-adding industry). • 14,000 ML/a for the BIA Groundwater Rescue Project. • 29,200 ML/a for other irrigation requirements in the Lower Burnett such as extension of the sugar cane or horticultural irrigated areas.
12.5 Summary of Hybrid Option Details
A summary of the details of the Hybrid Option are provided in Tables 12.5 & 12.6. Where possible water saved or supplied has been allocated to the horticultural industry for new irrigation areas. The Lower and Upper Burnett Regions have varying water use and crop yield. The water allocated has been allocated to the Lower and Upper Burnett Regions depending on the proximity of the source water in order to minimise losses associated with distribution.
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Table 12.5 – Summary of Hybrid Option Details Sector/ Water Potential Option Unit Crop Crop User Used Water Cost Cost Yield Value ML/a Saved $ m $/ Increase $m/a ML/a ML t/a Town/ 16,000 5,420 5.6 1,033 - - Water saved used to provide Urban water for growing pop using lower consumption due to demand management. 200 4 4 - - Jones Weir water used in UB Industry 25,800 - - - - - No savings identified Agriculture Sugar Cane 100,000 214,395 58.2 4,044 366,026 10.1 Water saved used more efficiently on existing area using BP to produce higher crop yields. 30,000 32.5 1,083 255,000 7 300 (50) ML on-farm storage units producing water yield of 30,000 ML used on existing areas using BP to increase crop yield. Horticulture 43,300 34,174 28.6 6,848 36,417 66.4 Water saved with concurrent increased yield in both LB & UB due to BP. 3 30,680 56.0 Water saved used on new horticultural area in LB (650 ha) & UB (378 ha) in proportions saved to increase crop yields using BP. 15,295 5.2 340 167,289 308.5 Walla Weir water used to irrigate new area of LB using BP 2,645 5.6 2,117 28,930 53.3 Reclaimed wastewater discharged to BIA system & used to grow new area of LB using BP 36,700 27.3 744 182,395 327.8 Eidsvold, Barllil & Jones Weirs water used to grow new area in UB (5,527 ha) using BP Field & 22,800 34,560 7.4 1,620 - - Water saved/increase in yield Fodder (not quantified) due to BP 3 22,663 40.7 Water saved used to irrigate new horticultural area in UB (687 ha) Stock & 2,100 3380 0.25 Water saved Domestic 3 669 1,889 3.4 Water saved used to irrigate new horticultural area in UB (57 ha) Distribution 1124,000 35,150 13.1 2,542 - - Water saved Losses 3 56,328 103.9 Water saved used to irrigate new horticultural area (2012 ha) in LB using BP. Total 210,000 118,920 183.8 1,548 977 1 – Water not used but transported, 2 – Water not actually saved due to current low allocations but more effectively used on same crop to produce increased yield, 3 – Where possible water saved used to grow horticultural crops in the LB or UB depending on proximity of the water to LB/UB. BP – Best/better practice, LB – Lower Burnett, UB – Upper Burnett 4 - cost covered in horticultural section
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Table 12.6 – Hybrid Option Program Details Sector/User Program Details Name Town/Urban WaterWise Burnett Apply COAG pricing policy. Towns Program Carry out education & assistance program covering residential population (including outdoor use). Conduct assessment and retrofitting program (showerheads, tap flow regulators, toilet flush reduction, leakage repair) worth $100 per house on 80% of houses. Audit and retrofitting program for 50% of commercial, institutional, industrial customers. Leakage detection and remedial works on distribution system. Industry WaterWise Burnett No program to be developed under this Study but recommend audits Industry Program should be considered. Agriculture Sugar Cane WaterWise Burnett Convert 15% of winch & furrow irrigated land to trickle & 10% to Sugar Industry alternate row trickle. Program Convert 50% of existing furrow irrigated land, 50% of winch & 100% of trickle to best practice. Convert 15% of winch & furrow irrigated land to close row cropping with trickle irrigation. Employ 4 full time and 1 part time extension officers for 4 years (including equipment). Provide technical equipment to farmers participating. Construct 300 (50 ML) on-farm storage on farms & employ 1 full time storage specialist. Horticulture WaterWise Burnett Convert 75% of area not using micro/drip irrigation to micro/drip Horticulture irrigation systems. Industry Program Convert 75% of farmers not currently using moisture/technical equipment to better management practice and provide moisture/technical equipment. . Employ 6 full time extension officers for 4 years including equipment. Field & WaterWise Burnett Provide moisture/technical equipment for all farmers participating. Fodder Field & Fodder Employ 7 full time extension officers to collect information on Industry Program industry and provide assistance in principles of Best practice irrigation techniques. Stock & Employ 1 full time extension officer to identify stock farmers and Domestic potential water savings, investigate efficient systems and provide assistance to farmers in implementing efficiency measures. Officer to work closely with other officers. Distribution WaterWise Burnett Conduct pipeline leakage test and remedial works. Losses SunWater Program Reline all 19km of leaking Woogarra Main Channel with impervious lining. Assume operational management improvements made. Other Alternative WaterWise Burnett Modifications to existing WWTPs and provision of reticulated system Supply & Government to Woongarra Channel to enable reuse of wastewater Reuse Program Construction/modification of Eidsvold. Walla, Barillil and Jones Weirs to provide additional water supply to more efficient system.
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13. IMPLEMENTATION
It is recommended that the Hybrid Option, or option that combines similar components, is adopted as an alternative to the Paradise Dam. For this type of Hybrid Option to work a detailed implementation strategy needs to be investigated and identified. Some of the issues that need to be considered include:
• the extent and timing of the various program components to be implemented as this type of option facilitates staging and response to water demand over time; • the combination of programs required at each stage as many are interdependent; • management of the programs implemented as they cover a diverse spectrum of end users; • integration of the programs with existing schemes such as the RWUEI to ensure such schemes are extended where working well rather then contradicted; • integration and timing with pricing reform policies etc. to assist in the effectiveness of the programs identified; • funding and potential stakeholder partnerships including industry; and • political and community based concerns.
The implementation strategy for the Hybrid Option has not been described in this Report. However, a separate document has been prepared which summarises one possible approach to the implementation of the proposed Hybrid Option, should this option be actively considered as a viable alternative to the Paradise Dam Option. This implementation strategy, of necessity, would require the involvement and input from a range of government and non- government stakeholders.
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14. RECOMMENDATIONS
From the investigations conducted under the Burnett Region LCP Study a number of recommendations have been identified. These recommendations are detailed as follows:
• The proposed Hybrid Option, or an option which combines similar components, should be adopted as an alternative to the Paradise Dam. The Hybrid Option details are provided in Tables 12.5 and 12.6 in Section 12. • Adoption of the programs developed under the Hybrid Option should be implemented in stages in order to cater for real water demand and minimise the risk of over supply and expenditure on unnecessary infrastructure and programs. • The staging of the proposed programs should be carefully chosen as many are interdependent. • Issues such as measurement of water used, pricing reform, effective two part tariffs, user pays principles and tradeable water entitlements need to be investigated and implemented for the whole catchment in order for the proposed programs to work effectively and the real value of water to be understood by the community. Hence bringing the region in line with COAG principles. • Demand management/efficiency measures need to be introduced before expansion of the irrigated agricultural industry in order to ensure water efficiency is maximised before additional supplies are provided. • Investigation of the current water used for each industry needs to be fully investigated, including unregulated groundwater resources, in order to monitor and control the limited water resources within the catchment more effectively. • Discussions with the relevant stakeholders and existing RWUEI teams etc. need to be conducted to ensure connectivity and integration of the proposed programs with existing schemes and potential key stakeholders that could be influential in the success of the proposed Hybrid (or similar) Option. • Auditing for the Industrial Sector has not been included in the Hybrid Option developed. However, auditing of the few industries identified should be considered as considerable additional water savings may be available. • Alternative supply options such as rain water tanks and greywater reuse have not been included in the Hybrid Option developed. However, these alternative supply options may be viable alternatives when considering new developments in the future. • Regulations associated with the requirements of new developments and modification of existing properties should be reviewed and water efficient fixtures identified as required in order to assist in minimising water demand in the future. • The Degilbo Dam has not been included in the Hybrid Option identified. However, this additional alternative supply option should be considered in future.
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15. REFERENCES
1. Barrett Purcell & Associates – Determining a Framework, Terms & Definitions for Water Use Efficiency in Irrigation, September 1999 2. Bureau of Sugar Experiments – Irrigation of Sugar Cane, 1998 3. Bundaberg Sugar – Sugar Cane Yields & Variety Performance, Bundaberg District, 1999. 4. Barraclough & Co. - Audit of Water Irrigation Use Efficiencies on Farms within the Queensland Horticultural Industry – Final Report, November 1999. 5. Barraclough & Co. - Audit of Water Irrigation Use Efficiencies on Farms within the Queensland Dairy Industry, February 2000. 6. Barraclough & Co. - Audit of Water Irrigation Use Efficiencies on Farms within the Queensland Lucerne Industry, April 2000. 7. BSES – Rural Water Use Efficiency Initiative , Milestone Report One for he Sugar Industry, November 1999. 8. DNR - Burnett River Catchment Appraisal Study – Technical Report, June 2001 9. DNR – Draft Water Allocation Management Plan (Burnett Basin), Draft WAMP, June 2000 10. DNRM – DNR Annual Water Statistics 1999 – 2000, 2001 11. GHD – SWP Distribution System Efficiency Review, Report on Bundaberg Irrigation Area, April 2001 12. P J Goyne, G T McIntyre & A L Spragge – Cotton & Grain Industries Stocktake Report, April 2000. 13. Lionel Tilley & Les Chapman (Consultants) – Benchmarking Crop Water Index for the Queensland Sugar Industry, October 1999. 14. Queensland Government – Irrigation for Profit, Dairy & Lucerne Adoption Program, Milestone 2 Report, June 2001. 15. RR Consultancy – Assessment of Irrigation Demand for Sugar Cane in the Bundaberg Area, Bundaberg 2000+ Project, June 2000. 16. NSW Agriculture – Drip on Lucerne saves water and time. 17. SKM - The Efficiency of Water Use in the Burnett Region – Final Report, March 2000. 18. SKM - An Economic Evaluation of Irrigation Methods & Programs, Bundaberg Irrigation Economic Assessment Report - Volume 1, September 1996 19. SKM – Burnett River Catchment Study, Catchment Overview, June 1998. 20. SKM – Burnett Catchment Water Infrastructure, Burnett River Dam, Environmental Impact Assessment, 2001. 21. SKM – Burnett River Dam, Supplementary Report, October 2001. 22. Water Services Association of Australia – Water Wise Management, A Demand Management Manual for Water Utilities, 1998
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APPENDICES
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APPENDIX A – Regional Rainfall Data
1600 Annual Rainfall Historic Average 1400
1200
1000
800
600
400
200
0 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000
Year Lower Burnett, (Historically 60 years of records – one station from 1913, other 1942)
1200 Annual Rainfall Historic Average 1000
800
600
400
200
0 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 Year
Central Burnett (Historically 90 years of records, one station 1898. other 1911)
900 Annual Rainfall 800 Long Term Average
700
600
500
400
300
200
100
0 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 Year North Burnett (Historically 110 years of records, station since 1898)
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1200 Annual Rainfall 1000 Long Term Average
800
600
400
200
0 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 Year South Burnett (Historically 90 years of records, station since 1905)
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APPENDIX B – Surface & Groundwater Water Supply Information (DNR 2001)
Surface Water
North Burnett - Three Moon Creek Irrigation Projects –- Cania Dam releases water into Three Moon Creek for surface water irrigation & groundwater recharge via several recharge weirs. Releases are made on an annual basis downstream as far as Abercorn (110km). 1,484 ML of surface water and 13,155ML of groundwater are allocated for irrigation of 2,270 ha. Monto & Mulgildie townships are supplied from groundwater.
Central Burnett - Upper Burnett River Irrigation Project –- Water is supplied from Wuruma Dam on the Nogo River via Jones Weir & Claude Wharton Weir on the Burnett River then downstream as far as the ponded area of Walla Weir. A total of 237 km of stream is regulated with nominal allocation of 27,450 ML. The project supplies 3,340 ha of riparian irrigation together with supplies for Eidsvold, Mundubbera and Gayndah townships and the Woodmillar Water Board. Further upstream on the Burnett River, John Goleby Weir provides 1,560 ML to 1,200 ha of land from the ponded area down to the Nogo River confluence.
Central Burnett - Boyne River Irrigation Project –- Boondooma Dam supplies water to the 87 km reach down to the confluence of the Boyne and Burnett Rivers. A total of 12,734 ML is available to 3,255 ha of farmland in addition to 29,946 ML of allocation for the Tarong Power Station, Proston Water Board, Proston town water supply and landholders along the pipeline.
South Burnett - Barker/Barambah Irrigation Project – Barambah Creek is supplemented from Bjelke-Peterson Dam via Barker Creek and the Redgate pipeline to Joe Sippel Weir. The regulated length of stream is 97 km and extends from Joe Sippel Weir to Stonelands. Unregulated inflows supply a significant component, the pre-development average annual discharge at Stonelands being 167,761 ML/a. The nominal allocation of 32,566 ML/a available to the regulated section supplies riparian irrigators on Barker and Barambah Creeks, the Murgon, Wondai and the Cherbourg communities and the Merlwood Water Board.
Lower Burnett - Bundaberg Irrigation Area (BIA) - The BIA draws from the Fred Haigh Dam, Bucca Weir and Kolan Barrage on the Kolan River, and from Walla Weir and Ben Anderson Barrage on the Burnett River. Water is also released downstream from Claude Wharton Weir and transferred from Fred Haigh Dam to supplement supplies in the Burnett River. A nominal allocation of 198,362 ML/a is supplied through 4 major reticulation systems and 128 km of regulated stream. Water is provided to 56,000 ha of irrigated land as well as urban demand from Bundaberg City and Burnett and Kolan Shires (DNR 25 p5-5).
Groundwater
North Burnett Region - Groundwater is available from the Quarternary Alluvium associated with Three Moon, Monal and Splinter Creeks. Cania Dam and in-stream weirs on the upper section of the Three Moon Creek recharge this system. Recharge has been adequate for the past 6 years. Water quality ranges from moderately saline in the upper reaches to very highly saline in the lower reaches, making the water only suitable for salt-tolerant crops.
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Central Burnett Region - Alluvial deposits are confined to a narrow strip adjacent to the Burnett River. Subartesian bores in the Precipice Sandstone have been developed in the Munduberra area.
South Burnett Region - Groundwater is associated with the alluvial deposits of the Barker, Barambah, Nangur and Boonara Creeks and Stuart River. These aquifers are unable to consistently meet irrigation demands and water quality is variable ranging from moderately saline to highly saline depending on location and proximity to the red volcanic soils of the Range Basalts. Along Barker Creek, groundwater is unpotable and only suitable for irrigation of very salt tolerant crops. At Mondure Flats on Barambah Creek, groundwater is suitable for stock and domestic use and irrigation of medium to high salt-tolerant crops. Away from the central area of the alluvium, quality rapidly deteriorates and groundwater is unsuitable for uses other than stock watering. Groundwaters are generally too hard for domestic purposes.
Lower Burnett Region - The Elliott Formation is located along the coastal strip from Gregory River to Littabella Creek. The Fairymead Beds underlie the Elliot Formation over much of its extent but higher yield rates and better transmissivity make the Fairymead Beds more susceptible to saltwater intrusion. Minor water supplies are derived from shallow bores in the Coastal Dune Sands north of Bundaberg and from fractures in the Hummock Basalt. These aquifers supply 20% of the BIA irrigation water and are also important for urban use. The water levels of Elliott/Fairymead are generally above sea level with an eastward gradient to the sea. However, during irrigation abstraction recharge of freshwater is slow and saltwater intrusion takes place. Away from the coast water quality is good and suitable for domestic and irrigation supplies although high magnesium levels south of the Hummock occurs due to leaching from the basalt and some bores show elevated nitrate levels (DNR 25 p5-14).
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APPENDIX C – Table C1 – Historic Use of Regulated Surface & Groundwater Supplies Year Allocation 1986/87 1987/88 1988/89 1989/90 1990/91 1991/92 1992/93 1993/94 1994/95 1995/96 1996/97 1997/98 1998/99 North Irrigation 14639 8906 10589 4290 6289 10310 10428 13386 10166 16009 11627 10613 11825 7341 Industry 125 0 0 0 0 0 0 0 0 0 0 38 52 19 Urban 580 421 443 345 416 518 520 604 433 391 382 350 347 280 Stock & Domestic 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Water Board 5332 50 61 56 74 75 65 78 64 64 55 56 67 64 Upper Irrigation 26119 18685 24951 18035 18257 25017 26347 26906 23426 25981 20228 22373 22772 25222 Industry 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Urban 1670 1297 1433 1210 1279 1465 1413 1571 1520 1385 1374 1584 1645 1577 Stock & Domestic 85 85 85 85 85 85 85 85 85 85 85 85 85 85 Water Board 80 71 67 76 76 75 53 66 73 72 59 69 67 66 Boyne Irrigation 12734 5963 7841 6556 5569 7687 6798 9234 5517 4371 2975 6612 6804 6412 Industry 29270 30021 27314 25828 26886 28751 30165 30825 28274 22900 21729 24998 22415 22268 Urban 0 21 24 21 10 35 24 29 46 24 18 21 39 27 Stock & Domestic 176 176 176 176 176 176 176 176 176 176 176 176 240 204 Water Board 500 391 424 397 350 468 501 493 443 446 423 424 458 402 Barker Irrigation 30257 0 0 0 5107 9722 12173 17021 15508 19876 9757 19152 18025 9285 Industry 127 127 127 127 127 127 127 127 127 127 127 127 127 127 Urban 2000 4120 4120 4220 4415 4369 4276 4048 4069 4536 4236 4379 1849 1356 Stock & Domestic 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Water Board 182 100 100 100 100 100 100 100 100 100 100 96 164 100 Lower Irrigation 252280 113167 157107 92709 193856 219819 158782 258576 160201 264411 118702 137786 82592 72367 Industry 20 0 0 0 0 0 0 0 0 10 12 7 13 11 Urban 18471 12606 14595 13835 14446 16211 15643 14241 9789 16768 15036 14911 11383 9070 Stock & Domestic 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Water Board 4500 0 0 0 0 0 0 0 0 0 219 1310 1609 121 Other 0 0 0 0 0 0 0 0 0 1642 40910 11305 33660 21083 Total 399147 196207 249457 168066 277518 325010 267676 377566 260017 379374 248230 256472 216238 177487 Source – DNR 2001
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Table C2 – Total Additional Potential Demand (Identified & Unconstrained)
Identified Potential Demands ML/a Additional Water Source TWS RWS GW Industrial Irrigation Required for Full Rescue Development of Irrigable Soils ML/a North Monal Creek 5,040 14,000 Three Moon Creek 100 2,720 53,295 Splinter Creek 3,250 29,270 Central Burnett River 180 15,700 151,090 Auburb River 3,000 6,600 Boyne River 6,700 71,280 Reids River 8,560 33,240 Barambah Creek 65,800 84,180 South Barambah Creek 200 400 3,500 16,000 Barker Creek 500 2,020 15,500 Boyne Creek 2,000 18,660 Stuart Creek 8,680 47,850 Lower BIA 6,800 14,170 25,000 133,800 366,600 Elliott River 7,920 Gregory River 1 Isis River 214,355 Total 8,680 500 14,170 27,000 258,770 929,840 Source – DNR 2001 1 – Gregory River TWS (Childers & Woodgate) demands are included in BIA TWS demands. 2 – Includes land along Cherwell River.
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APPENDIX D – Demand Sectors Information
Millaquin Sugar Cane Productivity against Total Water Use (1997/98)
100% Furrow Irrigation 160.0 140.0 120.0 100.0 80.0
Tonne/ha 60.0 40.0 20.0 0.0 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 Water Use (ML/ha)
100% Overhead Irrigation 160.0 140.0 120.0 100.0 80.0
Tonne/ha 60.0 40.0 20.0 0.0 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 Water Use (ML/ha)
100% Trickle Irrigation 160.0 140.0 120.0 100.0 80.0
Tonne/ha 60.0 40.0 20.0 0.0 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 Water Use (ML/ha)
Source – SKM – The Efficiency of Water Use in the Burnett Region – 2000
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Sugar Industry Cost Assumptions
Capital costs for the main irrigation systems considered have been obtained from those calculated by SKM (SKM 1998). These costs have also been used by BSES in their publication (BSES 1998). The costs calculated were for complete irrigation systems for a 50 ha farm using surface water. The costs used are identified in Table D1.
Table D1 – Irrigation System Costs Irrigation Cost for 50 Cost per Components Included System ha Farm ($) ha ($/ha) Trickle 154,754 3,095 Pumps, filters, mainline, trickle tube & fittings Winch 67,605 1,352 Pumps, mainline & irrigator hose Best Practice 73,015 1,460 Pumps, mainline, tailwater return earthworks & pump, Furrow initial land forming, & gated aluminium pipe Standard Furrow 63,015 1,260 Pumps, mainline, initial land forming & gated pipe (Source - SKM 1996)
The cost of 100% conversion from both best practice furrow to trickle and winch to trickle were also considered on 50 ha farms as shown in Table D2. This assumes using existing pipelines and equipment where possible to minimise costs.
Table D2 – Irrigation Conversion Costs Irrigation System Conversion Cost for 50 ha Farm ($) Cost per ha ($/ha) From winch to trickle 125,768 2,515 From best practice furrow to trickle 121,818 2,436 (Source - SKM 1996)
Cost assumptions are as follows: • Costs associated with the extension officers required and their equipment have been obtained from those identified in the RWUEI Milestone Reports (BSES 1999). • Each extension officer costs approx. $75,000 per year (salary & car). • Over four years each officer has a present value cost of $254,041. • Equipment costs for each officer are $62,000 (slightly less than RWUEI due to economies of scale, ability of officers to share equipment). • An allowance of $5000 for each farmer for moisture and flow measuring equipment (assuming just under 1000 farmers). • Costs associated with the on-farm storage option are based on RRC Report (RRC 2000).
The potential gross value to the farmer, in the form of cane price was calculated to be $27.56/t based on equation 1 below. This assumes that the Ps value used is $300/t (which is a below average figure for the last 6 years as the average has been approx. $337/t) and the CCS value used is 14 (which is the approx. average for the years 1994 to 1998).
Vc = (0.009 × Ps) × (CCS – 4) + 0.578 (Equation 1)
Where: Ps = price of raw sugar $/t CCS = commercial sugar index $/t Vc = value of cane to growers or cane price received by growers $/t
(Source – Tilley & Chapman)
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It should be noted that the crop yield increase has been estimated assuming the irrigation allocation rises from 2 to 4 ML/ha/a. Crop yield increase and water use are not a linear relationship. A high proportion of crop yield increase is obtained from the first 2 ML/ha/a of irrigation application. This yield increase diminishes gradually as additional water is added until the point of 6 ML/ha/a. At this point irrigation in the region tends to peak with little or no yield response if additional water is applied. If the allocation was increased from 4 to 6 ML/ha/a a less dramatic yield increase then that assumed would be observed.
Horticultural Industry Cost Assumptions
Average irrigation costs for perennial and annual irrigation systems according to Barraclough are: • perennial - $17,343 per ha; and • annual – $10,738 per ha.
For this Study it has been assumed that capital costs for conversion from an existing irrigation system to the more efficient micro irrigation systems are approx. 80% of those identified above. This assumes that some of the pumping and pipework within the existing system already on the farm can be used in the converted system.
Costs associated with the required soil moisture testing and flow measuring equipment are similar to those estimated for the sugar cane industry at $5,000 per farm. Costs for each RWUEI officer are again similar to those for the sugar industry options considered at $75,000 per officer (salary and car) for each of the four years (present value cost per officer is $254,041) and equipment costs at $62,000 per officer.
Field & Fodder Industry Cost Assumptions
Costs associated with the required soil moisture testing and flow measurement equipment are similar to those estimated for the sugar and horticultural industries at $5,000 per farm. Costs for each RWUEI officer are also similar at $75,000 (salary and car) for each of the four years (present value cost of $254,041 per officer). In addition equipment costs of $62,000 per officer have been allocated.
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APPENDIX E – Distribution Losses Information
Table E1 – Theoretical & Operational Water Delivery Efficiencies (1991/92 to 1996/97) System Mean Annual Average Theoretical Operational Efficiency (%) Use (ML) Efficiency (%) Average Minimum Maximum BIA 123,601 92.64 80.05 74.4 88.8 Abbotsford DS 972 99.99 89.46 83.5 98.3 Gooburrum DS 23,942 93.83* 81.43* 81.4 109.7 Gin Gin DS 77,234 98.10 91.64 89.1 98.7 Gin Gin M/C & L 75,761 97.93 90.26 86.8 98.0 Tirroan DS 2,553 99.82 86.54 72.6 108.3 McIllwraith DS 1,590 99.81 86.73 74.4 93.0 Bingera DS 16,819 99.97* 98.28* 98.3 145.6 (d/s Bullyard P/S) Bingera M/C & L (d/s 17,275 - - 100.0 148.0 Bullyard P/S)** Bucca DS 3,199 99.91 83.48 68.5 100.8 Isis DS 36,588 91.23 89.79 82.8 95.5 Isis M/C & L 36,123 90.62 87.77 85.5 93.0 North Gregory DS 2,187 99.48 86.04 78.5 104.5 Farnsfield DS 15,040 99.89 91.07 86.4 101.8 Childers DS 12,703 99.56 96.43 95.9 116.7 Childers M/C & L 12,867 99.75 97.01 96.1 121.0 Dinner Hill DS 3,991 99.49 89.99 77.3 109.2 Woongarra DS 31,067 93.55 83.18 77.8 89.2 Woogarra M/C & L 31,848 93.61 85.27 79.7 92.1 (u/s Walker St P/S) Woogarra M/C & L 17,538 99.90 88.98 86.3 110.6 (d/s Walker St P/S) *Average based on data from one water year only. All other years excluded due to missing or erroneous information. ** Operational efficiency calculated at greater than theoretical efficiency for all water years, hence no average could be calculated. DS – distribution system, M/C – main channel, L – lateral, d/s – down stream, u/s – up stream, P/S – pumping station
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Institute for Sustainable Futures Final Draft Report - March 2002
Table E2 – Operational Water Delivery Efficiencies (1994/95) System Inflow* Use Seepage & Additional (ML) Evaporation Losses/(Gains) (ML) (%)** (ML) (%)** (ML) (%)** BIA 226,030 ***169,220 74.9 11,358 5.0 45,452 20.1 Abbotsford DS 1,608 1,342 83.5 0 0 266 16.5 Gooburrum DS 38,757 31,562 81.4 2,390 6.2 4,806 12.4 Gin Gin DS 145,432 137,148 94.3 1,767 1.2 6,517 4.5 Gin Gin M/C & L 145,432 134,386 92.4 1,716 1.2 9,329 6.4 Tirroan DS 3,441 3,595 104.5 5 0.1 (159) (4.6) McIllwraith DS 2,652 2,444 92.2 3 0.1 205 7.7 Bingera DS 21,655 24,470 113.0 43 0.2 (2,858) (13.2) (d/s Bullyard P/S) Bingera M/C & L 21,655 25,358 117.1 39 0.2 (3,742) (17.3) (d/s Bullyard P/S) Bucca DS 5,545 4,657 84.0 4 0.1 883 15.9 Isis DS 57,816 52,121 90.2 4,791 8.3 904 1.6 Isis M/C & L 57,816 52,609 91.0 4,717 8.2 490 0.8 North Gregory DS 4,259 3,343 78.5 14 0.3 903 21.2 Farnsfield DS 22,925 20,514 89.5 17 0.1 2,393 10.4 Childers DS 17,921 18,793 104.9 43 0.2 (915) (5.1) Childers M/C & L 17,921 18,768 104.7 25 0.1 (872) (4.9) Dinner Hill DS 5,674 5,699 100.4 19 0.3 (44) (0.8) Woongarra DS 47,806 38,912 81.4 2,410 5.0 6,485 13.6 Woogarra M/C & L 47,806 42,347 88.6 2,388 5.0 3,071 6.4 (u/s Walker St P/S) Woogarra M/C & L 25,028 21,593 86.3 21 0.1 3,413 13.6 (d/s Walker St P/S) * - Inflow includes change in stored volume where available ** - %s are a fraction of the total inflow volume *** - Adjusted figure due to discrepancy in original report figures
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