WATER AND WASTE COMMITTEE - Cairns Regional Council · c. Independent Review of Groundwater...

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Agenda – Water and Waste Committee – 16 November 2011 - #3383028

WATER AND WASTE COMMITTEE

16 NOVEMBER 2011 2

MULGRAVE RIVER AQUIFER WATER SUPPLY PROJECT – REPORTS FROM THE COMMUNITY REFERENCE PANEL, GHD CONSULTANTS AND HERITAGE COMPUTING J. Turner : 1/58/13-23: #3377796-v2

RECOMMENDATION: That Council:

1. Receive and note the following reports;

a. Report from the Mulgrave River Aquifer Community Reference Panel to Cairns Regional Council, 26 October 2011;

b. Report for Mulgrave River Aquifer Scheme Stage 1 - Numerical Modelling and Ecological Investigations, GHD Pty Ltd, July 2011;

c. Independent Review of Groundwater Modelling for the Mulgrave River Aquifer Project, Heritage Computing, November 2011.

2. Formally write to the Reference Panel members and Dr Allan Dale the

Independent Chair thanking them for their valuable input into the panel review process and advisory role to Council.

3. Advise the Panel members that Council would like to have further

discussions regarding the involvement of Panel members in future investigations into the aquifer project including the development of adaptive management criteria should the project proceed.

4. Proceed with the process of installing flow monitoring stations and

additional monitoring bores in the vicinity of Behana Creek.

5. Note that these additional works will provide further data to assist Council and the Community in making a final decision on whether to proceed with the project or not.

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INTRODUCTION: The Cairns Water Supply Planning report considered by Council In April 2009 demonstrated that the safe yield of the combined Copperlode Falls Dam and Behana Creek water supply schemes has been exceeded in recent years, and the frequency of safe yield exceedance is forecasted to increase in the coming years hence posing a threat to the continuity of water supply for Cairns. At that time Council adopted the position that the Mulgrave River Aquifer stage 1 should be further investigated as the next potential water supply for Cairns. This investigation was to include concept and detailed design of the scheme, community engagement, and land acquisition and approvals acquisition. Stage 1 of the scheme involves development of a borefield in the Aloomba area to abstract up to 15 megalitres per day from the aquifer, and construciton of a water treatment plant at Draper Road, Gordonvale, to treat raw water from Behana Creek and the Mulgrave River Aquifer. Council engaged GHD consultants to undertake feasibility assessment work including detailed computer-based groundwater and surface-water modelling of the potential impacts from the proposed scheme. GHD have recently completed this body of work and submitted a final report to Council. Council engaged Heritage Computing to undertake an independent expert review of the computer modelling work undertaken by GHD. This review has been completed and a final report submitted to Council. To assist Council and the community in understanding the potential impacts of the project, the Mulgrave River Aquifer Community Reference Panel (MRACRP) was established in December 2010. The MRACRP recently presented to Council on their consensus view of the Aquifer Project and have submitted a formal report on their deliberations as per the Terms of Reference established for the Panel. This report seeks to table the above three reports for noting by Council. Further review and consideration of the reports will occur over the ensuing months with further reports back to Council in the New Year. The three reports are:

1. Report from the Mulgrave River Aquifer Community reference Panel to Cairns Regional Council, 26 October 2011 (MRACRP Report);

2. Report for Mulgrave River Aquifer Scheme Stage 1 - Numerical Modelling and Ecological Investigations, GHD Pty Ltd, July 2011 (GHD Report);

3. Independent Review of Groundwater Modelling for the Mulgrave River Aquifer Project, Heritage Computing (Dr Noel Merrick), November 2011 (Merrick Report).

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BACKGROUND: At the Closed Session Ordinary Meeting of Council on 8 December 2010 Council resolved to: 1. Establish the Mulgrave River Aquifer Community Reference Panel with the

following members:

• Mr Peter Flanders - Mulgrave Central Mill representative • Mr Bruce Corcoran - Mulgrave Landcare and Catchment Group

representative • Mrs Robyn Quick – Mulgrave and District Chamber of Commerce

representative • Mr Graham Wienert – Canegrowers Cairns Region representative • Mr Bernie Triggs – Aloomba Fishery Falls Progress Association

representative • Mr Clive Murray – Wanyurr Majay representative • Mr Douglas New - Community representative • Mr Bob Walker - Community representative.

2. Invite Dr Allan Dale from the Cairns Institute to be the independent Chair of the

reference panel. LEU/LANSKEY Mr Douglas New withdrew from the Panel early in the process and was replaced with Mr John Hartigan as a community representative. Terms of Reference for the MRACRP were endorsed by Council in early 2011 to guide deliberations. The MRACRP held 5 formal meetings with Council and a number of other meetings, email discussions and phone calls without Council involvement. The Panel had numerous discussions and access to GHD consultants and Dr Merrick from Heritage Computing throughout the Panel process. The MRACRP presented to Councillors on 26 October 2011 on their deliberations and submitted to Council the MRACRP Report consolidating the consensus view of the Panel. The MRACRP report also includes a formal response to the GHD and Heritage Computing Reports. In January 2010, Council resolved to proceed with engaging engineering consultants GHD Pty Ltd to undertake a significant body of investigation work towards proving the sustainability of the Mulgrave River Aquifer Scheme as a water supply source. This work followed on from the previous feasibility assessment undertaken as part of the Commonwealth Environment Protection and Biodiversity Conservation Act approval process.

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The work undertaken served a number of purposes namely;

- Acquiring further science to develop the scheme from a feasibility assessment to an actual concept in support of acquiring the necessary state approvals;

- Providing the community through the community engagement strategy opportunity to address potential impacts of concern to the community.

The investigation work involved largely additional field work in order to provide good data in supporting the development of a numerical modelling tool adequate for assessing the scheme and its impact on the aquifer, and the environmental and social values applied to the aquifer and its interaction with surface water streams - eg Behana Creek. This body of work culminated in the GHD Report which provided the necessary information to convey back to the community through the community engagement strategy. Through public meetings and other feedback forums it was apparent the community had concerns and a low level of confidence in the ‘good science’ underpinning the report. To assist with these issues, Council engaged Dr Noel Merrick from Heritage Computing, a nationally recognised specialist in the field of groundwater numerical modelling and assessment of aquifer systems to:

- Undertake an independent peer review assessment of the investigation work undertaken by GHD Pty Ltd

- Provide opportunity for the Panel members to make submissions to Mr Noel Merrick in carrying out the assessment

- Present the outcomes of the review to the Panel and Council. - Provide a report to Council detailing the findings of the review and any

recommendations. Both the GHD Report and Heritage Commupting Report have been made available to the Panel and are now in a final form for review by Council Officers and noting by Council at this time.

COMMENTS: MRACRP Report As a final deliverable of the MRACRP process, the MRACRP Report presents the consensus view of the Panel in relation to the Mulgrave River Aquifer Scheme. A full copy of the report is attached in the appendix. Notable points and messages raised in the report include the following extracts:

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- Formation of the Panel has been a significant step in the right direction in

changing the engagement approach taken by Council; - The Panel’s job was not to approve the Project, but to inform Council about the

Panels views following detailed engagement over the modelling; - The Mulgrave River Aquifer and associated surface systems have very

significant ecological, community, cultural and production values. Given the generations of experience people in our community have in the catchment we know these values are highly sensitive and that very occasionally function at critical thresholds during naturally dry events, making them very susceptible to any further artificial lowering of water-tables.

- While we accept (with some reservation) the quality of the modelling effort undertaken by Cairns Water, we consider that the process has reached the limits of what predictive modelling at this scale can tell us about possible adverse local impacts, particularly in very dry times; and

- With such a significant and sensitive system at stake, and the process having reached the limits of predictive modelling at this particular scale, we consider the proposal should not progress.

The MRACRP considered that if Council did proceed further with the project, then the following should occur:

- the development of agreed go/no-go trigger values beyond which impacts should be strictly avoided. Similar to the MRACRP review process, these triggers would need to be scientifically informed and well engaged with the wider community with an interest in the aquifer system. These triggers would also need to include hydrological, ecological, production and cultural thresholds of relevance to the community.

- Further, this work should form part of an integrated, whole of grid approach to water supply and demand management across Cairns’ key water storages. Additionally, scheduling or optimising the use of water from Behana to those times that would ensure least impact and deliver increased dam based storage outcomes would be needed.

- In partnership with a strong Community Reference Panel, immediate effort should be invested in establishing a long term monitoring framework for the Behana Creek system, particularly including the measurement of flows and surface/groundwater interactions.

GHD Report GHD Pty Ltd were commissioned by Council to undertake detailed planning and investigation for Stage 1 of the proposed Mulgrave River Aquifer Scheme. A major deliverable, inter alia, was a report detailing the hydrogeological modelling undertaken to determine the scheme’s interaction with the Mulgrave River Aquifer and its impacts on the social, economic and environmental values of the Mulgrave River and Behana Creek catchment surface water systems. The report builds on work previously undertaken and documented as part of Council’s Public Environmental Report (PER) on the project, completed in 2009.

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There are a significant number of positive outcomes from the report that build confidence in the sustainability of the aquifer resource as a long term sustainable water supply source. In summary the report concludes that;

“The enhanced model supplemented by additional field information and investigations provides increased confidence that the Mulgrave River Aquifer Scheme, Stage 1 can be developed as proposed. It should be operated at a maximum rate of 15 ML/day / 5475 ML/year within an adaptive management/monitoring framework to ensure no adverse impact on the social, economic and environmental values of the Mulgrave River catchment.”

In recognition of the natural progression of developing a new water supply source leading to acquiring all necessary state approvals, the report provides a number of important recommendations, as follows:

“1. Development of an adaptive management (monitoring and mitigation) approach to guide and direct the early operational stages of the borefield, while further informing and verifying the modelled assessment of interactions with aquatic ecosystem values;

2. Continued collection and assessment of dry season water levels, flows and

ecology within Behana Creek below Moller Road and the lower Mulgrave River prior to and throughout the early operation of the borefield;

3. Consideration of maximising groundwater system supply dependence during

wetter months (e.g. January-September) and maximising on-stream storage filling for preferential use over groundwater in the late dry season, thereby enhancing the complementary and conjunctive use of all available regional water supply sources for CRCWW; and

4. Additional model refinements and verification undertaken in parallel with the

borefield development for model incorporation into the overall borefield operational management and monitoring framework, with a view to the same use in operational resource performance assessment and strategic management within the overall CRCWW source management framework.”

Recommendation No. 2 is considered an immediate action that can be undertaken in order to gain further field information and inform the modelling and to provide further information for community consultation. Heritage Computing Report The scope of works for the independent review undertaken by Dr Merrick related specifically to the numerical modelling of the aquifer undertaken to date by GHD Pty Ltd, including the interaction between the groundwater and surface water and the potential impacts arising from the proposed abstraction.

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The scope of works relates to the analysis and interpretation of the data derived from field work and its application to the model. The review considered the modelling work undertaken to date in the context of current industry best practice. Dr Merrick’s brief extended to translating the findings of the review back to the MRACRP in a manner that would assist the MRACRP to understand the potential for impacts arising from development and operation of the borefield. Apart from Council’s commercial administration of Dr Merricks engagement, Dr Merrick largely interacted with both GHD Pty Ltd and the MRACRP with little involvement from Council. Conclusions drawn, inter alia, from Dr Merrick’s Report are summarised below;

“The Mulgrave River Aquifer (MRA) groundwater flow model has been developed competently and is regarded by this reviewer as “fit for purpose” for use as a quantitative tool for determining borefield yields and for giving quantitative indications of potential environmental impacts.

In the experience of this reviewer, the MRA model would rank easily within the top five percent (5%) of models reviewed across Australia. In many respects, the modelling exceeds best practice.

This reviewer considers that the modelling findings and consequent recommendations are well substantiated.

The Mulgrave River Aquifer Community Reference Panel and Cairns Regional Council Water and Waste can be reassured that they are the recipients of a stream-aquifer modelling study, with associated data analysis and data interpretation, of the highest quality. It compares more than favourably with any other Australian study examined by this reviewer in the past 10 years.”

The report classified concerns raised by the MRACRP as either valid, as misconceptions, or as unrealistic expectations. In addressing these matters, Dr Merrick considered that the modelling findings and consequent recommendations are well substantiated. It was agreed by all parties that all numerical modelling has intrinsic weaknesses. However, there is no comparable alternative when the aim is to predict potential impacts from anthropogenic stresses on a natural system. The adopted approach therefore in all jurisdictions once modelling is taken to its limits of capability as has been demonstrated by GHD Pty Ltd, is one of adaptive management. Regulators will impose performance indicators, performance measures, trigger levels and contingency actions agreed and articulated in a groundwater management plan. This is applicable to the Mulgrave River Aquifer as recommended by GHD Pty Ltd and Dr Merrick. Recommendations on short-term actions proposed for consideration by Council by Dr Merrick are summarised below:

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- Undertake predictive uncertainty analysis; - Consider the installation of a multi-level bore transect across Behana Creek,

equipped with data loggers; - Consider installation of a permanent gauging station in a stable reach of Behana

Creek; - Consider surveying the downstream reach of Mulgrave River with waterborne

resistivity imaging to locate the position of the saline wedge at depth; - Consider adoption of adaptive management principles and conditions for the

planned borefield; - Consider rigorous optimisation methods for determining the optimal production

rate from each bore subject to specified constraints on groundwater drawdowns and stream flow losses;

- During borefield operation, validate the model performance and re-calibrate as required; and

- Implement other future recommendations by GHD. Dr Merrick also proposed longer-term actions should the project proceed but these are not detailed here. Proposed Way Forward There is a large degree of consistency in the recommendations for the next phase of investigation between GHD Pty Ltd and Dr Merrick’s peer review. Most importantly is the onus on further field work by way of monitoring bores in close proximity to Behana Creek, and flow gauging that will provide additional field data immediately. More importantly this work will provide for the necessary long term monitoring of the performance of the aquifer and streams in response to the aquifer abstraction should the project proceed. Whilst it is acknowledged that the primary position taken by the MRACRP is for the proposal not to progress, the MRACRP has proposed certain conditions, should the development of the scheme proceed further. It is noteworthy that the conditions expressed by the MRACRP are actually consistent with the ongoing work expectations of Council and supported by the recommendations of the GHD and Merrick Reports. Most notably are the following activities;

- Additional field work in the vicinity of Behana Creek to increase the confidence level of the model to predict impacts;

- Develop the model to a confidence level that provides a valuable tool in informing the adaptive management approach recommended and accepted by all parties as the next step;

- Recognise the adaptive management approach as an essential step in securing the state approvals as well as provide opportunity for social, environmental, cultural, and water supply values to be incorporated into the trigger levels that underpin the operating protocol of the scheme;

- Using the modelling tool to optimise the borefield layout in order to minimise the impacts on recognised values and inform the adaptive management process.

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To this end it is concluded that those specific recommendations of the GHD and Merrick Reports and conditions proposed by MRACRP that can be immediately acted upon proceed. This is essentially the carrying out of additional fieldwork, establishing monitoring network, improvement in the model and conducting the uncertainty analysis. These activities in themselves will provide invaluable knowledge to reinforce the work undertaken to date, increase the confidence of the community, as well as inform the subsequent steps of embarking on the adaptive management process leading to securing the state approvals should the project proceed. Once this work has been progressed, further analysis of the project status should occur with appropriate reports to both the community and Council.

OTHER CONSIDERATIONS: Corporate and Operational Plans: Council’s Corporate Plan Goal 4 – Delivering Services and Infrastructure and the following objective are relevant to this report: Objective 4.1 Provide a robust, secure, high quality water supply to meet the growing needs of the community. Statutory: Water & Waste has a statutory obligation to ensure the security of our water sources to meet projected water demands into the future. Stage 1 of the Mulgrave River Aquifer Scheme has been identified as the preferred next source of supply for the Cairns area to meet this obligation. Financial and Risk: There is currently unexpended budget allocated to the Mulgrave River Aquifer. This reflects the outstanding works that are currently on hold pending a decision by Council to proceed with the Mulgrave river aquifer. These works include;

- Detailed design and documentation of the Mulgrave River aquifer borefield and pipework distribution system

- Design & Construction documentation for the Water Treatment Plant - Other activities required to submit and acquire the State Approvals.

It is envisaged that some of these works are unlikely to proceed until the additional fieldwork and adaptive management process is well underway, and subject to Council approval on the scheme, will not commence until after March 2012. It was originally anticipated that the monitoring network be established in parallel with the design and construction phases of the scheme infrastructure and therefore commence at a later time. Based on the recommendations of the three reports tabled, it would be prudent to bring forward this activity ahead of the detailed design phase of the scheme.

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Accordingly it is recommended that Council proceed with the process of installing flow monitoring stations and additional monitoring bores in the vicinity of Behana Creek. This presents a nil net increase in the budget but a redistribution in time of when the budget is required. Sustainability: The investigations into the Mulgrave Aquifer are focused on establishing what, if any, are the potential impacts on the social, environmental and economic factors in the Council area. This will include further Input from the Mulgrave River Aquifer Community Reference Panel as appropriate.

CONSULTATION There has been considerable consultation with the community on the proposed Mulgrave River aquifer Project. This has been furthered enhanced through the MRACRP process. It is however noted that the MRACRP view is that the first two and a half years of engagement in regards to this project proposal had major deficiencies, and that this led to significant conflict and mistrust. In contrast, the Panel considers that the Council’s approach to establishing and supporting an independently chaired Community Reference Panel represents a dramatic improvement in its engagement. Council officer’s view is that there was mis-alignment between the Community expectation of consultation timing and Council’s program for consultation via the EPBC process and the more recent consultation strategy. Council Officers consider the MRACRP has been an invaluable process and appreciate the input and advisory role provided to Council. As a show of appreciation, it is recommended a letter of thankyou be extended to each member of the Panel. The Panel has now fulfilled the requirements of the Terms of Reference for which it was established. The Panel has expressed that in moving forward there should be some ongoing Panel mechanism that is more scientifically informed and well engaged with the wider community with an interest in the aquifer system. Council Officers agree with this view and consider that an element of the adaptive management process may be the establishment of a technical reference panel with inclusion of stakeholder representatives. This is a process well established in natural resource development projects. Council would therefore like to have further discussions regarding the involvement of Panel members in future investigations into the aquifer project including the development of adaptive management criteria should the project proceed.

OPTIONS

Option 1 – Accept the primary position held view by the MRACRP that the proposal should not progress.

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Option 2 – Proceed with further investigation work leading into the adaptive management process to raise the confidence level in the modelling and address the reservations held by the MRACRP. Option 3 – Proceed directly into the state approval process for the Mulgrave River Aquifer scheme. Option 1 is recognised as the view held by the MRACRP. However, both the GHD and Heritage Computing reports present the view that the project could proceed with adaptive management. Council has also expended considerable resources into the investigations to date and there is no firm reason based on the investigation work to abandon the project at this point in time. Option 2 concurs with the recommendations from the GHD and Heritage Computing reports and is in accord with the conditions proposed by the MRACRP should the project proceed further. This option would also provide further details to assist in obtaining the necessary approvals for the project. Option 3 is likely to draw a great deal of criticism from the community and undo the good work and trust that has resulted from the MRACRP process. Whilst it is considered by Council Officers there is sufficient information to support the state approval process, it is considered prudent to undertake further investigation work expected by the Community but also reinforces the body of work undertaken to date. Option 2 is therefore considered the recommended way forward.

CONCLUSIONS: It is recommended that Council:

1. Receive and note the following reports;

a. Report for Mulgrave River Aquifer Scheme Stage 1 - Numerical Modelling and Ecological Investigations, GHD Pty Ltd, July 2011

b. Independent Review of Groundwater Modelling for the Mulgrave River Aquifer Project, Heritage Computing (Dr Noel Merrick), November 2011

c. Report of the Mulgrave River Aquifer Community reference Panel to Cairns Regional Council, 26 October 2011

2. Issue a letter from the Mayoral Office formally thanking the Mulgrave River

Aquifer Community Reference Panel members for their valuable input into the panel review process and advisory role to Council

3. Advise the Panel members that Council would like to have further discussions

regarding the involvement of Panel members in future investigations into the aquifer project including the development of adaptive management criteria should the project proceed

4. Proceed with the process of installing flow monitoring stations and additional

monitoring bores in the vicinity of Behana Creek.

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5. Note these works that will assist in providing further data to assist Council and

the Community in making a final decision on whether to proceed with the project or not.

ATTACHMENTS: The following report is available upon request due to size:

1. Report for Mulgrave River Aquifer Scheme Stage 1 - Numerical Modelling and Ecological Investigations, GHD Pty Ltd, July 2011; #3256444;

The following reports are attached:

1. Independent Review of Groundwater Modelling for the Mulgrave River Aquifer Project, Heritage Computing (Dr Noel Merrick), November 2011; #3386911;

2. Report of the Mulgrave River Aquifer Community reference Panel to Cairns Regional Council, 26 October 2011; #3378481.

Jon Turner MANAGER INFRASTRUCTURE Bruce Gardiner GENERAL MANAGER WATER & WASTE

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