This article was presented at the New South Wales Australia Water Association (AWA) Regional Conference in 2009.

Introduction

Prior to development of the Clarence Valley Coffs Harbour Regional Water Supply (CVCHRWS) project, separate water supply schemes serviced the two local government areas. These schemes were struggling to cope with existing population demand during drought, and a solution - or combination of solutions - was required to not only meet population growth, which was expected to almost double to 220,000 people within the next 40-60 years but also address environmental flow issues.

The introduction of New South Wales (NSW) water policy reforms in 1995, which included development of interim river flow objectives, required consideration of environmental protection for the Nymboida and Orara River systems. This involves eliminating the need to extract water during low flows in order to provide environmental flows.

In 1994, Clarence Valley’s water source run of the river flow in the Nymboida River reached its lowest level on record. The NSW Drought Task Force estimated at the time that the supply, which serves about 45,000 people, came within 60-90 days of failure. Drought modelling indicated that river flows during a repeat of the 1902 drought would be much less, and insufficient to meet basic community needs.

The short period of river flow records (about 100 years) made it impossible to predict the chance of having much worse droughts than those already recorded, and the predicted changes in rainfall due to climate change further exacerbated this issue. Even if the chance of a worse drought was low, there were significant detrimental consequences of a community of this size being without water. The risk of such an event was considered unacceptable.

The water supply system servicing Coffs Harbour was at the limit of its capacity, and supply security was protected by imposing frequent restrictions. The existing unrestricted peak water demand of the Coffs Harbour area in extended dry weather was estimated to be 6,500 ML/year and extraction from the Orara River was able to reliably supply only 4,000 ML/year. The Coffs Harbour demand was expected to double by about 2020.

An additional significant storage or an alternative secure source was deemed to be required to both secure the current supply (including providing for environmental requirements) and to provide for planned future population growth.

CVCHRWS strategy

In 1994 a group of Clarence Valley councils approached Coffs Harbour City Council with a proposal for a Regional Water Supply Strategy, based on using the Orara and Nymboida Rivers as surface water sources with a common storage on the upper reaches of Kangaroo Creek. A Memorandum of Understanding was signed by the six constituent councils involved (five of which were amalgamated into Clarence Valley Council in 2004) allowing joint investigations to proceed.

The RWS Strategy was developed with two aims:

• Meet current and future population demands for a secure bulk water supply.
• Protect the environmental flows in the Nymboida and Orara Rivers.

The Strategy has two key elements: a $180 million bulk water supply project (‘Build’ element), coupled with a regional water efficiency programme (‘Non-build’ element). The ‘Non-build’ element, known as the Regional Water Efficiency Programme, comprised:

• Exploring and implementing better ways to conserve water, to reduce our water needs and future augmentation requirements.
• A cooperative approach to better water management, by assisting regional cooperation between councils and government.
• Investing in alternative water sources and new technology, to meet future demands.

Developing a holistic strategy enabled both communities to provide enhanced environmental protection for the region’s river systems. It also ensured a secure, sustainable and affordable water resource for the long-term future without having to resort to extreme water pricing, harsh supply restrictions or increased pressure on environmental flows in the Orara and Nymboida Rivers.

Development of the RWS project

Prior to 1994 preliminary studies had assessed a range of options for meeting future water supply demand. In 1995, investigations of alternative water sources to the Orara and Nymboida Rivers found that, with the exception of large-scale desalination, none of the alternative water sources (including rainwater tanks) had the potential to completely replace the existing potable surface water supply during drought periods. The costs of alternative approaches were also significantly greater than for surface water schemes.

A Community Advisory Group was formed in 1996 and a Project Charter was developed in 1997. Concerns about ecological and heritage impacts in Kangaroo Creek resulted in further investigations of 14 locations, with three potential storage sites identified as warranting further investigation due to their lesser environmental impact and/or lower cost. Schemes based on these sites were developed, costed and assessed in accordance with the objectives and success parameters of the Project Charter, with Shannon Creek selected in July 1997 as the most appropriate site for a storage.

Environmental, cultural, economic and other logistical parameters guided the storage’s design and construction to provide the most sustainable solution for the region. Key issues for consideration included:

• Environmental impacts of a storage and construction impacts.
• Environmental impacts on rivers and other consequences of not building a storage
• Construction costs.
• Emerging technologies and the potential for new solutions in the longer-term.
• Possible need to extend storage capacity in the future.
• Protection of cultural heritage values.
• Storage destratification and multi-level offtake for water quality and aquatic and riparian ecosystems.
• The extensive pipeline network required to distribute water, and opportunities for reducing the potential carbon footprint.
• The need to protect the flow of Shannon Creek.
• The need to accelerate pipeline construction to address drought needs.
• The need to engage the community.

The project was refined through an Environmental Impact Assessment process, threatened species impact statement, an Environmental Commission of Inquiry (requested by the project proponents), an inquiry by the Healthy Rivers Commission, cultural heritage studies, economic appraisals and community and government agency engagement. Due to the presence of threatened species and communities on the site, project approval was also obtained under the Commonwealth Government’s Environment Protection and Biodiversity Conservation (EPBC) Act.

The eventual RWS Project comprised:

• A 30,000 ML Shannon Creek storage approximately 9 km west of Coutts Crossing.
• 90 kms of underground pipelines linking the Nymboida River with the new Shannon Creek storage, the existing Rushforth Road reservoir at South Grafton and the existing Karangi Dam near Coffs Harbour.

This paper focuses primarily on planning, design and construction innovations for the Shannon Creek storage.

RWS planning and design

The RWS project featured several planning and design innovations:

Protection of Shannon Creek flows

The environmental impact of major storages is a significant management challenge, and typically storage release results in the creation of flora and fauna monocultures due to regulation of the water creating static environments.

Shannon Creek Storage is essentially an off-creek storage filled from the Nymboida River, which provided an opportunity to protect natural flows in Shannon Creek by designing the storage to operate “transparently” and release any flow which lands in the storage’s own catchment area (up to the 1 in 2 year event) to approximate natural inflows.

Maintaining the downstream flow avoids ecological retardation in areas downstream of the storage as a result of flow modification. By mimicking the inflow into Shannon Creek the natural wetting and drying frequencies are maintained. This diversity in flow will maintain biodiversity by encouraging diverse habitats.

Construction issues for future augmentation

While many storages are designed for future augmentation, inadequate consideration of future construction can make augmentation difficult or impossible. The design of Shannon Creek Storage considered a future increase in capacity from 30,000 ML to 70,000 ML by raising the crest a further 9.6 metres if ever required. Construction of a future augmentation was facilitated by:

• Grouting the foundation to match the higher crest level.
• Locating the valve house some 65 metres downstream of the embankment to provide sufficient space for the embankment footprint to be widened and thus enable the higher crest level to be achieved while still maintaining the same embankment wall slope.
• Designing the decks of the intake tower and access bridge piers so they can be jacked up to the increased height of the embankment.

Provision of compensatory habitat

Storage projects frequently alienate significant areas of land. To address this issue, the project purchased a 700 ha buffer zone surrounding the storage, which is managed concurrently for water quality protection and flora and fauna conservation. In addition, the project purchased additional adjoining lands (up to 800 ha) as compensatory habitat and is establishing a Voluntary Conservation Agreement (VCA) with the National Parks and Wildlife Service for these lands. These lands will be managed by Clarence Valley Council in accordance with the requirements of the VCA and will be integrated with recently created adjoining nature reserves.

Planning Legal advice

Due to the complexity of the RWS project’s environmental approvals, and the possibility of legal action from project opponents, solicitors Blake Dawson were retained by the project team to provide specialist legal planning advice throughout the project. A result of this proactive approach was that, despite active objections from opponents of the scheme, including numerous submissions to approval authorities claiming that consent conditions were not being met (Water Engineering Australia, 2009, p27) [3], no action for breach on conditions was undertaken against the scheme.

RWS procurement innovation

An Early Contractor Involvement (ECI) process was specifically designed and developed by the NSW Department of Commerce (Commerce) in 2005 for the Shannon Creek Storage project, and incorporated the outcomes of a 1999 report by the Australian Contractors Association, based on a nationwide survey of their major public sector clients.

The survey found that clients believed all types of contracts could be improved if an approach was developed that allowed short listed tenderers to meet with the client, prior to detailed documentation, to work together to:

• Develop a risk allocation matrix in which all risks in the contract are identified and the responsibility for managing those risks is allocated.
• Develop a plain English contract which clearly established the rights of each party to the fundamental issues in that contract.

ECI was achieved through development of a co-operative contract, utilising the GC21 relationship contract developed by the NSW State Government over the past 10 years, and enabled the team to work with the shortlisted tenderers to improve contract documentation (particularly appropriate risk allocation and buildability) and facilitated improved project outcomes.

ECI’s key achievements included:

• An enhanced contract document in which risk allocation was well understood by all parties at the commencement of the pricing phase.
• Three tenderers who had a sound knowledge of the requirements of the contract, who had assessed the risks initially identified and allocated by the Principal, had added their own knowledge and experience in the final allocation of those risks while raising other risks not considered by the Principal.
• Established working relationships.
• Providing a framework for measuring performance and the health of the relationship with the successful contractor.

The successful construction contractor for Shannon Creek Storage was Leighton Contractors Pty Ltd. The ECI method initially developed by Commerce for Shannon Creek has subsequently been used for further water industry projects as outlined in Rayward (2007) [1] and Mashiah (2008) [2].

RWS environmental management

The environment within and around the Shannon Creek Storage Facility was identified as being infected by a soil borne fungus, known as Phytophthora cinnamomi. This was likely spread throughout the local area by past logging activities and farming practices.

Phytophthora spreads through contaminated soil and runoff and can result in mass dieback of affected native vegetation. It has been listed as a Key Threatening Process within NSW. Strict environmental controls were implemented onsite to minimise its spread into uninfected areas, including the establishment of wheel wash bays and strict disinfection requirements prior to entry into high value areas, such as the escarpment habitats which have been subject to less disturbance over the years. A Phytophthora specialist was also engaged to advise on best practice management strategies.

Underboring was used as an alternative to putting a pipeline though an area of high biodiversity value. The use of an underbore removed the requirement to clear an area of Brush Tailed Rock Wallaby (Federally protected threatened species) habitat, removed the need to eliminate a number of threatened species, reduced the need to destroy aboriginal cultural sites, and reduced the risk of spreading Phytophthora.

In August 2007 the project was selected for an audit by the Compliance and Enforcement branch of the Commonwealth Department of Environment, Arts and Heritage. The Audit Report, which was released in November 2007, contained the following statement:

“No non compliances were determined during the audit, and a high level of compliance with EPBC Act conditions of approval was noted.”

This finding represented an outstanding achievement and further evidence of the adherence to responsible environmental management

Heritage Protection

A cultural heritage management strategy was implemented as part of the storage construction. This strategy included an archaeological programme, cultural renewal programme, and integrated aboriginal employment generation and skills development with environmental and cultural heritage management programmes. Examples include training members of the aboriginal community in bush regeneration and employing these people in environmental regeneration works using traditional aboriginal bush tucker species. Leighton Contractors also employed three aboriginal trainees who successfully completed their course and moved on to further Leighton construction projects.

Effective consultation with the Aboriginal community involved the development of proper communication protocols which recognise the different rights of the traditional owners compared with the Local Aboriginal Land Council. These protocols have now been more widely accepted as a best practice approach to Aboriginal community consultation.

While no significant sites are impacted by the project, a range of measures were included in the strategy to mitigate the effects of the project on Aboriginal and European cultural values. This included an excavation and salvage programme at the storage site which documented the habitation history of the area. An Aboriginal elder was consulted to produce a recorded oral history of the area, and a smoking ceremony was conducted prior to construction commencing.

RWS construction innovation

Using an ECI process with a GC21 Contract at Shannon Creek enabled numerous innovations to be incorporated into construction of the storage which, as well as providing functional benefits, gave cost savings of $1.02 million.

Early construction of pipeline

During the 2002 drought, accelerated construction of 62.3 km of a DN600 steel pipeline was undertaken as the major plank in the regional drought management plan. The pipeline construction was competed in the record time of seven months, avoiding the significant risk of supply failure to over 100,000 people. Up to eight pipeline crews from two separate contractors were employed during the peak of construction, with minimal compromise on cost or quality.

Spillway wall lining

Spillway walls were lined by applying finished shotcrete in lieu of traditional methods of formwork and scaffolding to achieve the same finish. The benefits of using finished shotcrete were savings in time, savings in cost and increased quality of the finished product.

Construction methodology for pipes under dam wall

A challenge with constructing large diameter steel pipelines is providing safe access for welders to access the top of the pipe, as continually removing and erecting scaffolding to access the welding area is a time consuming operation. To address these issues a unique construction method was developed utilising a purpose-built relocatable fabricated scaffold. The scaffold provided safe access for the welders while also allowing transporting and erecting to occur quickly without causing any delays for the welders.

Another challenge with welding large diameter steel pipes is accessing the bottom of the pipeline. The project designed saddles for support of the 2,100 mm pipeline, which proved very effective and allowed for continual progress along the work areas.

Intake tower access bridge

During construction, Leighton Contractors redesigned the intake tower access bridge so that one pier was eliminated. The redesigned structure was lighter than the original design and thus required a much smaller crane to lift it into position.

Intake tower construction

The intake tower was a difficult structure to erect in that there were two internal shafts which were non-uniform in shape to account for the storage of rubbish racks and baulks and to allow these racks and baulks to be lowered up and down the tower to control water inflows/outflows of the storage.

The external cross section of the tower was square in shape. To construct the tower a combination of specially made peri formwork and two specifically fabricated internal steel forms were used. The internal steel forms were operated using hydraulic pistons.

This method reduced the amount of time that had to be spent inside the tower. Each pour was four metres in height and at the completion of each pour, the internal and external forms were raised by the use of cranes to construct the next segment. Sections of the concrete walls of the tower were two metres thick and other sections 500 m thick, and access to tie steel was difficult. To save on time and to improve safety, the steel reinforcement of each pour was fabricated on the ground and lifted into position using a specifically fabricated lifting frame. This lifting frame also doubled as a platform to allow safe placement of concrete. The platform enabled the construction team to properly place and vibrate the concrete, allowing access to each area of the intake tower.

Elimination of a standby transformer

During construction a standby transformer at the zone substation, which was originally required to provide redundancy for the destratification system, was eliminated by providing suitable attachment points for an emergency generator.

Using gravity inflow to provide destratification

Storage projects usually have significant energy requirements to provide for destratification. The location of Shannon Creek Storage allows gravity inflow, and Council is currently trailing an inflow mixer to utilise excess hydraulic energy to assist with destratification and hence reduce external energy demand.

Project OH&S – the Live it programme

The Shannon Creek Storage project was committed to providing a safe and healthy work environment for all employees and subcontractors associated with the project. Leighton Contractors developed a safety culture programme for the project known as Live It, which was rolled out to all involved in the project, including the workforce, staff, subcontractors and the client. Various core values were developed to assist with the implementation of the Live It safety culture programme onsite including:

• Risk Aware - To be forward planning, to assess the risks on a daily basis and respond to changes to eliminate or reduce the risks.
• Learning - Lessons learnt to be fully communicated for continuous improvement.
• Informed - No site activities to commence until inductions completed, SWMS and EAS conveyed and signed off. Encourage consultation and feedback
• Reports - Report ALL hazards, near misses and incidents.
• Owned and Just - Ownership of Safety is to be underwritten by Accountability which is based on each individual’s honesty.

Implementation of the Live It programme has paved the way for a safety cultural revolution. Changing the way people, act, feel, believe and understand site safety was always going to be a significant challenge, especially with some personnel having been in the construction field for over twenty years. The attitude of ‘I’ve always done it this way’ was a constant issue, but one in which Live It made progress to positively change people’s values and behaviours towards safety.

Recognition of RWS strategy and project

The Shannon Creek Storage component of the RWS project, which was completed in December 2008, was constructed in less than three years, within timeframes and budget. The storage was constructed during a buoyant period in the construction industry with increasing steel prices, a skilled labour shortage and increased construction activity. The time target was bettered by two weeks and the final construction cost of $99.35 million was only $0.1 million over the target cost, an ‘overrun’ of 0.1%. This was well within the project’s overall budget contingencies of $3 million.

The successful completion of the Shannon Creek Storage project has received significant industry recognition, including:

• A 2005 Australian Institute of Project Management National Award for Commerce’s Strategic Project Manager on the RWS project, Mr Gary Kennedy, for his role during the project’s development and design.
• The Federal Government’s 2006 ‘National Awards for Local Government’ in the Asset Management category.
• Winner of the overall 2009 Engineers Australia Newcastle Division ‘Engineering Excellence Award’.
• Winner of the 2009 IPWEA ‘Innovation in Water Supply and Wastewater Award’.
• Winner of the 2009 AWA NSW Branch ‘Construction Award’.
• The 2009 Australian Institute of Project Management NSW & National Project Management Achievement Award in the ‘Regional Category’.
• The 2010 IWA (International Water Association) Asia Pacific Regional Project Innovation Award in the ‘Planning’ category. (See box below)

Conclusion

Shannon Creek Storage is an outstanding example of the successful delivery of a large construction project, on time and on budget, through an effective partnership of government agencies, local government, contractors and the community. Environmental and cultural heritage considerations, as well as the site location posed significant construction management challenges, which were successfully addressed through cooperative contracting arrangements.

Acknowledgements

The authors would like to thank Clarence Valley Council and Coffs Harbour City Councils for permission to publish this paper. The opinions expressed in this paper are the authors’ and do not necessarily represent the views of Clarence Valley or Coffs Harbour City Councils.

References

[1] Rayward, Forster (2007). Developing New Directions in Procuring Public Works. In IPWEA NSW Division Annual Conference, Sydney, NSW, 13-15 May 2007

[2] Mashiah, G (2008). Ensuring “Buildability” of Sewage Treatment Plant designs: Clarence Valley Council’s ‘Early Contractor Involvement’ process. In 11th International Conference on Urban Drainage, Edinburgh, UK, 1-5 September 2008.

[3] Water Engineering Australia (2009) A Crowning Moment for a Regional Strategy. In Water Engineering Australia, May 2009, pp20-27.