An Integrated Water Team

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1 An Integrated Water Team Abstract Mark Baker, Three Waters Asset Manager, Queenstown Lakes District Council Deborah Lind, Manager,Performance and Strategy, Queenstown Lakes District Council Nasrine Tomasi, Team Leader Hydraulic Modelling, Mott MacDonald, Auckland The Queenstown Lakes District is a place of extremes and not just the adventure activities that people partake in. There are some unique challenges QLDC faces in maintaining the levels of service for 3 waters within the district including: The natural topography dictates a complex network that can be difficult to upgrade. Extremes of environment with long hot dry summers, frequent winter snow falls, frozen ground water and varying lake level A varying population culminating a ratio in excess of three visitors to each resident over the peak tourist periods. Rapid growth in resident and tourist population is quickly eroding headroom. QLDC identified the need to rapidly identify system performance issues by developing robust hydraulic models that can be used as an operational and strategic tool. A team of water experts were commissioned to ensure the most effective outcomes. The team, led by QLDC staff, includes operators, technical specialists and hydraulic modellers from multiple contractor/consultancies. Working within an integrated team has brought together a wide range of experience and has enabled cross pollination of ideas and knowledge. This paper case studies the development of the Queenstown Water supply model and its subsequent success in informing the Better Business Case approach to develop a Water supply strategy. Key Words Hydraulic Modelling, Network Strategy, Evidence Based Decision Making, Infrastructure Planning Introduction The Queenstown Lakes District is a place of extremes and that is not just regarding the adventure activities that people partake in. There are also some unique challenges that the Queenstown Lakes District Council (QLDC) faces in maintaining appropriate levels of service for 3 waters within the district including: A natural topography that dictates a complex network that can be difficult to upgrade. Extremes of environment with long hot dry summers, frequent winter snow falls, frozen ground water and varying lake level. A varying population culminating in a ratio in excess of two visitors to each resident over the peak tourist periods. Rapid growth in resident and tourist population is quickly eroding headroom in headworks and network infrastructure. QLDC have identified that having fit for purpose hydraulic models will be critical to

2 the development and implementation of network strategies for each of the three waters networks. These strategies would be used to populate the 2018 Long Term Plan with an evidence based, bottom up programme of works. In late 2015, with the 2018 Long Term Plan in mind, QLDC acknowledged that recent underinvestment in modelling had left the majority of models out of date and not fit for the purpose required of them. This was further exacerbated by the end of the global financial crisis and migration from the Christchurch earthquakes generating a growth boom, as well as a change in demographic with more families moving to the district and becoming residents. This has created some unique considerations and constraints in regards to developing models and then the infrastructure strategies which will underpin QLDCs next Long Term Plan (LTP). The scale of work required to deliver the LTP triggered a push to rapidly identify system performance issues by first developing robust hydraulic models that can be used as both an operational and strategic tool. Considerations and Constraints A Growing Population The Queenstown Lakes District has, for some time, been evolving from a small summer tourist destination with a small resident population into atown that is a premiere year round international tourist destination as well as a home to a burgeoning resident population. The district s resident population continued to grow steadily throughout the global financial crisis and is still regularly topping the charts in terms of growth rate. Growth in resident population is projected to remain at around 2.7% per annum for the next 10 years. However, that is only a part of the story for a district that is still heavily defined by the tourist industry. Looking at the 2016 National Performance Review results from water New Figure 1- Water New Zealand National Performance Review, Guest nights Zealand it can be seen that the Queenstown lakes District s commercial accommodation visitor nights exceed 4 million per year with the peak month surpassing that of the entire Wellington Region and only slightly behind that of Auckland. Recent analysis of mobile phone usage by Qrious also indicates that the visitors in commercial accommodation are only 50% of the visitors that QLDC might be hosting at any one time. The likes of AirBnB have enabled a whole new tranche of visitor accommodation to come online that is very difficult to monitor,using traditional methods, in regards to visitor numbers. It is hoped that further analysis using mobile phone data will improve confidence in the population data which is critical to the success of any analysis of water and wastewater network performance. For QLDC this results in a potential 8 million visitor nights a year that are supported by a small usually resident base of approximately 38,000 residents. On average, visitors make up 40% of the districts total population of 63,400, but through the peak month that number may increase to 68% of a total population of 118,000.

3 Extreme Water Demands The past 12 months have been relatively wet for the district, totalling 791 mm of rain at the Queenstown airport, by comparison the previous 2 years averaged 637 mm. This relatively low rainfall can result in peak demands in excess of 2 m 3 per connection per day for the schemes supplied by QLDC (by comparison the Auckland area has a peak demand of approximately 0.8 m 3 per connection per day). There are multiple factors explaining these high demands: The kiwi quarter acre dream (or far larger in this district) and the relatively dry climate can result in large irrigation demands. The peak day population tends to occur at the same time as peak irrigation. Most water customers have no meters quantifying their demands and are not charged based on the water volumes they use. The high rate of tourist accommodation potentially results in increased demands due to less water saving behaviours adopted by a transient population. The dwelling occupancy for seasonal workers is generally much higher than typical. The proximity of Lake Wakatipu produces a mind-set that there is an endless water resource. A town centre that s moving on Given the topographical constraints of Queenstown s historic town centre, and the growing tourist industry that calls it home, there is limited ability to service the growing needs of the districts residents. Residential and commercial growth is occurring in both Queenstown and Wanaka in new locations out of town. The infrastructure issues that this triggers are looming in Queenstown. The hills that Queenstown is built upon have defined the water supply network that services it, resulting in a network that is 16 km long, but generally less than 1 km wide. The network also has numerous pressure zones servicing the connections at elevations varying from 313 m to 493 m. Figure 2 - Queenstown Water Network With previous strategies falling by the wayside due to unaffordability, but with relentless growth, the network now has limited resilience and capacity for projected growth. The major compounding factor for Queenstown is that its major water intake is at the far end of the network from the boom of commercial growth, near to the airport, that is demanding the townships highest firefighting flows. Lake Snow, a Blooming Problem Previous thoughts that water demand management could defer significant capacity upgrades have also now been pushed aside as the discovery of Lake Snow in both Lake Wakatipu and Lake Wanaka have thwarted thoughts of metering and volumetric charging. A recent metering trial resulted in 20% of meters being removed in Wanaka due to being clogged with algae during the trial period of approximately 6 months. Bringing Together an Integrated Team To achieve the desire to populate the LTP from a robust model and strategy a team of water experts were commissioned to ensure

4 the most effective outcomes given the considerations and constraints above. At this point it was acknowledged that this model would only be generation 1 of an ongoing programme of improvement. In fact, a key output of generation 1 was to collate an improvement list that would be the catalyst to prioritised improvements to the data, network knowledge and the models over time. The team, led by QLDC staff, includes operators, technical specialists and hydraulic modellers from multiple contractor/consultancies. The QLDC asset manager is responsible for the delivery of a fit for purpose model and system performance to the Strategic Manager. By handing over the model at this point it allows a focus on delivering generation 2 of the model without the distractions of the day to day requirements however the Asset Manager is required to safeguard that the model is not being used beyond of its intended purpose. Building and Calibrating Fit for Purpose Models As QLDC did not have any modelling specifications the first step for the project team was to establish a complete methodology to build and calibrate hydraulic models that would meet QLDC s requirements and expectations. Through a series of workshops the following aspects were discussed and a common approach agreed to complete each: the end use of the water models (short term and long term), the data available, field testing requirements, model build and calibration methodology. system performance criteria These modelling guidelines have now been formalised to provide guidance for any subsequent water modelling projects. The models were built using QLDC s latest GIS and calibrated based on the field test data monitored by data collection specialists. Figure 3 - Integrated Water Team It was immediately obvious that working within an integrated team brought together a wide range of network and local knowledge as well a wealth of industry experience that has enabled cross pollination of ideas and knowledge that has meant that the team could achieve the key deliverables of this project. Having a team of dedicated water experts working together helped to address a multitude of issues during the model build and calibration phases. Close communication was maintained with the network operators and QLDC s Asset Manager to identify and investigate erroneous GIS and operational information. Theseinvestigations included correcting water supply zone boundaries, establishing network schematics toprovidean accurate representation of current operation for each scheme, and investigating calibration anomalies where necessary. The project team worked together to ensure that the field information relayed by network operators was included in the model and in QLDC s GIS system to guaranty consistency between all data sources.

5 At the end of the build and calibration phase the modelling team also included a detailed list of improvements recommended to improve the accuracy of the models in the future. For example, the installation of flow meters was recommended in multiple places where data was currently being assumed. These meters will help the understanding of demand distribution throughout the water networks with more accuracy. The Strategic Case for Change QLDC have adopted the Treasury s Better Business Case to tell the investment story and demonstrate that there is a compelling case for change. The BBC, informed by evidence, shows the problems being faced and the benefits (strategic objectives e.g. levels of service) that should be achieved. Key performance measures (KPIs) are used to demonstrate the success of the investment against the objectives. The integrated team have worked collaboratively, using the hydraulic models to: show evidence of problems create scenarios that can be tested for: o ability to achieve the strategic objectives o economic viability o achievability against critical success factors o commence the development of the long term plan for Workshops with the integrated team allowed challenge of problems and solutions and transparency in why some options were abandoned and why others were progressed. As preferred options are progressed through concept to detailed design, the BBC framework and hydraulic models enable the option to be continually re-tested against the original objectives and critical success factors. Building the Evidence Base Within a year the hydraulic models have already proven their value and have been used extensively by QLDC and their water team. The following are two key examples where the models have demonstrated their value. Analysing System Performance and Deriving a Strategy to Unlock Growth The hydraulic models were used to identify system performance issues for current and future conditions in regards to pressure, pipe capacity, fire flow and storage considering QLDC s specificities. QLDC s asset manager collaborated with QLDC s planning team to derive growth models that could be used to estimate future water demands. This information was used as a base input to create future scenarios for a medium term and long term horizon. The models were run for current and future conditions and highlighted that although the current system is currently generally sized adequately to meet the recommended levels of service, the growth expected in Wanaka and Queenstown cannot be serviced without significant network improvements. Based on these results the team, with the Strategic Manager at the helm, established a high level strategy by investigating multiple network options to supply future growth cells while maintaining satisfactory levels of service into the future. In Queenstown the hydraulic water model was used to assess a combination of options considering potential changes in water sources, network and storage upgrades. Three main options were considered and compared based on the level of service

6 provided by the option and based on the cost of the upgrades required. QLDC s Strategic Manager will take into consideration the outcome of the network assessment in combination with the water treatment plant assessment being conducted in parallel to this study to assist QLDC in finding the best solution for their network. Improving Network Operations Major commercial developments have recently occurred in the Frankton Flats area (located near the Queenstown airport as shown in the map below). Some of these commercial units have significant fire flow requirements (up to 140 l/s) that could not be met during hydrant testing. The map below shows the extent of the study area and the approximate location of the various hydrant tests performed during the investigation. StudyArea with developers was maintained and that the investigation met their expectations. Veolia provided the team with field knowledge including recent hydrant testing undertaken and operational regimes tried during the tests. Mott MacDonald then verified that the issue was replicated in the theoretical model, thus enabling them to identify the probable source of the problem with a high level of confidence. Mott MacDonald then developed proposed a short term operational solution to achieve the required LOS, prior to the implementation of the Queenstown Water Strategy. Veolia then carried out the implementation and testing of the operational solution proposed by modellers. This operational solution based on the model results proved to be successful in doubling the fire flow capacity in the study area to reach the required LOS. However, the model also demonstrates that growth will rapidly erode this LOS and that the strategy will be required in the near future. Conclusion Having an integrated team that specifically retains and includes those with network knowledge and an understanding of the idiosyncrasies of the district, and then adding acknowledged industry expertshas delivered on all the key aims of the project to date. Figure 4 - Study Area, Frankton Flats, Queenstown The water team helped investigating this issue by combining their knowledge of the network: QLDC staff provided the team with past studies that had been undertaken. They facilitated exchanges between all team members and ensured that communication By recognising that we would not be able to achieve modelling utopia with generation one of the model, the team has focused on delivering a model that is fit for purpose for the intended initial uses: to complete a initial assessment of system performance, developing a strategy that will enable the projected growth to be serviced,

7 understand our data and systems to focus on improvements that will enable the model to develop further. confidence as the focus moves to more detailed system performance and optimisation phases. Whilst the strategy work is still ongoing, QLDCs Asset manager and Veolia are already rolling out improvements that will see significant gains in model accuracy and Author Biographies Mark Baker, Queenstown Lakes District Council, Private Bag 50072, Queenstown, 9378 Mark is a senior 3 waters engineer with a strong technical background as a hydraulic modeller including previous roles on Water New Zealand s Modelling Group Committee. He currently heads up QLDCs 3 Waters Asset Management, Data and Analytics. Within that role he is responsible for the delivery of fit for purpose hydraulic models as well as other analytic data sets and tools. Dr Deborah Lind Queenstown Lakes District Council, Private Bag 50072, Queenstown, 9378 Deborah.Lind@qldc.govt.nz Deborah has 20 years utility and consultancy infrastructure experience gained in New Zealand, Australia and the UK. She has strategic, management, operations and customer experience, built upon earlier technical roles. Deborah also has a proven track record for pragmatism and delivering international best practice as well as innovation. She is committed to establishing and maintaining key relationships. Deborah also has a creative drive and enthusiasm, and has a supportive, collaborative and inclusive approach to working with others. Nasrine Tomasi Mott MacDonald, PO Box 37525, Parnell, 1151 Nasrine.Tomasi@mottmac.com Nasrine is a Chartered professional Engineer with nine years experience in Water Engineering. She has undertaken water supply, stormwater and wastewater model build, calibration and system performance using various software products. Nasrine is also an expert in the development and the maintenance of custom databases. She is actively involved in implementing Mott MacDonald's digital strategy.

8 Nasrine currently serves on the Management Committee of Water New Zealand s Modelling Group, involved in the development of best practice and improvement of this sector.