Elsevier

Environmental Modelling & Software

Volume 75, January 2016, Pages 348-361
Environmental Modelling & Software

Paradigm shift to enhanced water supply planning through augmented grids, scarcity pricing and adaptive factory water: A system dynamics approach

https://doi.org/10.1016/j.envsoft.2014.05.018Get rights and content

Highlights

  • System dynamics model integrates supply, demand and financial dimensions.

  • Diverse supply source portfolios that are grid connected alleviates water scarcity.

  • Desalination reduces need for restrictions compared to a rain-dependent portfolio.

  • Pressure retarded osmosis technology integration into desalination component of water supply networks for renewable energy.

  • Scarcity pricing is an effective strategy for reducing demand while simultaneously generating the additional revenues.

Abstract

This paper details a system dynamics model developed to simulate proposed changes to water governance through the integration of supply, demand and asset management processes. To effectively accomplish this, interconnected feedback loops in tariff structures, demand levels and financing capacity are included in the model design, representing the first comprehensive life-cycle modelling of potable water systems. A number of scenarios were applied to Australia's populated South-east Queensland region, demonstrating that introducing temporary drought pricing (i.e. progressive water prices set inverse with availability), in conjunction with supply augmentation through rain-independent sources, is capable of efficiently providing water security in the future. Modelling demonstrated that this alternative tariff structure reduced demand in scarcity periods thereby preserving supply, whilst revenues are maintained to build new water supply infrastructure. In addition to exploring alternative tariffs, the potential benefits of using adaptive pressure-retarded osmosis desalination plants for both potable water and power generation was explored. This operation of these plants for power production, when they would otherwise be idle, shows promise in reducing their net energy and carbon footprints. Stakeholders in industry, government and academia were engaged in model development and validation. The constructed model displays how water resource systems can be reorganised to cope with systemic change and uncertainty.

Section snippets

Socio-environmental system context

Potable water security is a growing concern, as population growth, development and climatic change increasingly limit the potential of traditional rain-dependent sources for augmenting supply. This poses new challenges to the governance of potable water resource systems.

Whilst Australia may appear abundant in its water supply, only utilising approximately 5% of its total renewable freshwater resources (SoE, 2013), it faces gross geospatial supply-demand mismatches and is afflicted with the

Approach to representing systemic change

Previous water resource system models have typically been supply-side oriented. This research sought to integrate demand, supply and asset management processes, to create a more holistic representation of the coupled socio-environmental system, as illustrated in Fig. 1 and discussed below. For the purposes of this paper, asset management encapsulates both the financial interactions influencing the management of water infrastructure, and the operating procedures that determine the utilisation of

Systems model development and exploratory sCenariOS

Voinov (2008) explains that when a model can effectively take into account the essential features of a real-life system, its behaviour under stress will likely be similar to the behaviour of the prototype model. Essential variables for model operation were identified by reviewing locally based literature for region specific inputs and examining world literature for more generic variables and their behaviour. System norms and rules were informed by the SEQ Water Strategy Reports in combination

Forecasts for water supply and demand

1.5% population growth sees the SEQ population rise to 4.13 million by 2031, 5.57 in 2051 and 13.6 million by 2110. Annual Water Demand is highly sensitive to population growth, per capita water use and climate variability. For fluctuating population growth between 1.5 and 2%, and varying per capita demand as outlined in the previous section, Annual Water Demand ranges from 1.86 million ML/year to 3.65 million ML/year at the end of the 100 year simulation. 30 years from today, the minimum

Diversifying the traditional rain-dependent water supply portfolio

As set out by the SEQ Water Strategy (QWC, 2010, QWC, 2012b), the drought storage reserve is defined as the stock of water below 60% of the working capacity of the region's working water supply capacity. This is the current means for the system to deal with uncertainty over adverse short to medium term climatic conditions. The drought response plan states that the drought storage reserve, in combination with rain-independent supply, must provide at least 36 months' supply under water

Conclusions

This paper detailed the development of an SDM developed to explore the behaviour of the SEQ water resource system over the next 100 years under systemic change brought about by climate change and population growth. The current supply-side oriented approach to water governance was found to be ill-equipped to cope with these changes, leading to economic hardship and chronic water shortages.

Reorganisation of the system through new water governance practices were proposed and simulated. These

Acknowledgements

This research is part of a study on desalinated water in Australian bulk water supply networks, funded by a grant from the National Centre of Excellence in Desalination Australia (NCEDA) to the Alfred Deakin Research Institute (ADRI) at Deakin University, in a project jointly managed with the Smart Water Research Centre at Griffith University, and with technical cooperation from AECOM Ltd. The authors acknowledge valuable comments on this paper from Dr Helen Scarborough, David Downie, Dr Joel

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