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Operators of Australia’s urban water systems are on a never–ending quest to secure supplies in the face of the triple–whammy challenges of expanding populations, economic growth and shifting climate. New systems must also be responsive to future needs while preserving environmental values of receiving waters.
Developing an integrated framework means capturing the various system drivers and options for management to optimise water managers’ choices. Integrating these elements and their aspects into a single program has been a long-term goal for eWater Product Leader Dr Matthew Hardy of BMT WBM Pty Ltd and colleagues.
The outcome of their R&D is Urban Developer, a new tool to support Integrated Urban Water Management (IUWM). Initially targeted at lot to cluster scale applications, it will ultimately allow urban water managers to compare options for integrated water management ranging in scale from the allotment to cluster. The beta version will be released in February.
Developed with urban water system operators in mind, Urban Developer incorporates all three urban water cycle services – potable, waste and stormwater – within a single framework. It can simulate demand and supply interactions at sub–daily time scales, and can deal with catchment rainfall–runoff responses at a range of scales.
“We have built Urban Developer to support the analysis of alternative service delivery and management strategies so that they can be compared alongside more traditional planning, design and management methods,” Hardy says.
“The challenge in developing an integrated framework is capturing the different system drivers. Stormwater arises from rainfall and runoff processes, whereas consumer demand drives mains water supply and waste water generation.
“Unlike other models, Urban Developer is focussed on resource use by households and industry, not just infrastructure. Consumption, storage and reuse are the basic starting points, and from there we can examine options like supply source substitution, for example sewer mining.”
This next–generation software tool from eWater builds on research Hardy completed while studying at the University of Newcastle as well as work by university colleagues George Kuczera, Peter Coombes and Mark Thyer (now at the University of Adelaide). eWater tools such as music also influenced development. The research is now continuing through a new crop of Ph.D. students like eWater Scholarship holder Andrew Graddon at the University of Newcastle.
“A key aim of my own research was providing a tool that could assist in the design and assessment of systems that find a balance between reticulated water and alternative supplies–such as recycled water and rainwater tanks,” Hardy says. “I wanted a way of making the best of both worlds in terms of security of supply and sustainability.”
As a conceptual and preliminary design tool, Urban Developer does just that, facilitating the selection of alternatives that lead to maximum efficiency.
“There is a dearth of comprehensive models out there that can be used for the assessment of IUWM,” Hardy says. “This especially applies to detailed representations of demand and supply relationships.
“If IUWM is to succeed, practitioners need tools like Urban Developer that can model and assess systems based on multiple and alternative service delivery strategies”.
Urban Developer will let users examine, design and assess how a system based on water–sensitive urban design principles will operate. The modelling framework is equally applicable to brown and greenfield sites, and can also be used to explore issues such as urban renewal by enabling exploration of innovative service delivery strategies.
It also lets users see the relationship between inputs, outputs and amounts in store. It readily highlights the potential interactions of water supplies from reservoirs, stormwater, rainwater tanks and wastewater.
The program allows the user to play with the factors affecting individual blocks and streets and will ultimately extend to the suburb scale.
Urban Developer joins the well–known music urban stormwater software in the eWater Toolkit.
While music addresses the water quality aspects of urban stormwater management, Urban Developer takes an integrated management approach to stormwater and provides support for the assessment of a broader range of options. This new addition to the eWater Toolkit can handle the required feedback loops and will ultimately evaluate water quantity and quality consideration in a single framework.
Scaling within urban systems
Urban Developer has in-built network hierarchies that make it possible to consider system links directly, from one scale to another, or between standard water supply options and alternatives. The program makes it relatively simple to integrate the scales and systems that make up urban water and to explore relationships across their boundaries. Users can then examine the available range of sources and sinks critically, and evaluate all possible internal loops and interactions.
Water cycle services have traditionally been planned and managed in isolation and from a top-down perspective. However, water cycle services and the institutional boundaries of service providers intersect at the allotment scale (Kuczera and Coombes, 2001), allowing reappraisal of the approach to their management when placed in an interacting system context (Hardy et al., 2003).
The Urban Developer modelling framework is founded on a representation of interactions between urban water cycle services at the allotment scale. Individual allotments, and the simulation of the water cycle elements at a sub-allotment scale, form the basis on which larger models are built and, from these fundamental units, users can explore relationships and performance at a range of spatial scales.
Sophisticated end-use modelling
In Urban Developer the demand predictions are provided by an innovative new approach to urban water use modelling.
The Behavioural End-use Stochastic simulator (BESS; Thyer et al., 2011) stochastically simulates individual end-uses (outdoor, shower, washing machine, toilet, tap etc) at the household scale at sub-daily time steps, for multiple households (100-1000s).
For the indoor end-uses, BESS can simulate differences in household size, uptake rates of water efficient appliances and diurnal variation in end-uses. This provides ability to incorporate various demand management scenarios.
For outdoor water use, BESS simulates the highly variable behavioural response of outdoor water use to prevailing weather conditions (e.g. rainfall and temperature). This provides reliable predictions of reductions in mains water demand when evaluating source substitution and/or re-use options.
The system dynamics of sub-allotment elements also requires the use of short time-steps to adequately represent their rapid responses to system fluxes, particularly those associated with stormwater. Urban Developer can employ time-steps of seconds, where necessary, to capture these dynamics.
Water security and service integrity for urban centres are major drivers for urban water policy and management. These objectives must be realised in an environment where urban development and population growth contribute to resource limitations, rising demand and prices for water, and system failures, on top of considerations to do with asset maintenance and replacement, climate variability, and the environment.
As a result integrated or total water cycle management strategies are being explored for their ability to provide long term security and service integrity to urban water cycle services. Integrated strategies are seen as being able to allow identification of opportunities not otherwise apparent when separate strategies are developed for each service in isolation.
Around Australia and internationally, integrated service delivery strategies have been shown to offer outcomes including greater resource efficiency, reduced environmental impacts, extended asset life and – importantly - increased water supply security. Urban Developer lets water managers conceive and plan IUWM strategies.
With Urban Developer, you can:
• represent all three urban water cycle service networks–potable, waste and stormwater
• deal with probabilistic demands and end–use simulation
• perform continuous simulation and simulation of multiple replicates at once
• integrate systems at a range of scales
• explore recycling and re–use loops; and
• manage network and computational complexity
Project leader Dr Matthew Hardy talks about Urban Water Management.
Further reading: Hardy, M. (2009) Integrated Urban Water Management and the urbanCycle Modelling Framework. (A Thesis for the Degree of Doctor of Philosophy, The School of Engineering, University of Newcastle.