Adapting Integrated Urban Water Management to Support Climate Adaptation
In Australia, Integrated Urban Water Management (IUWM) first rose to prominence in the late 1990’s in a shift to an era of doing more with less. Prolonged drought drove a desire to look more holistically at options for securing water for cities. A tipping point was the acceptance of the paradigm of water saved as being equivalent to water supplied. This ensured that a broadening set of options for both demand management (water saving) and new water sources (water supply) could be compared and considered on equal footing.
Actually broadening doesn’t even begin to describe the diversity of options that came forward. City water authorities evaluated options including rain tanks, appliance trade-ins and rebates, industrial water recycling, car washing manifestos, accelerated leak detection and repair programs, pool covers, efficient fixtures and fittings – with concerned citizens volunteering solutions through letters to newspaper editors and government ministers alike. A wide-ranging program addressing water efficiencyremains in place today.
Of course, for cities around the world, IUWM reflects much more than simply the integration of water demand and supply – wastewater management, the role of stormwater, linkages with groundwater systems are just a few further examples of what IUWM encompasses. While priorities will vary across cities both in the developing and developed world, IUWM is extremely flexible as a foundational approach to urban water planning [see this World Bank Report covering examples from around the world – Lessons and recommendations from regional experiences in Latin America, Central Asia and Africa].
Today new and re-emerging drivers are applying pressure on urban water systems – understanding climate impacts, or more specifically understanding the capacity to adapt to climate impacts, is a key consideration for urban infrastructure and services the world over.
Where does this leave IUWM as a methodology to support urban water planning? Does the water industry need new approaches and methods? Or do we need to adapt our existing approaches to address the challenge of climate adaptation?
To answer this question on the role for IUWM, we need to come back to the key principles of IUWM and consider the adaptation perspective. Here are two:
- Consider all elements of the urban water system - forecasts of water requirements, understanding of surface and groundwater availability and even wastewater flows can be analysed with respect to a changing climate. Is the yield from existing water sources likely to vary as the climate changes through reduced runoff and streamflow? Will water demand increase significantly with an increasing number of extreme heat events?
- Consider all options on an equal footing - from an adaptation perspective, this would mean evaluating each option in terms of likely performance under future climate scenarios and including this data with other metrics such as cost effectiveness and environmental benefit. For example, will preferred location for key infrastructure be at risk from storm events and coastal inundation? Will saline intrusion affect the quality of water drawn from surface and groundwater systems potentially requiring a higher level of treatment?
These examples show that we can incorporate climate adaptation into IUWM and the planning that IUWM supports. Of course, this implies that there is sufficient knowledge and data to support these steps. In reality, there may be limited capacity to assess suitability of options under a future climate – or even simply how the baseline assessment of water security is considered – if there is limited data. For example - is it even realistic to explore the likely variability in water demand due to climate change against a backdrop of significant and significantly uncertain population growth?
These are important questions to consider no matter how big or small your town. What we can conclude though is that the inherent flexibility of IUWM lends itself to inclusion of an assessment of climate change impacts and possible responses.
The benefit of bringing adaptation thinking into IUWM is that the integrated perspective is not lost as would be the case if adaptation were considered through a completely separate planning process. This is a critical point when thinking about co-benefits that options may generate – or conversely the unintended consequences or mal-adaptation that may result from a poorly understood (or poorly integrated) approach.