Page 118 - Materials Chemistry, Second Edition

Will the well run dry? Developments in water resource planning and impact assessment

This ‘ramping up’ of demand through complex infrastructure-utilisation relationships has 105
been extensively investigated in sociotechnical literature, where it has been shown that stake-
holders prescribe appropriate levels of demand into systems of provision, thus shaping
consumer behaviour (e.g. Chappells and Shove 2004). Oversizing water infrastructure systems
can therefore be expected to lead to increased use of latent capacity. Hence, seasonality and
appropriate sizing are important in a water-constrained environment. LCA as currently
deployed has little to say about these interrelations between design and environmental impact
outcomes, since the implication of sizing is generally considered to be simple – more impact
through more materials and energy used for the oversized system. Moreover, the general
assumption is that each unit of consumption is equally valid; indeed, the functional unit is
invariably ‘per unit of water consumed’, which does not account for total consumption or
types of consumption. There is ample scope to extend LCA in these areas.

8.5 Conclusions
As society begins to recognise the finite nature of water resources, LCA emerges as a tool to
assist development of more sustainable water practices by water supply authorities and water
users. Water is handled by LCA in two distinct ways: first, to characterise the potential envi-
ronmental impact of any system being analysed; and second, in the analysis of impacts of
water supply, management and treatment systems.
Water as an indicator of system impact must be interpreted carefully to ensure that real
environmental impacts are highlighted. Aggregate water use is an inventory item rather than a
direct representation of environmental damage, although the process of LCA, as defined by
ISO 14040, states clearly that impact indicators must only be used with interpretation. The
potential spectrum of actual environmental impacts can be carefully addressed by a thorough
and logically presented interpretation of water indicator results. Although alternative assess-
ment methods are available to reduce the need for interpretation, in many cases they can be
avoided by expanding system boundaries to capture complicating systems such as other users
of the same water resource.
The use of LCA to analyse water systems requires a broad perspective and a wide system
boundary. The multitude of interactions between water servicing systems requires both supply
and treatment systems to be considered when assessing a water saving or enhancing design.
Determining the life cycle impacts of water systems requires a detailed understanding of
system design, both its infrastructure and operation. Infrastructure designs need to be well
documented in order to capture the many materials and installation activities of the system
being considered. Detail is also required to understand likely operational impacts, including
energy use, material consumption and emissions.
In many cases, system infrastructure and operational behaviour are influenced by the
seasonal nature of water demand. Understanding seasonality often necessitates detailed mod-
elling of water demand and supply capacity. Modelling usually has to be undertaken at a fine
time interval to ensure that any shortfalls in system supply capacity are fully comprehended.
As indicated above, seasonal water demand fluctuations can have a direct impact on system
sizing, driving larger capacity systems than average data would suggest is necessary. Further-
more, water supply systems provide a good example of the interdependence between system
design and use. Where ‘unlimited’ use is enabled at the turn of a tap or the creation of well-
positioned drains, then what is considered to be a ‘normal’ rate of consumption is likely to rise,
with boundaries of normality being redrawn irrespective of previous ‘behaviour’ conventions.
‘Drought’ may then lead to these boundaries being (abruptly) redrawn. Thus, drought is at
once both a function and regulator of demand and supply systems, and incorporation of such

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