Case Studies Illustrating the Multiple-Use Water Services Options - Rethinking Infrastructure Design for Multi-Use Water Services - page 83

Bioretention basins: The stormwater run-off not captured by rainwater tanks is
captured in swales and treated in a bioretention system at the bottom of the

development.
Stormwater sensitive landscape: The landscape of the development ensures
that stormwater drains to the bottom of the subdivision where a bioretention basin
allows controlled discharge off the site and eventually back into Enoggera Creek.
The basin is 25 m wide and 80 m long with a central trench filled with sandy loam

and incorporates four crushed-rock filters and two 0.5 m high rock weirs.

4.2 What Were the Strengths?

Drought conditions in southeast Queensland have shown that decentralised sub-
divisions such as Payne Rd, with a water supply system based on rainwater col-
lection are a viable alternative to municipal water supplies. Between May 2006 and
December 2007, rainwater contributed almost 80 % of all water consumed at Payne
Road in spite of the reduction in average annual rainfall by 40 %.
Wastewater at Payne Road allowed approximately 75 % of the greywater gen-
erated to be reused for irrigation purposes. Moreover, rainwater quality after
treatment meets all of the current Australian Drinking Water standards. Feasibility
studies demonstrated that increased costs of implementing unconventional tech-
nologies were lower than projected rates for extending Brisbane City Council water
and sewerage infrastructure to the development.

4.3 What Were the Challenges?

Rainwater pumping and treatment systems within the houses are relatively ineffi- -

cient compared to business as usual and manufactured water sources. The speci c

energy at Payne Road of around 5 kWh/kL is 10 times higher than business as usual
main supply at 0.5 kWh/kL. However, when looking at the overall household
energy use, the rainwater systems use 7.5 % of the total household energy use.
Moreover, the direct energy use of the household is only around 20 % of the
greenhouse budget attributable to the house, suggesting that considerably greater
energy savings are available to householders by changes in other urban practices.
For example, producing or procuring local grown foods or using public transport
will rapidly replace the de cient rainwater pumping system. Other

suggestions on how to offset these energy losses include greenhouse gas ef

cit of an inef

cient

hot water system and grid connected photovoltaics (PVs).
Over instrumentation in the home and on-site: The many different monitoring
systems have generated excessive amounts of data, which have proved unnecessary.
Furthermore, over instrumentation was also linked to the issue of increased costs
required to maintain monitoring and evaluation systems. Increased cost relative to