Eurobodalla Integrated Water Cycle Management Strategy

Eurobodalla Integrated Water Cycle Management Strategy
68 ML/a of urban stormwater is discharged to the environment, consisting of approximately
64 500 kg/a of total nitrogen and 8 500 kg/a of phosphorus (based on median year rainfall).
Testing of urban stormwater from other coastal towns and villages suggests that urban
stormwater also contains significant loads of sediment, litter, bacteria and other pathogenic
organisms. At present there is limited urban stormwater quality control and management,
and no beneficial reuse of stormwater. Continual urban development without considering
appropriate stormwater management options will result in the continual decline of
environmental water quality and represent an increased risk to public health. The
stormwater issues relating to each individual town and village are discussed in more detail
in part C.
6.4.2 Urban Water Use and Discharge – Future Predictions
Urban Water Use
The population of the Eurobodalla Shire is expected to increase by 50% over the next three
decades, with most of this increase being accommodated within the major coastal urban
centres, as either new subdivision or as infill development within existing residential areas.
This increase in population will correlate to a growing demand for water, and consequently
increase wastewater and urban stormwater volumes.
The future urban water demands have been projected using three approaches as follows:
Traditional approach
Contemporary approach
Demand Managed approach (see section 8.1 for details)
Traditional Approach – In this approach the water demands are projected by modelling
the individual end uses for a typical property and then extrapolating this per property
demand to the whole community. The model is then calibrated against actual metered
quarterly consumption by estimating the residential indoor demand and the seasonal
demand variations. Thus the only factor that is considered to affect demand is population
growth. Macoun (1999) used this approach to forecast the demands. The population
forecast used was based on the low population increase predicted by DUAP.
Contemporary Approach – In predicting the water demands using this approach,
consideration is given to the mandatory plumbing regulation governing the toilet cisterns
and the future availability of plumbing fixtures and devices, and household white goods.
Consideration is also given to Council’s current water conservation initiatives along with the
past climatic and economic influences on demands. The population growth rate used in
this approach incorporated the 2001 census and was lower than that used in the traditional
approach as discussed earlier. The demand projected using this approach is referred to as
‘baseline’ in Figure 6-12.
Figure 6-12. shows the predicted annual water demands until year 2032.
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