Future Wastewater Flows
Based on the forecasts for population growth and water demand, annual wastewater flows for Perth and Mandurah are forecast to be:
- by 2020,155 gigalitres (426 megalitres a day);
- by 2030, 179 gigalitres (490 megalitres a day); and
- by 2060, 237 gigalitres (650 megalitres a day).
These projections reflect an increase in the proportion of residential areas sewered due to new land development almost exclusively occurring in sewered areas.
These forecasts are dependent on a number of factors including:
- in home and commercial water demand;
- number of properties connected to the Water Corporation’s wastewater system;
- the reduction in flows due to in home and business water use efficiency; and
- the location and density of population increases.
Western Australian Planning Commission forecasts provide the basis for the population projections used. In addition, they provide information on the expected distribution and density of people in the greater Perth and Mandurah areas.
These population forecasts have influenced Water Corporation decisions to increase capacity at existing wastewater treatment plants and invest in new treatment plants.