Urban water services in the Australian Capital Territory (ACT) are currently provided through conventional centralised systems, involving large-scale water distribution, wastewater collection, water and wastewater treatment. A study was conducted to assist Environment ACT in setting broad policies for future water services in Canberra. The current paper presents the outcomes of a study examining the effects of various water servicing options on water resources and the environment, for two townships in Canberra, one existing and one greenfield site. Three modelling tools were used to predict the effects of various alternative water servicing scenarios, including demand management options, rainwater tanks, greywater use, on-site detention tanks, gross pollutant traps, swales and ponds. The results show that potable water reductions are best achieved by demand management tools or a combination of greywater and rainwater use for existing suburbs, while third pipe systems are preferred for greenfield sites. For this specific climatic region and end use demands, modelling predicted increased water savings from raintanks compared to greywater systems alone, with raintanks providing the additional benefit of reduced peak stormwater flows at the allotment scale. Rainwater and stormwater reuse from stormwater ponds within the catchments was found to provide the highest reduction in nutrient discharge from the case study areas. Environment ACT amended planning controls to facilitate installation of raintanks and greywater systems, and commenced a Government funded rebate scheme for raintanks as a result of this study.

Continuous transects of near-surface water temperature and chlorophyll fluorescence on the northern Great Barrier Reef shelf were sampled in October 1987 and February 1990. In 1987, local spatial variability of both temperature and chlorophyll were higher within or close to the reef matrix than in open waters of the GBR lagoon. Temperature and chlorophyll fluorescence were negatively correlated at short length scales in data sets. Correlations at longer scales were inconsistent. Vertical mixing forced by flow diversion around reefs or through gaps between reefs appears to be the major process responsible for the observed spatial heterogeneity of near-surface temperature and chlorophyll fields. Individual features in linear transects, however, are often difficult to attribute to specific gaps between reefs at distances greater than a few kilometers from a particular gap.