Freshwater ecosystems are under increasing pressure, yet their sustainability is rarely assessed against ecological and human-use standards or over the long term. This study adopts a landscape-specific approach to assessing water sustainability across three contrasting landscapes in the Sydney Basin: urban (Parramatta), peri-urban (Hawkesbury) and rural (Shoalhaven). It examines what is happening to water quality from upstream to downstream in each landscape, whether conditions meet ANZG ecological-protection and NHMRC recreational guidelines, how the landscapes compare, and what this means for management.
The study draws on two data sources. First, a field campaign sampled one main river, one tributary, and one creek per landscape at upstream, midstream, and downstream reaches (27 sites) over five consecutive autumn weeks (2026), measuring physico-chemical, nutrient, microbial, and habitat indicators. Second, publicly available historical records spanning up to three decades were compiled from open government and council portals to provide long-term context. Both were benchmarked against the same guidelines.
A peri-urban creek showed severe nutrient enrichment, with every sample exceeding ANZG phosphorus and nitrogen guidelines, phosphorus up to 40 times and nitrate up to two orders of magnitude above them. Conductivity exceeding 20,000 µS/cm was recorded in tidally influenced downstream reaches under autumn low flow, reflecting estuarine intrusion in the Duck River (Parramatta) and Broughton Creek (Shoalhaven). Exceedances differed markedly across the landscape gradient and along the upstream-to-downstream continuum.
The findings also reveal concerns about the open-data record. Waterways within the Sydney drinking-water catchment, managed by WaterNSW, Sydney Water and councils, are comparatively well covered. By contrast, urban rivers and creeks lack consistent monitoring, and monitoring sites have declined sharply over time. By integrating reach-scale, community-led measurements into a landscape-comparison framework, the study offers a transferable method for evaluating freshwater sustainability. It underscores where monitoring, data access and governance must improve.