River water quality is monitored monthly at 35 sites across the region using a range of physical, chemical and microbiological variables or attributes that can be affected by land use activities, point and diffuse source discharges, and land and instream erosion. Instream macroinvertebrates and habitat quality is monitored across 72 sites. Twenty-seven of these water quality and ecology monitoring sites are paired at the same location.
These sites are fairly evenly distributed across the region, and across proportions of dominant land cover type, although there is a greater proportion of monitoring focused on urban streams recognising the high impact of urban activities on rivers.
In many of our river systems, the healthiest waterways are found at the top of the catchment where the land cover is predominantly native forest. Water quality, and overall stream habitat and functions decline as these river systems traverse productive rural areas and urban parts of their catchments. In many of our urban catchments the entire catchment may be heavily modified – giving rise to the term ‘urban stream syndrome’, characterised by elevated temperatures, nutrients and contaminants, modified stream channels and reduced biological diversity.