THE Bremer River received a D-, the worst ranking for south-east catchments, in the Healthy Waterways Report Card released yesterday.
The annual environmental analysis noted while the community highly valued the waterways, the Bremer catchment was under pressure from "very poor estuarine water quality and riparian extent" - a result of land clearing. Other western catchments also ranked poorly, the Lockyer River was rated D+, mid Brisbane River rated a D and upper Brisbane River rated a D, all with poor riparian extent and "very poor stream health".
The increasing amount of sediment entering south-east Queensland waterways was recognised as the number one issue affecting water quality.
Healthy Waterways executive science advisory committee member Adrian Volders said upgrades to sewerage treatment plants had reduced the pressures on waterways but the next challenge was tackling pollution from development and agriculture and the legacy from overclearing in the past.
"A lot of that historical clearing has smashed the catchment condition and it is going to take a lot of time and a lot of effort to bring it back," Dr Volders said.
"Because we are discharging directly into the rivers, there was historically high nitrogen and phosphorous load. Reducing that has made a big difference in terms of waterway health but the next challenge is tackling all of those diffuse sources of pollution, which is all the sediment inputs and pollution that is coming from urban and rural landscapes."
- Read related: Report targets sediment as number one issue
Ipswich Deputy Mayor Victor Attwood said sediment control off development sites was a major issue, particularly for the rapidly growing western corridor.
"The Bremer in particular has issues because if something enters the river here, it takes 90 days to get to the Brisbane River because of the tidal influences," Cr Attwood said.
Somerset Mayor Graeme Lehmann said it was time to look at the upper reaches in terms of sediment control.
"Everybody thinks most of it is coming off the farming land but per-hectare there is more coming off the industrial sites," he said.
South-east snapshotPressures Over 40,000ha of urban expansion by 2031 50,000 dump trucks worth of mud enter our waterways annually 14,400km of heavily degraded channels and riverbanks
Condition Only 36% of streams in major drinking water supply catchments have intact native riparian vegetation 2600km 2 of waterways are available for recreation 68% of estuarine areas contain habitat that supports fisheries
Update your news preferences and get the latest news delivered to your inbox.