The health of local waterways is holding steady, but the standard of Brisbane’s biggest aquatic playground has declined, according to an annual report into the state of South East Queensland ecosystems.

The Ecosystem Health Report Card found while local catchment areas showed marginal improvement this year, the health of Moreton Bay has dropped considerably.

The South East Queensland Healthy Waterways Partnership has monitored rivers, creeks and catchment areas in the region since 1999, using scientific data to produce annual report cards presenting an ‘A’ to ‘F’ health rating for waterways.

Their latest report found increased rainfall over the past year, the greatest downpours in ten years, improved the health of some freshwater streams but also had a negative affect on local waterways.

While intense rainfall following a period of sustained drought increased water flow and flushed out streams, sediment run-off from catchments is clogging up estuaries discharging into Moreton Bay.

Healthy Waterways Chair Professor Paul Greenfield said the overall health of Moreton Bay declined significantly in the past year, falling from a B– to a D grade.

While streams in the Pine catchment are of a fair quality and improved slightly on last year’s result, the standard of the area’s estuaries fell marginally.

That was despite high freshwater inputs resulting in the salinity in Pine estuaries being at its lowest level since 2001.

The biological health of Caboolture River improved, overturning last year’s failing grade to score a D–, while the standard of the Caboolture region’s freshwater streams remained relatively stable.

The quality of freshwater streams in the Stanley River catchment, which has the Woodford region as its centre point, remains in good condition despite falling slightly to a B rating.

Riparian vegetation along the upper reaches of the Stanley River remains in a very good condition, while freshwater streams across the south east recorded more native fish and a lower proportion of introduced species this year.

While the quality of waterways in the Pine Rivers region has virtually remained stable over the past six years, Melanie Brennan from the Pine Rivers Catchment Association said more needs to be done to maintain ecological health in the face of increased urbanisation.

“We need to make sure we do not degrade the health of the Pine Rivers further, but it is also reasonable for us to think we can improve its condition,” she said.

“We just need to be prepared to spend a little more now for benefits in the future.”

Ms Brennan said keys to improving waterways by reducing soil runoff included planting native vegetation and adopting water sensitive urban designs.

“We need to find a way to develop without leaving the soil bare in areas for long periods of time,” she said.

“It is a very costly venture to upgrade our stormwater systems to adopt water sensitive urban designs and that will take time.

“But we could definitely be doing more to stop pollution at its source such as new building sites and erosion scars along river banks.”