Water Quality Monitoring of the Bellinger & Kalang Rivers 2015-16

John Schmidt, OEH undertaking water quality sampling
John Schmidt, OEH undertaking water quality sampling

The ‘Water Quality Monitoring of the Bellinger and Kalang Rivers 2015-16’ Technical Report describes the water quality sampling regime completed by Council in 2015-16 and presents the results for public information.

In 2009-10, a pilot program of Ecohealth monitoring was completed in the Bellinger-Kalang catchments.  Ecohealth is an aquatic ecosystem monitoring program that measures how healthy our rivers and estuaries are for the plants and animals that live in them. Both the 2009-10 Ecohealth and 2015-16 water quality monitoring programs refer to the Australian and New Zealand Environment Conservation Council (ANZECC) and NSW Monitoring, Evaluation and Reporting (MER) water quality guidelines for healthy aquatic ecosystems i.e. they do not refer to water quality for drinking, recreational, agricultural, industrial or other purposes.

During the 2015 Bellinger River Snapping Turtle mortality incident, no agency involved in the investigation was able to provide an up to date assessment of the ecosystem health of the river. Council then decided to proceed with an interim water quality sampling regime to the value of $15,000 to gather up to date water quality data in the short term while options for additional funding to deliver a second round of Ecohealth monitoring were explored.

Technical report
Water Quality Monitoring of the Bellinger and Kalang Rivers 2015-16 Technical Report

Interpreting the results

  • The consistently high nutrient concentrations did not result in chlorophyll in concentrations exceeding the trigger values at any site or time.  This is an indicator of the algal productivity in the water column.
  • Total nitrogen concentrations were below trigger values at all sites except Spicketts Creek 23 June during post flood sampling.
  • All sites recorded turbidities below trigger thresholds at all times.
  • Both of the lower estuary sites (Bellinger and Kalang) recorded a low risk of faecal contamination in the post flood sampling June 2016.  There were no E.coli from human origin detected in the study.
  • Available nitrogen concentrations were consistently found to be above the trigger value in estuary and freshwater sites.
  • All estuary sites exceeded guidelines for available phosphorus at all sampling times.
  • Total phosphorus was above the trigger value for all sites on most occasions.
  • Total phosphorus was above the trigger value and mean low flow concentrations for all sites for 23 June post flood sampling.
  • Spicketts Creek stood out as the system with consistently elevated nutrient concentrations in both post flood and low flow periods, and the only system to record dissolved oxygen concentrations that may stress biota.
  • Spicketts Creek and the lower Kalang estuary were the only sites to have recorded an acidic pH (below the minimum trigger threshold) in the study.
  • Low dissolved oxygen saturation (%) in freshwater sites in February and April 2016 are likely due to extremely low discharges during this time.

In general, these results are similar to water quality results in the 2009-10 Ecohealth project, which resulted in overall grades of B for the Bellinger River and B- for the Kalang River.  A grade of B is considered to be ‘good’ and C, fair.  A report card for the 2015-16 water quality monitoring program will be available soon.

The associated Council report, which provides further background information, is available in the Agenda and Minutes of the Ordinary Council Meeting 14 December 2016