In September 2006 LEG commenced monitoring water quality in the Coxs River and all major tributaries, from its birthplace in Ben Bullen State Forest to about 40 kilometres downstream in the Kanimbla Valley.

The aim was to measure how development in the Lithgow area was affecting water quality over that distance.

This has shown that a small regional centre with a population of just 20,000 people can have a marked impact on water quality within a catchment. Some disturbing data has been recorded at various sites, such as:

• Salinity levels - up to 92 times higher than natural background levels
• Phosphate levels - up to 125 times higher than natural background levels
• pH levels - up to 1000 times higher than natural background levels
• Turbidity levels - up to 400 times higher than natural background levels
• Water Temperature in industrial discharges - 15 degrees higher than seasonal background levels
• Dissolved Oxygen levels - as low as 5%, which is lethal for aquatic life.

The sites that LEG is monitoring are shown on this map. The collected data is shown in this document.

Coxs River Salinity Updates

• May 2026
• December 2019
• May 2019
• August 2018
• May 2018
• December 2015
• November 2015

Water NSW Catchment Audit 2025

Read LEG's Water NSW Catchment Audit 2025 submission