Industrial Catchments

Industrial land-use continues to place significant pressure on waterway health in Hornsby Shire. Unfortunately, the critical goods and services provided by these commercial and industrial locations have led to significant modification of the catchments. In addition, the widespread use of products such as concrete and harsh detergents/surfactants often result in stormwater contamination. Council routinely monitors three sites adjacent to the Thornleigh, Hornsby and Mt Kuring-Gai industrial areas to better understand the impacts from industrial land use. A collaborative approach to managing industrial areas is important, with many businesses operating under state government EPA licences.

Industrial sites are monitored monthly and are characterised by highly elevated pH and nutrient levels, and lower dissolved oxygen. These sites also receive pulses of bacterial contamination, most likely due to problems with ageing wastewater (sewerage) infrastructure during wet weather. Rainfall runoff quickly reaches the creeks in these catchments, being directed straight off the hard surfaces to stormwater drains, carrying pollutants straight to the local creeks and waterways. Industrial areas also generally contain high percentages of hard (impervious) surfaces, which means that runoff and the flows in downstream creeks can increase very quickly. As a consequence, nearby waterways can become highly eroded, often resembling large concrete gutters instead of natural creeks.

Sampling parameters

  • Temperature (oC)
  • Electrical conductivity (µS/cm, mS/cm)
  • Turbidity (NTU)
  • Dissolved oxygen (%sat, mg/l)
  • pH
  • Salinity (PPT)
  • Total suspended solids (TSS)
  • Bacteria (Faecal coliforms, E.coli, enterococci)
  • Nutrients (TN, TP, NH3-N, NOx-N, SRP)
  • Fluoride (provides an indication of how much portable water runoff is reaching waterways in these heavily modified catchments)
  • CBOD5 (5-day carbonaceous biological oxygen demand)