Make a rough assessment of whether urban stormwater is likely to be significant for each kind of receiving water body.

• For wetlands:
• Check for evidence of weed invasion, dieback, etc.
• It can be assumed that if there is a non-trivial percentage of urbanisation in its catchment, then a wetland will be being affected.
• For other receiving water bodies:
• Estimate roughly the surface areas of the major land uses in the catchments of the more nearby receiving waters. Take these estimates and adjust them for the kinds pollutant loads that have been observed.
• Check for evidence of impacts from changed flow regime (e.g. scouring of creek lines, lowered base flow, …)

The NSW EPA's Catchment maps (accompanying the Water quality and river flow interim environmental objectives) show the extent of urban development in each catchment. They can be used to quickly assess whether urban areas are likely to be a large or small influence on the quantity and quality of water within a receiving water body. (For catchments not covered on this EPA web site see PlanConnect from iPlan.)

See also:

• Local State of the Environment Reports (which are often available online and are accessed here via a tailored Google search) may well assess the significance of urban stormwater within a catchment.
• OzEstuaries
  Data on Australian estuaries. Helpful when you are exploring the condition of coastal receiving water bodies.
• Australian Wetlands Database
  RAMSAR wetland sites and other nationally important wetlands.

And, if necessary, other catchment data online.

Local data sources to consult include reports held in Council corporate libraries and local tertiary education institutions.

Existing plans contain judgments of the significance of urban stormwater in catchment contexts. Plans to check:

• Stormwater Management Plans (accessed here via a tailored Google search)
• Catchment Blueprints prepared by Catchment Boards across NSW
• NSW Water Sharing Plans

There may well be some Local Council and State agency staff who are well-informed about the influence of Stormwater.

For contact information see:

• Directories (which includes Australian phone books)
• Organisations

Some simple calculations can help with assessing the significance of urban stormwater in a catchment or subcatchment context.

This site contains a number of calculators that can help you make an assessment of the load coming from a particular catchment and improve your understanding of how cost-effective any stormwater treatment might be.

Visit our Catchment Calculators page.

Methods:

• Informal look and see
• Rapid assessment techniques
• Formal monitoring and experimentation