Water Data Services - Planning

The following recommendation is based on a report commissioned by the Environment Protection Agency.

"To achieve greater effectiveness and efficiency within a water quality monitoring programs, redistribute funds internally in line with the following approximate breakdown:

  • Preparation and planning to meet program objectives - 15 per cent
  • Sampling and field analyses - 15 per cent
  • Laboratory analyses - 40 percent
  • Data storage, analysis and interpretation - 15 percent
  • Report preparation and dissemination - 15 percent."

When designing a new monitoring program please consider the following points:

Do you want to gain an understanding of catchment characteristics?

If so, then you need to collect either discrete samples or event based composite samples.

With discrete samples you can examine relationships between rainfall and concentrations and flow and concentrations. However, laboratory analyses will be expensive due to the large number of samples collected. Event based composite sampling would be a cheaper option (approx. 1/24th) but will not provide the same detail. For example you could not determine if concentrations increase or decrease during the flow peak or on the flow recession.

A compromise may be to use discrete sampling for 3 months and then switch to event based composite sampling.

Do you want feedback on Catchment Management initiatives?

If so, then a regular composite sampling program would be adequate. A regular composite sampling program would provide reliable estimate of loads and flow weighted mean concentrations. After a period of time (3 to 5 years), statistical methods could be used to determine if the water quality is improving.

Do you need to collect water quality information as part of a 'Licence Condition'?

Generally, use the composite sampling method - it provides better results than an adhoc grab sampling program and will demonstrate to the EPA a commitment to invest in the protection of the environment. In some cases in-situ water quality sensors can be used to measure a determinant continuously.

Over the last few years reliable water quality sensors have become available. For example conductivity, pH and turbidity sensors can monitor continuously and reliably. These sensors are expensive to purchase but are cheaper than on-going laboratory analysis over the duration of a 3-5 year project.