Increasing public debate on water quality issues such as altered flow regimes in rivers, nutrient and sediment export to estuaries have added extra pressure on the water quality monitoring and assessment process. These assessments are generally made against water quality guidelines, water quality objectives, pollutant loads and trend or pattern changes in certain indicators. Water quality information can also be used for many other purposes, such as to determine source(s) of pollution (establish cause-and-effect), regulatory purposes, to provide input for management tools such as models and to support scientific decisions on preserving or improving the quality of a water resource.

WQA is a collection of analytical tools, process based DSS, databases, electronic documents and frameworks designed to assist water quality data processing, analysis and assessment.

WQA has been designed for persons who are involved in water quality improvement, management or regulation activities. User groups for WQA includes State regulators, Local governments, NRM bodies, Industrial clients, Consultants, Catchments groups, Community groups, Land holders and Research & Education organisations.

Use of WQA requires some knowledge of water quality science. Its relatively easy-to-use interface means that users generally require only a limited knowledge of computer use. Availability of required input data is a major concern.

Guideline Tool: The Guideline Tool is statistical software developed to calculate locally relevant water quality guideline values, store guideline values in a searchable database for later and recall and test new datasets against guideline values to provide a statistically sound indication of the health of a site. The procedures used in this tool are based on the ANZECC 2000 methods. Both referential and biological approaches are available for setting up guidelines depending on the type of available data. The tool can also assist in the development of water quality targets by providing a method to calculate proportional improvements in a measured variable.

Loads Tool: The determination of constituent loads or loading rates from rivers and streams is not a trivial task. Due to the relatively sparse nature of concentration data and different sampling methods, special load estimation techniques should be applied to reduce estimation errors. The current version of the Loads tool presents nine of the most common methods for long-term load calculation and four methods for estimating loads from storm events. A built-in function is available to calculate event mean concentration (EMC) values which are useful in catchments modeling exercises.

Trend analysis tool: A tool for detection of water quality trends, statistical testing, change and randomness in water quality data and other time series data. Discovery of temporal water quality trends is a complex process due to characteristics of the non-normal distribution of data, seasonality, flow relatedness, missing values, values below the limit of detection, serial correlation etc. Further, preparing time series data sets and the checks for suitability of available data for trend detection add additional restrictions for trend analysis. Using this tool, users are able to perform explanatory data analysis before stepping into complex modeling processes. The current version presents 13 different statistical tests.

Time series data manager: A tool for manipulating, infilling, cleaning and transforming time series data. This tool comes with advanced data visualization capabilities to summarise and present a large amount of spatial and temporal data. It can also apply any rating curve to a time series to create new time series.

eGuide: This is an electronic document which consists of a number of commonly referred to water quality guideline documents. Users can select the document that they would like to browse manually or select the 'search' tab to search all the guides for some keywords. The searched items can be viewed, copied to another document or printed out for later reference.

WQA has been designed using contemporary science and state of the art decision support system technology, which includes interactive tools, databases, knowledge bases, statistical tools, decision-making processes and a comprehensive collection of relevant information and help material. This tool has a user friendly interface which requires no special skills to use.