You are here: ANRA home » Natural resource topics » Water » Quality » Queensland
This web site is no longer being updated
In this section you will find detailed information, including national overviews and state and regional level assessments, from the 2000-2002 National Land and Water Resources Audit theme assessments.
Water resources - Quality - Queensland
Basin: Boyne River
Surface water quality in Boyne River
Attributes for which trend analyses could be determined:
Salinity, pH, Total Phosphorus
The Boyne River Basin is located in the central coast region of the North East Coast Drainage division. It is characterised by undulating coastal plains and steep ranges, with rainfall ranging from low to moderate in the lower catchment and moderate to high in the ranges. Cattle grazing and, to a lesser extent, dairy farming are the main land uses of the area. These activities are confined to the coastal plains and slopes at the foot of the ranges. The upper ranges of the basin are still densely vegetated although some timber has been extracted from the area.
Data for the trend analysis were collected from two sites, which are located in Diglum Creek and Boyne River. Together, these sites represent approximately 54% of the basin. An exceedance analysis was not conducted for this basin.
Monitoring indicated that surface water turbidity, conductivity, and pH levels are not increasing in the basin. However, given the poor representation of the basin, a confident assessment of the basin's surface water quality cannot be made.
| Monitoring Station | Salinity - Electrical conductivity | Total nitrogen | Total phosphorus | Turbidity | pH | Blue Green Algae | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Exceed | Trend | Exceed | Trend | Exceed | Trend | Exceed | Trend | Exceed | Trend | Exceed | Trend | |
| 133003A | No Data | No Trend | No Data | No Data | No Data | No Data | No Data | No Data | No Data | No Trend | No Data | No Data |
| 133004A | No Data | No Trend | No Data | No Data | No Data | No Data | No Data | No Data | No Data | No Trend | No Data | No Data |
Select a station name in the table above to view a detailed station report.
Monitoring Water Quality Guideline exceedances and trends
Exceedance Classification
For the Audit assessment of surface water quality, individual monitoring sites were classified as good, fair or poor for each variable based on whether State and Territory water quality guidelines (see below) were exceeded. Generally a 'good' classification was achieved where water quality was within guidelines for a greater period of time while a 'poor' classification resulted where water quality did not fall within the guidelines for a greater period of time. A range of statistical measures including the median, 90th percentile, and % time exceedance, were used by States and Territories for this determination dependent upon the variable and whether the analysis was based on assessing acute (short term extreme event) or chronic (long term sustained event) water quality impacts. 'Fair' water quality describes situations intermediate between good and poor. Full discussion of the methods used for water quality exceedance and trend assessment are presented in the Water Quality Technical Report (see link to technical report).
Water quality Trends
Detecting trends in surface water quality is complicated by seasonal climatic variation and the influence of stream flows on the observed concentrations of water contaminants. For these reasons a long term (~10 year) data set containing relatively frequently collected water quality samples (monthly as a minimum) and concurrent flow data are required to support trend assessments. A range of statistical analyses were used by States and Territories to report on water quality trends, dependent upon the nature of the monitoring (i.e., flow based versus regular sampling) and quality of the data (i.e., the method's ability to accommodate missing data values). All used methods that accounted for seasonality and stream flow influences (see link to technical report).
The significance of observed trends were assessed statistically to ensure they were not the result of random variation. Significant trends were reported in terms of their magnitude (i.e., how much change per annum) and their direction i.e. whether they were increasing or decreasing. Results that indicated no trends were also reported.
Result Aggregation
To be able to build an overview of State and National water quality it was necessary to aggregate water quality results from individual sites to river basins. To do this an 'upstream area weighting' method was used. Results obtained from a monitoring station were multiplied by the amount of catchment area that it samples. Weighted results from individual monitoring stations allows a river basin to be characterised in terms of the percentage of area classified as good, fair or poor, or in terms of the area undergoing increasing or decreasing trends for a particular water quality variable. Results per basin are presented graphically as colored pie charts.
This method was supported and adopted by State and territory agencies when compiling the national assessment and can be rationalised in terms of the way water quality interacts within a basin. Nevertheless, the potential for error generation was recognised, particularly when monitoring station coverage across the basin is limited, the opportunity for bias in the characterisation of basin water quality increases. This may lead to the underestimation of the extent of a water quality issue where monitoring stations are not placed within impacted areas, or alternatively overestimation, where in the absence of upstream monitoring stations, results obtained by impacted lowland sites are used to characterise the upper basin.
The Water resources - Quality - Queensland's reporting capacity to interrogate data down to an individual monitoring site scale provides the opportunity for basin wide aggregations presented elsewhere to be further examined.
- Salinity
- Surface Water pH
- Nutrients
- Turbidity
- Faecal Coliforms
- Blue-green Algae
List of attributes:
Note: some attribute information may not be available for some areas
Trend Legend
Exceedance Legend
Salinity
Trend
Salinity describes the salt concentration in water. It is usually measured in terms of the ability of water to conduct an electrical current (electrical conductivity EC) in units of micro siemens per cubic centimetre (m Scm-1). EC is an appropriate indicator of salinity, as it is proportional to the concentration of total dissolved salts and is easily measured in the field or by later laboratory analysis. Salinity is also sometimes measured directly (as is the case in Western Australia) in terms of total dissolved salts (TDS).
The salinity guideline for the protection of aquatic ecosystems was used for the exceedance assessment. The values for this water quality indicator are also generally equivalent for the indicators values for drinking water and agricultural water use, although the latter can be crop specific. Guideline boundaries varied from State to State (see below) reflecting the variability of surface water conditions and management objectives.
The two pie charts present salinity results aggregated from individual monitoring stations to represent the salinity status of the entire basin. They show the relative proportion of the basin area that was classified as having good, fair or poor water quality in terms of salinity guideline exceedances and the relative proportion of the basin area that was assessed as having increasing, decreasing or static salinity trends.
The proportion of the basin for which no data was available is also presented and provides an indication of the monitoring coverage of the basin for salinity.
Exceedance
Surface Water pH
Trend
The acidity or alkalinity of surface waters is measured in units of pH which are a logarithmic scale measure of the concentration of free hydrogen (H+) ions in solution. Values at the low end of the pH scale (1-7) represent extreme to neutral acidity, while values at the high end of the pH scale (7-14) are a measure of the neutral to extreme alkalinity of water.
The pH guideline for the protection of aquatic ecosystems was used for the exceedance assessment. Guideline boundaries varied from State to State (see below) reflecting the variability of surface water conditions and management objectives.
The two pie charts present pH results aggregated from individual monitoring station to represent the pH status of the entire basin. They show the relative proportion of the basin area that was classified as having good, fair or poor water quality in terms of pH guideline exceedances and the relative proportion of the basin area that was assessed as having increasing, decreasing or static pH trends.
The proportion of the basin for which no data was available is also presented and provides an indication of the monitoring coverage of the basin for pH.
Exceedance
Nutrients
No Nutrient information exists for this basin
Turbidity
No Surface Water Turbidity information exists for this basin
Faecal coliforms
No Faecal Coliforms information exists for this basin
Blue-green algae
No Blue-Green Algae information exists for this basin
Further Information
Key
Links to an another web site
Opens a pop-up window