 Water is essential to human life and to
the health of the environment. As a valuable natural resource, it comprises marine,
estuarine, freshwater (river and lakes) and groundwater environments, across coastal and
inland areas. Water has two dimensions that are closely linked - quantity and quality.
Water quality is commonly defined by its physical, chemical, biological and aesthetic
(appearance and smell) characteristics. A healthy environment is one in which the water
quality supports a rich and varied community of organisms and protects public health.
Water quality in a body
of water influences the way in which communities use
the water for activities such as drinking, swimming
or commercial purposes. More specifically, the water
of the South East is used by the community for the
purposes of:
- supplying drinking water
- recreation (swimming, boating)
- irrigating crops and watering stock
- industrial processes
- navigation and shipping
- production of edible fish, shellfish and crustaceans
- protection of aquatic ecosystems
- wildlife habitats
- scientific study and education
Our water resources are of major environmental, social and
economic value to NSW, and if water quality becomes degraded this resource will lose its
value. Water quality is important not only to protect public health - water provides
ecosystem habitats, is used for farming, fishing and mining, and contributes to recreation
and tourism.
 If water quality is not maintained, it is not just the environment
that will suffer - the commercial and recreational value of our water resources will also
diminish.
"it is illegal to effect the natural balance
of a waterway in any manner" |
State of Water
Quality in the catchments of the South East
There is an assumption
that the overall water quality of the South East is
high. This is probably based on the general physical
appearance of most of the water bodies of the area
and the fact of relatively low levels of industrial
and urban development in their catchments. The relatively
sparse objective measures of water quality available
for the area are generally consistent with this view,
but problems have been highlighted in some localised
areas.
Of the streams monitored throughout the region, few have
experienced problems with parameter measures of health falling outside the accepted range.
It must be noted though, that relatively few locations and few parameters have been well
characterised.
To quote Gippel (1996)
who can speak with authority, having done the only
comprehensive study of water quality data for the
South East to date;
"Over the past 30 years water quality may have
improved or declined in response to changes in catchment condition, but it is unlikely
that this could be detected, let alone explained, using available data."
It is for these reasons,
among others, that the South East Water Quality Monitoring
Project was established. Two of the major objectives
of the program are to;
- Establish what is known about local water quality
- Assess the adequacy
of existing monitoring programs of the South East
What is Water Quality Monitoring?
Water Quality Monitoring refers to the examination of the
physical, chemical and biological characteristics of water – observing how these
factors change over time and over different positions along a water body. Monitoring
exercises will generally employ some or all of the following tests
| Faecal
Coliforms |
Faecal
Colliform bacteria are non-pathogenic organisms
which occur naturally in the intestines of
warm blooded animals. The number of coliform
bacteria present in a sample, serves as a
reliable indication of sewerage or faecal
contamination in water. Colliforms are measured
by incubating a sample on a nutrient pad and
counting the number of colonies present.
|
| Dissolved Oxygen |
Amount of oxygen in the water,
which is essential for the survival of most organisms. Water temperature can affect
dissolved oxygen levels so that the higher the water temperature, the lower the potential
dissolved oxygen level.
|
| pH |
Acidity or Alkalinity of the
water. pH is important as most organisms can only survive within a narrow pH band. The
solubility of many other chemicals varies with pH. A pH test is conducted with paper test
strips or measured with a meter.
|
| Total
Dissolved Solids |
A measure of dissolved minerals
in solution. High levels of total solids cause lower water quality and water dwellers can
suffer osmotic stress. A meter is used to measure total dissolved solids.
|
| Turbidity |
Clarity
of the water, or the amount of suspended particles
in the waterbody. In addition to blocking
out the light required by aquatic plants and
animals, suspended sediment can carry nutrients
and pesticides throughout the system. Turbidity
is measured with a meter, turbidity tube or
using the colorimetric method.
|
| Nitrates |
The amount of nitrates in the
water indicate organic enrichment and consequent health of a waterway. High levels can
lead to increased algal growth.
|
| Phosphates |
Phosphorous in the water
primarily comes from human and animal faeces runoff from rural and urban areas. This
parameter indicates the nutrient status and consequent health of the waterbody. High
levels may stimulate algal blooms, large swings in DO and imbalances in aquatic
communities.
|
| Temperature |
Indicates the approximate
temperature of the water which varies with depth season and time of day. Many of the
physical, chemical and biological characteristics of a stream are directly affected by
this parameter. Temperature is measured with a probe or thermometer.
|
| Biological Survey |
Abundance and diversity of
aquatic macroinvertebrate communities serves as a reliable indicator of stream health.
Nets or artificial substrates are used to collect aquatic macroinvertebrates, which are
identified and compared with records from other sites. |
Measurements of these indicators can be used
to determine, and monitor changes in, water quality, and determine whether the quality of
the water is suitable for the health of the natural environment and the uses for which the
water is required.
The design of water quality monitoring programs is a
complex and specialised field. The range of indicators that can be measured is wide and
other indicators may be adopted in the future. The cost of a monitoring program to assess
them all would be prohibitive, so resources are usually directed towards assessing
contaminants that are important for the local environment or for a specific use of the
water.
This water quality information can then be used to develop
management programs and action plans to ensure that water quality is protected. |
