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Conference Papers

'What's going into the Oceans and who's doing it?'

A Catchment Study and Water Quality Analysis for School and Community Groups.

Mrs. Leonie Hansen

Marine Studies Co-ordinator
Swansea High School
Park Avenue, Caves Beach NSW 2281

Workshop presenters: Michael Bailey, Trevor Cocksedge, Brendan Delaney, Shane Harding, Robert Hughes, Rebecca Young.

Year 12 - 2 unit Marine Studies

 Workshop Overview

Participants will be taken along a tributary of Port Phillip Bay \ Bass Strait in the Queenscliff area and identify the land uses of the area and possible sources of water pollution. They will then take water samples, under the direction of six Year 12 Marine Studies students, and test for phosphates, nitrates, dissolved oxygen, pH, temperature, turbidity, total dissolved solids and faecal coliform on location.

Aims of the Workshop

To demonstrate the ease with which school students and community groups can analyse water samples in the field producing high standard data for distribution to government agencies.

Outcomes of the Workshop

As a result of participating in this workshop participants will become:

  • familiar with the ease of water quality testing,
  • perform water quality testing in the field,
  • identify possible pollution sources in the catchment,
  • understand the benefits of peer instruction for students and community groups,
  • produce a snapshot of the water quality of a catchment.

Our oceans and waterways have always been an important resource. Humans obtain food, clothing and an enormous variety of chemicals from the aquatic environment.

We take from the sea but we also give back - urban runoff, industrial waste, garbage, effluent, nutrients, etc. In all communities throughout the world this give and take is proceeding almost unchecked at an alarming rate.

Through education these trends in human behaviour may be altered. With programs such as Waterwatch Australia awareness of our impact on the aquatic environment is heightened. Students and community groups are provided with the skills, support, knowledge and analytical equipment to go forth and test the waters. They have the ability to analyse water to a high standard, source problems and follow up through government bodies, who can, if possible, rectify them.

The investigation of the quality of a catchment can be achieved through a catchment study followed by water testing.

Catchments Study

A catchment is all lands that feed a waterway. Consequently what happens to that land will sooner or later effect the waterway.

eg. Cause Effect on the land Effect on the waterway

Loss of vegetation

increased runoff,


increased water velocity,

increased turbulence,

habitat destruction,

river profile altered,

increased turbidity,

reduced light penetration,

reduced biodiversity.

Wetlands drained and filled

altered water table

destruction of habitat,

loss of biodiversity,

altered foodweb,

loss of nursery for fish and invertebrates.

Grazing pastures

altered water table

increased nutrients,

algal blooms,

altered foodweb,

loss of biodiversity.

These effects and many others can be sourced by using simple catchment survey techniques.

For example, from a local topographic map identify the catchment by drawing in the catchment boundary. Then with the aid of the map walk the river system from its mouth and identify land uses. Complete Survey Sheet 1. Transfer this information onto the contour map. Choose appropriate water test sites and complete Site Investigation 1.

Survey Sheet 1: Catchment Land Use


Transport depot, e.g. road, rail



Other government buildings: __________________________________

Recreational park \ oval

Shopping centre

Natural bushland

Disturbed bushland

Main business area

Farm - sheep, cattle, pig, poultry

Farm - crops: ___________________________________________

Market garden

Light industry: __________________________________________

Heavy industry: _________________________________________

Sewage treatment works

Abattoir, feedlot

Others: ____________________

Others: ____________________

Others: ____________________

Others: ____________________

Site Investigation 1

A simple site description should be carried out before water monitoring. This will allow data comparisons across the testing period.

Date: ______________ Time: _________________

Name of creek, river or drainage: ___________________________

Location: __________________________ Map \ Grid reference: _________________

Water depth in centre of river: _________ Rate of flow: ____________( ms-1)

Weather: ______________________________________________________________

Temperature: _____________ Recent rainfall: __________________

Composition of river bed:





other __________________

other __________________

Evidence of pollution in the water:






other __________________

Riparian alteration:

trees planted


poisoned weeds

concrete walls

riverbed alteration

other __________________

Riparian flora:

native vegetation

introduced species

Aquatic plants:

free floating

floating attached

submerged plants with fine feathery leaves

emergent plants with fine feathery leaves

submerged - not feathery

emergent - narrow leaf

emergent - broad- leaf

trees and shrubs

Water Testing

Chemical and physical analysis of a waterway produces data that will indicate the quality of the water in a catchment. This water quality has far reaching effects on the aquatic habitats downstream.

The dissolved oxygen levels, number of faecal coliform, biochemical oxygen demand, total phosphorus and nitrates, pH, temperature difference, amount of turbidity and total solids and streamflow can be measures easily in the field.

Why test these parameters?

* Dissolved oxygen:


Levels affected by

Loss caused by

essential for aerobic organisms

amount of turbulence

organic waste (sewage \ runoff)

promotes biodiversity

rate of photosynthesis

levels of bacteria

increases biomass

flow rate

* Faecal coliform:

Originates from

Enters the waterway from


faeces of warm blooded animals

agricultural and stormwater runoff

may carry pathogens

sewage discharge

* Temperature:


Effected by

affects solubility of gases

stormwater runoff

rate of photosynthesis

industrial discharge
altered riparian vegetation

* Phosphorus:

Australian flora have evolved to cope with extremely low levels of phosphorus.

Levels are increased by

Increased levels of phosphates produce


excessive algal growth


encourages the growth of exotics

* Nitrates:

Caused by

Increased levels of nitrates produce


algal blooms

the decay of organic matter
sewage and fertilisers


* Turbidity:

Turbidity is a measure of the amount of suspended solids.

Caused by

High levels cause


loss of biodiversity

urban runoff

higher water temperatures

industrial discharge

reduced oxygen levels

excess nutrients

* pH

In Australian waters the pH range is 6.5 to 8.5

Changes in pH may cause the water to become unsuitable for the organisms living there.

* Biochemical Oxygen Demand ( BOD )

Is a measure of oxygen used by micro- organisms and indicates the level of micro-organism activity.

What the Test Results Mean



Mildly polluted

Medium to high polluted

Dissolved oxygen

80 to 125% saturation

70 to 80% saturation

125 to 130% saturation

< 70% saturation

> 130% saturation

Faecal coliform

0 to 100 colonies \ 100 mL

100 to 400 colonies \ 100 mL

> 400 colonies \ 100 mL


6.5 to 8.5

5 to 6.5

8.5 to 9

< 5

> 9


0 to 3 mg\L

3 to 10 mg\L

> 10 mg\L


0 to 50 C

5 to 100 C

> 100 C


0 to 0.5 mg\L

0.5 to 1.5 mg\L

> 1.5 mg\L


0 to 10 JTU

10 to 50 JTU

> 50 JTU

Total solids

0 to 80 mg\L

80 to 180 mg\L

> 180 mg\L

Total Phosphorus

0 to 0.1 mg\L

0.1 to 0.25 mg\L

>0.25 mg\L

From the results of the water tests and catchment surveys the water quality can be assessed. This information is compiled by the Department of Water Resources to assess the state of the river systems.


Department of Water Resources 1993, StreamWatch Students Manual ISBN 0 7305 78976