3.4 Environmental flows
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Curriculum Alignment

2, 5, 6, 9, 14, 18, 19, 22, 25

Years K-6: Science and Technology, HSIE, Creative Arts
Years 7-10: Agriculture, Science, Geography Technics  
Years 11-12: Agriculture, Geography, Earth and Environmental Science, Society and Culture

SOSE, Science, Geography

Futures, Interdependence, Thinking

Science, Thinking Processes, Geography

>Students will gain an understanding of the term “environmental flow”
>Students will review and assess environmental flow regimes operating in their region

1 hour 

Materials required
>Clear container of water
>One cup for each student
>Masking tape
>Butcher’s paper
>Flow levels and ecological roles 
>Homework sheet – Water disputes in a thirsty country project outline (see below) 

Land and Water Australia
The term ‘environmental flow’ has come into common usage. To some this term applies to releases from dams which are specifically for environmental benefit. To others it can be any flow which achieves an environmental benefit, or the flow at the end of a river system, or any flow event which should be retained. The term “environmental water” is likewise used in different ways. 

The diagram shows a section of unregulated river above a dam. Extraction of water at point A will affect river flow characteristics downstream. Environmentally important characteristics can be maintained by regulating the volume, rate and timing of extraction. The flow rules in

Healthy inland rivers need flows that vary with the seasons and provide regular flood events, as occurred naturally.  Photograph:  Bill Phillips
Healthy inland rivers need flows that vary with the seasons and provide regular flood events, as occurred naturally. Photograph:  Bill Phillips

water sharing plans for unregulated rivers (those without dams or weirs) typically specify how this should be done.
In the regulated section of a river the flow regime is changed by the operation of the dam or weir.

Restoration of important environmental flow characteristics normally requires releases of water to be made at times which are less than optimal for other users of water. For example, crop water demands frequently occur at different times of the year to when natural high flows happened. 

In some cases, a volume of water is held in the dam solely for release for environmental purposes.  When environmental releases are made it is often necessary to constrain extraction downstream to achieve the desired benefit. For example, extraction at point B (see the diagram) might be constrained to ensure a release reaches the wetland further downstream. ‘Caps’ (or limits) on extraction help ensure uncontrolled high flow events are preserved for environmental benefit. 

Environmental flow assessments generally aim to identify the particular flow characteristics which are important for the health of rivers and dependant ecosystems like floodplain wetlands (see below).

Water sharing plans for the river valleys (catchments) of the Murray-Darling Basin typically include various strategies to achieve these flow objectives. These include environmental flow rules relating to extraction or system operation such as:

>Limiting extraction volumes such as via a ‘cap’ on volumes that can be extracted.
>Managing the timing and rate of extraction to protect designated flow events or characteristics.
>Requiring certain flow characteristics to be achieved such as minimum flow to keep ecosystems functioning. 

An ecologically sustainable water management program must always be built upon a foundation of knowledge about the river flows needed to sustain ecosystem health. When the water needs of a river ecosystem are clearly defined, water managers are able to find ways of meeting human needs for water while maintaining adequate river flows for sustaining living rivers. 

Environmental flow
Cap (on extraction)

Lesson plan
1.   Get the students to list the many users of water in their local community and attempt to say what proportion each ‘sector’ might use of the total available. Based on data collected across the country, averages for these are as follows: 

>Agricultural uses: 65% 
>Household use: 11% 
>Water supply industry: 11% 
>Other industries (including electricity and gas): 7.4% 
>Manufacturing uses: 3% 
>Mining uses: 2% 

2.   Give groups of students the number of cups in proportion to the above breakdown.  For example in a group of 20 students, 13 cups represent agriculture, 2 each for household use and water supply and 1 cup for industry, mining and manufacturing (the latter two should only get 1/2 cup of water ultimately).

3.   Mark the water level in the clear container of water (this represents the ‘environment’). 

4. Invite the students to fill all their cups; all but the miners and manufacturers! Only 1/2 a cup for them.

5.   Examine with the students how the level of the water in the environment has changed after users have extracted water from the system.

6.   Based on what they have learned from other Sustaining River Life lessons, have students draw as a group on a large piece of butcher’s paper a diagram or mural showing how the aquatic environment (along your river or in your region) possibly looked before water extraction, then a second one portraying post-extraction effects.

7.   Have the students think about ways they can put water back into the environment, individually, as a class and school and as a family at home.

8.   Get the students to prepare a water usage diary for a week.

9.   Encourage each student to come up with at least one action they can take to conserve water, and put it into action.

Did they see any change
to how much water was 
used at home for example
by comparing quarterly
water bills?

10. Ask students to report back on their efforts across a school term.  

Secondary pathway
1. Work out with students what the term “environmental flow” means using the “Flow levels and ecological roles” sheet (see below).

2. Have the students locate and read about the water sharing arrangements for a nearby river catchment. 

3. Ask the students to explain how water sharing is organised for this river system and document how much water has been allocated for environmental use in the past five years compared to other allocations.

4. Break the students up into groups to critically consider those factors that indicate aspects of river health, such as condition of river bank and floodplain vegetation, macroinvertebrates, frog populations, fish communities and water quality.  

5. Groups should determine if they believe the ecological roles to be supported by environment flows are being met.

6. Have student groups present a five minute overview of their findings and conclusions.

7. Encourage students to contact the local river water managers, Catchment Management Authority (CMA) or similar body to clarify any aspects which remain unclear. 

8. Ask students to consider the long-term effects of climate change on environmental flow regimes.

9. Challenge students to look at the causes for water shortages and develop a class action plan to lower water use both in the school and at home (see RiverSmart Australia’s web site for do-it-yourself audits for both places).

10. Encourage students to attend a local community meeting regarding water issues, such as a local Council meeting, a Landcare, Waterwatch or CMA community session.