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The Lake Eyre BasinA unique river system worth maintaining

Teacher guide and lesson plans

Lower secondary

1 | The Lake Eyre Basin A unique river system worth maintaining

The Lake Eyre Basin: A unique river system worth maintainingTeacher guide and lesson plans – Lower secondary

ISBN: 978-1-74200-128-9

SCIS order number: 1523398

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Acknowledgments:

Front cover: NASA, above (left), below (far right); © Commonwealth of Australia – photograph by Paul Wainwright, above (centre), below (centre left and centre right); © Commonwealth of Australia – photograph by Allan Fox, below (far left).

Back cover: © Commonwealth of Australia – photograph by Allan Fox, above; © Commonwealth of Australia – photograph by Paul Wainwright, below (far left, centre left, centre and far right).

Background image (page 4): NASA.

Front and back cover images are repeated in the banners throughout the document.


CONTENTSBig Idea: How do we ensure that Australia’s water use is sustainable? 4

The Lake Eyre Basin – Overview 5

Investigation 1 How does the Lake Eyre Basin differ from other Australian river systems? 9

Lesson 1.1 What makes Lake Eyre unique? 12

Lesson 1.2 How do the Lake Eyre Basin catchments work? 18

Lesson 1.3 What affects the rate of evaporation? 24

Investigation 2 How is the Basin transformed after long dry periods? 28

Lesson 2.1 What is the recent history of the levels of Lake Eyre? 31

Lesson 2.2 What happens to river systems during extended dry periods? 39

Lesson 2.3 How does water transform the Basin? 42

Investigation 3 How do we manage the Lake Eyre Basin sustainably? 49

Lesson 3.1 What are the possible effects of diverting water from rivers in the

Lake Eyre Basin? 52

Lesson 3.2 How do we move from conflict to mutual benefit? 59

Glossary 63

Teacher guide and lesson plan | 3

BIG IDEA

How do we ensure that Australia’s water use is sustainable?

In a dry arid country such as Australia, our water resources are already

stressed, largely as a result of our extraction of water to suit our nation’s

needs. The river systems in the Lake Eyre Basin experience highly

variable and unpredictable flows. However, they are in good condition.

How do we manage the competing needs for water resources in the Lake

Eyre Basin to ensure their health and biodiversity is maintained for future

generations?


The Lake Eyre Basin

OverviewThe Lake Eyre Basin is an internal drainage basin that makes up an area of nearly one-sixth of the continent (16 per cent). Groundwater systems feed springs that are a source of cultural, economic and social importance. The highly variable climate affects river flows with periods of low or no flow and periods of flooding. In times of extended dry periods the springs and large permanent waterholes provide vital habitat for wildlife, livestock and communities. Periods of flooding reconnects isolated waterholes, recharges groundwater storage systems, revitalises aquatic and grassland ecosystems and infrequently leads to the filling of Lake Eyre, the lowest point in the Basin. The episodic floods that extend over vast floodplains result in increased yields of pasture grass that feeds livestock for months after the flooding. The survival of living things is influenced by the continual cycle of flooding and drying and leads to periods of boom and bust. When water is plentiful it seems an attractive and viable option to divert the water for other needs. The storage of water in this climate is impractical due to high evaporation rates and a very flat topography. So how can water resources be sustainably managed in such a harsh, unpredictable and variable climate?

Map 1.1 The Lake Eyre Basin

© Lake Eyre Basin Analogues Research Group, University of Adelaide; using topographic map data © Commonwealth of Australia


At a glanceGuiding investigations Lessons Outcomes

1 How does the Lake Eyre Basin differ from other Australian river systems?

1.1 What makes Lake Eyre unique?

Students describe what they know about Lake Eyre and what they want to find out about it. They follow a guided inquiry to answer questions of interest.

1.2 How do the Lake Eyre Basin catchments work?

Students use a model to demonstrate how water flows in a catchment. They represent the Lake Eyre Basin catchment using suitable materials.

1.3 What affects the rate of evaporation?

Students investigate factors that affect the rate of evaporation and relate their findings to the Lake Eyre Basin. They investigate and measure the electrical conductivity (EC) of a solution containing salt as it evaporates over time. They relate their findings to Lake Eyre.

2 How is the Basin transformed after long dry periods?

2.1 What is the recent history of the levels of Lake Eyre?

Students graph and interpret data of Lake Eyre flood levels.

2.2 What happens to river systems during extended dry periods?

Students describe the effect of extended dry periods on river ecosystems.

2.3 How does water transform the Basin?

Students describe adaptations and behaviours of animals and plants that assist their survival in an arid environment that undergoes periods of boom and bust.

3 How do we manage the Lake Eyre Basin sustainably?

3.1 What are the possible effects of diverting water from rivers in the Lake Eyre Basin?

Students describe the possible effects on various land users in the Lake Eyre Basin if water was diverted for use elsewhere.

3.2 How do we move from conflict to mutual benefit?

Students describe an issue, analyse the key points and work towards a solution of mutual benefit.


Australian Curriculum Links

Science – Year 7

Science Understanding Science as a Human Endeavour

Science Inquiry Skills

Biological sciences

There are differences within and between groups of organisms; classification helps organise this diversity

Interactions between organisms can be described in terms of food chains and food webs; human activity can affect these interactions

Chemical sciences

Mixtures, including solutions, contain a combination of pure substances that can be separated using a range of techniques

Earth and space sciences

Some of Earth’s resources are renewable, but others are non-renewable

Water is an important resource that cycles through the environment

Nature and development of science

Scientific knowledge changes as new evidence becomes available, and some scientific discoveries have significantly changed people’s understanding of the world

Science knowledge can develop through collaboration and connecting ideas across the disciplines of science

Use and influence of science

Science and technology contribute to finding solutions to a range of contemporary issues; these solutions may impact on other areas of society and involve ethical considerations

Science understanding influences the development of practices in areas of human activity such as industry, agriculture and marine and terrestrial resource management

Planning and conducting

Collaboratively and individually plan and conduct a range of investigation types, including fieldwork and experiments, ensuring safety and ethical guidelines are followed

In fair tests, measure and control variables, and select equipment to collect data with accuracy appropriate to the task

Processing and analysing data and information

Construct and use a range of representations, including graphs, keys and models to represent and analyse patterns or relationships, including using digital technologies as appropriate

Summarise data, from students’ own investigations and secondary sources, and use scientific understanding to identify relationships and draw conclusions

Evaluating

Reflect on the method used to investigate a question or solve a problem, including evaluating the quality of the data collected, and identify improvements to the method

Use scientific knowledge and findings from investigations to evaluate claims

Communicating

Communicate ideas, findings and solutions to problems using scientific language and representations using digital technologies as appropriate


Geography (from Shape of the Australian Curriculum: Geography)

Geographical knowledge and understanding

Year 7

Weather and water

the hydrologic cycle describes the movement of water between the atmosphere, land and oceans

weather can be a hazard, but the risks can be reduced through human adjustment to the conditions presented

water is a difficult resource to manage because it is integrated into environmental systems in complex ways, can be highly variable over time and across space, and has many competing uses

Geographical inquiry and skills

Developing a geographical question

observation can lead to questions for investigation

Planning a geographical inquiry

some geographical features can be explained by cause and effect relationships with other places

Collection, evaluating and managing information

primary and secondary data must be evaluated for accuracy and bias before being analysed

census data can be used to describe the growth, movement and characteristics of the populations of places

information collected in a survey should be evaluated for reliability

Making sense of the information

mapping the spatial distribution of a characteristic such as rainfall, can be a first step in developing an understanding of that characteristic and suggesting possible causal relationships

Communicating

each type of communication has conventions that should usually be followed for communication to be effective

the climate of place can be represented by a graph of average monthly temperature and precipitation

Planning and implementing actions

finding a way of resolving a problem depends on an understanding of the causes of that problem

Reflecting on the investigation

each investigation should be evaluated for what has been learned about the topic investigated and what has been learned about the process of investigation


INVESTIGATION 1

How does the Lake Eyre Basin differ from other Australian river systems?

IntroductionThe Lake Eyre Basin is a unique river system, which covers a significant area of the continent’s arid to semi-arid bioregions. It is home to a variety of flora and fauna, many of which are endemic, and it is one of the few unregulated dryland river systems in the world. While the rivers are in good condition they experience variable flows with periods of flood and no flow over extended dry periods.

Access to water influences settlement patterns. Aboriginal people have lived in the area for thousands of years and have many culturally significant sites with strong connections to water. Settlement across the Basin is limited and land use is greatly influenced by climate and availability of water resources.

The Lake Eyre Basin landscape is crossed by numerous meandering rivers, most of which do not flow permanently. The Lake Eyre Basin covers more than one million square kilometres (one-sixth of Australia), and is about the size of the Murray-Darling Basin. However, in contrast to the Murray-Darling Basin, the Lake Eyre Basin is an inland drainage system. No water flows from the Basin to the sea. It is one of the biggest inland drainage systems in the world.

Teacher guide and lesson plan: Investigation 1 | 9

Australian Curriculum links

Science – Year 7



Biological sciences


Chemical sciences

Mixtures, including solutions, contain a combination of pure substances that can be separated using a range of techniques








Evaluating


Communicating





Year 7

Weather and water














Communicating








Lessons

Lesson 1.1What makes Lake Eyre unique?

OutcomeStudents describe what they know about Lake Eyre and what they want to find out about it. They follow a guided inquiry to answer questions of interest.

BackgroundThis lesson is designed to enable students to connect with the Lake Eyre Basin by looking at its unique features and characteristics, and through this activity raise their awareness about the climate and variable flows that have a large influence on daily life.

The Lake Eyre Basin is an arid environment with high summer temperatures and highly variable rainfall. The Basin has a sparse population of less than 60,000 spread across 1.2 million square kilometres (0.05 people per square kilometre or 20 square kilometres per person). In contrast Sydney’s population density is 2,000 people per square kilometre.

Ephemeral rivers crisscross the landscape however reliable water comes almost entirely from natural springs or bores drilled into the ground to tap into groundwater from the Great Artesian Basin that extends under much of the Lake Eyre Basin.

The dry and wet periods influenced patterns of life of the early Aboriginal inhabitants of the Lake Eyre Basin. Floodwaters and localised rains impacted on food availability. The scattered springs and waterholes provided refuge during dry periods. These water resources are still an integral part of Aboriginal culture and life on their traditional country.

Resources and preparation

Part A

Figures, graphs, maps and tables

Figure 1.1 The Lake Eyre Basin in flood

Figure 1.2 The Lake Eyre Basin in flood – close up

Map 1.1 The Lake Eyre Basin (page 5)

Video

Behind the News, ABC,

www.internationalbenchmarking.org/btn/story/s2578003.htm

Student worksheets

Student worksheet 1.1 Know, What, How, Learned (KWHL) chart

Part B

Student worksheet

Student worksheet 1.2 Data chart: What makes Lake Eyre unique?


http://www.internationalbenchmarking.org/btn/story/s2578003.htm


ReferencesAustralian Desert Fishes, Rivers in Central Australia, www.desertfishes.org/australia/habitats/rivers/rivergen.shtml

Australian Government, Lake Eyre Basin Agreement, Lake Eyre Basin and its importance, www.lebmf.gov.au/basin/index.html

Australian Wildlife Conservancy, Well-timed pulse of water set to rejuvenate life on Kalamurina, www.australianwildlife.org/AWC-Sanctuaries/Kalamurina-Wildlife-Sanctuary.aspx

Aerial Video Australia, Video of Innamincka, www.aerialvideo.com.au/innamincka.html

Bureau of Meteorology, Daily rainfall totals for Australia, www.bom.gov.au/jsp/awap/rain/index.jsp

Commonwealth of Australia, GAB and Lake Eyre Basin Overlap, www.gabcc.org.au/tools/getFile.aspx?tbl=tblContentItem&id=77

Commonwealth Government, Lake Eyre Basin Agreement, www.environment.gov.au/water/publications/environmental/rivers/lake-eyre/pubs/assessment.pdf

Department of Sustainability, Environment, Water, Population and Communities, and the Queensland, South Australian and Northern Territory governments, Drainage, www.lebmf.gov.au/basin/drainage.html

Department of Sustainability, Environment, Water, Population and Communities, and the Queensland, South Australian and Northern Territory governments, Flooding in the Cooper Creek Catchment, January 2008, www.lebmf.gov.au/photos/cooper-creek.html

Lake Eyre Basin Coordinating Group, Lake Eyre Basin, www.lakeeyrebasin.org.au/index.html

Lake Eyre Basin Coordinating Group, Land Use in the Basin, www.lakeeyrebasin.org.au/land_use/land_use.html Lake Eyre Basin Coordinating Group

National Parks in the Outback, www.environment.sa.gov.au/parks/pdfs/parks-pdfs-guide-flinders.pdf


http://www.environment.sa.gov.au/parks/pdfs/parks-pdfs-guide-flinders.pdf

http://www.environment.sa.gov.au/parks/pdfs/parks-pdfs-guide-flinders.pdf

http://www.lakeeyrebasin.org.au/land_use/land_use.html

http://www.lakeeyrebasin.org.au/land_use/land_use.html

http://www.environment.gov.au/water/publications/environmental/rivers/lake-eyre/pubs/assessment.pdf


http://www.gabcc.org.au/tools/getFile.aspx?tbl=tblContentItem&id=77

http://www.gabcc.org.au/tools/getFile.aspx?tbl=tblContentItem&id=77

http://www.bom.gov.au/jsp/awap/rain/index.jsp

http://www.australianwildlife.org/AWC-Sanctuaries/Kalamurina-Wildlife-Sanctuary.aspx


http://www.desertfishes.org/australia/habitats/rivers/rivergen.shtml

http://www.desertfishes.org/australia/habitats/rivers/rivergen.shtml

Lesson outline

Part A: Know, What, How, Learned (KWHL) chart

Ask: What makes Lake Eyre unique?

This question will open discussion and reveal what students know about Lake Eyre, whether they have visited the region or what they have learned through mass media.

Show students Map 1.1 on page 5 in order to establish the area of the Lake Eyre Basin, the Territory and States it covers, the towns and the location of Lake Eyre and Figure 1.2.

Show students Figure 1.1 and Figure 1.2 and the video of the ABC’s Behind the News program www.internationalbenchmarking.org/btn/story/s2578003.htm

Figure 1.1 The Lake Eyre Basin in Flood

Use Student worksheet 1.1 to record students’ ideas about Lake Eyre together with their questions, which can be used as a guide to their research. Focus on completing the first two columns. The remaining two columns can be completed as students progress through the topic.

Figure1.2 The Lake Eyre Basin in flood (close up)

Provide relevant access to information, images or video to enable students to follow up research questions that arise from discussion and recorded questions on the KWHL chart.

Part B: Data chart and brochure

Set the task of creating a brochure highlighting what makes the Lake Eyre region unique. In the brochure include:

a map of the Lake Eyre Basin (using Border, Orientation, Legend, Title, Scale [BOLTS])

a description of the climate and tips about how to survive and when to travel/not travel

features and characteristics of the area

locations and places of interest.

Provide Student worksheet 1.2. This will help guide and focus students’ research and enable them to summarise their findings sourced from four suggested websites.


© Commonwealth of AustraliaPhotograph by Paul Wainwright



Students share their brochures about what makes the Lake Eyre region unique.

Use the key ideas developed in the brochures to draw out the main reasons that Lake Eyre is unique. Some of these ideas may include:

The region experiences a highly variable climate, high temperatures and extreme evaporation rates during long periods of dry, followed by periods of extensive rain and flooding.

Rivers in the Lake Eyre Basin do not permanently flow and often rely on rains from across the Great Dividing Range, which can take up to four months to bring water into the area via the ephemeral river system.

Rivers in the dry spell are a series of disconnected waterholes but in the wet can be likened to a slow moving inland sea.

The dry salt pans of Lake Eyre are transformed into breeding sites for migrating birds when sufficient flows reach Lake Eyre.

Mound springs, which are culturally significant, have been used by Aboriginal people for thousands of years as a source of water.

The native flora and fauna have adapted to a harsh arid to semi-arid environment and populations respond to situations of ‘boom or bust’.

Developing vocabulary

Create a word wall of terms that students come across in their inquiry which are unfamiliar and require further explanation. One idea could be to have individual words on cards, such as ‘ephemeral rivers’, and on the back of the card its meaning – ‘non-permanent flowing rivers’. These could hang down from string. Alternatively a word wall could be set up with the words on cards with the description beside it.

Another option is to provide students in pairs with an unfamiliar word and using a graphic organiser with the word written in the centre, establish a definition, characteristics and a relevant example and non-example. See the model below.

Unfamiliar terms may include underlined glossary terms

Definition Characteristics

Examples Non-examples


Student Worksheet 1.1

Know, What, How, Learned (KWHL) chart

What I knowK

What I want to knowW

How I found outH

What I learnedL


Student worksheet 1.2

Data chart: What makes Lake Eyre unique?

Use the following internet resources to locate information to help you answer the questions. Write a summary of what you found out in the table provided.

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http://www.lakeeyrebasin.org.au/index.html






http://www.lebmf.gov.au/basin/index.html



Lesson 1.2How do the Lake Eyre Basin catchments work?

Outcome

Students use a model to demonstrate how water flows in a catchment. They represent the Lake Eyre Basin catchment using suitable materials.

Background

In the previous lesson it was established that the Lake Eyre Basin is made up of an extensive non-permanent river system. This section can be used to develop students’ understanding of a catchment, waterflows and their relationship to the topography.

Floodwaters that reach Lake Eyre are often the result of cyclones and tropical rains in Far North Queensland. When heavy rain occurs, water flows into the catchments of the channel country and as a result upper reaches of the ephemeral rivers begin to flow. Creek flows and floods then slowly move across the flat landscape toward Lake Eyre. Floodwater from these rain depressions can take up to four months to reach Lake Eyre.

The channels of these rivers can fill from localised rainfall, but the most dramatic surges follow flood rains in the north. Sometimes rain enters the Lake Eyre Basin from the west to recharge the western rivers, but these are less frequent and usually smaller.


Part A


Figure 1.3 Different types of catchments

Materials

a funnel, a bucket, a tarpaulin (6 m x 4 m), several chairs

access to a large space outside

Part B


Map 1.2 Queensland’s channel country rivers

Map 1.3 Topographic map showing the elevation of the Lake Eyre Basin

References

Australian Government, Map of Lake Eyre Basin, www.environment.gov.au/water/locations/leb/pubs/leb-map.pdf

Australian Government, Regional Profile of the Lake Eyre Basin Catchments, www.desertknowledgecrc.com.au/resource/DKCRC-Report-45_Ch2_Regional-profile-of-the-Lake-Eyre-Basin-catchments_Herr-et-al.pdf

Cooper Creek Catchment Committee, Cooper Creek Catchment Strategic Plan, www.lakeeyrebasin.org.au/archive/media/cooper.pdf

Department of Water, Land and Biodiversity Conservation, The Lake Eyre Basin and Dryland Rivers, South Australia, www.lebmf.gov.au/publications/pubs/leb-proceedings-07.pdf


http://www.lebmf.gov.au/publications/pubs/leb-proceedings-07.pdf

http://www.lebmf.gov.au/publications/pubs/leb-proceedings-07.pdf

http://www.lakeeyrebasin.org.au/archive/media/cooper.pdf

http://www.lakeeyrebasin.org.au/archive/media/cooper.pdf

http://www.desertknowledgecrc.com.au/resource/DKCRC-Report-45_Ch2_Regional-profile-of-the-Lake-Eyre-Basin-catchments_Herr-et-al.pdf



http://www.environment.gov.au/water/locations/leb/pubs/leb-map.pdf

http://www.environment.gov.au/water/locations/leb/pubs/leb-map.pdf

Lake Eyre Basin Coordinating Group, The Lake Eyre Basin and Its Importance, www.lakeeyrebasin.org.au/archive/pages/page03.html

Monroe, MH, Australia: The Land Where Time Began, http://austhrutime.com/index.htm

New South Wales Government, Book 1 Dryland Salinity: The Basics, www.naturalresources.nsw.gov.au/salinity/solutions/solutions_book01.htm

Lesson outline

Part A: Modelling a catchment

Developing a concept of a catchment is difficult for students to grasp given the enormity of the area being discussed and the knowledge required about the topography, surface coverage and how water interacts and flows, both across the surface and infiltrating the soil.

This task can be used to generate discussion about how water flows in a catchment, relating direction of flow to differences in topography.

This activity is best undertaken outside in a grassy area where water wastage can be minimised.

What to do

Explain that you are going to use a model to discuss a catchment and describe how a catchment works. The model will use a tarpaulin to represent a large area of land. Relate this area to a familiar location so students get a sense of the expanse of area.

Refer to the funnel and make the connection that a catchment is like a huge funnel where water is

captured in a wide area and directed to converge into a smaller area following the slope of the land.

Explain that a very large catchment or a series of large, connected catchments are sometimes called a drainage basin or river basin. Ask: How does the height of the land change the way the water flows?

Ensure students are actively involved in creating the model. Organise a group of four to five students to hold ends of the tarp to create various catchments. Chairs can be used to create changes in topography. Water can be poured using the watering can to represent rain. Swap groups of students after each scenario. Explore the following scenarios:

a flat landscape, then a flattish landscape with a slight slope. Observe that water collects across a wide area, while the water flows down the sloping section.

a valley between two high mountainous regions; observe the water flowing between the two mountains through the valley and relate to a river flowing.

a mountainous region that flattens out to floodplains with rivers flowing to the sea. Discuss how the floodplains often contain wetlands and slow the flow of water (similar to the Murray-Darling Basin).

a flat landscape with low hills around all the edges. Observe that the water collects in the lowest point, similar to what happens in the Lake Eyre Basin. Describe this as an inland basin. Demonstrate how rain events in the far north of the catchment lead to the filling of Lake Eyre.


http://www.naturalresources.nsw.gov.au/salinity/solutions/solutions_book01.htm

http://www.naturalresources.nsw.gov.au/salinity/solutions/solutions_book01.htm

http://austhrutime.com/index.htm

http://www.lakeeyrebasin.org.au/archive/pages/page03.html

http://www.lakeeyrebasin.org.au/archive/pages/page03.html

What happened?

Summarise student observations and responses to questions, for example:

Where does water flow? (from higher to lower points)

Where do rivers often form? (in a valley between two higher land forms. Tributaries are branches off rivers.)

Rivers often flow out to sea.

In an inland basin, rivers terminate at the lowest point (lake).

Alternative: If not modelling a catchment, use Figure 1.3 to demonstrate and discuss waterflows.

Figure 1.3 Different types of catchments


© With kind permission of the Office of Heritage and Environment, NSW

© The Wilderness Society Australia Incorporated

Part B: Creating a model of the Lake Eyre Basin

This task enables students to apply what they know about the Lake Eyre Basin catchment to explain how water flows in the Basin.

Use Map 1.2 to explain that the Lake Eyre Basin is made up of several major catchments. The channel country is made of three river catchments. The Cooper Creek catchment comprises both the Thomson and Barcoo rivers.

Using Google maps or an atlas, students locate the Georgina and Diamantina rivers and Cooper Creek and trace their source and tributaries.

Ask: Where do the waters come from that fill Lake Eyre?

Map 1.2 Queensland’s channel country rivers


Show students Map 1.3.


Map 1.3 Topographic map showing the elevation of the Lake Eyre Basin

© Ninti One Limited 2009

Provide relevant options to create a model to visually present the Lake Eyre Basin to show how water flows in the Basin. The options you offer will depend on time available, resources and student skills and experience.

Options include:

3-D modelling using clay, papier-mâché

2-D drawing, bird’s-eye view/crosscut to show elevation

an electronic presentation, using Lake Eyre Basin images with animated text, arrows and colour.

Using their model, students could include:

names of major rivers of the Lake Eyre Basin

a scale to indicate distance

waterflows.

Questions

Lake Eyre is called a closed or terminal basin. What does this mean?

So why doesn’t Lake Eyre remain filled if the water flows to the lowest point?

What factors affect the filling of Lake Eyre?


Add any unfamiliar terms to the word hanging, word wall or graphic organiser. Ensure students have a good understanding of the underlined glossary terms.




Lessons

Lesson 1.3What affects the rate of evaporation?

Outcome

Students investigate factors that affect the rate of evaporation and relate their findings to the Lake Eyre Basin. They investigate and measure the electrical conductivity (EC) of a solution containing salt as it evaporates over time. They relate their findings to Lake Eyre.

Background

From the previous lessons, students will realise that the climate of the Lake Eyre Basin is characterised by variable rainfall and extensive dry periods. However, they may wonder why the majority of rivers do not flow continuously. The aim of this lesson is to link rates of evaporation, and factors that affect evaporation, to the lack of surface water at various times in the Lake Eyre Basin.

Ephemeral rivers fill from flooding rains which reconnects isolated waterholes. Except for rare very large floods, water in the Lake Eyre Basin rivers evaporates in the hot, dry winds of the arid landscape before reaching Lake Eyre.

This high evaporation rate contributes to Lake Eyre’s low water levels and explains why it is empty for long periods. However, this is not the only reason; the typical inflows are generally insufficient to maintain any significant water levels. Also, water infiltrates the soil and seeps underground.

Evaporation is the changing state of a liquid – such as water – to water vapour – a gas. Water vapour enters back into the atmosphere. Variables such as surface area, water temperature, air temperature, pressure and density, wind speed and humidity all affect evaporation rates.


Part A Materials

two containers each filled with 50 mL of water

suitable containers to investigate evaporation, such as plastic takeaway containers

Part B Materials

container with rock salt and tap water

shallow container marked with graduations

EC meter if available (to measure electrical conductivity)


Lesson outline

Part A: Exploring the rate of evaporation

Establish or review the variable climate conditions of the Lake Eyre Basin using the web resource: Daily rainfall totals for Australia, Bureau of Meteorology, www.bom.gov.au/jsp/awap/rain/index.jsp .

Compare climate data over various time periods (1 day, 7 days, monthly, month to date, 3 monthly, 12 monthly, year to date, and over 36 months).

What to do

Discuss the exceptionally high evaporation rates in arid environments such as occur in the Lake Eyre Basin. Put into a global context, the Lake Eyre Basin receives three times less rainfall than the world average; however, it experiences a a three times higher rate of evaporation.

Explain that the rate of evaporation refers to how fast or slow a certain quantity of water evaporates over time, for example, per day or per hour. Using two containers each holding 50 millilitres of water, if one container evaporated in three days (based on the world average), then in the Lake Eyre Basin that same amount of water would evaporate in a day.

Discuss: How high evaporation rates, variable rainfall and the occurrence of rivers that do not flow on a permanent basis may be connected.

As a lead in to investigating factors that affect evaporation, ask students to think about the conditions that will cause water to evaporate and then to list those factors.

Guide and support students undertaking their own investigations into evaporation.

Designing a scientific investigation

When discussing the process students should use to investigate evaporation, model and discuss the scientific process. An example is provided.

Begin with a question that can be investigated – for example, ‘Does surface area affect evaporation?’

Take the question and then turn it into a statement that is testable – an ‘If . . . then’ statement. If surface area affects evaporation, then water in a shallow tray will evaporate faster than in a narrower, deeper container of water.

Set up the investigation. Make the point of making the test fair or controlled; change only one variable and keep everything else the same. In this case, change the container shape only, and keep the location, amount of water, and temperature of the water the same.

Now make a prediction. The prediction could include a measurement of time or volume, which can be compared with the results collected.

Record results. Measure the time taken for water to evaporate in at least one of the containers or a measurement of remaining water after an allocated period of time has elapsed.

Draw a conclusion and relate findings to the Lake Eyre Basin.

Possible questions to investigate evaporation:

Does the rate of evaporation change in full sun compared to the shade?

Does the colour of the container affect evaporation?


http://www.bom.gov.au/jsp/awap/rain/index.jsp

Does the temperature of the water affect evaporation?

Where does the rate of evaporation happen fastest in the classroom?

Does wind (moving air) affect evaporation?

Students use these questions or their own questions about evaporation to design a fair test to collect data that can be used to answer their questions and compare to their prediction.

Part B: Evaporation and saltwater

View images of a dry Lake Eyre and establish the white crusty surface as salt. Introduce the term ‘salt pan’, which is the remains of salts from a shallow lake where the water has evaporated, usually in a desert environment. Ask: How does a salt pan form?

What to do

Have a container with rock salt crystals to represent the salt pan and a container of tap water to represent the floodwaters that flow into Lake Eyre. If available, measure the electrical conductivity (EC) of the fresh water using data-logging equipment and an EC probe or sensor. The EC is a measure of electrical conductivity that indicates the presence of salts; a higher reading indicates a higher concentration of salt. EC is commonly measured in microsiemens per centimetre (uS/cm). An expected range for EC of tap water is between 200–800 uS/cm.

Ask students to predict the EC reading when the rock salt is added to the tap water. Use a shallow container marked with 10 mL to 20 mL graduations. Add at least 500 mL of water to the rock salt. Place the container in a suitable position to ensure a good rate of evaporation.

Measure and record the EC over the week, as well as the water depth by referring to the marked graduations. Create a table that shows the EC measurements together with the water level. The temperature of the water must also be measured as this affects the EC reading.

What happened?

Make conclusions about:

the concentration of salt as the water evaporates

the substance left behind as the water evaporates

the mixing of fresh water with the salt pan and the implications for animal life carried into Lake Eyre.

Students relate their findings to Lake Eyre and what would occur as the lake fills with water and then water levels recede as the water evaporates. Discuss the formation of salt lakes and identify other salt lakes that occur globally. Identify common conditions.


Introduce the following idea and ask students to research it further and decide for themselves whether it is plausible.

IDEA

Can a filled Lake Eyre provide a continual source of rain for central Australia? Is it possible that the water from Lake Eyre evaporates and falls as rain to hydrate plants and the soil and then evaporates and falls again as rain in a constant cycle? Could this be a solution for drought-proofing central Australia?

Have students draw a scientific diagram and come up with their own explanations that support or reject this idea.






INVESTIGATION 2

How is the Basin transformed after long dry periods?

IntroductionThe complete filling of Lake Eyre occurs very rarely. Historically Lake Eyre fills completely only about four times a century. Local rains can contribute to maintaining lake levels when there is water in the lake; however, significant flows in the Cooper Creek, Diamantina and Georgina rivers are required to reach Lake Eyre. As an example, Cooper Creek only reaches Lake Eyre on average, once in six years. Major floods in the Lake Eyre basin result from annual rainfalls that exceed 500 millimetres. It is important that these rivers continue to be unregulated and their floodwaters not diverted for use elsewhere.

With water flowing from floodwaters into Lake Eyre, the lake is transformed from a dry salt pan, seemingly devoid of life, to an oasis. Large populations of pelicans, ducks, terns and other migratory birds feed on the abundant food sources that come to life when Lake Eyre fills with water. Floods reconnect isolated and disconnected waterholes, thereby connecting aquatic ecosystems.

Lake Eyre at its lowest point is 15 metres below sea level and is made up of two lakes joined by a narrow channel. Lake Eyre North is about 150 kilometres long and over 70 kilometres wide.

Lake Eyre South is smaller, about 60 kilometres long and nearly 25 kilometres wide. The lake goes from periods of being a dry, flat salt pan to rare occasions of being completely filled.

The lake is fed mainly by its eastern tributaries, the Cooper Creek and the Diamantina and Georgina rivers system.

The Lake Eyre Basin undergoes periods of widespread floods and extended dry periods, often referred to as the boom and bust phenomenon. This ongoing cycle has influenced flora and fauna species to evolve with particular adaptations that make them suited to the variable conditions. Often these species are able to make the most of the wet when it comes as they are able to produce offspring to coincide with favourable conditions.


Australian Curriculum links

Science – Year 7



Biological sciences












Evaluating


Communicating





Year 7

Weather and water















Communicating








Data courtesy of Bob Backway, Lake Eyre Yacht Club

Lessons

Lesson 2.1What is the recent history of the levels of Lake Eyre?

Outcome

Students graph and interpret data of Lake Eyre flood levels.

Background

From previous lessons, students would be familiar with the way in which Lake Eyre relies on floodwaters from rivers that feed into Lake Eyre. Using data of lake depth over a 30-year period students can draw conclusions about whether the lake is mostly dry or whether it holds some water more often than not.

Lake Eyre South has completely filled as many times as Lake Eyre North, about two to four times per century. A ‘complete’ fill is generally accepted as being at least five to six metres deep. Both lakes often hold small amounts of water, typically for thirty to forty separate years in a century. Data prior to 1950 is generally not accepted as reliable.

1950 Lake Eyre South and North completely filled (Lake Eyre North overflowed into Lake Eyre South)

1974 Lake Eyre South and North completely filled (Lake Eyre North overflowed into Lake Eyre South)

1984 Lake Eyre South filled to 3.4 metres from local rain and overflowed into Lake Eyre North. Lake Eyre North also filled to 3.5 metres

1989 Lake Eyre South filled to 3 metres from local rain and overflowed into Lake Eyre North. Lake Eyre North also filled to 3metres

1997 Lake Eyre South rose to a depth of 2.5 metres

2000 Lake Eyre North rose to a depth of 2.2 metres

2011 Lake Eyre South, at 2.55 metres almost overflowed into Lake Eyre North, which also reached 2.2 metres

Levels between 1.5 and 2 metres were recorded in the years 1979-80,1986-87,1991-94,2001-02,and 2009-10



Part A

Student worksheets

Student worksheet 2.1 Thirty-year history of Lake Eyre water depth

Student worksheet 2.2 Monthly data of Lake Eyre water depth for 2009

Part B


Figure 2.1 Elevation/surface area curve of Lake Eyre

Map 2.1 Bathymetric map of Lake Eyre showing metres below sea level

References

International Lake Environment Committee, Lake Eyre, www.ilec.or.jp/database/oce/oce-04.html

Lake Eyre Yacht Club, www.lakeeyreyc.com

Lesson outline

Part A: Is Lake Eyre mostly a dry lake bed?

View satellite images of Lake Eyre. Google maps offer a view of Lake Eyre; however, keep in mind that it is not an image of its current status. View: http://maps.google.com.au.

Note: White on the Google map indicates salt pans and the brown indicates dry arid surface.

The current Lake Eyre flood level status is available at Lake Eyre Yacht Club, www.lakeeyreyc.com/Status/latest.html.

If viewing the satellite, false colour images from Earth Observatory, white indicates salt crust, the pale blue to dark blue on the map image indicates water of various depths with the darker blue sections indicating depths greater than 0.5 metres and green–blue indicates algal growth and red– brown indicates algae in muddy sections of the lake.

Making predictions

Ask students to predict what proportion of years Lake Eyre was filled with at least 1.5 metres of water (for some part of that year) over the last thirty years. Tally the class’s response in a table such as the one below:

Years in which Lake Eyre was partially filled over the past thirty

Partially filled years out of 305/30 10/30 15/30 20/30 30/30

Provide students with Student worksheet 2.1, which shows the recent history of Lake Eyre filling. Explain that the data was made possible using technology from satellites, which scientists analyse and interpret. You could use this as a springboard to discuss how scientific work informs the broad community.

Have students graph and interpret the data and answer the questions on the worksheet.

Before they start, ask students to select the type of graph that would be most appropriate; for example, a column graph or line graph. Have them explain their choice. Note: a line graph would be the preferable selection.


http://www.ilec.or.jp/database/oce/oce-04.html

© Dr Vincent Kotwicki, Floods of Lake Eyre

Map 2.1 Bathymetric map of Lake Eyre showing metres below sea level


Figure 2.1 Elevation/surface area curve of Lake Eyre

Note: Elevation m AHD refers to elevation using sea level as the zero point. Therefore, at its deepest point, Lake Eyre is 15 metres below sea level.

The arrow point intersections indicate the surface area at different lake depths and the associated breakout maps show the area under water (blue) at that point.


Provide students with Student worksheet 2.2, which contains data for one complete year for the filling of one section of Lake Eyre and have students answer the questions about what the extra data shows.

Part B: Water levels and surface area

Students interpret Figure 2.1, which indicates rising water levels against increasing surface area.

Students relate Figure 2.1 to Map 2.1, which shows metres below sea level and answer the following questions.

Questions

How would you describe the depth across Lake Eyre North and Lake Eyre South?

What is the purpose of Figure 2.1 that includes a visual representation of the lake’s surface area?

What does the graph show?




Unfamiliar terms may include underlined glossary items.




© Bob Backway Lake Eyre YC.com


Thirty-year history of Lake Eyre water depth

View the data for the depth of Lake Eyre taken in January between the years 1979 and 2010.

To make sense of the data, display it as a graph and interpret the graph looking for any trends or patterns.

Before starting the graph, think about which type of graph to use. Will it be a column graph or line graph? Explain your choice.

Depth of Lake Eyre taken in January between the years 1979 and 2010Month/Year Lake Eyre flood

depth metres (m)Month/Year Lake Eyre flood

depth metres (m)

Jan 1979 0.0 Jan 1995 0.0

Jan 1980 1.5 Jan 1996 0.0

Jan 1981 1.0 Jan 1997 2.75

Jan 1982 0.0 Jan 1998 0.5

Jan 1983 0.0 Jan 1999 0.0

Jan 1984 3.5 Jan 2000 1.3

Jan 1985 2.5 Jan 2001 0.5

Jan 1986 0.0 Jan 2002 1.0

Jan 1987 1.5 Jan 2003 1.2

Jan 1988 0.0 Jan 2004 0.0

Jan 1989 3.0 Jan 2005 0.0

Jan 1990 3.0 Jan 2006 0.0

Jan 1991 0.0 Jan 2007 0.3

Jan 1992 0.0 Jan 2008 0.0

Jan 1993 0.25 Jan 2009 0.3

Jan 1994 0.1 Jan 2010 1.2

Note: Data is the greatest depth in any section of Lake Eyre North and South in January of that year.

Data sourced from Lake Eyre Yacht Club, http://lakeeyreyc.com/Photos/FloodGraph.jpg


Student worksheet 2.1 cont.

Questions

Do yearly data for a particular month over time provide a reasonable picture of what’s occurring with the depth of Lake Eyre?

What would more points of data on water depth levels provide (eg data for each month of the year over a range of years)?



Monthly data of Lake Eyre water depth for 2009

View the data for the depth of Lake Eyre taken for each month in 2009.

To make sense of the data, display it as a graph. Before starting the graph, think about which type of graph to use. Will you use a column graph or line graph? Explain your choice.

Interpret the graph, looking for any trends or patterns. Monthly data of Lake Eyre water depth for 2009

Monthly data of Lake Eyre water depth for 20092009 monthly data

Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec

Lake Eyre flood depth metres (m)

0.3 0 0.3 0.5 1.0 1.5 1.4 1.3 1.0 0.7 0.25 1.0

Note: The data is used for Belt Bay, Lake Eyre North

Questions

‘Lake Eyre is an inland dry basin for years at a time.’ Compare the above data set with the data set in Student worksheet 2.1. Discuss whether you agree with the above statement and explain your answer.

What different conclusions could you make about Lake Eyre if the water depth were measured over a single month for a number of years, rather than every month for a whole year?

What might be a more effective method for displaying yearly and monthly water depth data for Lake Eyre?


Lesson 2.2What happens to river systems during extended dry periods?

OutcomeStudents describe the effect of extended dry periods on river ecosystems.

Background

In previous lessons the focus was on observable changes in the river system itself, when the rivers have ceased to flow for extended periods of time. Floods then induce flows which feed into Lake Eyre, if conditions are favourable and the amount of waterflow is sufficient. This lesson explores how these variable flows affect organisms within the Lake Eyre Basin.

During an extended dry period, reduced river flows occur along with decreased surface runoff and decreased soil moisture. The area of aquatic habitat reduces as water evaporates, leaving behind shallow pools and mudflats. The remaining waterholes become a series of disconnected areas of refuge for the aquatic organisms. Scavengers feed on those fish and invertebrates that become stranded between waterholes.

As waterholes decrease in size, dead and decomposing aquatic plants and animals release nutrients, such as nitrogen and phosphorus, into the water. Nutrient levels increase, which can result in explosions of growth in algae. The algae provide food for macro-invertebrates, which are eaten by other organisms. Eutrophication may occur as a result of high nutrient levels. There is a rapid increase in algae and increased dead plant material as other plants and algae die. As a result, bacteria feed on the dead plant material

and use up oxygen in the process. This lack of oxygen in the water can result in fish and other aquatic animals dying.


Part A


Figure 2.2 Cooper Creek in a time of high flow

Figure 2.3 A waterhole in Cooper Creek after the water has receded

Figure 2.4 Refuge waterhole availability and population extinction risk

Figure 2.5 Satellite image of Lake Eyre 2009 – Rare refill begins

Figure 2.6 Satellite image of Lake Eyre 2009 – Rare refill continues

Reference

NASA, Earth Observatory, http://earthobservatory.nasa.gov

Lesson outline

Part A: Impacts of a variable flow

Cooper Creek is part of the channel country of the Lake Eyre Basin. Figure 2.2 shows the creek in a time of high waterflow. Ask: What types of aquatic organisms would they expect to inhabit it?

Provide an image of a river channel that has experienced an extended dry period (see Figure 2.3 and Figure 2.4). Ask students to describe their observations and discuss what would be happening as the riverflows decreased as a result of no rainfall.


Use the images provided to explain the process of a river system that has deep pools that are connected in times of high river flows and the subsequent isolation of these waterholes as rivers recede. Ask students to consider the importance of these deep pools (waterholes) for the remaining populations of plants, animals and other micro-organisms.

Figure 2.2 Cooper Creek in a time of high flowFigure 2.3 A waterhole in Cooper Creek after the water has receded

Figure 2.4 Refuge waterhole availability and population extinction risk


View Earth Observatory satellite images such as Figure 2.5 and Figure 2.6, which show waterflows into Lake Eyre. The images show the waters flowing into a delta, carrying silts and suspending solids.

Describe the dry riverbeds and remaining waterholes and what they would contain – for example, small populations of surviving species, remains of dead plants and animals as well as eroded material. Discuss the waterflows that reach Lake Eyre. The water would contain sediments, salts and nutrients.

Part B: Combining science ideas and creative writing

Students research and select a species of plant or animal that inhabits a river in the Lake Eyre Basin. Ask students to develop a creative writing piece to describe the impact of the shrinking aquatic habitat. Students write the narrative from the animal or plant’s pointof view.

Students write a creative piece of writing about the journey of a water droplet, starting from precipitation, falling to Earth, flowing throughthe catchment , reaching Lake Eyre, evaporating and ending up as precipitation.

Ask: What happens to a river after an extended dry period?

Students could present their ideas as a labelled diagram, an electronic presentation or a poster showing changes over time.

Ask: What if the river’s natural flow was diverted and regulated?

Figure 2.5 Satellite image of Lake Eyre 2009 – Rare refill begins

Figure 2.6 Satellite image of Lake Eyre 2009 – Rare refill continues


Identify the rivers that flow into Lake Eyre. Discuss the fact that they are largely unregulated (water is not diverted, stored and used for irrigation or watering livestock). Describe what impact diverting water might have on downstream ecosystems.

Write a response to a blog that started with the thread:

Dam the waters of Cooper Creek. Next time it’s in flood all that water could be captured, rather than letting it go to waste. The water could be stored and used in times of drought.


Add any unfamiliar terms to the word hanging, word wall or a graphic organiser. Ensure students have a good understanding of the underlined glossary terms.



Lesson 2.3How does water transform the Basin?

Outcome

Students describe adaptations and behaviours of animals and plants that assist their survival in an arid environment that undergoes periods of boom and bust.

Background

In previous lessons variable flows have been established and the concept of boom and bust was introduced.

Animals and plants that inhabit the Lake Eyre Basin have adapted to environmental extremes of long dry periods, followed by severe floods.

Some fish species have fast growth rates in good seasons and breed in response to floods. They survive dry times in permanent waterholes along river courses upstream from the lake. When floodwaters begin, they travel with the flow.

Water-holding frogs burrow down and form a cocoon where they can survive for several years.

River red gums send down very deep roots into groundwater in order to overcome extended dry periods.


Floods dramatically influence the food web of Lake Eyre and the rivers that flow into the lake. The survival of many species relies on their ability to distribute widely and to rapidly colonise suitable habitats when they become available.

Detritus (dead plant and animal materials), dormant in the dry, is carried by the floodwaters and provides food for decomposers such as bacteria.

Several species of phytoplankton (single-celled floating algae) and multi-celled algae attached to rocks inhabit the lake.

Zooplankton , which are tiny microscopic animals such as crustaceans, feed mostly on phytoplankton.

Many types of small crustaceans such as Daphnia (water fleas) and Ostracoda (seed shrimps) feed on algae or detritus; others are omnivores, predators or scavengers.

The larval stages of brine flies feed on algae. The larvae of midges (bloodworms) and other varieties of fly feed on detritus and bacteria.

The fish Macquaria ambigua (yellowbelly) are carnivorous and feed on zooplankton and crustaceans and aquatic insects when available. Craterocephalus eyresii (Lake Eyre hardyhead) is omnivorous and Nematalosa erebi (bony bream) feeds mostly on algae or detritus.

Four main species of birds form the top of the food chain, Pelecanus conspicillatus (pelican), Phalacrocorax carbo (great cormorants), Chlidonias hybridus (whiskered terns) and Larus novaehollandiae (silver gulls).


Part A

Student worksheet

Student worksheet 2.3 Adaptation of species in an arid environment

Part B

Student handout

Student worksheet 2.4 Lake Eyre food web

Part C

Publications

Australian Geographic article,www.australiangeographic.com.au/journal/lake-eyre-floods-again.htm

Well-timed Pulse of Water Set to Rejuvenate Life on Kalamurina, Kalamurina Wildlife Sanctuary, www.australianwildlife.org/AWC-Sanctuaries/Kalamurina-Wildlife-Sanctuary.aspx

References

The Lake Eyre Pelican Mystery,www.cairnsunlimited.com/popups/lake_eyre_pelicans.htm

CSIRO Publishing, Spatial and Temporal Variation in Fish Assemblage Structure, http://michaeldarby.net/Links/Arthington.pdf

Department of Sustainability, Environment, Water, Population and Communities, Lake Eyre Basin Assessment, www.environment.gov.au/water/publications/environmental/rivers/lake-eyre/pubs/assessment.pdf




http://michaeldarby.net/Links/Arthington.pdf

http://www.cairnsunlimited.com/popups/lake_eyre_pelicans.htm

http://www.cairnsunlimited.com/popups/lake_eyre_pelicans.htm



http://www.australiangeographic.com.au/journal/lake-eyre-floods-again.htm


Dryland River Refugia Project, http://freshwater.canberra.edu.au/Publications.nsf/0/8df7ad09f009bec0ca256f0b00234afb/$FILE/dryland%20refugia%201st%20newsletter.pdf

Environment Protection Authority SA, Critter Catalogue, Insects and Springtails, www.sa.waterwatch.org.au/pdfs/critters_6_insects.pdf

Griffith University, Dryland River Waterholes – Aquatic Refugia, www98.griffith.edu.au/dspace/bitstream/10072/34424/1/64567_1.pdf

Griffith University, Food Resource Variability in an Australian Dryland River: Evidence from the Diet of Two Generalist Native Fish Species, www98.griffith.edu.au/dspace/bitstream/10072/21296/1/50812__1.pdf

Griffith University, Progress in Understanding Dry Rivers, www.ewater.com.au/drought/downloads/1000021.pdf

Kalamurina Wildlife Sanctuary, Well-timed Pulse of Water Set to Rejuvenate Life on Kalamurina, www.australianwildlife.org/AWC-Sanctuaries/Kalamurina-Wildlife-Sanctuary.aspx

Northern Territory Government, Feral Animals of the Northern Territory, www.nt.gov.au/nreta/wildlife/animals/feral/gambusia.html

South Australian Arid Lands Natural Resources Management Board, Common Native Fish of the Lake Eyre Basin, www.sardi.sa.gov.au/__data/assets/pdf_file/0014/126032/Common_Native_Fish_Of_The_Lake_Eyre_Basin_Rivers.pdf

Lesson outline

Part A: How have living things adapted to an arid environment?

Introduce a range of adaptations of organisms that inhabit Lake Eyre and rivers that feed into it.

Provide Student worksheet 2.3 and ask students to fill in the last column, describing the way the adaptations of particular species help them survive in an arid environment.

Part B: Interrelationships between organisms in an arid ecosystem

Discuss the role floodwaters play in bringing to life the aquatic ecosystems that are linked to Lake Eyre. Discuss the microscopic plant such as algae and the tiny creatures that seem insignificant but are so important for the survival of many species that rely on these organisms being able to respond to the increase in waterflows.

Create a simple food chain, using a pelican to demonstrate how energy from one organism is transferred along the food chain. Discuss the importance of producers that use the sun’s energy for photosynthesis.

Provide Student worksheet 2.4. Ask students to create their own food chains or create a more complex food web including a range of organisms that inhabit Lake Eyre. These include:

algae, bacteria and zooplankton

small crustaceans, water fleas and seed shrimps

larvae of brine flies, midges and other varieties of fly


http://www.sardi.sa.gov.au/__data/assets/pdf_file/0014/126032/Common_Native_Fish_Of_The_Lake_Eyre_Basin_Rivers.pdf



http://www.nt.gov.au/nreta/wildlife/animals/feral/gambusia.html

http://www.nt.gov.au/nreta/wildlife/animals/feral/gambusia.html



http://www.ewater.com.au/drought/downloads/1000021.pdf

http://www.ewater.com.au/drought/downloads/1000021.pdf

http://www98.griffith.edu.au/dspace/bitstream/10072/21296/1/50812__1.pdf

http://www98.griffith.edu.au/dspace/bitstream/10072/21296/1/50812__1.pdf

http://www98.griffith.edu.au/dspace/bitstream/10072/34424/1/64567_1.pdf


http://www.sa.waterwatch.org.au/pdfs/critters_6_insects.pdf

http://www.sa.waterwatch.org.au/pdfs/critters_6_insects.pdf

http://freshwater.canberra.edu.au/Publications.nsf/0/8df7ad09f009bec0ca256f0b00234afb/$FILE/dryland%20refugia%201st%20newsletter.pdf



fish such as the carnivorous yellowbelly, the omnivorous Lake Eyre hardyhead and bony bream

the four main species of birds including pelicans, great cormorants, whiskered terns and silver gulls.

Indicate decomposers, producers, consumers and interrelationships such as predator–prey and competition.

Students use their food web to explain:

the role of micro-organisms

the importance of algae and detritus

what happens when the water recedes

why hundreds of thousands of pelicans and other migratory birds visit Lake Eyre at the time it fills with water

which animals compete for the same food.

Invite students to research the effect feral species could have on the aquatic ecosystems, for example the introduced fish species Gambusia holbrooki commonly known as mosquitofish. What may happen if mosquitofish colonise a waterhole?

Other feral species to research include:

cane toad – Rhinella marina

feral camel – Camelus dromedarius

European red fox – Vulpes vulpes.

Part C: Boom and bust

Write an article for a nature magazine about Lake Eyre with the theme ‘boom and bust’. See the following Australian Geographic article for an example: www.australiangeographic.com.au/journal/lake-eyre-floods-again.htm

Explore different genres of writing for students to present evocative, persuasive or informational texts about aspects of interest that depict life and events in the Lake Eyre Basin. Here is an example of combining an evocative text with scientific ideas to be shared with students or used to guide teacher lessons.

Lake Eyre Life Cycles

Lake Eyre a dry, desolate, salt pan; few signs of life

Eggs of the brine shrimp laid seasons ago, blow in the wind

Flood waters from the north approach carrying nutrients and life sustaining water

The onset of water sets off a chain reaction of events; shrimp emerge from their eggs food for frenzied fish

Thousands upon thousands of fish follow the flows, breeding begins; the time is right

Pelicans and other birds obey the signals; food is abundant, fledglings cry out for food

As time passes floodwaters cease, lake levels recede; evaporation and seepage take their toll

Fish fight to find their way to permanent waterholes, pelicans and other migratory birds head for home

What was a-buzz with life, returns to an eerie parched environment

The sun beats down on the white, dry salt pan; shrimp eggs blow freely across its surface




Students read the article: Well-timed Pulse of Water Set to Rejuvenate Life on Kalamurina, Kalamurina Wildlife Sanctuary, www. australianwildlife.org/AWC-Sanctuaries/ Kalamurina-Wildlife-Sanctuary.aspx

Ask ‘What if...’ questions:

What if:

pelicans and other migrating birds travel to Lake Eyre to feed and breed, but the filling is only partial and the water levels recede quickly. What might occur?

the unconnected permanent waterholes are used by livestock to drink in times of drought or drained for other purposes?

introduced fish colonise permanent waterholes and out-compete native fish?







Adaptation of species in an arid environment

Species Adaptation How this would help their survival

Fish Fast growth rates when conditions are favourable and breed in response to floods, ability to migrate to permanent waterholes

Fish (yellowbelly, Lake Eyre hardyhead and bony bream)

Tolerate a wide range of salinity, from fresh to salt concentrations higher than sea water, and can tolerate a wide range of temperatures

Frogs (water- holding frog)

Burrow down in the mud and form a cocoon and lie dormant until favourable conditions

Pelicans and other migratory birds

Have a sense of when food is in abundance and fly long distances to source favourable conditions for breeding

Crustaceans (brine shrimp and other types of shrimp)

Survive long periods of dryness, usually as eggs that can blow around on the lake surface

Brine flies, midges and other varieties of fly

Lay eggs in water, larvae emerge from eggs and feed on algae and dead plant matter

Algae and bacteria

Produce drought-resistant spores that lie dormant until conditions are favourable

River red gums Send down very deep roots into groundwater


Student handout 2.4

Lake Eyre food web

Floods dramatically influence the food web of Lake Eyre and the rivers that flow into the lake. The survival of many species relies on their ability to distribute widely and to rapidly colonise suitable habitats when they become available.

Task

Use the information below about feeding relationships between organisms that inhabit aquatic ecosystems at Lake Eyre to create your own food chains or food web.

Locate images of each organism and use these in your food chains and food web.

Feeding relationships

Detritus (dead plant and animal materials), which is dormant in the dry, is carried by the floodwaters and provides food for decomposers such as bacteria.

Several species of phytoplankton (single-celled floating algae) and multi-celled algae attached to rocks inhabit the lake.

Zooplankton, tiny microscopic animals such as crustaceans feed on phytoplankton.

Many types of small crustaceans, such as water fleas (Daphnia) and seed shrimps (Ostracoda) feed on algae or detritus, while others are omnivores, predators or scavengers.

There are also the larval stages of brine flies, which feed on algae. The larvae of midges called bloodworms (family Chironomidae) and other varieties of fly feed on detritus and bacteria.

The fish Macquaria ambigua (yellowbelly) are carnivorous and feed on zooplankton and crustaceans and aquatic insects when available. Craterocephalus eyresii (Lake Eyre hardyhead) is omnivorous and Nematalosa erebi (bony bream) feeds mostly on algae or detritus.

The four main species of birds that form the top of the food chain are aquatic birds, Pelecanus conspicillatus (pelican), Phalacrocorax carbo (great cormorants), Chlidonias hybridus (whiskered terns) andLarus novaehollandiae (silver gulls).


INVESTIGATION 3

How do we manage the Lake Eyre Basin sustainably?

IntroductionThe ecological integrity and natural function of river systems within the Lake Eyre Basin need to be maintained through careful management. Conflict occurs when land use threatens environmental and cultural values. Water and related natural resources in the Lake Eyre Basin need to be managed through an approach that aims to achieve outcomes that are sustainable and fair for all, considering all points of view.


Australian Curriculum Links

Science – Year 7



Biological sciences












Evaluating


Communicating





Year 7

Weather and water















Communicating








Lessons

Lesson 3.1What are the possible effects of diverting water from rivers in the Lake Eyre Basin?

Outcome

Students describe the possible effects on various land users in the Lake Eyre Basin if water was diverted for use elsewhere.

Background

In previous lessons it was established that there are different land uses across the Lake Eyre Basin and that these have some effect on the environment, particularly on native fauna and flora. By looking at how particular land uses affect the environment, as well as culturally significant sites and also considering economic and social implications, students will become more aware of the complexity of issues and begin to understand why there is conflict.

Despite the harsh arid environment there is a diversity of land use across the Lake Eyre Basin. The pastoral industry is the major land user – grazing beef cattle and sheep. Other land use includes Indigenous cultural activities, conservation, tourism, mining and petroleum, harvesting of wild animals and plant products, as well as small-scale urbanisation. All of this land use needs to be sustainably managed to protect the natural ecosystems.

Sustainability is defined in many different ways. COAG’s (Council of Australian Governments) endorsed National Strategy for Ecologically Sustainable Development 1992 provides the following definition of ecologically sustainable development: ‘Using, conserving and enhancing the community’s resources so that ecological processes, on which life depends, are maintained, and the total quality of life, now and in the future, can be increased.’


Part B

Student worksheet

Student worksheet 3.1 Diverting water from Cooper Creek

Part C

Student worksheet

Student worksheet 3.2 Potential conflicts among community members and stakeholders


References

Ausyfish, Aquaculture Australian Golden Perch, www.ausyfish.com/golden_perch_aquaculture.htm

Griffith University, Importance of Maintaining Flow Regimes, www98.griffith.edu.au/dspace/bitstream/10072/22082/1/50567_1.pdf

Australian Government, Indigenous Land Use, www.aiatsis.gov.au/research/publications/Land&Water/pn30117.pdf

ABC News online, Legislation Aims to Protect Lake Eyre Basin, www.abc.net.au/news/stories/2010/10/27/3049425.htm

CSIRO, Sustainability in Australia’s Arid Lands, www.csiro.au/science/arid-land-sustainability--ci_pageNo-4.html

Lake Eyre Basin Aboriginal Forum, Part 3 – Issues, Outcomes and Recommendations, Mount Serle Station, SA, 22–23 August 2006, www. lebmf.gov.au/publications/pubs/second-leb-forum - part3.pdf

South Australian Government, Wildlife of the Desert Parks, www.environment.sa.gov.au/parks/pdfs/BROCHURE_DP_WIDLIFEWILDLIFE.PDF

Lesson outline

Part A: What is sustainable land use?

Discuss what students know about the term ‘sustainability’ and list students’ ideas. Create two lists that describe what sustainability is and what it is not. This approach can help students develop their own concept of sustainability.

Compare the students’ ideas to an Aboriginal definition: ‘healthy country – healthy people’.

Read out the following quote and ask students what it means:

These are the last major dryland rivers left on the planet that aren’t seriously impacted by water extraction, so we’ve got a huge moral responsibility to actually look after these systems.

Angus Emmott, chair of the Lake Eyre Basin Community Advisory Committee www.abc.net.au/rural/news/content/201009/s3011115.htm

Have students draw their representation of what Lake Eyre Basin would look like in 2030 if managed in a sustainable way. This could be contrasted with what the Lake Eyre Basin would look like if land and water use were not managed sustainably.

http://www.abc.net.au/rural/news/content/201009/s3011115.htm

http://www.abc.net.au/rural/news/content/201009/s3011115.htm

http://www.environment.sa.gov.au/parks/pdfs/BROCHURE_DP_WIDLIFEWILDLIFE.PDF

http://www.environment.sa.gov.au/parks/pdfs/BROCHURE_DP_WIDLIFEWILDLIFE.PDF

http://www.csiro.au/science/arid-land-sustainability--ci_pageNo-4.html

http://www.csiro.au/science/arid-land-sustainability--ci_pageNo-4.html

http://www.abc.net.au/news/stories/2010/10/27/3049425.htm

http://www.abc.net.au/news/stories/2010/10/27/3049425.htm

http://www.aiatsis.gov.au/research/publications/Land&Water/pn30117.pdf

http://www.aiatsis.gov.au/research/publications/Land&Water/pn30117.pdf



http://www.ausyfish.com/golden_perch_aquaculture.htm

http://www.ausyfish.com/golden_perch_aquaculture.htm

Part B: How might diverting water affect different parts of the Basin community?

Introduce a scenario that focuses on a water management issue and requires students to consider and take on a particular point of view.

SCENARIO

A 3,000-hectare property was the site for a proposed development to grow various crops in a small town in Queensland that is within the Lake Eyre Basin.

The development would provide new jobs in the area including for Indigenous people. There are few other employment opportunities.

The company applied for a water harvesting licence to take 42,000 ML annually from Cooper Creek.

Introduce a range of community members and discuss their roles and how they could be affected by the development and harvesting of water for irrigation.

Provide the table of roles described in Student worksheet 3.1.

Organise students to take on the role of a community member and role-play to discuss various points of view. Each community member discusses the pros and cons of the development. Focus on listing possible solutions.

Part C: Is there a possible conflict?

Ask students to use the conflict matrix on Student worksheet 3.2 to identify if conflict exists between particular community members of the Lake Eyre Basin.




Unfamiliar terms may include underlined glossary items.





Diverting water from Cooper Creek

Read the descriptions about each community member and how they rely on water in the Lake Eyre Basin.

Describe ways in which each community member may be affected by the following scenario.

Community members and stakeholders

SCENARIO

A 3,000-hectare property was the site for a proposed development to grow various crops in a small town in Queensland that is within the Lake Eyre Basin.

The development would provide new jobs in the area including for Indigenous people.

There are few other employment opportunities.

The company applied for a water harvesting licence to take 42,000 ML annually from Cooper Creek

Roles About them How might this development impact them?

Pastoralist running beef cattle in the Cooper Creek catchment

Runs beef cattle on large pastoral lease of land managed with relatively low environmental impact. No fertilisers are used. After decent rains and flooding, grasses grow and provide sufficient feed for stock. The number of stock is limited to the coverage of naturally occurring grasses. Water is supplied by bores. Sometimes cattle access springs for water. Our cattle are also competing with feral at the waterholes and feed on animals especially goats and camels that drink the grasses.

Traditional Aboriginal landowner

Water and rain are significant to Aboriginal culture. Water is needed for the animals we hunt and the food we harvest. Aboriginal people rely upon waterholes, springs and rivers.


Roles About them How might this development impact them?

Local school-leaver

The development would increase employment opportunities, which are currently limited.

Lake Eyre National Park Ranger

Lake Eyre National Park is an important conservation area for native plants and animals that have adapted to survive the boom and bust conditions of an arid environment. These animals and plants must be protected. Feral animals are competing with native species for space, food and water.

Owner of the proposed development

Growing crops requires irrigated land to grow plants that produce pasture grass, cereal and other crops depending on water availability. Without irrigated water the yield of crops would be greatly reduced.

Tourism operator: Eco tours to Lake Eyre

Lake Eyre rarely fills but when it does tourists are attracted in great numbers. People come from many different places to visit the outback. The small towns of the outback benefit from tourism.

Lake Eyre Yacht Club member

When Lake Eyre fills to a level of at least 450 mm yachts can be sailed across its surface. Sailing is a low impact way to experience the lake.

Local community member and mayor

People are needed to grow and harvest crops. Our community is made up of people who use the land in different ways.

Queensland Government

We need to ensure the land is used sustainably so that others are not disadvantaged.



Potential conflicts among community members and stakeholders

In the following diagram, use a 1, 2 or 3 to describe the level of conflict you believe would exist between community members, using the following scale:

1 = minimal conflict 2 = moderate conflict 3 = strong conflict

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Pastoralist running beef cattle in the

Cooper Creek catchment

Traditional Aboriginal landowner

Lake Eyre National Park

Ranger


Owner of the proposed

development

Tourism operator: Eco tours to

Lake Eyre

Lake Eyre Yacht Club member

Local community member

and mayor

Queensland Government


Student worksheet 3.2 cont.Write an article for the local press, taking on a particular role from those in the above diagram. Put forward your arguments against the proposal or reasons you support the proposal. Use valid evidence to support your case.

Questions

Which people would have similar or common goals? Explain your answer.

How would taking water from Cooper Creek be any different to just experiencing a longer period of drought?


Lesson 3.2How do we move from conflict to mutual benefit?

Outcome

Students describe an issue, analyse the key points and work towards a solution of mutual benefit.

Background

Previous lessons established that there are different land uses across the Lake Eyre Basin and that these land uses have some effect on the environment, particularly its native fauna and flora. It’s important to consider land use from all perspectives to overcome any conflict that may exist and work towards a mutually beneficial arrangement.

Public meetings of community members are often held as a forum to raise major issues about land and water management. This approach allows for all opinions to be heard. The issues help guide land and water management strategies. Issues dealt with on a regional level where negotiation is encouraged can be a way to address problems equitably and fairly.


Student worksheets

Student worksheet 3.3 Conservationists and pastoralists

Student worksheet 3.4 Towards a mutually beneficial solution

Lesson outline

Use Student worksheet 3.3 to discuss how people of the Lake Eyre Basin can work together to solve particular problems.

Use the context of a public forum to discuss issues of water and land management that are relevant to the Lake Eyre Basin. Encourage students to reflect on what mutual benefit means, and how the following situations could be resolved with mutual benefit.

Examples of points raised at the public meeting of Lake Eyre Basin community include:

1. An Aboriginal traditional landowner made the point that beef cattle and sheep were fouling waterholes and causing erosion around mound springs. The pastoral land often has access to vital water supplies from rivers, waterholes, bores or mound springs. Cattle often cause problems as they access water for drinking at waterholes of cultural significance. They also eat the grasses that native animals eat.

In response a pastoral landowner explained that they manage their land to ensure as low an environmental impact as possible. He went on to make the point that they move their stock over the whole property to limit the impact on the grasses but they need access to water so they can continue their enterprise.


2. The local national park ranger made the point that weeds and feral animals, such as camels, goats, pigs and rabbits, were a real issue in the Lake Eyre Basin. Open bores provide drinking holes for feral animals. Goats out-compete native animals such as rock wallabies. Rabbits eat grasses which puts pressure on livestock and native animals. Some of the ways weeds are often transported is through seeds carried by sheep and even by tourists travelling from place to place.

3. Mining and petroleum bring in a large amount of money and provide jobs to the community and is important to Australia as a nation. There is however an impact on the environment. Disturbing the land can lead to erosion. Water holes can fill with silt and sediments putting an already stressed ecosystem under more pressure. Water is also required to take on these ventures. Can we afford to use water for these purposes in times of drought?

Have students use the table on Student worksheet 3.4 to guide their discussions towards a mutually beneficial solution.

As a class, share suggested solutions and talk through the implications and decide whether both parties would in fact benefit equally and whether one party or both parties would need to compromise.







Conservationists and pastoralists

Read the following article about a land use issue that occurred in the Lake Eyre Basin.

Ten years ago, there were less than 100 Yellow-footed Rock-wallabies on Plumbago Station in the Olary Ranges south of Lake Frome. More than 10,000 feral goats roamed the hills, coming down to the flat country and competing with the sheep when feed became scarce. This reduced the carrying capacity and dictated that sheep be sold when the season turned dry.

Enter Darren Wilson, self-confessed goat-hater and unashamed friend of the wallabies. ‘I got rid of all the goats on Plumbago and the Yellow-foots have increased to more than 2,500 – they doubled in number over the last 2 years. We have the largest concentration of Yellow-foots in the world,’ Darren says with quiet pride.‘They don’t worry the sheep,

he adds. ‘In fact we don’t need to lighten off (sheep numbers) as much in dry times now and our lambing percentages are consistently 10% to 20% better than our neighbours who have feral goats.’

‘As far as I’m concerned there is a mutual benefit for pastoralists and conservationists to work hand-in-hand.’

© Reproduced with permission, Desert Channels Group

Questions

What was the issue and how was it solved?

What were the benefits of Darren’s actions?

Who benefited in the end?



Towards a mutually beneficial solution

What is the problem?

Who is affected? What are the key points? What are some options?

What is a possible solution? How does it benefit both parties?


GLOSSARYarid

A region lacking sufficient water or rainfall.

bathymetric

A map or chart of land formation, depths or terrain below sea level or water level in a lake, using depth contours or isobaths.

bioregions

Large areas of land that have similar climate patterns, geology and landscape features and are characterised by similar types of vegetation and animals.

catchment

The geographical area that collects and funnels water to its connected waterway such as a river and its tributaries, lakes or other water sources. The water can flow along the surface or seep into groundwater.

channel country

A large region of north central Australia that includes an area in the Northern Territory, a large section of southwest Queensland, the northwest corner of South Australia as well as a small section in the far northwest of New South Wales. The name comes from the numerous intertwined rivulets or ‘channels’ that cross the region. Channel country features an arid landscape with a series of ancient floodplains from rivers which only flow intermittently.

colonise

Successful introduction into a new habitat by a species.

community

A group of people living in a particular local area or, in biological terms, a community is a group of organisms that interrelate within an ecosystem.

compromise

To make a deal where one party gives up part of, or all of its demands.

conflictA clash between two opposing groups.

conservation

The aim of protecting species, their habitats, and ecosystems.

consumer

In biological terms an organism that feeds on another organism. A first order consumer feeds on plants (herbivore). A second order consumer feeds on other animals (carnivore) or feeds on plants and animals (omnivore).

delta

A flat plain of soils and deposits situated between diverging branches at the mouth of a large river.

detritus

Remains of dead plant and animal materials.

divert (water)

Changing the flow of water to suit a particular need, for example a channel to divert water from a river to a farm.

drainage basin

All the land that serves as drainage for a specific stream or river.

64 | A unique river system worth maintaining The Lake Eyre Basin

ecosystem

A system formed through complex relationships between living organisms functioning as a community and interacting with their physical environment.

electrical conductivity (EC)

A commonly used method of measuring the salinity of water.

elevation

A geographic location where its height is given above a fixed reference point, such as the height above sea level.

endemic

Native to a particular region.

ephemeral river

A river that flows irregularly; a non-permanent flowing river.

erosion

A process that moves solids such as soil or rock particles in the natural environment and deposits them elsewhere.

eutrophication

A body of water acquires a high concentration of nutrients, which, in turn, promotes the excessive growth of algae; as the algae die the build-up of decomposing matter depletes the water of available oxygen, causing the death of other organisms, such as fish.

evaporation

The process of changing from a liquid to a gas – for example, water in its liquid form changing to water vapour.

false colour images

Instead of the real colours of an object being represented, arbitrary colours can be chosen to highlight different features. In satellite images for example, small differences in intensity can be made more obvious if they are presented with sharply contrasting colours.

floodplain

A flat or quite flat land next to a stream or river that experiences occasional or periodic flooding.

forum

A public meeting or assembly for open discussion.

hydrate

To supply water or liquid to in order to maintain a healthy balance.

infiltrationWhen water on the ground surface enters the soil.

interrelationships

A relationship between different species of organisms.

invertebrates

Animals that do not have backbones.

irrigation

Supplying land with water by means of some form of control, for example channels to direct the flow and storage of the water for use in irrigated pasture.

livestock

Animals domesticated for cultivation, for example cattle, sheep and pigs.

Glossary | 65

macro-invertebrates

An invertebrate animal (animal without a backbone) visible to the unaided eye.

micro-organisms

An organism of microscopic size.

microsiemens

A measure of electrical conductivity. Because it is full of charged particles, a salty solution will conduct electricity. Therefore a good way to measure salinity (salt levels in water) is to use a conductivity meter and read off the electrical conductivity in microsiemens.

mound spring

Point of surface flow of artesian water. Often of high cultural significance to Aboriginal people.

mutual benefit

When both parties benefit from a particular solution.

nutrients

Any matter that, taken into a living organism, helps to sustain its life.

omnivore

An organism that feeds on plants and animals.

pastoralist

A person who is involved in the branch of agriculture concerned with the raising of livestock.

photosynthesis

A process that converts carbon dioxide into organic compounds, such as sugars, using the energy from sunlight.

phytoplankton

Floating single-celled microscopic plants such as some types of algae that photosynthesise to produce their own food.

predator

An animal that hunts and seizes another animal for food.

producer

An organism that makes its own food in the form of sugars, such as a plant.

salinity

The degree of saltiness which may relate to rivers or other waterways.

salt pan

A shallow basin in a desert region that contains salts that remain after the water evaporates.

scavenger

An organism that feeds on decaying organic matter.

sea level

The height of the surface of the oceans.

semi-arid

A climactic region of low rainfall that only supports scrubby vegetation and grasses.

solution

In chemical terms a mixture of two or more substances.

spring

A place where water comes up from the earth to make a pool or flow away in a small stream


sustainable

The use of natural and human resources in a way that does not put at risk the opportunities of future generations.

terminal basin

A river basin where water flows inland to a central location, such as a lake, and not out to sea.

topography

The arrangement of hills and valleys in a geographic area.

tributaries

Small streams that feed into a main river that form part of a catchment.

unregulated

In the context of river systems, this is one that has not been diverted or controlled for human needs such as irrigation.

waterhole

A natural hollow or depression in which water collects, such as at a natural spring or at a low section of a dried-up river course.

zooplankton

Microscopic aquatic organisms that drift in water and feed on phytoplankton.

Glossary | 67

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