Topic 3.2a Freshwater Resources
Topic Aims
In this topic we will consider and discuss the following issues:
- Supply, renewal and use of fresh water resources
- What causes fresh water shortages
- Water use in agriculture
- How we can increase fresh water supply
- How we can waste less water and achieve more sustainable water use
Water Cycling and Ecosystem Services
Water is an essential life requirement for all organisms. It is also one of the most important factors, if not the predominate reason for life on earth and an environment that is hospitable for humans. There is an abundance of water on earth, approximately 1400 million km³, however only a tiny fraction of this is fresh water that is readily available.
The ecosystem services involving water cycling, filtration, storage and mediation are essential for maintaining a constant supply of fresh water. These services will provide a constant supply of fresh water provided:
- the ecosystem processes and functions, and the natural capital they depend on are not disrupted by human activity
- we don’t overload water resources with slowly degradable and non-degradable waste
- we don’t withdraw water from underground supplies faster that it is replaced.
The three challenges of managing fresh water resources:
- Providing water & food for an increasing population
- Maintaining and improving ecosystem health
- Preventing regional tensions within & between water poor countries
Activity 3.19
Q1. Develop a list of 5 ecological services and 5 economic services provided by freshwater systems. Describe the process by which they are produced. Refer to module 1.
| Ecological Service | How the service is produced |
|---|---|
e.g. Flood control |
Rainfall flows overland or via small creeks and rivers into large water bodies and rivers which hold water or move water to sea or lakes. |
Supply renewal and use of fresh water resources
Over 97% of the world’s water is salt water in oceans and saline lakes.
2.6% of all water is fresh most of which is locked up in ice caps and glaciers, or in ground water too deep or too salty to be used.
Only about 0.014% of the Earths total volume of water is easily available as soil moisture, usable ground water, water vapour, lakes and streams etc.
Activity 3.20
Read Miller & Spoolman (2012) pages 318 – 319, and answer the following questions:
- The amount of fresh water readily available, although only a tiny fraction of the total water on earth is a generous supply that is continuously collected, purified, recycled and distributed by the hydrological cycle provided we do not do what things?
- The difference in average annual precipitation divides the world's countries and people into water haves and water have-nots. What percentage of the world's water and people does Canada have compared to China?
- Give examples of where regional tensions within and between countries will increase due to water shortages.
- Read the case study on water in the Middle East and explain why there is a danger of water wars or economic competition between countries for food imports in this region. p. 305
- Since 1900, how much has the total use and per capita use of water by humans increased?
- About what percent of the world's reliable surface runoff is used by human's (including both withdrawn runoff and instream use)?
- What are the 3 main uses of water?
Water use in Australia
Australia is the world's driest inhabited continent. Over 80% of Australia has an average rainfall of less than 600 mm/year. It is also the land of flood and drought - from the tropical north to the arid interior droughts and floods are common.
Water is a precious commodity and the ecological services provided by freshwater systems is vital for our lives and our industries to survive.
Unfortunately, the poor use of water since European settlement has had a dramatic effect on freshwater systems. For example, the Australian State of Environment Report (2001) showed that 1/3 of Victoria's wetlands have been permanently destroyed since European occupation. Freshwater availability and quality has declined dramatically due to overuse and pollution of water resources.
An assessment of Australia's water use, and pressures on water use were undertaken during 2003, which was the Year of Freshwater! A summary of major findings is available at http://www.deh.gov.au/events/iyf/publications/poster.html 
Here is a summary of some important facts and figures about Australia's water use, taken from the National Land & Water Resources Audit, 2000
- The total water use in Australia is approximately 23 000GL/year
- 70% irrigation
- 21% urban and industrial
- 9% other
- Currently irrigated agriculture in Australia uses less than 1% of agricultural land and produces 30% of the value of all agriculture in Australia and this percentage is increasing.
- By percentage irrigated land is comprised of
- 57% Pastures
- 18% non-cereal crops
- 15% cereal crops
- 6% fruit and vege
- 4% vege
Australia's domestic water use is the 2nd highest users of mains water after agriculture (using about 16%). The toilet and shower use 40% of this amount http://www.deh.gov.au/events/iyf/publications/poster.html#statistics
The Australian Government has tried to take a number of steps to reduce water use. One of these is to increase the domestic use of energy efficient appliances. Information on this scheme is available at http://www.waterrating.gov.au/index.html.
There are many programs to improve water management at a regional scale, for example the Water Reform Framework, the National Action Plan for Salinity and Water Quality, the National Heritage Trust. A summary is available at http://www.environment.gov.au/events/iyf/publications/resources.html
NOTE: For those interested, a summary of the current state of Australia's inland waters is available at the State of the Environment (2001) summary at:
http://www.environment.gov.au/soe/2006/publications/commentaries/water/index.html
Freshwater shortages around the world
Activity 3.21
Read Miller & Spoolman pages 323 – 324, and answer the following questions:
- List and define the four causes of water scarcity.
- With reference to Figure 13-6 list some of the countries and regions suffering from high water stress
- According to the United Nations how many people currently live in water scarce or water stressed countries? How many might there be by 2025?
- What proportion of the world's people do not have access to adequate and affordable freshwater? What might this rise to in 2050?
How can we increase fresh water supply?
Activity 3.22
Read Miller & Spoolman (2012) pages 324-325, and answer the following question
- What are four possible ways to increase fresh water supply in a particular area?
In addition the most important changes that can be made to increase supplies of fresh water are to reduce the massive amounts of water currently wasted and to work with natural hydrological cycles.
(a) Withdrawing groundwater
Activity 3.23
- With Reference to Miller& Spoolman (2012), pages 326 – 329, list and explain the advantages and disadvantages of withdrawing groundwater.
Advantages and disadvantages of Withdrawing Groundwater Advantages of Withdrawing Groundwater Disadvantages of Withdrawing Groundwater e.g. can be removed as needed
e.g. lowers the water table etc etc
- Explain why excessive withdrawal of groundwater can be viewed as an example of the tragedy of the commons and how it can increase the gap between the worlds rich and poor.
- With reference to Figure 13-12 Miller & Spoolman (2012) list ways to prevent or slow groundwater depletion.
(b)Using dams & reservoirs to supply more water
The number of large dams worldwide has increased dramatically over the last 50 years. This increase in dams has largely been to; supply for increasing water demands, produce hydroelectricity, and to control floods.
There are a number of important ecological services provided by rivers that are decreased, damaged or removed when a dam is installed. These services are currently not adequately considered in the process of designing and installing new dams.
Activity 3.24
- With Reference to Miller & Spoolman (2012) pages 328 - 330, including the 2 case studies, list and explain the advantages and disadvantages of using dams to increase water availability. You should be able to list the effects on ecosystem services, and social and economic effects.
| Advantages of large dams | Disadvantages of large dams |
|---|---|
e.g. Transfer water from the catchment to highly populated areas |
e.g. Degradation of river systems due to water removal |
| etc | etc |
(c) Transferring water from one place to another
Another way in which fresh water supply can be increased in a water stressed area is through the use of tunnels, aqueducts and underground pipes to transfer stream runoff collected by dams and reservoirs in water-rich areas. Such water transfers have a number of benefits, however, they also create environmental problems.
Dam projects and water transfers (discussed in the following section) clearly illustrate that we cannot influence or change one part of an ecological system without affecting other parts of the system as well as the overall behaviour of the system. Many of the undesirable effects of dams and water transfers demonstrate this principle. (Hint: keep this principle of how human intervention affects ecological systems in mind when considering the pro's and con's of any resource use issue).
Activity 3.25
- With reference to Miller & Spoolman (2012) pages 330 – 333, and the case studies, list and explain the advantages and disadvantages of transferring water using examples from the case studies where relevant. Hint: use a two column table, similar to the one above to complete your answer.
(d) Desalinisation
It is timely to consider the advantages and disadvantages of desalinisation given the announcements by the NSW and WA Governments to pursue these options for supplying freshwater.
Activity 3.26
Read Miller & Spoolman (2012) pages 334 – 336 and answer the following:
- What is desalinisation? What are the 2 main methods of desalinating water?
- What are the 2 major problems with desalinisation?
- Do you think there are better options in Australia before we pursue desalinisation, or is it a well-conceived solution for increasing available water?
Activity 3.27
Using a diagram of the water cycle, such as that given below discuss how a dam, water transferring and withdrawing ground water affects the water cycle and disrupts the provision of ecosystem services by the disturbed catchment. Refer also to Activity 1.4 in the ecosystem services module.
Reducing Waste
It is estimated by the World Resources Institute that 65-70% of the water people use throughout the world is lost through evaporation, leaks, and other losses. However, it is also believed to be economically and ecologically possible to reduce this water loss to 15%, allowing most of the world's water needs to be meet for the foreseeable future. This will require greatly increasing the use of water-saving technologies and practices.
Activity 3.28
Read Miller & Spoolman (2012) pages 337 – 339 and answer the following questions.
- What are the four benefits of wasting less water?
- Discuss the two major causes of water wastage and how they lead to water being wasted.
- Do you think that the price of water should be raised significantly to help reduce waste?.
How can we waste less irrigation water?
Activity 3.29
Read Miller & Spoolman (2012) pages 335 – 337 , and answer the following questions.
- Describe 3 new technologies for applying water that will reduce water wastage in irrigation.
- Describe 6 other solutions to reduce irrigation waste water (refer to Figure 13-19).
How can we waste less water in industry, homes and businesses?
Activity 3.30
Read Miller & Spoolman (2012) pages 335 – 337, and answer the following question.
- List as many ways as you can that water wastage could be reduced (Hint: use the ideas in Figure 13-21 Miller & Spoolman (2012)).
Achieving a more sustainable water future
Sustainable water use is based on that same commonsense principle of all sustainable resource management, maintaining the continued supply of the resource. Ensuring the continued supply of sufficient clean water, or any other resource, requires that the ecosystem processes and functions, and the natural capital that produce the desired ecosystem services are maintained. In addition to this the resources that are produced need to be used wisely and with minimum waste to ensure there is enough to meet human demands whilst causing as little environmental disruption as possible.
Achieving sustainable water use will require a mix of strategies built around irrigating crops more efficiently, using water-saving technologies in industry and homes, and improving and integrating management of water catchments and groundwater supplies (Miller 2004)
Activity 3.31
Read section 13-6 in Miller & Spoolman (2012), pp. 334-339, and answer the following questions:
- What are the 7 ways Miller & Spoolman (2012) list to use the world’s water resources sustainable? How would each of these tactics contribute to more sustainable water use?
- Which of these tactic(s) do you think would be the most effective, i.e., contribute the most to sustainable water use, and the most important to implement as soon as possible and why?
Review questions
- Is there sufficient water for agricultural, industrial and domestic use and for maintaining our natural waterways? What steps actions or policies would be required to manage the earth’s water resources sustainably and what is the role of ecosystem services in this process?
- What options are there for capturing more fresh water? What are the impacts of each of these on ecosystem services and is supplying more fresh water the answer to water scarcity?
- List four causes of water scarcity. Describe the factors which play into a positive feedback loop creating water stress. Assess the significance of water resources for international relations.
- List five ways to increase the water supply. List advantages and disadvantages of each strategy. Summarize a key lesson learned from the following case studies: the Colorado River; China’s Three Gorges Dam; the California Water Project; the Aral Sea disaster.
- What percentage of the water used by people is wasted? List 4 benefits of conserving water. List three major causes of water waste.