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Product Details
| ISBN-13: | 9781780325439 |
|---|---|
| Publisher: | Bloomsbury Publishing |
| Publication date: | 08/08/2013 |
| Series: | 0 |
| Sold by: | Barnes & Noble |
| Format: | eBook |
| Pages: | 320 |
| File size: | 812 KB |
About the Author
Dr Mark Everard's work in all four sectors of society - private, public, academic and voluntary - has taken him across five continents to undertake applied research, policy development and capacity-building relating to the ways in which people connect with ecosystems. The author of 14 other books, including Common Ground (Zed Books, 2011) and The Hydropolitics of Dams (Zed Books, 2013), over 60 peer-reviewed scientific papers and over 250 technical magazine articles, Mark is also a communicator on sustainability and wider environmental and resource-use matters on TV and radio. He has served on numerous government advisory and expert groups in the UK, as well as advising other governments and multinational corporations on sustainability matters. His speciality is systemic thinking, particularly around connections between the water environment and other environmental media and the human activities that depend on and influence them. Mark's work includes environmental ethics and economics as a means to bring our intimate interdependencies with ecosystems into the mainstream of public awareness and government thinking.
Read an Excerpt
The Hydropolitics of Dams
Engineering or Ecosystems?
By Mark Everard
Zed Books Ltd
Copyright © 2013 Mark EverardAll rights reserved.
ISBN: 978-1-78032-543-9
CHAPTER 1
Replumbing the modern world
Manipulation of water flows to and from land is as old as settled agriculture. Irrigation and river management practices are found widely across the ancient human world, constituting one of the most fundamental technologies to enhance natural soil productivity and overcome limitations to survival and progress. Indeed, they were pivotal in the ascent of humanity from the moment Homo sapiens appeared in the fossil record in Africa about 130,000 years ago to eventually displace wider groups of hominids.
Settled agriculture in turn marked a revolution in human ingenuity, bringing into cultivation and domestication various species of plants and animals to provide staple foods. It signalled an evolution in human consciousness to the extent that farmers' decisions were premised upon future yields, rather than merely current availability, providing the need for the establishment of permanent communities, new levels of social structure and communication, and for the transfer of knowledge between individuals and generations. These innovations laid some of the foundations of modern culture. Writing systems were developed, empires were created often in the quest for more resources, and monumental buildings were constructed by a better-nourished populace less vulnerable to the vagaries of hunting and gathering. Many assign the origin of economic systems to the transition to settled agriculture as, released from the daily drudgery of pursuing food, societies were able to internally differentiate responsibilities and labour, and so to need a trading system for fair exchange between social groups.
The evolution of agricultural principles and applications, critically including the management of water, was followed by advances in the entrainment of water for defensive, industrial, municipal and other purposes. These broad and fascinating innovations have substantially shaped human history.
A brief history of dams
Dams were an early innovation in the rise of human civilizations. ICOLD, the International Commission on Large Dams, defines a dam as a barrier or structure across a stream, river or waterway to confine and then control the flow of water. Dams vary in size from small slip dams built to intercept springs and small streams emerging from hillsides and gorges, generally for farm use, through to progressively larger engineered structures, generally used for water supply, hydropower and irrigation and including some of the modern world's most massive civil engineering schemes.
Across the globe, major river systems have been progressively dammed over a period of centuries. The earliest unambiguous records of human agriculture appear in the 'fertile crescent' of Mesopotamia, between the rivers Tigris and Euphrates in land now covered by modern-day Iraq, with evidence of river engineering found in the ruins of irrigation canals over eight thousand years ago. At 104 metres (340 feet) long, 61 metres (200 feet) high at the crest and built of masonry blocks with a gravel and stone centre, Sadd el-Kafara, the Dam of the Pagans, is the world's oldest big dam built between 2950 and 2750 BC and today crumbling in the Egyptian desert. The remains of water storage dams dating back to at least 3000 BC have also been found in Jordan, Egypt and other parts of the Middle East, though no more large permanent dams were built in Egypt until the twentieth century. In China, a system of dams and canals was constructed in 2280 BC, the Dujiang irrigation project once supplying 800,000 hectares in China. The 1,500-year-old Grand Canal, one of the wonders of ancient China, was once the largest artificial river of the pre-industrial world and was also the first to have lock gates. It was used to transport rice from the wet south of the country, primarily from the monsoon-fed Yangtze valley, to centres of population in the north. One of the oldest dams still in use today is an earth- and rock-fill embankment dam built around 1300 BC in what is now Syria. The building of the Marib Dam in Yemen began around 750 BC and took 100 years to complete, comprising an earth embankment 4 metres high with stone sluices to regulate discharges for irrigation and domestic use. In 1986, the existing Marib Dam was raised to a height of 38 metres, creating a reservoir of 398 million cubic metres of water. The famed though potentially mythical 'hanging gardens of Babylon', considered one of the Seven Wonders of the Ancient World and attributed to the neo-Babylonian king Nebuchadnezzar II, who ruled between 605 and 562 BC, were probably more miraculous for their water engineering than for the vegetation they supported.
In Sri Lanka, ancient chronicles and stone inscriptions state that numerous dams and reservoirs were built as early as the third century BC. Inter-basin canals built for irrigation augmented many of these large reservoirs. One of these large dams, the Minneriya dam, was constructed during the reign of King Mahasen (AD 276–303), and was still intact when it was rediscovered in 1900. It was restored in 1901 and is still in use today. More than fifty other ancient dams in Sri Lanka have been restored.
The Romans built an elaborate system of low dams for water supply. The most famous was the Cornalbo earth dam in southern Spain, which had a height of 24 metres (78 feet) and a length of 185 metres (606 feet). After the Roman era, very little development in dam construction took place until the end of the sixteenth century, when the Spanish began to build large dams for irrigation. European engineers refined their design and construction knowledge in the nineteenth century, giving rise to the capability to construct dams to a height of 45–60 metres (150–200 feet).
The first recorded dam in India was on the Cauvery river ('Kaveri' in the native tongue), the southernmost of the three great river catchments draining the Deccan peninsula. Here, the Grand Anicut (in Tamil, anai means 'to hold' and katta is 'something that is built') spanned the Cauvery near Tiruchirapalli in the time of King Karikala in the second century AD. The dam is still in use today, albeit massively altered and reinforced, and is just one of many ancient dams subsequently reconstructed throughout India, with a particularly pronounced period of dam-building as long ago as the thirteenth century AD, when the Hoysala Empire ruled much of modern-day Karnataka in the Deccan peninsula.
The Sayamaike dam, one of the oldest dams in Japan, was built early in the seventh century AD and, after several modifications and a raising of height, it is still in use today. Several ancient dams from the thirteenth to the sixteenth century in Iran are also still in use today.
In the 1950s, the German-American historian Karl A. Wittfogel coined the term 'hydraulic civilizations' to describe societies managing their use of water through technology rather than local access. Today, much of the developed world constitutes hydraulic civilization, with many emerging nations aspiring to exploitation of technology rather than local access to natural resources to meet their water needs. Living with a significant legacy of engineering-dependent water management, we risk losing sight of other meanings of water, ranging from its cultural and spiritual importance to different people through to a respect for the ecosystems we depend on to maintain the quality and quantity of the basic resource of water that enters our ever more complex societal plumbing systems.
Different types of dam
Dams are classified by the material used to construct them. Embankment dams are constructed of either earth fill or a combination of earth and rock fill, while dams built of concrete, stone or other masonry are called gravity dams, arch dams or buttress dams. Engineers generally choose to build embankment dams in areas where large amounts of earth or rocks are available. Gravity dams depend entirely on their own weight to resist the tremendous force of the stored water. Some early gravity dams were constructed with masonry blocks and concrete, and are known as masonry dams. Today, gravity dams are constructed by mass concrete or roller-compacted concrete (concrete placed in layers and compacted by a roller) and are referred to as concrete gravity dams.
Arch dams are concrete dams that curve upstream towards the flow of water, built in narrow canyons such that water pushing against the dam transfers its force to the canyon wall. Arch dams require much less concrete than gravity dams of the same length, but need a solid rock foundation to support the weight of the dam. Conversely, buttress dams depend for support on a series of vertical supports (buttresses) running along their downstream face to transfer the force of the water downwards to the dam's foundation.
Topography, geology, foundation conditions, hydrology, likelihood of earthquakes and availability of construction materials are some of the factors affecting the selection of the type of dam. Narrow valleys with shallow sound rock favour a concrete dam, while wide valleys with varying rock depth and condition favour embankment dams. Earth embankment dams are the most common type encountered today, comprising 43.7 per cent of the global total, since they accommodate all the material from the required excavation. Gravity dams account for 10.6 per cent of the total, while rock-fill embankment dams total just 5.3 per cent.
Contested resources
It is not surprising that, with so much water collected and/or diverted by dams globally, there is a long history of conflict over potentially contested resources. As one striking example, approaching 100 per cent of the water needs of the South African province of Gauteng are diverted from outside its natural catchment, adding value to the recipient region while diverting the resource from donor catchments. But South Africa, formerly infamous for asymmetries in power under the apartheid regime, has been far from alone in the appropriation of water and other resources by a powerful elite to the detriment of other communities.
To this we can add the many international examples of often fiercely contested water rights. Examples of international tensions related to trans-boundary rivers, as well as some resolutions, are seen between India and Pakistan concerning sharing of the Indus river, between China and India contesting ownership of the waters of the upper Brahmaputra river, between Ethiopia and Egypt, regarding rights to the flow of the Blue Nile, and between the USA and Mexico regarding allocation of the Colorado river's water.
Contested rights also occur within nations. Former racial divisions in South Africa, including rights-related issues behind the diversion of water between regions, again serve as a classic example. However, the numerous dams, ancient and modern as well as periodically modified, that interrupt India's Cauvery river and its tributaries through Kerala, Karnataka and Tamil Nadu states are also a cause of ongoing tension. The river's waters are put to work throughout its course, including the headwaters in the state of Kerala and downstream in the union territory of Pondicherry, to irrigate crops and to water livestock, provide domestic and industrial supply, and to generate electricity. Many dams throughout the catchment store water during monsoon periods when around 100 hours of rain typically falls in just 100 days. This stored water is released during the drying months, though water reserves become very low in the driest months of February to May, and some riverbeds dry out entirely. Of the river's flow, some 60 per cent is thought to be used for irrigation, dwarfing but also potentially conflicting with other uses and the needs of ecosystems. Karnataka diverts water for irrigation and to provide virtually the entire water supply for the burgeoning cities of Mysore and Bangalore as well as many other towns and villages. Rights to this water are hotly contested by the downstream state of Tamil Nadu, through which the Cauvery river is also intensively dammed on its way to its delta as it enters the Bay of Bengal. Water sharing from the Cauvery has been a major issue of contention between the four states and a frequent cause of protests within them, with a central government agency – the Cauvery Tribunal – now set up to look into this issue. The Cauvery river, which has served as the lifeblood of ancient kingdoms, and continues to support modern cities throughout much of southern India, also absorbs the industrial, domestic, mining and diffuse wastes of an ever-larger human population, compounding the relative sharing of benefits and burdens.
The history of dam-building observed in the Deccan peninsula is mirrored elsewhere in India and around much of the rest of the world, from China and other Asian countries, throughout Africa, across North America, central Europe and Australia. In every case, the distribution of benefits and associated costs raise profound rights issues. With such large-scale and widespread rights issues associated with contested water resources, it is surprising that they have not been an even greater historic source of conflict.
The large dam revolution
Since 1900, the world has, on average, completed one large dam every day. The global economic recovery following the Second World War was accompanied by phenomenal growth in infrastructure systems that included the world's largest dam construction period. From the 1930s, dam-building reached a whole new scale, entering the era of 'large dams'. ICOLD, the International Commission on Large Dams established in 1928, defines large dams as those with a height of 15 metres or more (fifty or more feet) from the foundation, in addition to dams of 5–15 metres in height retaining a reservoir volume of 3 million cubic metres or more. The construction of large dams became, in the eyes of many, synonymous with development and economic progress. They were viewed as symbols of modernization and humanity's ability to harness or control nature, and construction accelerated dramatically. This trend peaked in the 1970s, during which decade 7,511 large dams were built: an average of two or three large dams commissioned each day somewhere in the world. A total estimated investment of $US2 trillion was ploughed into large dam construction worldwide during the twentieth century. Average height, resource volume and overall mass increased during the second half of the twentieth century.
Undoubtedly, large dams around the world have played an important role in helping communities and economies harness water resources for food production, energy generation, flood control and domestic and industrial use. However, the technology has been widely taken up around the world to serve many different purposes with varying degrees of success, unintended consequences and controversy. There are many oversights in planning, contributing to very many conflicts and disbenefits. The disadvantages include access to and sharing of water, energy, habitat impacts and viability of ecosystems, extinction of species, international allocation of water, displacement of people, spread of diseases, loss of river structure and many factors besides. Growing environmental awareness and the rise of the environment and human rights movements have been instrumental in this broadening of consciousness. All of this means that dams today are widely acknowledged as far from the panacea for water supply and other development needs that they were almost universally perceived to be up until the late 1970s.
Nevertheless, the 'big engineering' approach to development, of which dams are a dramatic manifestation, has attracted considerable support from political, engineering and economic institutions. Clearly, controlling water can deliver targeted benefits, meeting development agenda that may include food security and the supply of water and power. However, laudable though these aspirations may be, the wider ramifications of technology choice and implementation have often been overlooked in favour of immediate benefits for an advantaged minority of people, overlooking long-term consequences and the implications for historically marginalized communities, which often gain little or nothing yet shoulder the bulk of the disadvantages of dam creation and operation.
These unintended consequences, arising from narrow technical solutions to address the most noble of aspirations, can also be compounded by strongly vested interests as well as entrenched thinking. There is also something of a triumphal approach to big, emblematic solutions that demonstrate 'man's power over nature', including not only the building of great edifices but also a similar approach to the construction of large engineered solutions to 'tame' flooding, retain water, irrigate deserts and otherwise suppress natural processes in favour of technology-based advancements. Indeed, 'big technology' solutions including dam-building have often been conflated with nation-building, sometimes explicitly so, as we will see in the cases of India and Egypt, but often also implicitly. Problems, however, are inevitable when natural processes are so vigorously suppressed or overridden in pursuit of a narrowly framed set of benefits.
(Continues...)
Excerpted from The Hydropolitics of Dams by Mark Everard. Copyright © 2013 Mark Everard. Excerpted by permission of Zed Books Ltd.
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Table of Contents
IntroductionPart I: Development, water and dams
1. Replumbing the modern world
2. Temples of the modern world
3. Stemming the flow
4. A changing mindset
5. The World Commission on Dams and beyond
6. The state of play with dams
7. Dams and ecosystem services
8. A new agenda for dams
Part II: Water in the postmodern world
9. Water in the postmodern world
10. Managing water at landscape scale
11. Catchment production and storage
12. Water flows through society
13. Markets for water services
14. Nature's water infrastructure
Part III: Rethinking water and people
15. Living within the water cycle
16. Governance of water systems
17. Towards a new hydropolitics
Annexe: Principles for sustainable water sharing