Global Hydrology

Processes, Resources and Environmental Management

J. A. A. Jones

• Publisher: Routledge
• Year: 2014
• ISBN:
  9781317894735
• Edition: 1
• Topic: Physical Sciences
• Subtopic: Geography
• Index: Geography

Global Hydrology illustrates in detail the growing importance of understanding hydrological processes and pathways as a means of effective and safe management of water resources. It describes current management practices and past environmental impact. It analyses the options for improving water supply and protecting the environment, emphasizing the need for international collaboration in a changing societal and environmental context

CHAPTER 1

Water for the world

Topics covered

1.1 The basic issues

1.2 The demand curve

This book aims to analyse the major problems of matching supply and demand in the modern world from the basis of current scientific knowledge of natural processes and of man’s effect upon them. It is also very much concerned with the environment and the effects of man’s alteration of hydrological regimes upon that environment. Its principal thesis is that harmonious, and ultimately successful and sustainable, development requires a sound and thorough understanding of hydrological processes both on land and in the atmosphere.

1.1 The basic issues

Water is the most fundamental ingredient of all life on Earth; it is more universally necessary even than free oxygen. It is the most abundant component of any organism and the medium for most biochemical reactions. It plays an essential role in the exchange of material between an organism and its environment. The Earth-atmosphere system contains approaching 1500 million gigatonnes (Gt)¹ of free water compared with little more than 12 million gigatonnes of free oxygen, including oxygen dissolved in water. Despite this, in most environments outside the oceans and the great lakes water is more likely to be in short supply than oxygen. For most terrestrial life forms the supply of water in the local environment determines where they may live, where they may move and where they may die.

Man is the exception. The ability of the human race to manipulate water in the environment, to redistribute it in time and space, is one of the major characteristics that sets civilized man apart from the rest of the living world. Mankind took a giant step about 6000 years ago in Mesopotamia by diverting riverwater for use in irrigated agriculture. These first hydraulic engineers freed man from subsistence agriculture and enabled tradable agricultural surpluses to be created. In turn this permitted the job specialization and extensive socioeconomic reorganization that led to the development of the first cities, the Urban Revolution, and the development of writing to manage these new city states and their trade. Civilization was born. Even when urban civilization spread to better-watered regions, it still required dams, aqueducts, pipes and drains to service man in his built environment.

Throughout history, water engineering has lain at the very foundation of civilization itself. States have fallen for lack of adequate provision. In the modern world, we can see the retreat of settlements from the desert margins as the mismanagement of soil and water resources combines with natural climatic stress. Indeed, the dual impact of agriculture and urban society has permanently altered global hydrology. Wherever they have spread, they have so modified the surface of the Earth that the flows and exchanges of water bear their imprint, in some cases millennia after the impact occurred. Water has been an important element in the many-sided conflict between civilization and nature, and the roots of the conflict were present at the dawn of history.

The twentieth century has seen the most extensive manipulation of water: large dams to provide water supply, generate hydropower or regulate riverflow, extensive groundwater schemes often linked to complex multi-source centralized public water supply systems, sewage disposal and in latter decades a rapid and vast expansion in the area under irrigated agriculture. About 13 per cent of global riverflow is now controlled by mankind, but our influence extends far wider. Though some of the grandest schemes, like the former Soviet proposal to reverse Arctic rivers, may never come to fruition, in some areas of the world impacts have gone beyond the stage of mere alteration and are reaching the point of crisis – for the environment as well as for humans.

1.1.1 Global concerns

As the world prepares to enter the twenty-first century, three issues dominate: (1) the provision of sufficient water for a growing and increasingly demanding population; (2) the impact of water development, and of other developments involving hydrological effects, on the environment; and (3) anticipated problems with climatic change and the unreliability of water resources.

The overwhelming bulk of water on Earth can be used neither by man nor by the majority of terrestrial plants and animals, because it is either too salty or frozen. Even so, the remainder is no mean quantity and it does have the advantage that it is naturally recycled, so that although it is finite in quantity it is ultimately unlimited in supply. Practical limits to both the quantity and quality are nevertheless imposed by recycling times.

The need for conservation and the careful control of exploitation is now almost universally acknowledged. This recognition owes much to fears that resources in general may be running out, to the rise of the environmental movement and to practical experience over recent decades, particularly with catastrophes and failures, both man-made and natural.

Limited and shifting resources The realization that mankind’s use of many resources is approaching global limits hit the world community very forcibly in the early 1970s as a result of an unusual conjunction of events: the Club of Rome’s computer simulations published in The Limits to Growth (Meadows et al. 1972), the 1973 oil crisis and a series of droughts and agricultural disasters, especially the series of Sahelian famines between 1968 and 1973, and the USSR’s disastrous harvest in 1972.

The droughts had immediate repercussions on water management, including rainmaking activities in West Africa, a plan to divert the Congo to enlarge Lake Chad, and a Soviet scheme to divert major rivers of the Arctic basin south to irrigate the grain lands of the Ukraine and adjoining republics (Box 9.2). The 1970 drought in the eastern United States and the 1976 drought in the UK also had major impacts upon management procedures. The 1988 drought caused a 30 per cent shortfall in the North American grain harvest. Above all, the stress put on world agriculture by the combination of population growth and climatic events has led to a vast expansion in irrigation.

The national water surveys in Canada and the USA in 1978 and 1981 both foresaw critical shortages before 2000. The US report expressed particular concern for southern and western states. This view was reiterated in the global survey by the Worldwatch Institute of Washington, DC, in 1984 entitled Water – the next resource crisis?, which also focused on North Africa and the Middle East as regions potentially in great danger without very careful planning. Even in England and Wales, the National Rivers Authority’s water resources strategy indicates concern over regional water shortages (NRA 1994).

The expansion of water pollution, also predicted in the The Limits report, could be as crucial for world water resources. Less well publicized calculations by the Soviet hydrologist M I Lvovich (1977, 1979) suggested that if water pollution remained unchecked the world would essentially run out of usable water resources by the year 2000 (section 1.2.4). He proposed strict pollution controls and widespread recycling of water as solutions. Many have criticized the details of these calculations, as with The Limits predictions. Nevertheless, the fact remains that, despite rigorous pollution controls in Western Europe and North America, the problem has barely been contained. In Eastern Europe, the effects of non-containment were plain for all to see after the collapse of Communism in 1989–90 (Peterson 1993).

The problems of quantity and quality in water supply are now seen as a single entity and Lvovich himself must take part of the credit for the emphasis that has ensued, despite some criticism of his assumptions (section 1.2.4). The US Congress set up the Environmental Protection Agency in 1970 to control water pollution. The European Union has issued a series of Directives to control water pollution since the 1974 Bathing Waters Directive, and the National Rivers Authority (NRA) was established in England in 1989 to protect both the quantity and the quality of water in supplies and in the environment. Globally, the UN World Health Organization (WHO) designated the years 1981–90 the International Drinking Water Supply and Sanitation Decade. The WHO aimed to provide potable (literally ‘drinkable’) water supply for 1.8 billion additional people in the Developing Countries during the decade along with access to proper sanitation for 2.4 billion.

Reorganization of water industries to combine responsibilities for all stages of water use and recycling was seen as an important means of tackling these problems, at least since the publication of the UN revised guidelines (UN 1970). These proposed that the hydrological concept of an integrated circulating system from source to reclamation should take precedence over existing ad hoc administrative and commercial development. The report also established the principle that the natural river basin should be the basic unit for administration and development. Reorganizations like those in England and Wales in 1973 and in Spain in 1985 followed these guiding principles.

By recognizing the essential unity of the cycle of water use within the administrative structure, it may be possible to select alternative solutions more easily, or to reduce reprocessing costs. Kaminskii (1977) strongly urged the Soviet government to consider the advantages of water recycling before implementing the vast plan for diverting the Arctic rivers. This unity of interest is underlined by the late-twentieth-century Western vogue for using rivers as open pipelines for public water supply, by regulating their flow in order to guarantee a minimum discharge at certain abstraction points downstream. Regulated water supply rivers cannot logically be used as a dumping ground for wastes in the old way (section 9.3).

Unfortunately, international boundaries will continue to disregard natural drainage basin units. Globally, one-third of rivers pass through more than one country. Good international collaboration is possible in these circumstances, as between Canada and the USA on the Columbia River or between the states along the Rhine. But all too frequently there are conflicts of interest (section 11.4). Indeed, halting cross-boundary riverflow might even be used as a military weapon, as the USA reportedly discussed with Turkey during the Gulf War, and as Saddam Hussein appears to have used against the Marsh Arabs (section 11.4). Similar problems can arise with shared groundwater reserves.

The most recent fear has been the potential impact of an enhanced greenhouse effect on global and regional resources (sections 2.6 and 11.5). The Intergovernmental Panel on Climate Change, set up in 1988 to analyse available evidence, clearly established the need for concern. The UK Climate Change Impacts Review Group (1991) demonstrated that, even in a country where overall annual rainfall is expected to increase, severe stresses could be put on resources in certain regions, at certain times of the year and on specific users.

From a political viewpoint, Sir Crispin Tickell (1977, 1991), former British ambassador to the UN, has predicted that future climatic change will so strain agriculture and water resources in many of the Least Developed Countries that civil disobedience, political coups and massive international migration will occur.

Environmentalism In contrast, the philosophy of the environmental movement, developed largely from the opposing, geocentric rather than anthropocentric viewpoint. Rachel Carson’s book Silent Spring (1962), which highlighted the effects of pesticides on wildlife, is often cited as a founding text for the modern movement. Numerous conflicts since have focused on the environmental impact of large dams, including destruction of ancient ecosystems and the displacement of native populations (section 9.2.1).

What began as a concern for preserving vanishing nature, however, has grown into a belief that mankind’s continued existence depends upon maintaining important natural balances. The 1971 Stockholm Conference on Man and his Environment focused world attention especially on the effects of acid rain on the biosphere. As a result of that conference, the UN Environment Programme (UNEP), the World Meteorological Organization (WMO), the World Health Organization (WHO) and UNESCO agreed to collaborate in a Global Environmental Monitoring System (GEMS), of which GEMS/WATER is a major arm.

More recent WMO conferences, such as the 1985 Villach Conference on Carbon Dioxide and Climate Change and the Second Global Climate Conference in 1990, have expressed deep concern over the effects of burning fossil fuels and the felling of native forests on the greenhouse effect and resulting shifts in water resources. The UNFPA (1992) report on Population, Resources and the Environment continues to underline the dangers of current trends in exploitation.

The concerns of environmentalists have therefore expanded from biological preservation to the ‘global commons’, the atmosphere and the hydrosphere. The links are highlighted in James Lovelock’s (1979) Gaia Hypothesis, which proposed that life both creates and maintains a suitable environment for itself. The hypothesis remains unproven, but much important feedback has been noted over the past decade, including the possibly critical role of oceanic phytoplankton in reducing global warming either by absorbing excess atmospheric carbon or releasing dimethyl sulphide (DMS), which stimulates cloud formation (sections 2.3.1 and 2.6).

One of the more apparent results of pressure from environmentalists on water resources engineering has been the trend towards so-called ‘non-structural solutions’. These consist of replacing traditional hardware solutions, such as impounding dams or flood control structures, with more environmentally friendly ‘software’ solutions, or at least solutions which require less hardware. Software solutions often use computer-based monitoring and modelling systems to provide early warning of floods, or to control pumping and flow regulation in relation to ‘real-time’ inputs and demands. A less sophisticated software solution might simply involve planning controls on floodplain development, which eit...

Table of contents

• Cover
• Title Page
• Copyright Page
• Dedication
• Table of Contents
• Foreword
• Preface
• Acknowledgements
• Chapter 1 Water for the world
• Chapter 2 The global hydrological cycle
• Chapter 3 Hydrological processes within the river basin
• Chapter 4 Floods, droughts and magnitude-frequency relations
• Chapter 5 Monitoring and assessing processes
• Chapter 6 Modelling runoff processes
• Chapter 7 Inadvertent impacts on hydrological processes 1: water quantity
• Chapter 8 Inadvertent impacts on hydrological processes 2: water quality
• Chapter 9 Managing runoff 1: the design of major water management systems
• Chapter 10 Managing runoff 2: unconventional and environmentally sound solutions
• Chapter 11 Towards a sustainable future?
• References
• Index