D+C Development and Cooperation (No. 2, March/April 2001, p. 10)

Water facts

Today, around 3800 km3 of fresh water is withdrawn annually from the world’s lakes, rivers and aquifers. This is twice the volume extracted 50 years ago.

World population has passed 6 billion. Projections: a peak of between 7.3 billion and 10.7 billion around 2050 before total population begins to stabilise or fall.

50 litres per person per day (or just over 18.25 m3 a year) covers basic human water requirements for drinking, sanitation, bathing and food preparation. In 1990, over a billion people had access to less than 50 litres of water a day.

Agriculture accounts for about 67 % of withdrawals, industry uses 19 % and municipal and domestic uses account for 9 %.

One third of the countries in water-stressed regions of the world are expected to face severe water shortages this century. By 2025 there will be approximately 6.5 times as many people - a total of 3.5 billion - living in water-stressed countries.

By the end of the 20th century, there were over 45 000 large dams in over 150 countries.

The average large dam today is about 35 years old. Since average construction periods generally range from 5 to 10 years, this indicates a worldwide annual average of some 160 to 320 new large dams per year.

During the 1990s, an estimated $ 32-46 billion was spent annually on large dams, four-fifths of it in developing countries. Of the $ 22-31 billion invested in dams each year in developing countries, about four-fifths was financed directly by the public sector.

About one fifth of the world’s agricultural land is irrigated, and irrigated agriculture accounts for about 40 % of the world’s agricultural production.

Half the world’s large dams were built exclusively or primarily for irrigation, and an estimated 30 to 40 % of the 271 million hectares of irrigated lands worldwide rely on dams. Dams are estimated to contribute to 12-16 % of world food production.

Hydropower currently provides 19 % of the world’s total electricity supply, and is used in over 150 countries with 24 of these countries depending on it for 90 % of their supply.

Floods affected the lives on average, of 65 million people between 1972 and 1996, more than any other type of disaster, including war, drought and famine.

There are 261 watersheds that cross the political boundaries of two or more countries. A number of key international rivers lack a basin-wide agreement that defines a process for establishing equitable water use between riparian States.

Cost effectiveness

Cost performance data in the WCD Knowledge base confirms that large dam projects often incur substantial capital cost overruns - for 250 projects examined. The average overrun was half again as much as the projected cost.

The bulk of hydropower projects in the WCD Knowledge base have delivered power within a close range of pre-project targets but with an overall tendency to fall short of targets.

At current rates, water fees are rarely sufficient to recover both capital and recurrent costs for water supply systems in many developing countries.

Growing concern over the cost and effectiveness of large dams and related structural measures as long-term responses to floods has led to support for integrated flood management as opposed to flood control.

Multi-purpose schemes are inherently more complex, and many experience operational conflicts that contribute to under-performance on financial and economic targets.

Substantive evaluations of project performance are few in number, narrow in scope, and poorly integrated across impact categories and scales.

Ecological costs

Dams, inter basin transfers, and water withdrawals for irrigation have fragmented 60 % of the world’s rivers.

As a physical barrier the dam disrupts the movement of species leading to changes in upstream and downstream species composition and even species loss.

In Africa, the changed hydrological regime of rivers has adversely affected floodplain agriculture, fisheries, pasture and forests that constituted the organising element of community livelihood and culture.

Problems may be magnified as more large dams are added to a river system, resulting in an increased and cumulative loss of natural resources, habitat quality, environmental sustainability and ecosystem integrity.

The Cross Check survey found that almost 60 % of the impacts identified were unanticipated prior to project construction.

Good site selection, such as not building large dams on the main-stem of a river system, and better dam design also played significant roles in avoiding or minimising impacts.

The Cross-Check Survey demonstrates that economic appraisal techniques such as risk and distributional analysis were still mandated for only 20 % of large dam projects even in the 1990s.

EIA is recorded for less than 40 % of dams commissioned in the 1990s.

Social costs

At the planning and design stage, an important social impact is the delay between the decision to build a dams and the onset of construction. This can result in communities living for decades starved of development and welfare investments.

The overall global level of physical displacement could range from 40 to 80 million.

In India and China together, large dams could have displaced between 26-58 million people between 1950 and 1990.

Little or no meaningful participation of affected people in the planning and implementation of dam projects - including resettlement and rehabilitation - has taken place.

Empowering people, particularly the economically and socially marginalised, by respecting their rights and ensuring that resettlement with development becomes a process governed by negotiated agreements is critical to positive resettlement and rehabilitation.

Poor accounting in economic terms for the social and environmental costs and benefits of large dams implies that the true economic efficiency and profitability of these schemes remains largely unknown.

The WCD Case Studies show that the direct adverse impacts of dams have fallen disproportionately on rural dwellers, subsistence farmers, indigenous peoples, ethnic minorities, and women.

Where costs and benefits accure to different groups, the standard procedures for adding up and discounting the expected costs and benefits do not provide an appropriate measure of changes in societal welfare.

Of the 34 dams in the Cross-Check Survey that involved resettlement of displaced people, only 7 required participation as part of the decision-making process.

Financing

Almost 2 billion people, both urban and rural poor, have no access to electricity at all.

Most efficiency measures and technologies are cost - effective at today’s electricity prices and the use of full environmental and social costing of electricy supply options makes them even more so.

Among advanced technologies in research and development, microturbines and fuel cell show the greatest near and mid-term promise.

Total financing for large dams from multi-lateral and bi-lateral development banks comes to more than $ 4 billion annually at the peak of lending during 1975-84. Although the proportion of investment in dams directly financed by bilaterals and multilaterals was perhaps less than 15 %.

The total investment in dams by the multilaterals and bilaterals since 1950 is approximately $ 125 billion.