Water for people.pdf - WHO Thailand Digital Repository

M I T I G A T I N G R I S K A N D C O P I N G W I T H U N C E R T A I N T Y / 2 7 5devastating consequences downstream. In coastal areas, floods mayresult from rising sea levels and tropical cyclone-driven storm surges.It is important to remember that flooding also has positivebenefits. Floods can play a positive role within our ecosystems andthe environment at large, for floodwaters carry nutrients that allowfor fertile flood plains and are important for various aquatic species.Integrated risk-based management provides the opportunity to takeaccount of these benefits as well as mitigate the adverse impacts offloods (see box 11.1).DroughtsDroughts are undoubtedly the most far-reaching of all naturaldisasters. From 1991 to 2000 alone, drought has been responsiblefor over 280,000 deaths and has cost tens of millions of US dollarsin damage. For example, sub-Saharan Africa suffered its worst dryspell of the century in 1991/92 when drought covered a region of6.7 million square kilometres (km 2 ) and affected about 110 millionpeople. While droughts have always been a fact of life in Africa, thecombination of drought with human activities such as overgrazing ordeforestation may dramatically affect the desertification process andlead to a permanently or near-permanently degraded environment.By the year 2025, the population projected to be living inwater-scarce countries will rise to between 1 and 2.4 billion,representing roughly 13 to 20 percent of the projected globalpopulation. Africa and parts of western Asia appear to beparticularly vulnerable.Droughts have been categorized in three ways: as meteorological(due to a lack of precipitation), hydrological (lack of water in streamsTable 11.1: Major drought events and their consequences in the last fortyyearsDate Country or Fatalities Economiccontinentlosses (US$M)1965–1967 India 1,500,000 1001972–1975 Africa 250,000 5001976 United Kingdom 1,0001979–1980 Canada 3,000April–June 1988 United States 13,000June–July 1988 China 1,4401989–1990 Angola 10,000Summer 1989 France 1,600Jan.–Oct. 1990 Greece 1,300Summer 1990 Yugoslavia 1,000Jan.–March 1992 Africa 1,000May–Aug. 1998 United States 130 4,275Jan.–Aug. 1999 Iran 3,300Jan.–April 1999 Mauritius 175June–Aug. 1999 United States 214 1,000Source: Munich Re, 2001.and aquifers) or agricultural (when conditions are unable to sustainagricultural and livestock production) (Hounam et al., 1975). Theconcept of what constitutes a drought varies between countries. InEngland, three weeks without rain is considered a problem; in manyparts of the world much longer dry periods are normal.Durations and extents of droughts vary greatly. Examples ofsevere, persistent droughts over large geographical areas include theSahel covering 7.3 million km 2 from 1970 to 1988, continentalEurope covering 9 million km 2 from 1988 to 1992, and India covering3 million km 2 from 1965 to 1967. There are other examples ofextreme droughts in North America and Australia. Table 11.1 providesa summary of major drought events and their associated loss of lifeand economic losses as established by Munich Re. Extreme droughtcan affect large tracts of land and large numbers of people anywherein the world and can persist from a few months to several years. Theimpacts of a drought hazard can have far-reaching social, economicand environmental consequences.The effects of disastersHigh stress results when many large disasters occur within a limitedtime span. The year 1999, for example, with several earthquakes, theLothar storm in France, floods and mudslides in Venezuela and morethan 50,000 deaths, still remains in political memory as the secondmost costly year in terms of global disaster and risk insuranceindemnities. Stress is also high when one single region is hit by asequence of several major catastrophes. One example is the Indianstate of Orissa, which experienced massive flooding in 2000, followedin 2001 by the worst drought in a decade and new floods. Out of apopulation of 32 million, some 27 million people were affected.In poor countries, natural disasters generally result in largereconomic losses in proportion to the economies.Depending on the robustness of the national economies, thenegative consequences of disasters tend to be amplified as theyerode the political and social stability of countries and upset thebalance between the three necessary pillars for water resourcesmanagement: economic development, environmental conservationand social stability (Appelgren et al., 2002). This is particularly thecase when one disaster can virtually wipe out the investments madein infrastructure over the previous decade. Table 11.2 lists thesevere natural disasters resulting in more than about 1,000 deathsin recent years. Most of these disasters occurred in developingcountries, and the majority of the losses were uninsured.The Zimbabwe drought of the early 1990s was associated withan 11 percent decline in Gross Domestic Product (GDP) and a60 percent decline in the stock market; more recent floods inMozambique led to a 23 percent reduction in GDP, and the 2000drought in Brazil to a halving of projected economic growth. Even indeveloped countries, an extreme drought may cause considerable