The ups and downs of dams

摘要

The trouble with water is that it is all politics, no economics. The costs of poor management are large: groundwater depletion takes 2.1% off Jordan's gdp; water pollution and scarcity knock 2.3% off China's; 11% of Kenya's was lost to flooding in 1997-98, and 16% to drought in the next two years. Rich countries build sewers, drains, dams, reservoirs, flood defences, irrigation canals and barrages to avoid such problems. Poor countries, with some ex-rnceptions, notably China, find large projects much more difficult. But at least large projects give politicians a monument to boast about. Small projects-weirs and wells and waterworks-have no allure for big-headed politicians.