ISTANBUL – The global economic crisis threatens to shrink investment in water infrastructure, an already underfunded sector vital to growth and public health, the World Bank said yesterday. The first global economic contraction since World War II threatens to overshadow the scarcity of clean water in many poor regions, where inadequate sanitation is a major cause of deadly disease and a drag on economic development. The United Nations says the total cost of replacing aging water supply and sanitation infrastructure in industrial countries could be as high as $200 billion per year. Jamal Saghir, director of energy, transport and water at the World Bank, said there were not significant funds earmarked for water investment in the stimulus packages of the United States and other countries fighting the economic meltdown. He appealed for greater efficiency in water management. «We can do more with the same or even less,» he said in an address to a packed auditorium at the World Water Forum, a weeklong global conference that is held every three years to issue recommendations on how governments should conserve, manage and supply water. It ends on Sunday. Thousands of delegates from governments, nonprofit groups, businesses and other institutions have gathered for the conference, which is being held in a converted slaughterhouse on the banks of the Golden Horn inlet in Turkey’s biggest city. Waste, sanitation, climate change and a debate over privatization and government policies on water are key topics. Some experts estimate that most of the world’s population will face water shortages in the decades ahead as populations expand and ecosystems deteriorate. The International Union for Conservation of Nature, an environmental network based near Geneva, said increasing demand requires effective laws to sustain the resource. «Water laws must seek a workable balance between the water rights of business users and people who have traditional livelihoods,» said Alejandro Iza, director of the union’s environmental law center. «Without this, the costs to the economy and damage to the environment can be very high.» The union said poor water and sanitation services have sapped an estimated 1 percent of GDP in Colombia and 1.4 percent in Bangladesh through environmental and health deterioration. It cited South Africa as an example of how to do things the right way; there, laws guarantee a basic water supply, protect water-based ecosystems and allow people a say in how the resource is used at the community level. Two activists from California-based International Rivers were detained and escorted yesterday to the airport for deportation after demonstrating at the opening ceremony, the group said. Ann-Kathrin Schneider of Germany and Payal Parekh, a US citizen, unfurled a banner and shouted slogans to protest the construction of dams that they say destroy communities and the environment. Some activists have said the forum helps big water companies to promote their own interests at the expense of the needy. But Caroline Boin of the International Policy Center, a London-based research center, said less than 5 percent of global water management is private and that the «real culprits» are governments that encourage waste by allocating water to special interests and other political allies.