US Secretary of State Hillary ClintonRivers know no borders, but dams doBy Michael RichardsonBack in 1986, when China began building the first of a series of dams on the Mekong River, hardly anyone in the downstream countries of Southeast Asia paid attention. But today, as China races to finish the fourth dam for generating electricity on the upper reaches of Southeast Asia’s biggest river, concerns about possible environmental impacts in the region are rising fast. Moreover, fear about antagonizing China and Southeast Asia’s internecine dispute might make any concerted move unlikely.The sheer scale of China’s engineering to harness the power...