A visit to a vital Swiss water source during a record-setting drought reveals a spring holding steady on the surface but a water supply picture that’s shifting in ways the country is only beginning to understand. In a corner of canton Fribourg, western Switzerland, Julie Boillat peers into a spring burbling 1,100 litres of clear water every minute. "I think we could drink it," says Boillat, a hydrogeologist with the canton's environment office. She and her team have come to gather data for so...