Ancient Chinese irrigation system stands test of time -- and quake by Ian Timberlake Thu May 22, 11:55 PM ET DUJIANGYAN, China (AFP) - High above the world's oldest operating irrigation system, Zhang Shuanggun, a local villager, stands on an observation platform cracked by China's massive earthquake last week. She has a simple answer for why the ancient, bamboo-based Dujiangyan irrigation system sustained only minor damage, while nearby modern dams and their vast amounts of concrete are now under 24-hour watch for signs of collapse. "This ancient project is perfection," Zhang said. From the hillside platform, the workings of the...