In my travels, I have been fortunate to come upon the Yellow River in various stages along its course. Most recently it was from a high-speed train heading to Xi’an passing a lake backed up behind the dam at Sanmenxia. However, go back to 1996 when I had come by train from Xining in Qinghai to Lanzhou. Standing at that city’s iconic Zhongshan Bridge I looked at the river as it flowed beyond and wondered why it did not continue directly eastwards toward Xi’an. Instead it turns northeast, heading on a colossal journey right up to Inner Mongolia before reversing south on its long push toward Sanmenxia. The answer lies partly in geology with mountains east of Lanzhou, but this extensive loop, the greatest of the Yellow River’s nine bends has allowed a band of life through a quite hostile, dry environment up to and through Ningxia (Ningxia Hui Autonomous Region) where I was heading in 1997.

Looking at the river from today’s satellite imagery it is fascinating to follow its course, seeing how, for example, it forms the lengthy border between Shaanxi and Shanxi provinces. Two years ago was another memorable personal moment standing on its shores at Shanxi’s Qikou village while recalling how hydrological science started to develop along the river more than 4,000 years previously - a science still very relevant today in controlling and taming its sometimes perilous nature.