The difficulty of dredging the Yellow River is self-evident, as a poem attests:
"Through fractured stone and clouds, by narrow gorges bound,From shattered cliffs, a furious, white-capped torrent pounds.The Suspended River hangs, a sword of direst threat,By deep-sunk silt transformed to hills of mud and wet.The flood crests surge like untamed horses, wild and free,The old course shifts, bringing all humanity misery.A thousand years of troubles stretch for endless miles,The Earth Pivot cannot tame the water dragon's wiles."
In the past two thousand years, the Yellow River has undergone six major course changes. The most recent occurred during the Ming and Qing dynasties, when the river shifted from flowing south into the Yellow Sea to flowing north into the Bohai Sea.
Drought in the dry season and floods in the rainy season. The upstream waters are steep and turbulent, while downstream lies an eight-hundred-li stretch of the Suspended River.
