Gangou Drain (the section between Huaiyin and Yangzhou of the Grand Canal of China) connected the Yangtze River and the Huai He delta region. The Qian Road and Shan Road that traversed the region reached Southern and Northern China. Thus, Huaiyin was critical area for several strong states in Spring and Autumn period. The region was occupied by the Wu, Yue and Chu states, one after another. During the Qin and Han Dynasty, great improvements, especially in irrigation, were made to agriculture and manufacturing. In the later years of East Han Dynasty, the Governor of Guanglin, Cheng Deng, built the Gaojiayang Levees, 30 miles in total, which kept out flood waters, and protected farmlands. He also built Pofu Pool for farm irrigation. Iron-made apparatus and bull-farming were widespread.