《明史·志·卷六十》
去年，草湾以束自决一口，应当在决口之西开挖新口，以迎埽湾之急流，而在金城至五港岸筑堤束水。
去岁，草湾迤东自决一口，宜於决口之西开挑新口，以迎埽湾之溜，而於金城至五港岸筑堤束水。
Last year, Cao Bay decided to open one on his own accord, and a new opening should be dug to the west of the opening to meet the torrent of the sweeping bay, and a dike should be built from Jincheng to the bank of the Five Ports to restrain the water.
<s>[INST] Kindly elucidate the central themes in this passage in English: 去岁，草湾迤东自决一口，宜於决口之西开挑新口，以迎埽湾之溜，而於金城至五港岸筑堤束水。 [/INST] Last year, Cao Bay decided to open one on his own accord, and a new opening should be dug to the west of the opening to meet the torrent of the sweeping bay, and a dike should be built from Jincheng to the bank of the Five Ports to restrain the water.</s>
Kindly elucidate the central themes in this passage in English: 去岁，草湾迤东自决一口，宜於决口之西开挑新口，以迎埽湾之溜，而於金城至五港岸筑堤束水。
user
Last year, Cao Bay decided to open one on his own accord, and a new opening should be dug to the west of the opening to meet the torrent of the sweeping bay, and a dike should be built from Jincheng to the bank of the Five Ports to restrain the water.
assistant