《明史·志·卷六十四》
从前，人们在下游开挖成池塘沟渠，导引各湖水往北流入长江，往东流入大海，又导引入江潮水广泛流布于冈陇之外蓄水排水有法度，发生水灾旱灾没有忧虑。
昔人於下流疏为塘浦，导诸湖水北入江，东入海，又引江潮流衍於冈陇外。潴泄有法，水旱无患。
In the past, people dug ponds and canals in the downstream, guiding the water of all lakes to the north into the Yangtze River and to the east into the sea. They also guided the Jiang tides to flow widely outside the Ganglong. There were rules for storing and draining water, and there was no worry about floods or droughts.
<s>[INST] Kindly elucidate the central themes in this passage in English: 昔人於下流疏为塘浦，导诸湖水北入江，东入海，又引江潮流衍於冈陇外。潴泄有法，水旱无患。 [/INST] In the past, people dug ponds and canals in the downstream, guiding the water of all lakes to the north into the Yangtze River and to the east into the sea. They also guided the Jiang tides to flow widely outside the Ganglong. There were rules for storing and draining water, and there was no worry about floods or droughts.</s>
Kindly elucidate the central themes in this passage in English: 昔人於下流疏为塘浦，导诸湖水北入江，东入海，又引江潮流衍於冈陇外。潴泄有法，水旱无患。
user
In the past, people dug ponds and canals in the downstream, guiding the water of all lakes to the north into the Yangtze River and to the east into the sea. They also guided the Jiang tides to flow widely outside the Ganglong. There were rules for storing and draining water, and there was no worry about floods or droughts.
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