《汉书·志·沟洫志》
修渠不是挖地，衹建东方的一道堤，向北行三百多里，流入漳水中，它的西面因为山脚是高地，各渠都往往分别引水；干旱时就打开东方低地的水闸灌溉冀州，水涝时就打开西方高处的水闸进行分流。
治渠非穿地也，但为东方一堤，北行三百余里，入漳水中，其西因山足高地，诸渠皆往往股引取之；旱则开东方下水门溉冀州，水则开西方高门分河流。
Building canals is not about digging the ground, but only to build an embankment in the east, extending northward for more than 300 miles before flowing into the Zhang River. Its west side is high due to the foot of the mountain. Each canal tends to divert water separately; the sluices of the eastern lowlands are opened for irrigation of Jizhou when it's drought, and the sluices of the western highlands are opened for diversion when it's flooded.
<s>[INST] Kindly elucidate the central themes in this passage in English: 治渠非穿地也，但为东方一堤，北行三百余里，入漳水中，其西因山足高地，诸渠皆往往股引取之；旱则开东方下水门溉冀州，水则开西方高门分河流。 [/INST] Building canals is not about digging the ground, but only to build an embankment in the east, extending northward for more than 300 miles before flowing into the Zhang River. Its west side is high due to the foot of the mountain. Each canal tends to divert water separately; the sluices of the eastern lowlands are opened for irrigation of Jizhou when it's drought, and the sluices of the western highlands are opened for diversion when it's flooded.</s>
Kindly elucidate the central themes in this passage in English: 治渠非穿地也，但为东方一堤，北行三百余里，入漳水中，其西因山足高地，诸渠皆往往股引取之；旱则开东方下水门溉冀州，水则开西方高门分河流。
user
Building canals is not about digging the ground, but only to build an embankment in the east, extending northward for more than 300 miles before flowing into the Zhang River. Its west side is high due to the foot of the mountain. Each canal tends to divert water separately; the sluices of the eastern lowlands are opened for irrigation of Jizhou when it's drought, and the sluices of the western highlands are opened for diversion when it's flooded.
assistant