This year water levels in the middle and lower reaches of the Yangtze are unusually high.

今年长江中下游的水位高得不正常。

《柯林斯英汉双解大词典》

Every river has its upper, middle and lower reaches.

每条河流都有上游、中游、下游。

youdao

Middle and lower reaches of the River from the vicinity of Shek Pik to Walled coconut, gentle tame the river.

万泉河的中下游，从石壁至椰子寨一带，河水温顺平缓。

youdao

Beginning on the fifth day of the fifth lunar month, people of several ethnic groups throughout China and the world celebrate the Dragon Boat festival, especially in the middle and lower reaches of the Yangtze River.

UNESCO: Culture