First, there is a connection.
It has been pointed out that if Sichuan Basin is compared to a big wooden barrel, and the shortest batten is located in the Three Gorges, this naturally formed narrow gap becomes the key to transporting water and gas to the basin. However, the dam artificially changed the natural landscape, lengthened the short wooden strips, blocked the main channel of water and gas circulation, caused the perennial temperature imbalance in the barrel, and severe drought and high temperature weather appeared, which is the "barrel effect".
The second is that there is no connection.
Some experts say that this high temperature phenomenon is caused by the background of a large system. This summer, the "western deep gathering point" of subtropical high is generally higher than in previous years, and the subtropical high as a whole deviates to the north-northwest direction for a long time. The theory of "barrel effect" has no sufficient scientific basis. Although the Three Gorges basin is long, its width is not large, which has little impact on the climate along the basin, and even less on the Sichuan basin. Moreover, according to the scientific simulation of the Three Gorges experiment, the construction of the Three Gorges Dam will not lead to drought in the surrounding areas, but will increase the precipitation by about 10%. According to historical records, before the construction of the Three Gorges Dam, there was also a drought in Sichuan Basin in history (of course, I don't think historical records can be used as favorable evidence to prove that it is not the cause of the Three Gorges Project).
I am not an expert in this field, but I often read newspapers and watch such discussions. I'm not sure if it's the Three Gorges Project, because I haven't studied the barrel effect at all. I studied international trade. In my opinion, it is only because of the combination of two reasons, namely the barrel effect and the subtropical high, that it is so hot. Hehe, just kidding.