Zhejiang Province is located on the coast of the East China Sea, with high terrain in the southwest and low terrain in the northeast, which inclines from southwest to northeast, showing a cascade decline. The southwest is a mountainous area with an average elevation of 800 meters, and most of the peaks above 1.500 meters are concentrated here. The Huangmao Peak in Longquan County is the highest peak in the province, with an altitude of 1.929 meters. The central part is dominated by hills, large and small basins are scattered between hills and mountains, and the northeast part is alluvial plain with flat terrain, deep soil layers and dense river networks. The mountains extend all the way to the East China Sea, and the peaks above the water constitute peninsulas and islands. There are more than 2,000 islands along the coast of Zhejiang, which is the province with the largest number of islands in China. The vast sea area constitutes Zhejiang's marine fishing ground.

The main mountain range in this province is southwest-northeast, which is divided into three branches from north to south. It starts from Huaiyu Mountain at the junction of Zhejiang and Jiangxi in the north and reaches Tianmu Mountain and Ligang Mountain in Zhejiang in the east. The middle branch extends northeast from Xianxialing at the junction of Zhejiang and Fujian to Tiantai Mountain, Siming Mountain and Huiji Mountain. Tiantai Mountain does not enter the sea from west to east, forming Zhoushan Islands. The south branch extends from Donggong Mountain at the junction of Zhejiang and Fujian to the northeast as the South Yandang Mountain Range, and crossing the Oujiang River is called the North Yandang Mountain Range and the Kuocang Mountain Range.

Zhejiang is located in the subtropical zone, with mild and humid climate and four distinct seasons. The reasons for the high tide of Qiantang River are as follows: Firstly, it is related to the shape and special topography of Hangzhou Bay where Qiantang River enters the sea. Hangzhou Bay is trumpet-shaped with a big mouth and a small belly. The channel of Qiantang River narrows and rises sharply from the west of Ganpu, which leads to the sudden decrease of riverbed capacity, and a large number of tides flood into the narrow and shallow channel, and the tidal head is blocked, and the tidal head behind it advances rapidly, forcing the tidal head to stand, break and roar, forming a breathtaking and spectacular scene. Secondly, there is a huge sandbar in the estuary. When the tide rushes in and meets with strong resistance, it will definitely lift the sky. The front wave was suppressed and the back wave rose again. Waves push waves, and waves overlap. The tide naturally surges and growls, coming like an avalanche. The height of tidal head can reach more than 3.5m, and the tidal range can reach 10m. Third, the spring tide is related to the gravity of the moon and the sun. Tide is a periodic fluctuation phenomenon of seawater under the gravity of the moon and the sun. The tide in Qiantang River is mainly caused by ebb tide, so it is also related to the gravity of the moon and the sun.

The reason for the high tide in Qiantang River is the gravity of the moon and the rotation of the earth. The actual tide will also be restricted by many factors such as geographical environment, coastal location, ocean current movement and so on. Taking the tide of Qiantang River as an example, we know that Hangzhou Bay at the mouth of Qiantang River is trumpet-shaped and narrower and narrower. In addition, the sediment brought in during the high tide is deposited at the bottom of the river to form sandbars, which leads to the surge of the tide.