Characteristics of Hanzhong-Chenggu section of Hanjiang River

The characteristics of Hanzhong-Chenggu section of Hanjiang River are as follows:

Specific content:

Upstream: The total length of the upper reaches of Hanjiang River is 956 kilometers, and the catchment area is 95,220 square kilometers. The mainstream is east-west, passing through the canyon basin between Qinling and Daba Mountain. The riverbed is mainly composed of pebbles, gravels and bedrock, and the river slope is large.

Middle reaches: Danjiangkou to Nianpanshan reach, with a total length of 223 kilometers and an area of 45 1.20 square kilometers. The river in this section passes through the hilly and Pinggu basin, and the average ratio drops to 0. 1.9 ‰. The river bed is wide and shallow, with scattered water flow, and there are many Jiang Xinzhou of different sizes. This section belongs to wandering river.

Han Jiang said:

The Hanjiang River, also known as Hanshui River and Hanjiang River, is the largest tributary of the Yangtze River. Modern hydrology believes that there are three sources: Shui Yang in the Central Plains, Qushui in Beiyuan and Daiyu River in Nanyuan, all of which are located in ningqiang county, Shaanxi Province at the southern foot of Qinling Mountains. When it flows through Mianxian (now Mianxian) and flows eastward to Hanzhong, it is called Hanshui River. The section from Ankang to Danjiangkou was called Canglang Water in ancient times, and Xiangyang was nicknamed Xiangjiang River, Xiangshui River and Xianghe River below.

The Hanjiang River is the longest tributary of the Yangtze River and occupies an important position in history. It is often juxtaposed with the Yangtze River, Huaihe River and Yellow River, and is collectively called "Jianghuai Hehan". There are many dangerous canyons in Hanjiang beach, with large runoff, rich hydraulic resources and good shipping conditions.

Overview of Hanjiang River Basin:

1, landform features

According to the stratigraphic situation of Hanjiang basin, the basin has not been invaded since the orogeny at the end of Triassic. During the Jurassic period, the low-lying areas of the basin became inland lakes with sandstone and shale deposits. The orogeny at the end of Jurassic was very strong in this basin, which completed the outline of the basin landform.

In Cretaceous, only Hanzhong basin was slightly deposited in this basin, and the rest areas may be eroded areas. At the end of Cretaceous, orogeny caused the surface of the basin to rise, and folds and faults occurred, forming many basins and grabens, such as Yunxian Basin, Xunxian Basin, Shangxian Graben in Feng Dan and Xixia Graben. Himalayan movement took place from the end of Tertiary to the beginning of Quaternary, which led to the uplift of the whole basin.

2. Climate characteristics

The wind direction of this basin is influenced by the monsoon in winter and summer, with northeast and northwest winds in winter and southeast and southwest winds in summer. Spring and autumn is a transitional period, and the wind direction changes greatly, but it is still northerly. Geographically speaking, generally speaking, there are southeast and south winds in spring and summer, and north and northwest winds in winter in the Hanjiang River basin below the Baihe River.