Overview of Kuye River Basin

The terrain of the Kuye River Basin is high in the northwest and low in the southeast. Above Shenmu County, sand dunes are densely covered with quicksand, and it is located at the southeast edge of Mu Us Desert, with flat terrain and little fluctuation. Below Shenmu county is the loess hilly and gully region, covered with loess and the ground is broken. It is a ravine with vertical and horizontal beam and Mao terrain, lacking vegetation and serious soil erosion. Estuary is a rocky mountainous area, where rivers cut bedrock, with steep slopes and high banks, and few tributaries.

Generally, there are three terraces in the valley, and the first terrace is 5 meters higher than the riverbed1~, which is an accumulation terrace composed of alluvial sand and sandy clay. The second terrace is higher than the riverbed 10 ~ 20m, which is a basement terrace with some residues. The third terrace is 40 ~ 50 meters higher than the riverbed, which is a denudation terrace.

The average gradient of the whole river is 3.44‰, including 4.28‰ from Fangzita to Hekou, 2.83‰ from Wulanmulun River and 2.43‰ from Niuchuan River. According to the characteristics of the river, the Kuye River can be divided into three sections:

From Fangzita to Shenmu, the river valley is wide, the riverbed is dominated by gravel and sediment, and there is no rock bank, with an average length of 10.46 km and shoals.

The upper section of Shenmu-Shatou River bed is relatively flat and wide, mainly composed of silt, alternating with rocks and earth dikes, and the coast is flat, with an average length of 4.32 kilometers and dangerous beaches.

From Shatou to Shamaotou, the riverbed is gentle, composed of silt and gravel, with twists and turns and many shoals, with an average length of 1.73 km.

The water system of Kuye River is simple in structure, and the main stream is slightly "Ya"-shaped. Among them, the Kuye River is a straight river with short tributaries on both sides and the longest tributary is less than 42 kilometers. There are 12 tributaries in the southwest coast and 9 tributaries in the northeast coast, which are slightly asymmetrical.

Wulanmulun River, with a total length of132.5km, has a drainage area of 3,837.27km2, and is 36.5km and 770km2 in Shaanxi. There are two larger tributaries: Limeditch, with a river length of 20 kilometers and a drainage area of 327.2 square kilometers, with a river gradient of 8.81‰; Zhugaigou, the river is 29 kilometers long, with a drainage area of 177.0 square kilometers and a river gradient of 8.57‰.

Niuchuan River is 87.5 kilometers long with a drainage area of 2,276.65 square kilometers. The length of rivers in Shaanxi is 36.7 kilometers, and the drainage area is 72 1 square kilometer. An important difference with Wulanmulun River is that it is a seasonal river north of Miao Xin, Inner Mongolia, accounting for about 1/2 of the whole river. There are two large tributaries: the length of Yu He River is 2 1.0km, and the drainage area is147.8km2; Dabantuchuan is 29.05 kilometers long, with a drainage area of 238.3 square kilometers and a river slope of 8.24‰.