How many tributaries are there in the Yellow River?

The main tributaries of the Yellow River are Baihe, Heihe, Huangshui, Zuli, Qingshui, Dahei, Kuye, Wuding, Fenhe, Weihe, Luohe, Qinhe and Dawenhe. Weihe River is the largest tributary of the Yellow River.

There are many tributaries of the Yellow River, and the important tributaries mainly include:

I. Baihe and Heihe rivers

Baihe River and Heihe River are two main tributaries in Sichuan in the upper reaches of the Yellow River. They are located at the southernmost tip of the Yellow River Basin and flow through the Zoige Plateau in northern Sichuan. The watershed between the two rivers is low, and there is no obvious watershed boundary. In addition, the characteristics of each basin are basically the same, which can be called "sister river".

Heihe River (also known as Moqu) is named as a gray river because of the development of swamp peat on both sides. Since the river (also known as Gaqu), the terrain is higher, the peat is not obvious, and the river is clear.

The Baihe River originates in Chaleken, Hongyuan County, flows through Hongyuan County from south to north, and flows into the Yellow River near Tangke Town, ruoergai county. The river is 270 kilometers long and the basin area is 5488 square kilometers. The mainstream is the mud river bed. Heyuan to Longriba, with a total length of 38 kilometers, flows through hilly areas, with a large drop, with an average gradient of 24‰ and a valley bottom width of 0.5~ 1.5 kilometers. From Longriba to Wache, the river is 155km long and flows through hilly areas. The river channel is curved, and the specific gradient has been reduced to 0.6‰, and the valley bottom is 2 ~ 3 kilometers wide. There are many beaches on both sides, some areas have been flooded, and there are five big tributaries at intervals. From Wache to the Yellow River Estuary, the river is 77 kilometers long and flows through the plain area. The river twists and turns, with an average slope of 0.3‰ and a valley width of 3-5 km.

Heihe River originates from Dongyacha at the foot of Minshan Mountain at the junction of Hongyuan and Songpan County, flows from southeast to northwest, passes through ruoergai county, and joins the Yellow River in Quguoguomang, Maqu County, Gansu Province, with a total length of 456 kilometers and a drainage area of 7,608 square kilometers.

Baihe and Heihe river basins are located in the inner side of Hongyuan arc structure and controlled by arc structure. In the early Pleistocene, due to the geological tectonic movement, it broke into a lake, gathered the surrounding mountains and rivers, and formed its own independent water system, called Tangke Lake, which gradually became a swamp. Baihe River and Heihe River are developed in this swamp area, so most of these two rivers meander between swamps at the bottom of the basin except for obvious valleys in the upper hilly area, and the water system develops into a series of lakes. There are many swamps and lakes. The larger swamps are Kaha Hadjo, Cho Rejo, Jodi Gongma, Heiqing Bridge, Orenia and Rishjo, and the larger lakes are Haqiu, Tsorajian and Mou Zogel. The area of lakes and marshes is * * * 4,322 square kilometers, including 1020 square kilometers in Baihe basin and 3,302 square kilometers in Heihe basin, accounting for 18.6% and 43.4% of each basin area respectively. In these swamp areas, the rivers are gentle, the drainage is not smooth, the bottom layer is cohesive soil, the permeability is poor, the soil is often saturated, and the sunshine is strong, and the plants grow luxuriantly, which is beneficial to the development of peat and swamp. Under the comprehensive action of this natural geographical condition, the largest swamp in China has been formed. Peat layer thickness can reach more than ten meters, reserves 19.65438+ 100 million tons, concentrated distribution and good quality. According to local tests, the calorific value of peat is very high, reaching 3000 calories per kilogram, which is roughly equivalent to firewood. Peat is not only an energy source, but also a good organic fertilizer. It can also extract rare metals and chemical raw materials.

Baihe and Heihe river basins belong to continental cold temperate climate, and they are also the areas where Songpan Depression is located all the year round. The ground elevation is above 3400 meters above sea level. The annual average temperature is only 0.7~ 1. 1℃, and the extreme minimum temperature is -33.7℃. The climate is characterized by "long winter without summer and short spring and autumn". The average air pressure for many years is 666~670 mbar, with little change. The boiling point of water is very low, only about 88℃. The oxygen content in the air is about 40%~67% of that in the inland plain. The annual average precipitation is 640~750 mm, which is one of the high-value areas in the Yellow River Basin. The precipitation from July to September accounts for about two-thirds of the annual precipitation. The magnitude and frequency of rainstorm belong to the low-value area in the Yellow River basin, and there is no big flood peak due to the sluggish effect of surface swamp on runoff. On July 7th, Heihe Zoige Hydrological Station 196 1, the measured peak flow 19 1 m3 per second lasted for one month, and the total flood reached 33 1 10,000 m3. The average runoff for many years is 65.438+0.78 billion cubic meters for Baihe River and 65.438+0.83 billion cubic meters for Heihe River, and the runoff modulus per square kilometer is 324,000 cubic meters and 2,465,438+0.00 cubic meters respectively, ranking first among the tributaries of the Yellow River.

Second, Taohe River.

Taohe River is a big tributary on the right bank of the upper reaches of the Yellow River. Originated in Henan Mongolian Autonomous County, Qinghai Province, west of Shandong Province, it flows into Liujiaxia reservoir area of the Yellow River in Yongjing County, Gansu Province. It has a total length of 673 kilometers and a drainage area of 25,527 square kilometers. According to the statistics of Goumen Village Hydrological Station, the annual average runoff is 5.3 billion cubic meters, and the annual sediment transport is 29 million tons. The average sediment concentration is only 5.5 kilograms per cubic meter, with more water and less sediment. Among the tributaries of the Yellow River, the annual water volume of Taohe River is second only to Weihe River. Runoff modulus is 208,000 m3/km2, which is second only to Baihe River and Heihe River, and it is a tributary with the largest inflow in the upper reaches of the Yellow River.

Taohe River Basin is located in the northeast edge of Qinghai-Tibet Plateau and the west of Loess Plateau, which has the characteristics of these two regions. Terrain types are complex and diverse. The upper reaches are Heyuan grassland, and the middle reaches are rocky mountain forests and loess hilly areas. Most areas are vast grasslands and dense forests with high ground coverage and good water conservation conditions. The lower reaches belong to the whole loess hilly and gully region, accounting for about 27% of the basin area. Gullies are vertical and horizontal, vegetation is scarce, loess is exposed, and soil erosion is serious, which is the main source and area of sediment in the basin. Although the climate of the basin is continental, due to the influence of the intersection of the Qinghai-Tibet Plateau and the Mongolian Plateau, most areas are wet and rainy, with heavy precipitation. In addition to the annual precipitation in the northernmost part, the annual precipitation in more than 90% areas is above 600 mm, and in some areas it is as high as 8900 mm.

Taohe River system is developed, influenced by the western Qinling tectonic system, with complex geological structure and frequent folds. Faults are mainly high-angle faults, mostly in the northwest direction, so the mainstream is in a big "L" shape, and its turning point is in Yumin County. From Heyuan to Yumin County, Taohe River flows from west to east along the west Qinling Mountains. 417km to Yumin county, then turn sharply to the northwest and flow northward, and then enter Liujiaxia reservoir area for 256km. Taohe River Basin in Min County is one of the main agricultural areas in this basin, with a relatively open shape and many beaches and terraces. After Min County went out of the river, the river valley and Sichuan land alternated, with a large population, concentrated agriculture, large valley gap and rich hydraulic resources. The average width of Taohe river basin is only 38 kilometers, so it is not easy to form a big flood.

Third, Huangshui

Huangshui is a big tributary of the left bank of the upper reaches of the Yellow River. It originated in Haiyan County, Qinghai Province, at the southern foot of Daban Mountain, flows through Xining City and joins the Yellow River in Fuzi Village, Yongjing County, Gansu Province. It is 374 kilometers long and has a drainage area of 32,863 square kilometers, of which about 88% belongs to Qinghai Province and 12% belongs to Gansu Province.

Huangshui is located in the northwest corner of the Yellow River Basin, with the towering Qilian Mountain adjacent to the Hexi Corridor water system in the north, Laji Mountain and the main stream of the Yellow River in the south, and Sun Moon Mountain adjacent to Qinghai Lake in the west. Huangshui River Basin is located at the junction of Qinghai-Tibet Plateau and Loess Plateau. The geotectonic structure belongs to Qilian Mountain fold belt, with complex geological conditions and unique water system structure. The main landscape pattern of the basin is composed of three mountains parallel to the northwest and two valleys sandwiched between them, which constitute two parallel geographical landscape areas, the main stream of Huangshui River and the tributary of Datong River, but the natural conditions are completely different.

Datong River, a tributary, is located in the north of the basin and consists of Qilian Mountain and Daban Mountain next to it. Datong River flows through it, with marshes in the upper reaches and alpine valleys in the middle and lower reaches, with a river length of 56 1 km. The intersection of the two rivers is 256 kilometers longer than the main stream of Huangshui River. Datong River basin covers an area of 15 130 square kilometers, accounting for 46% of Huangshui River basin, with an average width of only 30-50 kilometers. The elevation of the basin is 3000~4000 meters, the climate is cold, the forest and grass are lush, and the population is sparsely populated. Animal husbandry is the main industry.

The main stream of Huangshui River is located in the south of the basin and consists of two parallel mountains, Daban Mountain and Laji Mountain. The Huangshui River flows through it, with an average width of 60~ 100 km. There are many tributaries on both sides of the strait, which are arranged symmetrically in parallel. The larger tributaries are Yaoshui River, Xinachuan, Beichuan River, Shatangchuan and Yinshenggou. Beichuan River covers an area of 337 1 km2, second only to Datong River. The main features of Huangshui River valley are loess hills, deep soil layers, high altitude and low rivers, mild climate, dense population, early agricultural development and serious soil erosion.

Huangshui basin belongs to continental climate. Because of the great difference in topography in this area, the temperature changes greatly in time and space. There is a folk saying in Xining: "The climate in the ancient city is always changeable, so you should bring clothes for all seasons in one day, and there is heavy snow in the Baihua Mountain below, which is rainy during the day and frosty at night", which vividly describes the changeable climate in this area. The basin has high terrain and low temperature, with an annual average temperature of 0.6~7.9℃ and an average temperature of only 10 ~ 22℃ in July. It is a good place for summer vacation. Precipitation increases with altitude, with annual precipitation of 300-500mm in most areas and over 600mm in Datong River. The water and sediment conditions of Huangshui River and Datong River tributaries are quite different. According to the statistics of Minhe and xiang tang Hydrological Stations, the average runoff of Huangshui River for many years is 4.65 billion cubic meters, and the average sediment transport for many years is 24 million tons. The average annual runoff of Minhe Station in the main stream of Huangshui River is 65.438+0.79 billion cubic meters, the runoff modulus is 654.38+0./kloc-0.5 million cubic meters/square kilometer, the average annual sediment transport is 20.5 million tons, and the sediment transport modulus is greater than 6.5438+0.3 million tons/square kilometer, which belongs to mild erosion. Datong River is a tributary with abundant water. According to the statistics of xiang tang Hydrological Station, the average runoff for many years is 2.86 billion cubic meters, and the runoff modulus is 65.438+0.89 million cubic meters/square kilometer, which is 64% higher than the main stream of Huangshui River. The amount of sediment is very small, only 15.5% of the main stream of Nieshui River, and the average sediment concentration is only 1. 13 kg per cubic meter. This is a clear river.

Fourth, the river.

Located in the northeast corner of Hetao area in Inner Mongolia, Dahei River is a big tributary at the end of the upper reaches of the Yellow River. Originated in Ba Ding Cun, Zhuozi County, Inner Mongolia, it flows through the suburbs of Hohhot and joins the Yellow River near Tuoketuo County. Its main stream is 236 kilometers long and its drainage area is 17673 square kilometers. The basin area within the basin is 5 154 square kilometers, accounting for 29% of the basin area. The land is flat and fertile, with vertical and horizontal canals. It is one of the important grain bases in the autonomous region. The northern part is mountainous, accounting for about 54% of the basin area, and the rest is loess hilly area. In Inner Mongolia, the Yellow River flows from west to east, and the main stream of Dahei River flows from north to east, forming a convection pattern, so it is called a reverse tributary.

Geographically, the northern mountainous area of the Dahei River Basin belongs to the Yinshan east-west structural belt, and the southern plain belongs to the faulted basin. This faulted basin, called Hetao Lake, was formed in the Early Tertiary and became its own independent water system. Dahei River was only a big tributary of the eastern part of the water system around the basin at that time. Since the late Pleistocene, the tributary winding from the south of the basin to Tuoketuo has been eroded by the source of the Yellow River, the lake basin has been included in the Yellow River system, and the Dahei River has become a tributary of the Yellow River.

The Dahei River system consists of three parts: the tributary of the Dahei River in the east, the tributary in the west and the Hasuhai backwater. The main stream of the river runs from Heyuan to Meidai, with a total length of1.20km, and runs through rocky ravines, with an average gradient of 4.7 ‰. Plum belt reaches the estuary, with a river length of116km, which flows through Tumochuan plain and is a soil bed. Among them, the length from Mei Dai to Sanliang River is 63 kilometers, with a gradient of 1.63‰, and the length from Sanliang River to Hekou River is 53 kilometers, with a gradient of 0.36‰. There are large tributaries such as Shilaosu River and Baobei River on the left bank below Meidai. The tributaries in the west all originate from Daqingshan Mountain, and the larger ones are Halaqin Gully, Wutugou, Gunpan River (Shuimogou), Wanjiagou, Meidai Gully and Shuijian Gully. The catchment area ranges from several hundred square kilometers to more than 1,000 square kilometers, and the gully is tens to hundreds of kilometers long with steep slope. There is an alluvial fan near the gully mouth, but there is no obvious riverbed after leaving Meiyukou. The mountain torrents overflow on Pingchuan and enter the Dahei River. Hasuhai backwater channel flows through the low-lying plain from north to south, which divides the plain into two parts, the eastern part is called Dahei alluvial plain, and the western part is called Huanghe alluvial plain, which collects backwaters from various canal systems and flows into the tail of Dahei River. The characteristics of the river system are that the main stream and tributaries have fixed flow paths in mountainous areas, but there is no fixed flow path after entering the plain, and most of them are intertwined with irrigation canals, so the water system is chaotic and the drainage is not smooth. In the flood years in history, the vicinity of Tuoketuo is often surrounded by high water on three sides and supported by the Yellow River in the south, which is known as "ten thousand waters are entrusted".

The basin is located in mid-latitude, with continental climate, cold and little snow in winter, dry and windy in spring and concentrated rainfall in summer. The average annual rainfall is 330 ~ 460mm, which decreases from east to west, with great interannual variation and uneven distribution during the year. The water and sand in Heihe River mainly come from mountainous and hilly areas. The annual runoff of Meidai Station on the left bank of the main stream and downstream reaches is 65.438+0.96 billion cubic meters, and that of the tributary on the right bank of Daqing Mountain is 233 million cubic meters, with an annual runoff of 429 million cubic meters and an average runoff modulus of 24,000 cubic meters per square kilometer. Based on Meidai Station, the annual sediment transport capacity is 6 million tons, and the average sediment transport modulus is 1.400 tons/km2. Water and sediment are mainly concentrated in the flood season, and floods often occur in July and August, with steep ups and downs. When mountain torrents break out, they often carry a lot of sediment and contain a lot of organic matter, which makes Tumochuan Plain silted up and become fertile soil. As early as more than 200 years ago, people have cited mountain floods to irrigate farmland. After the founding of the people's Republic of China, there has been greater development. Many flood diversion and siltation projects have been built under the main stream and its tributaries, which have led away the flood and sediment step by step. Since 1968, except for a few flood years, the flood of Dahei River rarely flows into the Yellow River.

Verb (abbreviation for verb) Kuye River

Kuye River, a tributary on the right bank of the middle reaches of the Yellow River, originates in Badinggou, Dongsheng City, Inner Mongolia Autonomous Region, flows southeast and joins the Yellow River in Shamaotou Village, Shenmu County, Shaanxi Province. The main stream is 242 kilometers long and the basin area is 8706 square kilometers. According to the measured data of Wenjiachuan Hydrological Station 1954~ 1980, the annual runoff is 747 million cubic meters, the annual sediment transport is 654.38+36 million tons, the average sediment concentration is as high as 182 kg/cubic meter, which is 6.4 times that of the Yellow River, and the sediment transport module in the basin is as high as/kloc-0. Coarse sediment with particle size greater than 0.05 mm accounts for 60% of the total sediment. Therefore, the Kuye River basin is one of the main sources of coarse sediment in the Yellow River, which has a serious impact on sediment deposition in the lower reaches of the Yellow River.

The terrain of the Kuye River Basin is high in the northwest and low in the southeast, and the altitude drops from 1500m to 740m, with a large average slope. The distribution of the water system is dendritic, and it is divided into two tributaries above the Shenmu Fangzi Tower. The west tributary is called Wulanmulun River. Niuchuan in the east is the largest tributary, with a river length of 109 km and a catchment area of 2,274 square kilometers, accounting for 26% of the basin area. After the two rivers meet, it is called the Kuye River. The two banks are hilly and gully areas of loess, with many branches and canals, and soil erosion is particularly serious. The northwest of the basin is a sandy arid grassland area with scarce vegetation and serious wind erosion.

The exposed rocks in the basin are mostly sandstone or interbedded sandstone and mudstone, which are arranged horizontally, with low strength and easy weathering. The upper part of bedrock is red soil, red soil and new loess. The new loess is formed by wind, and its median particle size is greater than 0.045 mm The Kuyehe River basin is one of the common rainstorm centers in the middle reaches of the Yellow River. The intensity of short-duration rainstorm can reach more than 2 mm per minute, which often forms a flood with rapid fluctuation and extremely high sediment concentration. According to the actual measurement of Wenjiachuan Hydrological Station, the maximum peak discharge of 1976 reached14000m3 per second, and the high sediment concentration of1700kg per cubic meter appeared in 1958 in July. The Kuye River Basin belongs to the border between the Loess Plateau and the desert, with dry climate and fragile ecological environment. The basin is rich in coal resources, and the famous Dongsheng and Shenmu rich (valley) coalfields are quite large. Speeding up the regulation of Kuyehe River plays an important role in improving the ecological environment, promoting the economic development of the basin and reducing the input of coarse sediment in the Yellow River.

The intransitive verb indefinite river

Wuding River is a sandy tributary on the right bank of the middle reaches of the Yellow River. Originated in Dingbian County at the foot of the northern mountain in Shaanxi Province, it flows through Uxin Banner in Yikezhaomeng, Inner Mongolia, flows to the northeast, then turns to Yuhebao to the east, then turns to the southeast, and flows into the Yellow River in Hekou Village, Qingjian County, Shaanxi Province, with a total length of 49 1 km and a drainage area of 3026 1 km2. According to the measured data of Kawaguchi Hydrological Station 1957 ~ 1967, the average annual runoff15.35 million cubic meters, annual sediment transport 21700,000 tons, and average sediment concentration 14 1 kg/cubic meter.

Wuding River Basin is located in the northern part of the Loess Plateau and the edge of the Mu Us Desert, which has both geomorphological features. According to the landform and soil erosion characteristics, the basin can be divided into three types: one is the sandstorm area, which is located in the northwest of the basin and covers an area of l6446 square kilometers, accounting for 54.3% of the basin area. The ground is covered with Quaternary loose sand and sandy loess, and the landform includes mobile, semi-fixed and fixed sand dunes and beaches, with slight water erosion and serious wind erosion. 2. The area between beams at the source of the river is located in the southwest of the basin, with an area of 3,454 square kilometers, accounting for 1 1.4% of the basin area. Gully erosion is particularly serious, and the annual erosion accounts for 2 1.4% of the annual sediment transport in the basin. 3. The whole loess hilly and gully region is located in the middle and lower reaches of the basin, with an area of 1036 1 km2, accounting for 34.396% of the basin area. The annual erosion accounts for 72.6% of the annual sediment transport in the basin, which is the main source area of sediment in the basin, and the erosion modulus is as high as 1770 tons/km2.

Over the years, the Wuding River has been listed as the focus of soil and water conservation management, and the comprehensive management has achieved remarkable results. Among them, Yulin area has made great achievements in sand control, and a large number of sand dams and reservoirs have been built on tributaries of the basin, especially a series of water storage and mud dams in the upper reaches of Wuding River, which have effectively stopped sand. Through comprehensive management, the water and sediment conditions in the basin have been changed. According to the measured data of Kawaguchi Hydrological Station, the average runoff ratio of1971980 decreased by 25.3% and the annual sediment discharge decreased by 62%. 4% (including the small impact of rainfall) In recent years, huge natural gas resources have been discovered and developed in the basin. 1997, the natural gas in wuding river basin was transported to the capital Beijing by pipeline.

Seven, Fenhe River

Fenhe River originates from Guancen Mountain in ningwu county, Shanxi Province, runs through the central part of Shanxi Province, flows through Taiyuan and Linfen great basin, and joins the Yellow River in Wanrong County. The length of the main stream is 7 10 km, and the drainage area is 3947 1 km2. It is the second largest tributary of the Yellow River and the largest river in Shanxi Province. Fenhe River basin accounts for 25% of Shanxi Province, covering 47 counties and cities, with a population of 910.7 million mu and cultivated land10.7 million mu, accounting for 37% of the total population and 30% of cultivated land respectively, of which 710.9 million mu is irrigated, accounting for 44% of the whole province. Many important industrial cities, such as Taiyuan, Yuci, Linfen and Houma. , are concentrated in the Fenhe River, and their location is very important.

Influenced by the meridional tectonic systems such as Luliang Mountain and Taihang Mountain, the Fenhe River system developed into a river in a series of graben basins. The Fenhe River in ancient times was longer and bigger than it is now. In the late Pliocene, the Fenhe River has a long history. It flows through Ding Xin, Taiyuan, Linfen and Yuncheng, and flows south through Zhongtiao Mountain, where Jinmao in Pinglu County joins the Yellow River. After the Himalayan movement, both sides were attacked. According to textual research, today's upper reaches of Hutuo River still entered Taiyuan Basin from Shilingguankou in the early Pleistocene, which is the east branch of the upper reaches of Fenhe River. Later, due to the rapid traceability erosion of the Shilingguan uplift and the rivers on the east side of Taihang Mountain, it attacked the east branch of Fenhe River and became the upper reaches of Hutuo River, leaving an unnatural bend in the landform, while Fenhe retained the west branch and became the upper reaches of Fenhe River today. In Pliocene, the lower reaches of Fenhe River still flowed into the Yellow River through the Yuncheng Basin in the south, but it was revived by the ne-trending fault in the Sushui River Valley, causing it to fall again, causing the ancient Fenhe River to turn around and run along the lower reaches of the Sushui River Valley and merge into the Yellow River near Yongji County. During the Upper Pleistocene, the fault between Longmenshan and Gufengshan revived, the middle collapsed and the south rose rapidly, forcing Fenhe to abandon the ancient river course and turn west to flow into the Yellow River, forming the current water system.

Influenced by human activities, the water sofa in Fenhe River Basin has undergone great changes. According to the measured data of Hejin Station, the average annual runoff from 195 1 959 is 177 billion cubic meters, and the annual sediment discharge is 0.7 1 100 million tons. Since 1959, the average annual runoff of Hejin Station 1960 to 1978 has decreased to 144 billion cubic meters, and the annual sediment discharge has decreased to 28 million tons, respectively, which is 18% lower than that of the previous period. Since 1980s, the runoff of Hejin Station has decreased sharply, and the contradiction between supply and demand of water resources in the basin is prominent. The shortage of water resources is the main problem facing Fenhe River Basin.

Eight, Weihe River

Located at the base of the hinterland of the Yellow River, the Weihe River starts from Wushushan in the west, reaches Tongguan in the east, Bai Yushan in the north and Qinling in the south, with a drainage area of134,800 square kilometers, which is the largest tributary of the Yellow River. According to the test data of hua county Hezhuangtou Hydrological Station, the annual runoff of Weihe River is 65.438+0.005 billion cubic meters, and the annual sediment discharge is 534 million tons, accounting for 65.438+09.7% and 33.4% of the annual water and sediment discharge of the Yellow River respectively. It is a tributary that transports the most water and sediment to the Yellow River. The Weihe River basin covers 87 counties and cities in the three provinces of Shaanxi, Gansu and Ningxia, with a population of 24.06 million and cultivated land of 58.67 million mu, accounting for 28.5% of the population and 30.4% of the cultivated land in the Yellow River basin respectively. The area to the east of Baoji Gorge is the famous Guanzhong Plain, where large-scale irrigation areas are concentrated and contiguous, and there are many large and medium-sized cities, so its economic status is very important.

The development of Weihe River system is influenced by the belt structure system of Qinling Mountains and the zigzag structure system of Qi, Lu and Heshan. The geological structure is complex, and the tributaries on both banks are asymmetrically distributed. The main stream of Weihe River is in the south of the basin, flowing eastward along the northern foot of Qinling Mountains, with a total length of 865,438+08 km, in which the source of Weihe River passes through the mountains and the valleys alternate with each other. Below Baoji Gorge, it flows through the graben fault basin, which is called Guanzhong Plain. The valley is wide, the slope is gentle and the water is curved. Nan 'an water system originates from Qinling Mountains and flows through rocky mountainous areas. It is a tributary with short flow, large slope and little water and sediment. The north bank water system developed in the Loess Plateau has a long history, large catchment area and serious soil erosion, and is the main sediment-producing area in the basin. The larger tributaries are mostly concentrated in the north bank, and there are three tributaries with the size exceeding 10000 square kilometers, namely Hulu River, Jinghe River and Beiluo River.

Hulu River originates from Moon Mountain in Xiji County, Ningxia, flows through Jingning County, Zhuanglang County and Qin 'an County in Gansu Province, and joins Weihe River in Sanyangchuan, Tianshui. The river is 300 kilometers long, with a drainage area of 10730 square kilometers and an annual runoff of 500 million cubic meters.

Jinghe River, which originates from the eastern foot of Liupanshan Mountain in Jingyuan County, Ningxia, joins Weihe River in Gaoling County, Shaanxi Province. The river is 455 kilometers long and the drainage area is 4542 1 square kilometer. According to the statistics of Zhangjiashan Station, the annual runoff is 2 billion cubic meters and the annual sediment transport is 282 million tons, which is the main sediment-producing area of Weihe River. The main stream of Jinghe River runs from Heyuan to Kongtong Gorge, and the downstream breakfast head reaches Zhangjiashan in Jingyang, which is a canyon reach. The rest reaches are wide, from Pingliang to Jingchuan, and the valley is 2~3 kilometers wide, which is the largest Sichuan area of Jinghe River. The distribution of Jinghe River system is slightly palm-shaped, and there are many tributaries, among which there are 7 tributaries larger than 1000 square kilometers, mostly concentrated in the area from Zhengping to Tingkou, and frequent floods occur. Due to the influence of geography and climate, the distribution of water and sediment in the basin is very uneven. Most of the water comes from the Liupan Mountain area in the upper reaches and the tributaries on the south bank of the main stream, and most of the sediment comes from the tributaries on the north bank. Malian River is the largest tributary of Jinghe River, originating from Dingbian County, Shaanxi Province, with a drainage area of 19086 square kilometers. The second largest tributary is the Puhe River, which originated in Huan County, Gansu Province, with a drainage area of 7,478 square kilometers. These two tributaries flow through the loess hilly and gully region and the loess plateau gully region, with loose soil and serious soil erosion, which are the main sources of sediment in Jinghe River.

Beiluohe River originates from the southern foot of Bai Yushan Mountain in Dingbian County, Shaanxi Province, and joins the Yellow River in Dali County. It is 680 kilometers long and flows from northwest to southeast. Beiluohe River system is dendritic, with many tributaries, with a drainage area of 26,905 square kilometers, among which there are three tributaries, namely Hulu River, Qushui River and Zhoushui River, which are larger than 1 0,000 square kilometers. Hulu River is the largest tributary of Beiluo River, which originated in Ziwuling, Huachi County, Gansu Province. This river is 235 kilometers long and covers an area of 5,449 square kilometers. Vegetation in the basin is good and soil erosion is slight. According to statistics of Zhuangtou Hydrological Station, the annual runoff of Beiluo River is 924 million cubic meters, and the annual sediment discharge is 98 million tons. The upper reaches of the basin belong to the loess hilly and gully region, with deep ditch and steep slope, broken terrain, scarce vegetation and serious soil erosion. Second, it is the main sand-producing area in the basin. According to the statistics of Liu Jiahe Hydrological Station, the upstream control area accounts for only 30% of the whole river, but the annual sediment discharge accounts for 90% of the whole river. The middle reaches of the basin, especially Ziwuling in the west and Laoshan and Huanglong Mountain in the east, are the main water-producing areas with large forest area and good water conservation conditions. The tail section of Beiluo River is close to the Yellow River. Historically, due to the westward invasion of the Yellow River, it once entered the Yellow River directly.

Although Jinghe River and Beiluohe River belong to the secondary tributaries of the Yellow River, they are often studied as independent water systems because of their large basin area and large amount of water and sediment, and they are often juxtaposed with the main stream of Weihe River, and are called "Luo Jing, Weihe River and Weihe River". The slope of the lower Weihe River is gentle, and the reach near the Yellow River estuary has been affected by the swing of the Yellow River and flood jacking. After the construction of Sanmenxia Reservoir, the riverbed of the Yellow River silted, and the lower reaches of Weihe River silted, and the river course and flood level rose, which aggravated the flood disaster.

Nine, Luohe

The Luohe River originated in Lantian County, at the southern foot of Huashan Mountain in Shaanxi Province, and joined the Yellow River in Gongxian County, Henan Province. The river is 447 kilometers long, with a drainage area of 1888 1 square kilometer and an average width of 42 kilometers, showing a long and narrow shape. According to the statistics of Heishiguan Hydrological Station, the annual average runoff is 3.43 billion cubic meters, the annual sediment transport is 0./kloc-0.80 billion tons, the average sediment concentration is only 5.3 kilograms per cubic meter, and the runoff modulus is/kloc-0.82 million cubic meters per square kilometer, with more water and less sediment. It is one of the many tributaries of the Yellow River. The basin covers 2 1 county and city in Shaanxi and Henan provinces, with a total population of 5.69 million and a population density of 30 1 person/square kilometer. The Luohe River Basin is adjacent to Huashan and Xiaoshan in the north, Funiu Mountain and the Yangtze River system in the south, and Fangshan in the southeast is adjacent to the Huaihe River. The terrain is high in the southwest and low in the northeast. This river is roughly parallel to the main stream of the Yellow River. The rocky mountainous area in the basin accounts for 45.2% of the basin area, mainly distributed in the middle and upper reaches, with good vegetation, large forest coverage and good water conservation conditions. Loess hilly area accounts for 5 1.3% of the basin area, mainly distributed in the middle reaches, with sparse vegetation, dense population and high farming index, which is the main source area of sediment in this basin. The alluvial plain covers only 3.5% of the basin area and is located in the valley basin along the river. It is the main agricultural base in the basin, and also an area with early cultural development in history, with dense population and prosperous economy. Luoyang, the ancient capital, is located in the lower reaches of Luohe River Basin.

Luohe River Basin is located in the south of warm temperate zone, with annual precipitation of more than 600 mm, and the mountain area in the south is as high as 900 mm. There are many rainstorms in the basin, with high rainfall intensity and large rain area. Rainstorm centers often appear in the middle of the basin. For example, in July of 1982, the maximum 24-hour rainfall of the rainstorm center in Shi Jian town of Yiyang was as high as 734.3mm. According to the analysis of historical data, the Luohe River was one of the main flood sources of the Yellow River. Because the Luohe River is adjacent to the lower reaches of the Yellow River, the flood of the Luohe River poses a great threat to the lower reaches of the Yellow River. The middle and upper reaches of Luohe River have narrow valleys, hard lithology and many excellent dam sites. There are many tributaries on both sides of the Luohe River, with short source and rapid flow, and most of them are symmetrically arranged in parallel. The largest tributary is the Yi River, which is located in the south of the basin, separated from the main stream by Xiong 'er Mountain, with a basin area of 6,029 square kilometers, accounting for 3 1.9% of the Luohe River basin area. Its flow direction is parallel to the mainstream, and its valley shape is similar to the mainstream. Jianhe, the second largest tributary, is located in the north of the river basin, with a basin area of 1.349 square kilometers, accounting for 7. 1% of the Luohe river basin area. These two tributaries meet with the main stream between Luoyang and Yanshi, and form a fan-shaped water system together with the main stream. Often, the three rivers, Yi, Luo and Jian, flood at the same time, and their confluence is concentrated, forming a large peak flow. Two large reservoirs, Luhun and Guxian, were built on the Yihe River and Luohe River respectively, which played a role in reducing floods and developing and utilizing water resources.

Qinhe river

The Qinhe River originated in Heicheng Village, Pingyao County, Shanxi Province, from north to south, crossed the Lu Qin Plateau and Taihang Mountain, entered the alluvial plain from wulongkou, Jiyuan, and joined the Yellow River in Wuzhi County, Henan Province. The river is 485 kilometers long and the drainage area is 13532 square kilometers.

The elevation of the mountain range at the edge of the basin is mostly above 1500m, and the elevation of the central mountain range is about 1000m. The rocky mountain forest area in the basin accounts for 53% of the basin area; The area of earth-rock hills accounts for 35% of the basin area; Valley basin accounts for10% of the basin area; The alluvial plain accounts for 2% of the basin area, which is distributed below wulongkou in Jiyuan, which is beneficial to irrigation and threatened by floods.

The main channel is divided into four sections: from Heyuan to Anze Ling Fei, the length is 13 1 km, with an average gradient of 8‰, the riverbed is all gravel, the valley is 400~ 1000 m wide, and the mountains on both sides are 50~ 100 m high; The length from Lingfei to Huze River mouth is 179 km, with an average gradient of 2.4‰. The upper valley is deep and winding, and the lower valley runs through Runcheng Basin. The valley is generally 200 ~ 500m wide, and the mountains on both sides are 50 ~ 150m high. Many turbine pumping stations have been built for irrigation and power generation. Huzehekou to wulongkou is 85km long, with an average gradient of 3.6‰. The river cuts the Taihang Mountain and runs through canyons about 200~300 meters wide. The cliffs on both sides are steep and the water is fast. Karst cave water is developed in the limestone area of this reach, and the maximum flow of Mashan Spring is 4 cubic meters per second. From wulongkou to Qinhekou, it is 90 kilometers long with an average slope of 0.5‰. The river flows through the alluvial plain, commonly known as the lower reaches of the Qinhe River, and receives the largest tributary, Dan River, near Beijin Village in Boai. The Danhe River originates from Danzhuling, Gaoping, and flows through Zezhou Basin, with a length of 169 km and a drainage area of 3 152 km2. Embankments are built on both banks of the lower reaches of the Qinhe River, with a total length of 150 km. The riverbed is 2-4m higher than the ground on both sides. The Beilin River near Muluandian in Wuzhi County is 7- 10 meter, which is close to the lower reaches of the Yellow River and is also a "river on the ground" with frequent breaches in history.

Qinhe River Basin has a continental climate, with an annual average temperature of 10~ 14.4℃ and a frost-free period of 173~220 days. The annual precipitation decreases from south to north, with an average of 6 17mm in the middle and upper reaches and 600-720mm in the lower reaches. The annual average natural runoff of Xiaodong Station is 65.438+0.78 billion cubic meters, of which 82% comes from wulongkou and the rest comes from Danhe River. The interannual variation and annual distribution of annual runoff are very uneven. The measured annual runoff of Xiaodong Station 1965 ~ 1966 is 200 million cubic meters, which is only 13% of the average runoff for many years. The runoff from 7- 10 accounts for more than 60% of the annual runoff, while the runoff from March to June in spring irrigation only accounts for 17%. The average annual sediment discharge is 7.2 million tons, 80% of which is concentrated in July-August.

Qinhe River Basin is one of the flood source areas between Sanmenxia and Huayuankou of the Yellow River. About 60%~70% of the flood in Qinhe River comes from above wulongkou. According to the investigation and research, in the eighteenth year of Chenghua (1482), there was a flood peak flow of 14000 cubic meters per second at Yangcheng Jiunvtai.

The total population of Qinhe River Basin is 210.7 million, of which the agricultural population accounts for 92% and the cultivated land is 5.37 million mu. According to legend, the irrigation area in the lower reaches of Qinhe River began in Qin Dynasty. After the founding of People's Republic of China (PRC), the water conservancy construction in the whole basin developed rapidly. According to statistics, the irrigation area of 198 1 has reached 2.05 million mu (including the irrigation area outside the downstream basin). Five medium-sized reservoirs, including Mi Shan, Renzhuang, Dongfeng, Shangjiao and Qingtianhe, have been built, with a total storage capacity of 1.5 1 100 million cubic meters. In the dry season, the amount of water can no longer meet the water demand.

Xi。 Jindihe

Jindi River originates in Xinxiang County, Henan Province, flows northeast, flows through Henan and Shandong provinces, and crosses the Yellow River near Zhangzhuang, Taiqian County. The main stream below Huaxian County is 158.6 km long, which is a plain inclined river. The main tributaries are Huangzhuang River (including Liuqinghe River), Huimugou and Menglou River. The basin is long and narrow, covering an area of 4,869 square kilometers, with a total population of 2.88 million and cultivated land of 5.3 million mu.