What kind of river is Tuojiang in Sichuan?

Tuojiang River is a unique river in Sichuan. The birthplace of Tuojiang River is Jiuding Mountain on the northwest edge of Sichuan Basin, also known as Chaping Mountain. Many streams flow from the east, middle and west of the mountain and gradually merge into three larger tributaries: a river in the west, with a length of 139 km; There is a Shiting River in the middle with a length of 14 1 km, and a Mianyuan River in the east with a length of 180 km. They met near Zhao Zhen in Jintang, and then officially became the mainstream of Tuojiang River. Because Mianyuan River is the longest, it is now considered as the main source of Tuojiang River, and the other two rivers are considered as parallel tributaries. Tuojiang River is located in the middle of Sichuan Province, China. Originated in the south foot of Jiuding Mountain in northwest Sichuan, and in Daheiwan, Duanyantou, Mianzhu City. The south flows to Zhao Zhen and Jintang County to accept the four upstream tributaries of Tuojiang River-Pihe River, Innocent River, Juanjiang River and Shi Ting, and then flows through Jintang Gorge of Longquan Mountain, and then flows into the Yangtze River through jianyang city, ziyang, Zizhong County, Neijiang City and Luzhou City. The total length is 7 12km, and the drainage area is 32900km2. From the source to Jintang Zhao Zhen, it is upstream, with a length of 127 km, which is called Mianyuan River. From Zhao Zhen to Hekou, it is called Tuojiang River, with a total length of 522 kilometers. The average annual precipitation in the basin is 1.200mm, and the annual runoff is 35 1 100 million cubic meters, of which the Minjiang River supplies about 33.4%. The reserve of hydraulic resources is about 6.5438+0.867 million kilowatts. Wooden boats and motorboats can be used in the main stream for many years, and many tributaries in the middle and lower reaches have been channelized. The forest coverage rate of Tuojiang River Basin is only 6. 1%, which is the lowest among all rivers in Sichuan. There are Chengdu, Chongqing, Deyang, Neijiang, Zigong, Ziyang, Mianyang, Suining, Luzhou and other large and medium-sized cities. There are more than 1,000 large and medium-sized factories in Tuojiang Valley, which is Sichuan Province.

Where industry is concentrated, the population density is the highest in other rivers. Tuojiang River Basin is also the largest cotton and sugarcane producing area in Sichuan. The Tuojiang River system is developed, and the Mianyuan River, Qingbaijiang River and Pi River in the upper reaches are connected with the Minjiang River system in the adjacent basins, which constitutes the characteristics of Tuojiang River as an open basin. The tributaries in the middle and lower reaches are symmetrically distributed with the main stream. The main tributaries are Jiangxi River, Qiuxi River, Zishui River, Mengqian River, Daqingliu River, Fuxi River and Laixi River. Tuojiang River originated from Jiuding Mountain at an altitude of 4,984 meters. Divide into three strands. East source: Mianyuan River length 180 km, middle source: Shiting River length 14 1 km, and west source: Juanjiang River length 139 km, which meet near Zhao Zhen in Jintang County to form the main stream of Tuojiang River. In addition, the flowing water at the source of the Tuojiang River comes from the Infinite River and the Pi River, so there are five sources. Moreover, the Minjiang River water network is intertwined and the basin is disrupted. The water of Minjiang River is still flowing in Tuojiang River. Therefore, unlike other rivers, Tuojiang River is a mixed-race river. But in the end, because Mianyuan River is the longest, it is regarded as the positive source. Tuojiang River meanders from Zhao Zhen to Luzhou, with a total length of 522km, which is 2. 1 1 times longer than the straight line. The riverbed of Tuojiang River is not flat, but the ridges and valleys are staggered and rugged. Although it is not conducive to shipping, navigation is early. Jintang Gorge, the first gorge of Tuojiang Three Gorges, is 13 km long, like a big "S", with Baotai Mountain on the right bank and Genting Mountain on the left bank, and the river width is about 100 m. At the end of the Southern Song Dynasty, Sichuanese built a city to protect themselves in the dangerous place of the Yangtze River tributary in order to resist the invasion of the Yuan Army. Now there is a Genting stone town built at that time on Genting Mountain. The second gorge, Moon Gorge, is 2 1km from Dengyingyan in Zizhong County to Guide Township. The mountains here are steep and not high, and the momentum is not as good as Jintang Gorge. The rocks here are easily weathered, so many caves have been formed, and there are also some collapsed boulders in the river. During the flood, the width of the river was only 200 meters. The Three Gorges, Qingshan Gorge, is located in Anxi Town, Fushun County, with a total length of only 2 kilometers. Qian Qian Mountain and Qingshan Ridge on both sides of the river were originally a continuous mountain range, which was abruptly cut off by Tuojiang River, so the width of the river was less than1.20m.. It is said that during the Ming Dynasty, Emperor Wen Jian lived here and became a monk in Qian Qian Temple. The average annual discharge of the estuary is 982 cubic meters per second, and the estuary is 562 meters wide. Hydrology 1. The precipitation in the Tuojiang River basin belongs to subtropical warm and humid weather, with the annual average temperature of the whole basin 17. 1℃. The average annual precipitation for many years in the upper reaches of mountainous areas is about

Evening in Tuojiang River [1]

1200 ~ 1700 mm, upstream 900 ~ 1500 mm, middle and lower reaches 870 ~ 1 100 mm. Precipitation is concentrated from June to September, accounting for about 70% of the whole year. 1978 The annual precipitation of Tianchi Township Station in Mianzhu County is 2363.6 mm, which is the highest in the whole basin. The precipitation in the basin changes greatly every year. The minimum annual precipitation in the upper reaches is usually 550 ~ 1 100 mm, and that in the middle and lower reaches is 520 ~ 800 mm, mostly between 600 ~ 750 mm The minimum annual precipitation in Huang San Miao Station of Jintang County is 5 1969. 1995 Tianchi station has a 24-hour precipitation of 447mm and a three-day precipitation of 673mm, which is the largest record in Tuojiang River Basin. 2. Runoff and Sediment The average annual runoff of the main stream in the upper reaches of Tuojiang River is 46/kloc-0.04 million cubic meters in Mianyuan Tianhe Wangchang, 673 million cubic meters in Shi Ting Gaojingguan Station and 7 104 million cubic meters in Jiangweiguan Station respectively. In the upper reaches of the river, most of the leveled areas are not closed, and water supply is introduced from Minjiang River. According to the incomplete data measured by Shidiyan Hydrological Phenomenon Station of Pihe River and Xinqiao Hydrological Phenomenon Station of Puyang River, the annual water intake is close to 2.5 billion cubic meters. Combined with land leveling and runoff between dikes in Longquan Mountain, the annual average runoff of Miaozhan reached 7.64 billion cubic meters, and the downstream control station increased to 65.438+0.29 billion cubic meters. Together with the runoff in the area below Li Jiawan Station, the average annual runoff in the whole basin of Tuojiangkou is about 654.38+0.4 billion cubic meters. Due to the rapid growth of industrial and mining enterprises along the Tuojiang River basin, a large number of untreated sewage and wastewater are discharged into the river, which leads to the deterioration of the water quality of Tuojiang River.

According to the monitoring results of several groups of water samples in 198 1 by Sichuan Hydrological Phenomenon Station and other units, it is found that the average or extreme value of oxygen consumption and ammonia nitrogen greatly exceeds the surface water standard, and even the river length that meets the national 1 and the second-class water quality standard in the comprehensive evaluation of organic matter in rivers only accounts for 465433 of the river length involved in the evaluation. Of the total river length evaluated, only 1.8% is of excellent water quality, and the detection rates of phenol, cyanide, arsenic, mercury and hexavalent chromium in most river sections all exceed the standard by more than 50%, and the section from Jianyang to Neijiang is seriously polluted (Class IV), indicating that the water quality in Tuojiang River Basin is seriously polluted. Tuojiang River Basin is a weak sediment-producing area in Sichuan Province, and the average sediment transport modulus of Li Jiawan Station for many years is 503 tons/km2. The average annual sediment discharge of each control station in the main stream is 5.82 million tons at Miaozhan, 8.92 million tons at Dengyingyan Hydrological Phenomenon Station in Zizhong County and 6.5438+0.65438+0.7 million tons. The foothills of the upper reaches of the Tuojiang River and the Guadai belt of leveled land belong to the rainstorm area of Longmen Mountain. Due to the long and narrow shape of the basin, under normal circumstances, the rainstorm is separated, the main stream and tributaries are staggered, and the flood peak shape is fat. However, if the rainstorm covers a large area or lasts for a long time, the flood in the middle and lower reaches and the flood peak in the upper reaches will suffer, which will cause a major flood or a catastrophic flood in the main stream. For example, in July of 198 1, heavy rain occurred in the middle and upper reaches of the Tuojiang River Basin, 16543. The rainfall in many land leveling areas in the upper reaches exceeds 300mm, and the average rainfall depth in the basin above the station reaches Netease millimeter. The daily peak flow of Miao Hydrological Phenomenon Station on June 5438+04 is 8 1 10 m3/s, which exceeds the maximum flood in the investigation history (1840). Below Miaozhan, tributaries and interval floods flow into Dengyingyan Hydrological Phenomenon Station. 14, 15, the peak flow reaches 14000 m3/s, the highest water level of Li Jiawan Hydrological Phenomenon Station 16 reaches 273.26 m, and the peak flow reaches 15200 m3/s, only lower than/kloc-0. In winter with less precipitation, there is no surface runoff supply, and the low water flow is very small, sometimes even cut off. The average minimum flow of Li Jiawan Station in the main stream for many years is 32.5 cubic meters per second, and the minimum flow of 1978 in March is only 6.72 cubic meters per second. exploit