Is there any composition describing Nenjiang County in Heilongjiang Province?

Nenjiang River originates from the south side of the middle section of Ilhuli Mountain in Daxing 'anling, and its source is Nanweng River (also known as Nanbei River). Its source is 1030 meters above sea level, and its source is a network stream of snowmelt and springs. At 127.2 km, it flows from northwest to southeast, and then flows south with Ergen River, which is called the main stream of Nenjiang River. Since then, the water has flowed from north to south. It flows through Oroqen Autonomous Banner, Qiqihar City, Da 'an City, etc. 15 cities, counties (flags) and joins the second Songhua River originating from Tianchi Lake in Changbai Mountain near Sancha River in Songyuan City, Jilin Province. From Heyuan to Sanchahekou, it is1.370km long, the main stream is 975km long, and the drainage area is 282,748km2.

Nenjiang River is divided into upstream section, middle section and downstream section according to its topography, landform and valley characteristics. From the source of Nenjiang River to Nenjiang County, the total length is 66 1km. The source area is the famous mountain forest area in Daxing 'anling, with dense forests, numerous swamps, narrow valleys, steep river slopes and fast-flowing water, and the water surface width is100 ~ 200m. The river is composed of pebbles and gravel. Below the source area, the river gradually widens, with the river gradient decreasing by 3. 1 ‰ ~ 3.6 ‰, with tributaries flowing in one after another, and the water volume increasing, and the width of the river valley can reach 5 ~ 10 km. From Nenjiang County to Nierji (formerly known as Buxi) in Molidawa Daur Autonomous Banner, it is the middle reaches from mountainous areas to plains. Compared with the upstream section, the terrain is flat and the two banks are asymmetrical, especially on the left bank, where the river valley is very wide. There are few tributaries in the middle section, except that the river passes through Nenjiang County for 4 kilometers, and there is a large tributary trunk river on the right bank, and the rest are small tributaries or small mountain streams. From Nierji to Sanchahekou, the downstream section is 587 kilometers long. This section of the river enters the vast Songnen Plain, with winding rivers, beaches, sandbars and rivers. The widest point can reach more than 10 km, and the maximum water depth is 7.4 meters. Foam swamp, wetland and oxbow lake are widely distributed on the beach. The average gradient of the upper reaches of Qiqihar City is 0.2 ‰ ~ 0./kloc-0 ‰, and the water surface of the main channel is 300 ~ 400 meters wide and the water depth is 3 ~ 4 meters. The downstream river network is dense, and there are Nuo Min River and Weihe River on the right bank.

Most tributaries of Nenjiang River are on the right bank, and six of the eight tributaries with a basin area of 6,543,800 square kilometers or more are on the right bank. The tributaries on the left and right banks all originate from the branches of Daxing 'anling, form along the slopes of Daxing 'anling, and merge into the main stream from northeast to southwest or northwest to southeast. There have been many floods in Nenjiang River in history, most of which were caused by water from the tributaries on the right bank of the eastern slope of Daxing 'anling Mountains. Due to the topographical conditions, once there is a rainstorm in summer and autumn, it often forms a rainstorm center. At the same time, because the middle and upper reaches of the main tributaries are mostly hilly areas prone to runoff, in previous heavy rains or continuous rainfall, the water from the main tributaries has been injected into the main stream one after another, forming a major flood in the main stream. Nenjiang 1998 that thrilling once-in-a-century flood was formed in this way.

The meteorological and hydrological elements of Nenjiang River vary greatly within the year, between years and between regions. The maximum annual precipitation is 937.4 mm, and the minimum annual precipitation is152.5 mm. The annual precipitation is mainly concentrated from June to September, accounting for 82% of the annual precipitation, with July and August accounting for the largest proportion.

The average annual runoff of Nenjiang estuary is 22.5 billion cubic meters. Runoff is unevenly distributed within and between years. It is the largest in September, but the difference between the maximum and minimum average runoff in these months is 50 ~ 80 times. The difference between the maximum and minimum annual average runoff is generally 4 10 times, and the difference between the maximum and minimum runoff is 30 ~ 60 times.

Nenjiang river basin belongs to the continental climate of cold temperate zone and semi-humid, with long and cold winters and short and rainy summers. The annual average temperature is 2 ~ 4℃, the lowest temperature is -39.5℃, and the highest temperature is 40. 1℃. The freezing period of Nenjiang River in winter is about 150 days, and the ice thickness is about 1 meter.

Nenjiang River Basin spans 6 cities (leagues) and 26 cities (counties) in Heilongjiang Province, Jilin Province and Inner Mongolia Autonomous Region. The left bank is all in Heilongjiang Province, and the right bank is mostly in Inner Mongolia Autonomous Region. There are only the lower reaches of Taoer River and the right bank of Nenjiang River in Jilin Province.

In order to build water conservancy projects and eliminate water disasters in Nenjiang River Basin, five large reservoirs, 28 medium reservoirs and 74 small reservoirs/kloc-0 have been built. The Nierji Reservoir, a large-scale control project, is being built in Molidawa Daur Autonomous Banner, the main stream of Nenjiang River. After the completion of the reservoir, the flood control benefit is very significant.

In order to solve the problems of water use in Daqing Oilfield, agricultural irrigation water use in Songnen Plain and people's domestic water use, develop fish farming, reed farming and improve grassland, since the early 1970s, three water diversion projects, namely "three water diversion projects", have been invested and constructed successively. "Three Diversion" extends from the ferry of Laha Town, nehe city, the main stream of Nenjiang River, to the hinterland of Songnen Plain, with a control area of 37.5 million mu and a main diversion canal of 45 kilometers long. The diversion flow is per second 100 cubic meter. The "South Transfer Project" is located on the left bank of Nenjiang River in the southwest of Songnen Plain, with a control area of 3,600 square kilometers. "Middle water transfer" is located in the closed flow area at the tail of Wuyuer River and Shuangyang River in Songnen Plain. The project covers an area of 7,500 square kilometers, with a length of 150 kilometers from north to south and a width of 50 kilometers from east to west.