Dazhangxi

Dazhangxi

Dazhang River, the largest tributary of the lower reaches of Minjiang River in central Fujian Province of China, originates from Daiyun mountain in Chishui town of Dehua County, and its source is Guobao river. From Dehua to Nancheng, it is called Chanxi River, and from Nancheng, it is called Dazhang River, which is joined by houting River and Tongguan river. From the estuary of Minhou County, it flows into Nangang of the lower reaches of Minjiang River, with a drainage area of 4843 square kilometers and a river length of 234 kilometers (231 kilometers)

）The average gradient of the river is 2.1 ‰.

Since the history of Dazhang River, it has been the main waterway for the three coastal counties to connect with the Minjiang River and the surrounding areas. The basin is rich in water resources. In history, many water diversion projects were built on the main and tributaries, and a large number of reservoirs and power stations were built after the founding of the people's Republic of China. In particular, Longmen beach water diversion and power generation project, located in shueru village, Xiabi Township, is a cross basin water diversion, cascade power generation and comprehensive utilization project. It provides important conditions for local economic and social development.

Business card picture: Yongtai section of Dazhang River

General situation of main stream

The main stream of Dazhang River starts from Chishui Town, Dehua County, and its upstream is Chanxi and Yongxi. It flows through Yongtai County and Minhou County, and then flows into Nangang in the lower reaches of Minjiang River.

Chanxi Yongxi

Chanxi, also known as xunshui. Located in the upper reaches of Dazhang River, it is the longest river in the territory. The total length is 101 km. Chishui town of Dehua County, which originates from the south slope of Daiyun mountain, flows through Guobao township (so the upper section is also called Guobao stream), gaide Township, county seat of Dehua County, Longmentan town and Nancheng town. It surrounds the southeast of the county and joins Yongkou and Yongxi at Huban village of Shuikou Town, which is called Dazhang stream. The drainage area is 985 square kilometers.

This stream is the source of Fujian Provincial chronicles. The source is guobaoxi. Dehua to Nancheng is called Chanxi.

Yongxi, originated in Chishui town at the West foot of Daiyun, flows through Shangyong town and Gekeng town of Dehua County, and surrounds the north of the county. It is the second largest river in the territory. The upstream is Ludi stream, which joins Zhangyan stream in Jiuxian east to form Xixi stream, and Shangyong town joins dongkengyang stream, which is named Yongxi stream; Huishan tea stream turns east to flow through zengban, and then to the northeast to join Xianglin stream, to Litian to join Gekeng stream and zhongkeng stream, and flows east to pengkengwei stream. After flowing southeast to Nazi stream, Shuikou Town Huban village joins Chanxi stream, which is called Dazhang stream. From Xixi to hubancun Yongkou, it is 60 km long, with a drainage area of 453 square kilometers.

Dazhangxi

In Yongtai County, the main stream of Dazhangxi flows into the county from west to East, cutting the county into two parts: North and south. Yongtai County is 121 kilometers long, with a drainage area of 4573 square kilometers. The stream flows through 53 villages, including 9 towns, namely, Kou Kou, song Kou, Wutong, Chai Xi, Fuquan, Chengfeng, Zhang Cheng, Ge Ling and Tong Qian.

In Minhou County, they enter from Longquan Village, Nanyu Town, and converge into Nangang of Minjiang River at Xinqi village, Nantong town. The area of water flowing through the county is 10.5 square kilometers. The water depth is slow and the flow is slow. It can pass through boats and rafts.

hydrographic features

According to the records of Dehua County, the water potential of Chanxi river is estimated to be 75000 kW. The average annual discharge is 25.9 m3 / s. The annual average runoff is 1172.2 million cubic meters, and the annual average sediment concentration is 0.183 kg / cubic meter.

The annual average discharge of Yongxi is 15.87 m3 / s, and the estimated hydraulic reserve is 30000 kW.

According to the hydrological records of Yongtai County, the main stream of Dazhangxi has an annual runoff of 4.03 billion cubic meters, with a hydropower installed capacity of more than 720000 kilowatts.

The hydrological records of Minhou County are as follows: the annual runoff is 4.41 billion cubic meters, the annual runoff depth is 993.8 mm, and the annual runoff modulus is 31.5 L / s per square kilometer.

Main tributaries

Chanxi tributary

Huaqiao river is located in gaide Township, Dehua County. It originates from Lushan Mountain, flows through Shangdi village of Dehua County, reaches nawuhua mountain in Linlin village, and flows eastward to Chanxi through Shishan village.

Gaide River, located in gaide Township, Dehua County, originates from Shipai Gejin mountain, Fengshan village, Dehua County, and flows northeast through Fengshan, Sanfu, gaide and Tuban villages to Chanxi.

Dingxi, originated at the foot of the snow mountain, enters Chanxi in front of Dehua county government, so it is named because of the character "Ding". The upstream is Youji River, which flows through Fuyang, Youji, Yingshan, Dinglong and Dingxi villages to Chanxi.

Yingxi, originated at the foot of Gezai houjinji mountain, flows through fairyland, Longhan and Xunzhong village in Dehua County, and flows into Chanxi.

Dayun River, originated at the northern foot of Tianma mountain, flows through Jinshan, rukeng and qiaonei of Dehua County, to the water at the northern foot of sanbanshou Luocheng mountain, to Xiacun River and Gaoyang River, and to huichan river of kuidou village to Longmen.

Jiaoxi, 10km northeast of the county, originates from Xiashan mountain in the southeast of Daiyun mountain, and ends at Xiangyun river. Shangyang river flows southward around Huben, passing Lixi, Panci, Jiaoxi, Ximei and other villages in Dehua county to Jiaokou and Chanxi. It has a total length of 28 kilometers, a drainage area of 112 square kilometers, a riverbed slope of 18.2 ‰, and an average annual runoff of 133.8 million cubic meters.

Shilong River, known as Shiniu River in ancient times, originated in shibagutou, Xianyou County. It twists and turns to the West and flows into Chan River through Xiabi, Dehua County and Tadao, Nanbu township. This is the only stream that comes from other counties.

Shuangqin river originates from Qili river at the eastern foot of Daiyun. It flows through Shuangqin, Jianjie, xucuo, Wangyang and Nancheng in Dehua county to Chanxi. The runoff is 25 kilometers long, with a drainage area of 148 square kilometers and an average annual runoff of 180 million cubic meters.

Yongxi tributary

Zixi, also known as Zuoxi. It originates from huangshanglin village, Dehua County, at the north foot of Daiyun mountain. The upstream huangshanglin river flows eastward through Chenxi and houzhaixi, and then flows into Yongxi through Houzhai, Chenxi, Zixi, Zilong and other villages to Shuangxikou of Jiuzhu village. The flow is 29 kilometers long, with a drainage area of 145 square kilometers and an average annual runoff of 140.4 million cubic meters.

Leitan river originates from the northern foot of tienailjian mountain, Yangmei Township, Dehua County, flows through Yangmei, Ancun, Xilang and other villages, and joins houting river. It has a total length of 26 kilometers, a drainage area of 120 square kilometers, and an average annual runoff of 120 million cubic meters.

Houting River, originated in beishangyun village, Yangmei Township, Dehua County, flows through Yuxi of Youxi County and xihuiyun river of Heshun and honggulin Township, which is called houting river. It flows to Leitan river of fufenglin Township, Songkou Township through Dazhuan village and Minjiang River through Yongtai County. It flows 12.2km in Dehua, with a drainage area of 75.5km2 and a riverbed gradient of 19.8 ‰.

Dongkengyang stream, which originates from the northern foot of Daiyun mountain, flows through Huiyang, Dehua County and chencuoping, Shangyong village, and enters into Yongxi stream.

Tributary of Dazhang River

There are 24 tributaries in the Tai Zhang river basin with an area of more than 10 square kilometers, of which 5 are the tributaries of the river basin with 200 square kilometers or more, including the mouth mouth, the lower stream, the Wutong River, the Fuquan stream, and the Qing Liang river.

General situation of water conservancy

Zhenpi

Dehua county mainly includes:

Xunzhongdazhen (baomeizhen), formerly known as lincuozhen, is located at Dingxi at the foot of shuangyushan. In Fu Zhong of song and Yuan Dynasties, "Yi Shen Lin Cheng donated money to dredge the Dingxi River, rebuild the Pi River and open the channel to irrigate the fields.". Shenzhen long two Li Xu, from the county Qiannan Shiban to the county Dongxia dongban are invested in its profits. The pond is seven feet high. It is dry built with pebbles and sealed with clay. It is often destroyed by floods. Until the middle of Ming Dynasty, Lin changniang donated money to repair PI and Zhen, with an irrigation area of more than 400 mu. During the period of the Republic of China, the peasants were unable to build, so that the PI and Zhen could not bring their benefits into full play. After 1950, the dam was rebuilt and expanded with funds and loans from the people's government. The dam height was increased to 3 meters and the irrigation area was expanded to 600 mu.

Dalongzhen, located in Dingxi village, starts from yingshanwei at the head of the dam. In the early years of the Ming Dynasty, it was built from tongshui to Shenzhen. During the Wanli period of the Ming Dynasty, it was continued by Yuanwai Li Longyun. The total length of the canal extends to Ximen Qiaotou, with a length of 7 km. In 1953, some water canals were blocked by roads, which were rebuilt with funds from the people's government. The dam was raised to 4 meters, the width of the bottom of the canal was 0.80 meters, the height of the canal was 1.2 meters, the diversion flow was 0.25 cubic meters per second, and the irrigation area was more than 700 mu.

Hubanzhen is located in Huban village, Shuikou township. Built in 1966, it is a dry built pebble dam with a height of 1m, a main canal of 7km long and a diversion flow of 0.25m3/s. In 1981, the channel was widened 3 km from Batou, and a power station was built, with an effective irrigation area of 600 mu.

Longmen beach water diversion project is located in Dehua and Yongchun counties. The project crosses the Minjiang River and Jinjiang river systems. The dam is built in Longmen gorge of Chanxi in the upstream reach of Dazhang river of Minjiang River to store water. A 3 km long diversion tunnel is excavated to cross the watershed and lead the water to Jinxi, the upstream reach of Huyang River, a tributary of Dongxi river of Jinjiang River. It is a cross basin north to south water diversion, cascade development, and water diversion, power generation and irrigation Irrigation, breeding and tourism are integrated to realize the optimal allocation of water resources. The whole diversion works are: Longmentan reservoir and first-class hydropower station; second-class reservoir and second-class hydropower station; third-class reservoir and third-class hydropower station; Neibi reservoir and fourth-class hydropower station, which control the area of huyangxi basin of 304 square kilometers, and the tail water of cascade hydropower stations flows into Shanmei reservoir. Longmentan reservoir controls Chanxi drainage area of 360 square kilometers, annual runoff of 440 million cubic meters, annual average flow of 14.0m3/s, and natural drop of 50 meters for inter basin water diversion. Cascade hydropower stations are arranged along 56 km sections of Jinxi River and Huyang River, with a total natural drop of 256 meters. The first phase of the project includes two reservoirs (50.48 million m3 of primary reservoir capacity and 700000 m3 of secondary reservoir capacity) and a total installed capacity of 4.4 million m3

Chinese PinYin : Da Zhang Xi