Oujiang River[37], ChinaThe East China SeaThe river flowing into the sea alone, the second largest river in Zhejiang, is located in the south of Zhejiang, and was once named Yongning River, Yongjia River, Wenjiang River and Shenjiang River in history.Originating from Guomaojian at the northwest foot of Baishanzu at the junction of Longquan City and Qingyuan County, it flows from west to east through the mountains in southern Zhejiang and through Lishui, Wenzhou and other cities, with a total length of 388 kilometers and a drainage area of 18028 square kilometersWenzhou CityinflowThe East China SeaWenzhou Bay.The average annual runoff of Oujiang River is 20.27 billion cubic meters (the maximum is 30.85 billion cubic meters, the minimum is 9.28 billion cubic meters), the theoretical reserve of hydropower is 1.9 million kilowatts, the developable installed capacity is 1.7 million kilowatts, and the annual power generation is 5.4 billion kilowatt hours.Oujiang Estuary is listed in ChinaChangjiang Estuary, the Yellow River Estuary, the Pearl River Estuary, and a major estuary after the Qiantang River Estuary.The shipping industry is developed.
The upstream of Oujiang River is an important hydropower development area,Lishui CityIt was awarded the title of "No.1 Hydropower City in China" by the Ministry of Water Resources.There are famousJinshuitan Hydropower Station。[1]The lower reaches of the Oujiang River is the center of the ancient culture of the Eastern Ou and the main industrial and agricultural economic zone in Zhejiang Province. Six major industries in Wenzhou, including electrical machinery and equipment manufacturing industry, leather, fur, feather (down) and its products industry, power and heat production and supply industry, general equipment manufacturing industry, textile and clothing industry, rubber and plastic products industry, rank first in Zhejiang Province.[2]The natural environment in the basin is well protected, and the tourist attractions are all over JinyunXiandu、Yandang Mountain、Nanxi River、Baizhang Waterfall－Feiyun LakeIt is famous all over the country.It is known as one of the most livable areas on the west coast of the Pacific Ocean.[3]
Oujiang River, an ancient name of Shenjiang River, used to be called Yongning River, Yongjia River and Wenjiang River.Originating from the cap tip of Baishanzu pot at the junction of Qingyuan and Longquan counties (cities), it flows through Longquan, Yunhe, Lishui, Qingtian, Yongjia, Ouhai, Lucheng and Longwan[5], Yueqing[35]Wait for 9 counties (cities and districts) to enter the East China Sea from Wenzhou Bay.It covers 18 counties (cities) in Lishui, Jinhua, Wenzhou and Taizhou.The main stream is 384 kilometers long, and the drainage area is 18100 square kilometers, making it the second largest river in Zhejiang Province.The main and tributaries of Oujiang River are distributed in tree shape, mostly parallel to the mountain trend. The terrain on both sides of the river valley is steep, the precipitation converges quickly, the beaches are many, and the floods rise and fall sharply.Below Wenxi is the tidal reach, which is open to 10-200 ton ships at ordinary times, and 500 ton seagoing ships when waiting for the tide.From Wenzhou to the first 14.9 kilometers, 3000 tons of seagoing ships can enter and leave at tide.[5]
The main stream of Oujiang River is divided into three sections from the source to the estuary, namely Longquan Stream, Daxi Stream and Oujiang River.
Longquan Stream
Longquan Stream, originated fromQingyuan CountyAt the northwest foot of Guomaojian, the source stream of the upstream main stream is Meixi. After Meixi and Qingxi meet at the head of Huangnan Village, they are called Longquan Stream, flowing eastwardLongquan Chatian, Lanju, Longyuan Town and other towns, via Daotai Township to Wuxi VillageYunhe CountyBoundary (the section from Wutongkou to Wuxi is the reservoir area of Jinshuitan Reservoir);Out of the tight water beach, Fuyun River flows from the right bank to Shitang in the northeast;From Shitang Reservoir to Dagangtou, Songyin River flows from the left bank.The flow is 197.5 kilometers, and the drainage area is 3566 square kilometers.The natural fall is about 1106.5m, with an average gradient of 5.6 ‰.
Jinshuitan Reservoir Section, Yunhe County, Longquan Stream, the source of Oujiang River[6]
There are 19 tributaries flowing into Longquan Stream, including 8 tributaries flowing into Longquan Stream from south to north from Donggong Mountain, including Qingxi (Qinxi), Nanjiao Stream, Shilong Stream, Badu Stream, Hengxi, Sangxi, Yuzhang Stream and Junxi;From north to south, it flows into Longquan Stream. There are 11 tributaries from Xianxialing Mountains, including Jinxi, Yanzhang Stream, Dagui Stream, Linyang Stream, Tashi Stream, Baiyan Stream, Daotai Stream, Anren Stream, Anfu Stream, Dashi Stream and Wuxi Stream.[7]
Dasi
Longquan Stream, called Daxi after converging with Songyin Stream, turns east to north, and flows from Xikeng to the right bank;It flows to the port, Xuanping River flows from the left bank, turns northeast to Minhe River, Xiao'an River flows from the left bank, turns east and turns northLishui City, flows eastward to Xiahe River and the ancient city, and Haoxi flows from the left bank to the southeastgreen rice fieldIn the territory, after receiving Guanzhuangyuan, Zhenbu Port, Haixi, Xiongxi, Chongkengshui, Zhixi, Shigaiyuan water, it turns east to Chuanliao, receives Chuanliao Port, turns south to Hubian Village, and streams flow in from the right bank.
Qingtian County Section, Daxi, upstream of Oujiang River[8]
From Dagangtou to Hubian Village, the flow is 92.5km, the drainage area (including Songyin River, Xuanping River, Xiao'an River, Haoxi River and Xiaoxi River) is 9564km2, the natural fall of the river channel is 58m, and the average gradient is 0.6 ‰.[7]
river ou
Yongjia County Section of Oujiang River[9]
The big stream, called Oujiang River after receiving the small stream, turns southeast. Shiguo River and Sidu Port flow into it from the right bank, continue to flow east and turn north, and Gui'aoyuan flows into it from the left bank and turns northWenxi TownBack, turn eastYongjia、OuhaiMushi River flows into Wenzhou from the left bank and flows eastward. Xixi River flows eastward from the left bank. Xupu River flows eastward from the right bank, turns eastward to pass Mei'ao in the south, and then flows southward into Wenzhou City. Xianhemen River flows eastward from the right bank, turns eastward through Shuangyu, and then flows eastward. Nanxi River flows eastward from the left bank.
Wenzhou Bay, where Oujiang River enters the sea[10]
After Oujiang River receives Nanxi River, its current is vast, and it continues to flow eastward. It receives the water from Quxi, Guoxi, Xiongxi, Huichang Lake, Wenruitang River, and Zhuangyuanqiao Town on the right. There are seven sandbanks in the center of the river, and the river water is divided into two branches, the south and the north.It flows through Longwan in the south and Wuniuma Road in the north. Wuniu River flows from the left bank and continues to flow eastward to Nabaishi River.The north and south branches converge and continue to flow eastward, separated by Lingkun Island to form the south and north entrances.Nankou Nayong Qiangtang River flows out of Wenzhou Bay into the sea;The north entrance passes through Huanghua and QitouWenzhou BayInto the sea.
Oujiang River is 98 kilometers long from Qingtian Hubian Village to Hekou, with a drainage area (including Nanxi River) of 4729 square kilometers, a natural fall of 6 meters and an average gradient of 0.06 ‰.[7]
Tributary Tanghe River
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Main tributaries
A small stream, the largest tributary of Oujiang River, converges with the main stream of Oujiang RiverQingtian CountyShixi Village.The main stream source of the stream is called Nanyang Stream, which originates from the foot of Damaofeng Mountain in Qingyuan County. After Fengtanyang meets the left stream from the right bank, it flows northward into Jingning and is called Maoyang Stream;The Naxi Stream continues to flow northward, Yingchuanyuan flows into the river from the left bank, turns southeast, the Biaoxi Stream flows into the river from the right bank, then turns north to Wutong, and Wutongkeng flows into the river from the left bank, which is called a stream;Turn north to receive water from Beikeng, turn southeast to receive water from Najitou and Yeyuan, turn north, there is Hexi River flowing from the right bank, after receiving Hexi River, turn east to north, water from Namei River and Dashan River flowing along the way, turn east, Luxi Pit flowing from the right bank, turn north, large and small Shunxi streams flowing from the left bank, turn south from the east, Naxiaowukeng, turn west to north, Fukou flowing from the right bank, turn north,The left bank is injected into the Zhangjiakou Pit, turning into the source of Naren Village and Dayi Pit in the east, turning northeast to the Hubian Village and flowing into Daxi.The main stream of the stream has a total length of 215.9 kilometers, a drainage area of 3405 square kilometers, a river width of 150~190 meters, a natural fall of 1282 meters, an average gradient of 5.9 ‰, an average annual runoff of 3.98 billion cubic meters, and a large range of changes between wet and dry seasons. It has the characteristics of mountain streams.
Songyin StreamIn ancient times, it was called Songchuan, as well as Songxi, Songyang Stream and Songyang Port.Originated fromSuichang CountyAt the foot of Huangfeng Cave in Guiyi Mountain, Longquan River flows into Dagangtou, Lishui.The main source of Songyin Stream is Shishiduyuan, also known as Pingyuan, Shangtongyuan.It flows northward from the source, from Najin'ao River and Ankeng River to Miaogao Town of Suichang County through Chengpingyuankou, called Nanxi;After flowing through Yetan Bridge, Beixi River flows from the left bank and is called Jinxi River. It continues to flow north to the ferry head, turns southeast to Zhuangshan, and Lianxi River flows from the left bank;After receiving Lianxi River, Jinxi River flows through Zikou into Songyang, which is called Songyin River at first. The river flows straight southeast. Twelve rivers flow into the river from the right bank. The river flows eastward to Wutong River from the left bank, flows southeastward to Gushi, and 13 rivers flow into the river from the right bank. After flowing southeastward to Dongguanyuan, Zhuangmenyuan, Liuduyuan, and Dongwuyuan, the river flows eastward through the foot of the Temple Ridge. Zhuyuan River flows into the river from the right bank, and Siduyuan River flows into the river from the left bank,The river flows southeastward along the way to the port from Huangkengyuan, Guanxi, and Huangyuan. The small port flows from the right bank, and then flows eastward from the southeast, winding through the low mountains and hills to Yakou. After flowing from the left bank, Yaxi flows eastward to Nankengyuan, Shimayuan, and Jingjuyuan, and then flows southeastward. After flowing into Namudaikeng, Yuxi, and Fengnongyuan, it enters Lishui City and passes through Tongjiyan Dam,Go straight to Dagangtou.The main stream of Songyin Creek is 109.4 kilometers long, with a drainage area of 1995 square kilometers, a channel width of 120~160 meters, a natural fall of 854 meters, an average gradient of 7.8 ‰, and an annual average runoff of 2.03 billion cubic meters.Its main tributary, Xiaogang, is second only to Xiaoyuanxi of Nanxi River among the secondary tributaries of Oujiang River. The main stream is 63 kilometers long and the drainage area is 500 square kilometers.
HaoxiBefore the Tang Dynasty, it was called Evil Stream.Because there are many beaches and the water is fast, boats and boats are often destroyed,Li BaiHe once sighed, "But go to an evil stream, and be afraid of the evil stream. Roar 70 beaches, and water and stone spray each other".Since the Dazhong period of the Tang Dynasty, the river channel has been dredged, weirs have been built, and the name has changed to Haoxi.Haoxi originates fromPan'an CountyDapan Mountain is located at Yangcaojian, and its upstream is called Jiuqu Brook. It flows to the south to accept Hengkeng, Dongkeng, Kongzhaikeng, Bogong source water, to Incheon to accept Yangkeng, brook, Dongkeng, and to the west to cold water;After passing through the cold water, it continues to flow westward. After receiving the Longxi River, Lingxi River, Yukeng River, it goes to Pantan and enters Jinyun County, which is called Haoxi River;The Nabai Zhuxi River flows southward, and the Tangxi River flows in from the left bank. After passing the Zuoku Reservoir, it turns westward and southwards to the Pot Town. The Nabai Liuxi River and Huanxi River flow southwestward, and the Zicaokeng River on the right bank flows into it. It flows into the Dongjindai Shixi River, passes the Dongfang Town, and then goes straight to the famous scenic spot Xiandu;After passing Xiandu, the river passes through Wuyun to the east, and Zhangxi flows from the left bank;After Nazhang Creek, it continues to flow southward. Nachangkeng flows from the south to the west into Liandu District, and then into Netting Pit, Shanshukeng, and Pengtou. Fangxi flows from the left bank, crosses Qiutang, turns south-west, and flows into Daxi at Gucheng Village.The mainstream river is 129 kilometers long, with a drainage area of 1380 square kilometers, a width of 90~150 meters, an average annual runoff of 1.22 billion cubic meters, a natural fall of 847 meters, and an average gradient of 6.4 ‰.
Xuanpingxi, also known as Xuanping Port, the Republic of China's "Zhejiang General Annals Draft", known as Quanxi, flows throughWuyi County, SongyangLishui CityLiandu District。Xuanping River originates from Dingtougang, Wuyi County, and the mainstream of its source is Dongxi River.It flows southward from the source, from the left Nahongtan River and Yunhua River, and from the right Nasongxi River, it flows southward to Liucheng Town. The west stream flows into the right bank and is called Xuanping Stream;Continuing to flow southward, Zhuke Stream flows into the village from the right bank, turns eastward to the water coming from Zuona Monk Temple at the mouth of the stream, and still turns southward. Tuokeng water flows into the village from the left bank, and Wukeng water flows into the village from the right bank, turning southeast to Lixin Township, Liandu District. After receiving the old bamboo water, it turns eastward and flows into the stream.The main stream of Xuanping River is 72.8 kilometers long, with a drainage area of 860 square kilometers, a river width of 50~100 meters, a natural fall of 990 meters, an average gradient of 13.6 ‰, and an average annual runoff of 820 million cubic meters.Historically, the Xuanpingxi River Basin was setXuanping County, second only to Zhejiang ProvinceJingning She Autonomous County Second largest ofthe She ethnic groupResidential areas.
Xiaoanxi, also known as Taiping Port, and the Republic of China's "Zhejiang General Annals Draft" called Anxi.It originates from Xuefeng Mountain in Xinzhai, Wuyi County, and flows through Wuyi County and Liandu District.The source of Xiao'an River is called Juxi River, also known as Li Village Water, flowing south to Xinzhai Wumen, and Dalai River flows from the right bank;The Nadalai River flows eastward to the mouth of the stream, along the stream from the left bank to the bottom of the stream, and Jinyan River from the right bank;Najinyan Creek flows southeastward into Liandu District, which is called Xiao'an Creek. It turns southward. After Naxi Creek and Gedu Creek, it flows southward to Xiao'an Village. Xianghou Creek flows southward from the right bank, and then continues to flow southward. Along the way, Naxiaoxikou, Fengkengyuan and Liancheng rivers flow into Daxi Creek via Subu.The main stream of Xiao'an River is 72 kilometers long, with a drainage area of 575 square kilometers, a river width of 30-50 meters, a natural fall of 902 meters, an average gradient of 12.5 ‰, and an average annual runoff of 630 million cubic meters.
Nanxi RiverOriginated from Huanglikeng at the junction of Yongjia and Xianju.In KuocangYandang MountainFrom north to south, it flows through the central hinterland of Yongjia and directly into the Oujiang River. It is the second largest tributary of the Oujiang River, with a total length of 140 kilometers, a drainage area of about 2490 square kilometers, a natural fall of 1030 meters, an average gradient of 7.4 ‰, an average river width of 50 meters in the upper and middle reaches, an average river width of 375 meters in the lower reaches, and an average annual runoff of 2.85 billion cubic meters.The main tributaries of Nanxi River include Yantan River, Zhangxi River, Hesheng River, Xiaonan River, Huatan River, Wuchi River and Doumen River.[7]
Xixi, a primary tributary in the lower reaches of Oujiang River, originates fromYongjia CountyIn the northwest of Waidang Village, Xiasheng Township, from northwest to southeast, it flows through Jingyuan, Ouqu, Liulong, Xu'ao and Qiaoxia townships, and enters Oujiang River near Yang'a Village.The source is 1041 meters above sea level, forming a surface water flow of 970 meters above sea level. The main stream is 32.5 kilometers long, with an average gradient of 29.90 ‰, and the basin is 166.05 square kilometers.The upstream source is short and the current is fast, and the valley is deep and the beach is dangerous.The downstream section from West Bank Village to Hekou is a tidal river with a length of 5.9 kilometers, which can be reached to Wenzhou by boat.There are many terraced valleys along the stream, and the downstream is the alluvial plain, which is the main grain producing area in the county.There are 5 tributaries, with Ouqu Stream and Xu'ao Stream as the largest.
Ouqu Stream, originated fromYongjia CountyTo the west of Shimajian, Ming'ao Township, it runs through Ouqu Township from north to south, and enters Xixi near Shanghu Village, Liulong Township.The headwater is 893.5 meters above sea level, the surface water flow is 230 meters above sea level, the main stream is 11.7 kilometers long, the average gradient is 57.30 ‰, and the drainage area is 24.43 square kilometers.There are many terraces and terraces on both sides of the river, and few terraces and valleys on the terrace.
Xu'ao Stream originates from Baiyantou, Kunyang Township, Yongjia County, runs through Xu'ao Township from northeast to southwest, and enters Xixi near Dianhou Village.The source is 1027.8 meters above sea level, forming a surface water flow of 920 meters above sea level. The main stream is 9.70 kilometers long, with an average gradient of 94.00 ‰, and the drainage basin is 50.12 square kilometers.There is a small amount of terrace valley on both sides of the stream.
Mushi River, a primary tributary of the lower reaches of Oujiang River, originates from the east side of Fengshan Village, Qingtian County, flows from northwest to southeast, flows through Wukeng Township, Qingtian County, enters Yongjia County, passes through Baiyun, Qiaotou and Zhutu townships, and enters Oujiang River near Zhutu Village, Zhutu Township.The headwater is 930 meters above sea level, the surface water flow is 880 meters above sea level, the main stream is 35.15 kilometers long, the average gradient is 25.10 ‰, and the drainage basin is 153.29 square kilometers (including overseas area).From Qiaotou Town to the source, the stream is relatively smooth and straight, and there are both Taitian and small pieces of gravel beaches along the coast;The section from Qiaotou Town to Hekou is a tidal river with a length of 4.9km, which can be reached to Wenzhou by boat.The two banks along the stream are alluvial plains.The tributaries include Pingtou Mountain, Panluo, Changtian, Xiaozhoushan and other streams.
Wuniuxi is a primary tributary at the lower reaches of Oujiang River, which is the boundary river between Yongjia County and Yueqing County.It originates from the northeast of Wuyan Village, Renxi Township, Yongjia County, flows through Renxi and Wuniu Townships from north to south, and enters Oujiang River near Wuniumadao Village.The headwater is 665.0 meters above sea level, the surface water flow is 550 meters above sea level, the main stream is 21.1 kilometers long, the average gradient is 26.16 ‰, and the basin is 87.63 square kilometers (including overseas area).The upstream is mountainous and hilly, with short source and rapid flow, deep cut river valley, and many canyons and rapids;From Baishuiji Power Station to the source, the average gradient is 97.58 ‰;The lower reaches are alluvial plains with flat terrain.There are 14 tributaries with a total length of 46.8 km.Ma'ao Stream on the west bank originates from Dazhang Mountain, flows eastward to Wuniu Stream near Hengyu Village, and the main stream is 7.5km long.The canal on the east bank is connected with the water network area of Baixiang in Yueqing County, which plays a major role in regulating runoff.[11]
Other tributaries
Other primary tributaries of Oujiang River with a drainage area of more than 200 square kilometers include:
Badu Stream, located in the west of Longquan City, is 44 kilometers long, with an average gradient of 19.8 ‰, and a drainage area of 396 square kilometers. It flows into Longquan Stream from the left bank.
Junxi River, located in the south of Longquan City, is 27 kilometers long, with an average gradient of 51.5 ‰, and a drainage area of 207 square kilometers. It flows into Longquan River from the right bank.
Yanzhangxi, located in the north of Longquan City, is 28km long with an average gradient of 26.8 ‰ and a drainage area of 229km2.
Fuyun Creek, also known as Wuxi, Yunhe Creek, is located in the middle of Yunhe County. The river is 28 kilometers long, with an average gradient of 39.7 ‰, and has a drainage area of 338 square kilometers. It flows into Longquan Creek from the right bank.Wuxi Reservoir is built in the upper reaches of the river.
Zhenbu Stream, located in the west of Qingtian County, is 35 kilometers long, with an average gradient of 22.1 ‰, and a drainage area of 225 square kilometers. It flows into Daxi from the right bank.
Chuanliao Creek, located in the north of Qingtian County, is 41km long, with an average gradient of 19.5 ‰ and a drainage area of 358km2. It flows into Daxi from the left bank.
Sidu Port, located in the southeast of Qingtian County, has a river length of 45km, an average gradient of 18.3 ‰, and a drainage area of 301 square kilometers. It flows into Oujiang River from the right bank.
Shupu River, also known as Shupuxi River and Tengqiao River, is located in the west of Ouhai County, with a length of 44 kilometers, an average gradient of 22.8 ‰, and a drainage area of 247 square kilometers. It flows into Oujiang River from the right bank.[12]
Tanghe River System
Wenruitang River, which starts from Wenzhou in the north and ends in the urban area of Rui'an City in the south, is the main inland river connecting Oujiang River and Feiyun River. The territory of Wenzhou City and Ouhai County is formed by the confluence of Quxi River, Xiongxi River and other rivers, and is divided into Oujiang River basin with an area of 353 square kilometers.
Yongqiang Tanghe River is composed of Zheng'ao, Baishui, Shuang'ao, Yaoxi, Huang'ao and other rivers, with a total length of 238 kilometers and a drainage area of 146 square kilometers.
Liushitang River, also known as Baishi River System, mainly includes Liushi River and Baixiang River.The main source of the two rivers is Baishi Creek, which originates from Huangtan Cave of Guogong Mountain, flows through Baishui Waterfall of Zhongyandang Mountain, flows into two reservoirs, Zhongqian and Baishi, and discharges to the water from Nadong Waterfall of Hehu Lake. After leaving Hehu Lake, it is divided into Liushi River and Baixiang River, and enters the plain river network, with a drainage area of 245 square kilometers.[12]
Island Jiangzhou
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Qidu Island[13]
Qidu Island, located in the southeast of Yongjia County, downstream of Oujiang River, in an oval shape.It is 6 kilometers long from east to west, 3.1 kilometers wide from south to north, and 18.4 kilometers long.The total area is 23.9 square kilometers. The water depth around the island ranges from 2 meters to 11 meters. It is deep in the northwest and shallow in the southeast.The whole island is flat, with an average elevation of about 3 meters, and the highest elevation is not more than 4 meters.There are 11300 mu of arable land, which is a light mud field.Island flora is relatively rich, with 347 species of vascular plants belonging to 239 genera and 84 families.The island is densely covered with 21 main canals.Laotu, Yinzhou, Zhangli, Banqiao, Shangsha and Qiansha used to be separated from each other by a pool. Now they are surrounded by people and connected as a whole. The pool has also become a freshwater lake.Qidu Island is affected by the runoff and tide of Oujiang River, and the tide is irregular semi diurnal tide. The highest tide level is around August 15 of the lunar calendar, with a limit record of 6.33 meters.In case of typhoon and rain, the island is often flooded and traffic is cut off.With mild climate, warm winter and cool summer, and beautiful scenery, the island is an ideal place for tourism and vacation.[14]
Lingkun Island, which belongs to Lingkun Street, Dongtou District,[36]Located at the estuary of Oujiang River, 120 ° 41 'east longitude and 28 ° 00' north latitude, it is the largest island among the four major islands of Oujiang River, with an area of 19.5 square kilometers. It is adjacent to the East China Sea in the east, Yongqiang in the south, Qidu Island in the west, and Huanghua Qili Port in Yueqing in the north.Lingkun Island is an alluvial and silted island at the Oujiang Estuary, and the geomorphic unit belongs to the alluvial plain;It is surrounded by water on all sides, and the plane is in the shape of water drops. The east and west ends are about 9 kilometers long, and the south and north ends are 4.5 kilometers wide.The roundabout is 20 kilometers long along the river bank.The land area is low-lying and flat, with crisscross river networks, low-lying and flat terrain, and the ground elevation is generally 2.2-2.8m.The island has a population of 20000;Lingkun Town, with a total economic volume of 570 million yuan, is the seat of Lingkun Town Government.[15]
Jiangxinyu, located in the Oujiang River in the north of Wenzhou City, with a total area of about 70000 square meters, it is long from east to west and narrow from north to south.In ancient times, there were two islands.Xie Lingyun, the governor of the early Song Dynasty in the Southern Dynasty, once boarded the isolated island and wrote the famous sentence, "The turbulent flow is becoming more and more serious, and the isolated island is beautiful to Zhongchuan. The clouds and the sun shine on each other, and the empty water is clear and fresh.".During the Tang Dynasty, Fanyu and Futu were gradually built on the island.In the seventh year of Xiantong (866), Jingxin Temple was built at the eastern foot of the west mountain.In the second year of Kaibao in the Song Dynasty (969), Puji Temple was built at the west foot of the East Mountain, and the West Tower and East Tower were built successively.In the fourth year of Jianyan in the Southern Song Dynasty (1130), Zhao Gou, Emperor Gaozong of the Song Dynasty, once stayed in Puji Temple to avoid the golden army.[16]
Xizhou Island, located in Linjiang Town, Lucheng District, is the third largest island of Oujiang River.Overlooking the island, it looks like a carp, also known as the carp island.With an area of 1.9 square kilometers, it is also an integral part of the provincial tourism resort planning system.The natural scenery of the island is beautiful, the ecological environment is well protected, the tourism resources are rich, and mountains, countryside, beaches, and villages complement each other.The island is also called "Longevity Island" because it is rich in high-quality fresh water and a variety of beneficial minerals.Since the island has never been submerged during flash floods or typhoon tides, it is also called "floating island".[17]
Estuarine characteristics
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Oujiang River is a tidal reach from Wenxi to Qitoujiao, 78 kilometers long, which is the Oujiang River estuary. It is a mountain stream tidal estuary.Out of the mouth, due to the diffusion of water flow, sediment deposition, the underwater delta stretching forward, and the entrance is surrounded by Damen (Huangda'ao), Xiaomen, Niyu, Zhuangyuan'ao, and Dongtou islands, the water flow into the sea is divided, forming Shatou Waterway, Huangda'ao Waterway, Chongshan Waterway, and South Waterway to communicate with the open sea.
River conditions
From Kuishi to Mei'ao, the river is 31km long, 400-700m wide, and the river channel is relatively stable;From Mei'ao to Longwan, the river is 32km long and 500-3000m wide. Its plane shape is wide and narrow, with many beaches and shallow water. The river is bifurcated. The river bottom topography is intertwined with beaches and channels. The riverbed is subject to scouring and silting changes, and the navigation channel is uncertain;From Longwan to Qitoujiao, the river is 15km long, and the riverbed is rapidly widened. The river below Panshi is divided into the south and north of Oujiang River by Lingkun Island and Wenzhou Shoal.The north entrance is deep, always the main branch, and the river channel is stable;Nankou beach is wide, shallow and sandy. Since 1964, the beach has been silted up year by year.From 1978 to 1979, Wenzhou tried to throw and block the dam at Nankou. The average elevation of the dam crest was 1.36m (Wusong base level), and then the project was suspended for some reason.
The bed material is composed of well sorted medium sand and medium fine sand, with a median diameter of 0.2~0.4mm, and those larger than 0.1mm account for more than 80%~95%, with little change along the way.
Incoming water conditions
Oujiang River has abundant water and large peak flow.The annual average total runoff is 19.55 billion cubic meters (first, the average annual runoff of Oujiang River is 20.27 billion cubic meters (the maximum is 30.85 billion cubic meters, and the minimum is 9.28 billion cubic meters)[7]）The historical maximum peak flow of Qingtian Weiren Station is 30400 cubic meters per second, and the minimum flow is 10.6 cubic meters per second, with a variation of more than 2000 times.The annual runoff distribution is uneven, and the runoff from May to September accounts for two-thirds of the total annual runoff.After the construction of Jinshuitan and Shitang power stations, the flow has been adjusted, the flood peak has been reduced, and the flood volume has been reduced.
The tide at the Oujiang River estuary is an irregular semi diurnal tide in the shallow sea. The tidal range is large. The average tidal range along the estuary is more than 3 meters, and the maximum tidal range is 7.2 meters (Longwan), but the tidal speed is not large. When the upstream is the average flow, the average flow rate of the rising tide in Longwan during spring tide is only about 0.7 meters per second. When the flood discharges, there is no rising tide in Longwan, and the role of flood in bed building is greater than the tide.
Sediment conditions
Oujiang River has a small sediment concentration, beautiful water color and clear bottom in flat and dry water.During the flood period, the river still carries a lot of sediment and the water body is turbid.The average annual sediment concentration is 0.168 kg/m3, and the average annual sediment transport for many years is 1.96 million tons. The maximum annual sediment transport (1975) is 5.36 million tons, and the minimum annual sediment transport (1979) is 394000 tons.The amount of sediment transport in the dry season only accounts for less than 1% of the total amount of the year, while the flood season accounts for 95% of the total amount of the year. Outside most of the export ports, the Oujiang River on average transports 2.34 million tons of sediment to the sea every year.
There is a lot of sediment coming from the sea area, mainly suspended sediment, with the median particle size of 0.02~0.04 mm. The sediment concentration carried by the tide during the dry season and spring tide is between 2~5 kg/m3, and there is a trend that the sediment concentration decreases with the increase of upstream runoff.In flood season, there are few measured sediment concentration data at Oujiang River estuary.At the south and north entrances of Oujiang River, the sediment transport volume of one ebb and flow tide reaches 500000 tons at neap tide and about 1 million tons at spring tide.
River bed evolution characteristics
The seasonal scouring and silting of the riverbed of the Oujiang River estuary has the law of "flood scouring and dry silting", and the long-term scouring and silting is in a relatively balanced state.The riverbed deformation is often reflected by the lateral swing of the stream line, the movement of the river center island and the edge beach, and the frequent cutting and merging of the beach island.The riverbed is also subject to scouring and silting in longitudinal direction, which makes the water depth of the channel shallow and deep. For example, in 1960, the water depth at the wharf front of Wenzhou Old Port was silted from more than 6 meters to 0.5 meters, which seriously hindered the development of water transportation in Wenzhou Port Area and the estuary in Wenzhou City.After the implementation of the five phase Oujiang River Estuary Regulation Project started in 1971, the water depth at the wharf front of Wenzhou Old Port increased from 0.5 m in 1965 to more than 5 m in 1984, and the water depth of Yangfushan Channel increased from 1 m to more than 2.5 m, and 3000 ton ships can enter and leave at tide.
Port and waterway resources
There are many deep water bank sections on both sides of the Oujiang River estuary. Some ports of a certain scale have been built, such as Wenzhou old port area and Yangfushan port area.Longwan on the south bank of Oujiang Estuary and Qili Huanghua on the north bank are both port resource areas of over 10000 tons.Longwan shore section is generally 5-10 meters deep, and the deep-water line of 9-12 meters is about 200 meters wide and 1000 meters long.The Qili Huanghua bank section has a water depth of 10-12 meters, a width of more than 200 meters, and a length of 9.4 kilometers, which has been stable for more than 100 years.There are three main approaches to the open sea. One is the Shatou Channel, with a water depth of about 3 meters, for ships below 3000 tons;The second is Huangda'ao Waterway, which is generally more than 5 meters deep and is a channel for 3000~10000 ton ships to enter the bay;The third is the South Waterway, which is about 1-2 meters deep for small boats to enter and leave.[18]
Overview of water conservancy
Announce
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Channel port
The upstream Lishui section is 299.3 kilometers long, with four first class tributary channels.
Xiaoxi, from Shawan, Jingning County to Xikou, Shixi Township, Qingtian County, has a navigation mileage of 141 kilometers. The main ports along the line are Biaoxi, Wutong, Xinting, Waishe, Jinzhong, Bohai, Chencun, Baiyan, Rengong and other villages and towns.This section passes through the valley, with pebble riverbed and rapids. There are 136 shoals and 69 dangerous shoals, with an average gradient of 0.15%, 0.3%~0.467% above the shoal. The river is 80~200 meters wide, the lowest navigable water level is 0.4 meters, and the shallowest water depth in dry season is only 0.2 meters. It is very difficult to navigate.The suspension period is from November to January of the next year.1.5-2.5 ton wooden sailboats can be reached from Shawan to Waishe, and 2-2.5 ton motorized wooden sailboats can be reached from Waishe to Shixikou.Songyin River, Xuanping River and Haoxi River were not open to navigation after 1985.
The main stream of Oujiang River is deeply incised into the valley, and the peaks on both sides of the river are high and steep.The above Wenxi Street is a mountain stream river, with lithologic river bank, pebble riverbed, wide and narrow river channel, deep pool and shoal alternating, and the whole river almost runs through the valley.Along the river, there are only small plains in the middle reaches from Dagangtou to Lishui and downstream alluvial plains below Mei'ao, except for some platforms at the confluence of Shan'ao and its tributaries.With the completion of Jinshuitan and Shitang power stations, Shitang Longquan will become two backwater areas of the reservoir.The Longquan Lishui section of the Longquan Lishui navigation route is 117 kilometers long, passing through villages and towns such as Dabai'an, Daotai, Anrenkou, Wuxi, Chishi, Longmen, Shipu, Jucun, Shitang, Dagangtou, Bihu, Shiniu, Subu, etc.The fall of the whole section is 130 meters, with an average gradient of 0.134%. There are more than 120 beach hazards, of which 65 are major obstacles to navigation.Generally, 2.75 ton ships are navigable. It takes 7-8 days for normal water level to go up and 2-3 days for normal water level to go down.During the flood period, the current was rapid and the water was turbulent, so the ship was suspended for a period of time to avoid the flood.In dry season, due to the lack of water depth, the 2.75 ton boat carries only 600~1000 kg upstream and 1000~1500 kg downstream. When the boat reaches the shoal, it needs to cross the shoal in groups. The boatmen launch barefoot, carry on their backs and push on their shoulders, which is very difficult.The raft goes down the river. Due to the small curvature radius of the low water trough and the influence of cross flow, the tail of the raft often hits the beach, causing the raft to break up and causing disaster.
The channel from Lishui (Dashuimen) to Xiahuamen of Wenxi in Lishui Wenxi section is located in the middle reaches of Oujiang River, with a total length of 86.5km.The main villages and towns along the line are Shifan, Lakou, Jinshui, Wuliting, Zhenbu, Haikou, Shimen Cave, Gaoshi, Zhixitou, Chuanliao, Shixi, Qingtian, Weiren, Wenxi Street, etc.The current in this section of channel is fast in flood season, and shallow in dry season, making navigation difficult.The total fall of the channel in this section is 42m, with an average gradient of 0.05%. There are 60 dangerous shoals along the whole line, and one shoal is 1.5km on average. The water depth of the shoal is generally 0.6~0.8m, the flow velocity is generally 1.0~2.0m/s, and the gradient is generally 0.1%~0.2%.
The navigation section from Xiahuamen to Hekou is the downstream of Oujiang River, 76.2km long, completely located in the alluvial plain. The river bottom is muddy, the river surface is open, and the normal water surface width is about 1500m. It is a tidal river section. A 500 ton sea liner can arrive at Wenxi Port when waiting for the tide.[19]
Wenzhou Port Channel in Wenzhou City at the downstream is divided into internal channel (i.e. Oujiang River downstream channel) and entrance channel.
The channel in the estuary (downstream channel of Oujiang River) starts 1 km upstream of the Oujiang River Bridge and ends at Neiqitou, Oujiang River estuary, with a total length of 47.5 km.According to the water depth, it can be divided into four sections from west to east: the first section is from the starting point to the foot of Guogong Mountain, with a length of 12 kilometers, a river surface width of 300~1300 meters, and the shallowest water depth of 1.1 meters. It can be used to sail 500 ton seagoing ships by tide;The second section starts from Guogong Mountain, passes through Huiqiao Shoal, and ends at Yangfushan Port. The channel is 6.5 kilometers long. There is a transition shoal at Huiqiao, and the water depth is less than 2.5 meters.It can pass 10000 ton seagoing ships in shallow water by tide;The third section is from Yangfushan to Longwan, passing through Qidutu North Channel or South Channel in the middle.Since November 1985, due to the siltation of the southern channel of Qidu, the northern channel of Qidu has become the main channel, with a length of 14 kilometers, a river surface width of more than 800 meters, and a shallowest water depth of 2.9 meters. The river channel has been stable for years, with good river facies relations, and can pass 10000 ton seagoing ships in shallow water by tide.The channel from Longwan to Qidu Tuwei has a large bend with a turning angle of 1200.Qidu South Channel is an auxiliary channel with a length of 13.5km, a river surface width of 1100-2000m, many beaches and shallow water, and the shallowest water depth is about 1.4m.The fourth section, from Longwan to Qitou, is 15 kilometers long. The channel is straight, the river surface is more than 1500 meters wide, and the water depth is good. The shallowest water from Panshi to Longwan is more than 4 meters.
The entrance channel is divided into two channels, one is Shatou Waterway, from Qitou in the port to Xiaowuxing Island in Dongtou County. The channel is 12 kilometers long and the shallowest water depth is 2.5 meters.Before 1970, it was the main approach channel.Since then, the waterway has been silted up year by year, and the tonnage of incoming ships has been increasing. In 1973, it was adjusted as an auxiliary channel for ships below 3000 tons to enter and leave the port.The other is Huangda'ao Channel, which is 14km long from Qitou to Dongtou, the Qinglingyu Quarantine Anchorage.The shallow section of Qinglingyu Island is less than 6 meters deep, and the shallow section 4.5 kilometers west of Wuxianzui is 4.5 meters deep.During the period of the Republic of China, this channel was the main channel for steam ships to enter the port. In recent decades, the water depth has been deepening year by year. Since October 1, 1972, this channel has been open to foreign ships and can pass 10000 ton water turbines when riding the tide.[20]
Wenzhou Port, located at the estuary of the lower Oujiang River, gradually expands from more than 1000 meters to more than 5000 meters from west to east.Jiangxin Island, Qidutu Island and Lingkun Island are in the middle of Hong Kong in order.There are 103 islands on Dongtou Island outside the estuary. The whole port area is wide, deep and calm. It is a natural harbor with both estuary and bay ports.Wenzhou Port is located in the middle of China's coastline, with north-south radiation in the middle.The main ports along the coast are symmetrically distributed: 320 nautical miles away from Shanghai Port and 219 nautical miles away from Ningbo Port in the north;It is 192 nautical miles away from Fuzhou Port, 393 nautical miles away from Xiamen Port and 203 nautical miles away from Keelung Port in Taiwan in the south.Many ports in Japan, North Korea, Southeast Asia and Hong Kong are located on the north and south fan-shaped sea surface of Wenzhou Port.[21]
Estuary regulation
Oujiang River starts from Wenxi, the boundary of the tidal zone, to Qitoujiao, with a length of 78 kilometers, which is the estuary.From Wenxi to Mei'ao, it is 25km long, and the riverbed is mainly formed by runoff, which is relatively stable;From Mei'ao to Longwan, it is 38 kilometers long. The interaction between runoff and tide is relatively strong, and the river width is also rapidly enlarged. At the middle tide level, the width of Mei'ao River is 485 meters, and to Longwan, it is 2400 meters. In the river section, there are many beaches, many shoals, and the tributary Nanxi River flows in. The riverbed changes a lot in erosion and deposition;Longwan to Koumen, 15 km long, is basically controlled by the tide. The river surface is wide and restricted by some mountain mouth rocks. The riverbed is stable.
Seawall construction
According to the Records of Wenzhou Prefecture by Jiajing, during the Zhenyuan period of the Tang Dynasty (785~805), Wenzhou's provincial governor's road should be ordered to build embankments to succeed (today's Yueqing County) and Hengyang (today's Pingyang County) in view of the long abandoned river defenses and frequent floods.During the reign of Song Chunxi (1174~1189), the east and west causeways of Huanghua in Yueqing were built. Later, they were built in generations. From east to west, there are 11 seawalls, including Huanghua Pond, Zhiguang Pond, Chenjiatang, Zhujiatang, Baihe Pond, Fakong Pond, Pujue Pond, Badu Pond, Shiyi Pond, Panshi Pond and Chongshi Pond, with a total length of 4165 zhang.The Zhiwan Pond and Tianjiang Pond from Chongshi to Guantou with a length of 1227 Zhang, and the Guantou Pond, Yiqian Pond and Xiangpu Pond from Guantou to Bailu Island with a length of 1325 Zhang were built.On the south bank of Oujiang River, Antang was built in the second year of Hongzhi in the Ming Dynasty (1489), with a length of 700 zhang.During the reign of Emperor Jiajing of the Ming Dynasty (1522-1566), Shacheng Pond was built, that is, the coastal levee, starting from Changsha in the south and ending at Shacun Village in the north. The pond was 2619 zhang long and built with block stones.In the 13th year of Qianlong's reign in the Qing Dynasty (1748), Changsha Pond was built, starting from Furong Rock in the south to the outside of Sanduning Village in the north, with a length of 4706 zhang;As well as Shanbeitang, it starts from Lantian Horse Road in Sandu in the south and ends at Sandu Sancuo in the north, with a length of 1050 zhang.
Most of the seawalls built in ancient times had low standards and low flood and tide control capacity. Especially from the late Qing Dynasty to the Republic of China, the seawalls were in serious disrepair and out of control.After the founding of the People's Republic of China, the seawall was comprehensively renovated and strengthened in the 1950s.From 1964 to 1966, Lingkun 64 ponds, Tianhe Phase I seawalls and Haibin Phase I seawalls were built in the suburbs of Wenzhou.In the 1970s, two standard ponds, Longwan and Zhuangyuan, were built, with a total length of 6.9 kilometers.By the end of 1990, 112.31 kilometers of seawalls had been built in coastal areas such as Ouhai, Lucheng, Longwan and Yueqing Liushi, with 271400 mu of farmland protected and 465300 people in population.Among them, the seawalls that protect farmland of 10000 mu and have a population of more than 10000 people include Lucheng Pond, which starts from Yudu and ends at Xiaxintu, with a length of 16.17 kilometers;Longwan Pond starts from Xiaxintu and ends at Longwan Pond with a length of 14.42km; Yongqiang Pond starts from Longwan Pond and ends at Mouse Mountain with a length of 32.4km;Lingkun Pond, built around Lingkun Island, is 17.6km long;Guantou Pond, 1.1 km long, starts from Wuniu Sluice and ends at Guantou;Shenjiangtang, 4.14km long, starts from the west of Xidai and ends at the east of Xidai;The new Doumen Pond starts from Tianwanjiao and ends at the south gate of Panshi, with a length of 2.73 km;Panshitang, 1.92km long, starts from the south gate of Panshi and ends at Hengheba.
Tideland reclamation
Sea beach reclamation and seawall construction complement each other.With the siltation of the beach, the seawall moves outward, and the reclamation area continues to expand.The early coastline of the Oujiang River estuary is from the east to Wenruitang River, from the north to Leguantang River, from Kangxi to Guangxu in the Qing Dynasty, the southern coastline has moved to the east of Yongqiangtang River in Ouhai County, and from Huanghuatang to Panshitang and Sanyutang in the north.Longwan in the urban area of Wenzhou today, Yongqiang and Wudang in Ouhai County, and the east of Liushi in Yueqing, are all the results of beach siltation and long-term human reclamation.
After the founding of the People's Republic of China, the coastline extended at the speed of 10-20 meters every year, and reclamation was conducted every three or five years.In the 1950s and 1960s, the main reclamation projects were the reclamation of high beaches. Lingkun 64 Ponds, Tianhe Phase I, Haibin Phase I and other three reclamation projects were completed.In the 1970s, six reclamation projects with an area of more than 1000 mu were completed, including Sanjiang, Tianhe Phase II, Lingkun 74 Pond, Lingkun 75 Pond, and Haibin Phase II and Phase III projects, and they developed from high beach reclamation to low beach reclamation to promote siltation.From 1978 to 1979, the first phase project of blocking the river and promoting siltation at the south entrance of Lingkun Island was implemented, with a total investment of 250000 workers and 1.03 million yuan. 233000 cubic meters of riprap and 278.5 meters of submerged dam were completed.After the implementation of the project, the siltation volume at Nankou has reached 4.36 million cubic meters in the past 10 years, with good siltation promotion effect.By the end of 1990, 46000 mu of land had been reclaimed on both sides of the estuary.
Port construction
Wenzhou Port at the Oujiang River estuary is located between Ningbo and Fuzhou, with superior geographical location and water environment.Tang and Song dynasties began to flourish, and it was an important port for foreign trade at that time.In the Ming Dynasty, the "sea ban" was implemented and ports declined.In the second year of the reign of Emperor Guangxu in the Qing Dynasty (1876), it was listed as a foreign trade port. The next year, Wenzhou Customs was established, and the port recovered.After the founding of the People's Republic of China, a comprehensive port opening to the outside world has been built.There are 62 wharfs, 76 berths in total, with a total length of 4266m. The original largest berth was Yangfushan No.1 Wharf of 5000 tons. In 1989, Longwan Port District built a 10000 ton general cargo berth and a multi-purpose berth respectively. In 1990, Wenzhou Power Plant built a 20000 ton special coal berth, and there were also a 10000 ton and 20000 ton barge pontoon berths in the Panshi waters.The total annual throughput of Hong Kong is 4.97 million tons.
Due to frequent beach movement, the channel of Oujiang River estuary is uncertain.Since the opening of Wenzhou in the second year of the reign of Emperor Guangxu in the Qing Dynasty (1876), the water depth of the river section from Ximen to Shuomen has reached 5.5 to 6.7 meters. After the two major typhoons and floods in the first year of the Republic of China (1912) and 15 years (1926), the Oujiang River, which originally passed through the south of Jiangxin Island, was changed from the north, and the water depth conditions around Shuomen worsened, bringing serious impact on port shipping.After the founding of the People's Republic of China, in 1964 and 1968, although there were two dredging operations, the effect was not significant.In order to find out the river bed evolution law and regulation scheme of mountain creek tidal estuary, the Oujiang River estuary scale model was made by the Nanjing Institute of Water Resources Science. After repeated tests, research and demonstration, it was decided to adopt the regulation scheme to stabilize the river regime and control the main flow direction.Since 1971, the waterway has been renovated for many times: in 1971, the main stream of the Oujiang River was forced to pass through the Nanjiang River by dumping 500000 cubic meters of rock, building two straight dams and one submerged dam, with a total length of 5175 meters, near the village on the north bank of the Oujiang River to Xintu, Jiangxin Island.At the same time, a deep trench with a length of 4150 meters and a width of 60 meters was excavated in the Nanjiang River, and a total of 1.19 million cubic meters of mud was dredged, so that the water depth of the wharf apron around Shuomen and Ximen in the Nanjiang River gradually reached more than 5 meters;In 1972, east and west spur dikes were built at the foot of Guishan Mountain at the Nanxi River mouth on the north bank of Oujiang River to carry the water to the south bank, scour the river beds of Anlan and Zhenhua port areas, and dig a 2525m long and 120m wide deep groove at the front of each dock, so that the water depth at the front of Anlan dock was restored to more than 5m, and the sand ridge at the gate gradually disappeared. In 1973, to stabilize the water depth of the southern channel of Qidu, the east spur dikes at Laohuyan were built,In 1974, in order to improve the water depth of Yangfushan Port, the Huiqiao downstream dam was built with a length of 7600 meters;In 1976, 700 m spur dike was built to renovate Qidu Nanbanqiao shoal.A total investment of 7 million yuan was made for the above renovation projects.[22]
Development and utilization
After the founding of New China, great efforts have been made to build water conservancy. At present, 289 large and small reservoirs have been built in the Oujiang River basin, including 22 large and medium-sized reservoirs with a storage capacity of more than 10 million cubic meters.In the late 1950s, a number of small hydropower stations were built;In the 1960s and 1970s, a large number of small backbone hydropower stations were built;Since the 1970s, the policy of "self construction, self use and self management" has been implemented, and the construction of small hydropower has flourished;In the 1980s, a large hydropower station in Jinshuitan and a medium-sized hydropower station in Shitang were built in the Longquanxi reach of the main stream;In the 1990s, Yuxi medium-sized hydropower station was built;The Tankeng Hydropower Station, the highest dam in East China in the new century, was successfully completed and impounded.[7]
Before the founding of New China, there was no reservoir with a storage capacity of more than 100000 cubic meters in the basin.After the founding of the People's Republic of China, Oujiang River governance and development has gradually shifted from a single prevention and treatment to a comprehensive development and utilization of irrigation, water supply, shipping, tourism, etc., with hydropower as the leader.By the end of 2008, 33 large and medium-sized reservoirs had been built, including 2 large reservoirs, namely, Jinshuitan Reservoir and Tankeng Reservoir, with a total capacity of 6.24 billion cubic meters;436 hydropower stations have been built with a total installed capacity of 715300 kilowatts, including 10 hydropower stations with an installed capacity of more than 10000 kilowatts with a capacity of 520000 kilowatts.
Large and medium-sized reservoirs in Oujiang River basin
Project name
category
River
Total storage capacity
10000 m3
major function
Catchment area
(square kilometers)
Jinshuitan Reservoir
large
Longquan Stream
one hundred and thirty-nine thousand and three hundred
Power generation, flood control, shipping, fishery
two thousand seven hundred and sixty-one
Tankeng Reservoir
large
brook
four hundred and fifteen thousand
Mainly power generation, flood control, irrigation
three thousand three hundred and thirty
Zhongqian Reservoir
medium-sized
Baishixi
two thousand three hundred and forty
Irrigation, flood control, water supply and power generation
thirty-eight point seven
Baishi Reservoir
medium-sized
Baishixi
one thousand and three hundred
Irrigation, flood control, water supply and power generation
forty-eight point five
Jinkeng Reservoir
medium-sized
Chuanliao Port
two thousand and forty
Mainly power generation, irrigation and breeding
ninety-seven point three
Dayikeng Reservoir
medium-sized
Dayi Kengyuan
two thousand eight hundred and forty
Power generation
sixty-one point eight one
Beixi Reservoir
medium-sized
Dayuan Stream
three thousand eight hundred and twenty
Mainly for power generation, flood control and aquaculture
one hundred and thirty-two
Wuxi Reservoir
medium-sized
Fuyun Stream
one thousand one hundred and seventy
Mainly irrigation and flood control
twenty-nine point seven
Gaoxi Reservoir
medium-sized
Gaoxi
one thousand and seventeen
Mainly irrigation, flood control and power generation
twenty-six
Dayang Reservoir
medium-sized
Panxi
one thousand six hundred and eighty-eight
Power generation and flood control
thirty-six point nine four
Jinxi Reservoir
medium-sized
Jinxi
one thousand nine hundred and seventy-three
Power generation and flood control
one hundred and eighteen
Yangyi Reservoir
medium-sized
Quxi
one thousand three hundred and fifty
Water supply, irrigation and flood control
eleven point five
Yuxi Reservoir
medium-sized
Longquan Stream
one thousand four hundred and fifty-three
Power generation, water supply and shipping
three thousand four hundred and seven
Dabai'an Reservoir
medium-sized
Longquan Stream
two thousand four hundred and seventy
electricity generation
one hundred and fifty
Shitang Reservoir
medium-sized
Longquan Stream
eight thousand two hundred and seventy-one
Mainly for power generation and shipping
three thousand two hundred and thirty-four
Ruiyang secondary reservoir
medium-sized
Longquan Stream
one thousand four hundred and eighty-five
electricity generation
eighty-six point two
Grade I rock camphor
medium-sized
Longquan Stream
one thousand one hundred and forty-three
electricity generation
one hundred and nine
Dayankeng Reservoir
medium-sized
Nanyang Stream
one thousand one hundred and twenty-five
Power generation, aquaculture and downstream water supply
one hundred point two
Ruiyang Reservoir
medium-sized
Ruiyang Stream
one thousand and sixty-six
Mainly power generation, flood control and irrigation
twenty-three point six five
Zeya Reservoir
medium-sized
Shupu River
five thousand seven hundred and thirteen
Flood control and water supply
one hundred and two
Screen forming level II
medium-sized
Songyin Stream
one thousand three hundred and forty-six
Mainly for power generation, irrigation and flood control
two hundred and fifteen
One screen
medium-sized
Songyin Stream
five thousand two hundred and thirty
Mainly for power generation, irrigation and flood control
one hundred and eighty-five
Dongwu Reservoir
medium-sized
Songyin Stream
one thousand four hundred and sixty
Water supply, irrigation, power generation
fifty-two
Yingcun Reservoir
medium-sized
Songyin Stream
two thousand three hundred and forty-nine
electricity generation
seventy-nine point six
Wutongyuan Reservoir
medium-sized
Songyin Stream
one thousand six hundred and fifty-eight
Mainly irrigation, combined with power generation
fifty-three point two
Yaxi Reservoir
medium-sized
Xiaoanxi
three thousand
electricity generation
one hundred and eighty-four
Shangbiao Reservoir
medium-sized
brook
two thousand one hundred and fifty-nine
electricity generation
thirty point one
Yingchuan Reservoir
medium-sized
brook
three thousand seven hundred and thirty-one
electricity generation
one hundred and ninety-nine
Shuangkengkou Reservoir
medium-sized
brook
one thousand four hundred and seventy
electricity generation
thirty-eight
Zuoxi Primary Reservoir
medium-sized
brook
one thousand three hundred and forty-six
electricity generation
ninety point two
Xiecunyuan Reservoir
medium-sized
Xie Cunyuan
one thousand four hundred and seventy-three
Mainly irrigation, combined with power generation
forty-seven point two
Huangcun Reservoir
medium-sized
Yan Xi
one thousand eight hundred and forty-five
Mainly urban water supply, power generation
one hundred and fifty point seven
[7]
Tongji Weir[23]
Tongji WeirIt is located near Yantou Village, Bihu Town, Liandu District, Lishui City, Zhejiang Province. It was built in the fourth year of Xiaoliang Tianjian in the Southern Dynasty (A.D. 505) and has a history of 1500 years. It is the oldest large-scale water conservancy project in Zhejiang Province. It was listed as a provincial cultural protection unit in 1962.On June 25, 2001, as an ancient building from the Southern Dynasty to the Qing Dynasty, Tongji Weir was approved by the State Council to be included in the fifth batch of national key cultural relics protection units.In 2014, Tongjiyan was successfully selected as the World Irrigation Engineering Heritage.The whole water conservancy project, together with the inscriptions on the steles, is a precious material for studying the ancient water conservancy projects in China.From the Song, Yuan and Qing Dynasties, it has been renovated for many times.The arch shape of the dam is 275 meters long, 25 meters wide, and 2.5 meters high. It was originally a wooden bar structure, but was changed into a stone dam in the Southern Song Dynasty. It is a water conservancy project focusing on irrigation diversion and combining storage and discharge.The upstream catchment area of Tongji Weir is 2150 square kilometers, which can block more than 200000 cubic meters of weirs and canals every day, irrigating more than 40000 mu of grain fields in the middle and south of the whole Bihu Plain.The ancients took advantage of the situation to build a dam here to block water into the canal, which could make the canal water flow from high to low to irrigate the whole plain.The dam is 500 meters west of the Dagangtou at the junction of the Daxi River and the Songyin River. The south end of the bow foot of the arch dam is at the foot of the Weishan Mountain, and the north end is at the levee on the east bank of the diversion canal. Thousands of thousands of thousand year old camphor trees are planted on the levee, making the foundation at both ends of the dam more solid.At the same time, the flow of the stream coming down from Longquan Port must rotate at the confluence, and part of the flow rushes westward to the dam, which can offset the impact of the Songyin Stream on the dam.This is one of the reasons why Tongjiyan retaining dam has been fixed for thousands of years.[24]
The ancient square pond, with a history of more than 1700 years, is the earliest recorded water conservancy project in the Oujiang River basin.Gufangtang in Zhejiang ProvinceJinyun CountyOn the ancient mountain top near Shangdang Village and Shangping Village in Huyuan Township, with an altitude of nearly 1200 meters, it is the birthplace of Panxi, the main tributary in the upstream of Oujiang River.The ancient square pond was built in the second year of Wu Chiwu in the Three Kingdoms (239), and rebuilt on August 15 in the eighth year of Yongle in the Ming Dynasty (1410). It is recorded that an ancient stone tablet stood beside the pond.The old ancient pond is about 18 meters high, 26 meters long, and has a storage capacity of 100000 cubic meters.After being rebuilt in 1970, the dam is 38 meters high, 130 meters long and has a storage capacity of 1.28 million cubic meters.It mainly irrigates most of the townships in Huyuan Township, such as Shangdang Village, Shangping Village, Jiaokeng Village and Hucun Village. At the foot of Gufang Mountain, there is an impact hydropower station, giving full play to the comprehensive role of power generation and irrigation.
Tankeng Hydropower Station, located in Zhejiang ProvinceLishui CityIn the middle of the stream, a tributary of Oujiang River, most of the reservoir area is located inJingning She Autonomous County , the power station is located atQingtian CountyDomestic.On October 31, 2004, the main works of Tankeng Hydropower Station were commenced. On April 29, 2008, the Tankeng Hydropower Station was officially closed for water storage.On August 15, 2008, Tankeng Power Station Unit 1 was connected to the grid for power generation, and on January 12, 2009, Tankeng Power Station Unit 2 was connected to the grid for power generation. On July 10, 2009, Tankeng Power Station Unit 3 was connected to the grid for power generation and entered into commercial operation.The total reservoir capacity of Tankeng Hydropower Station is 4.15 billion cubic meters, the installed capacity of the station is 600000 kilowatts, and the annual power generation of the station is 1.035 billion kilowatt hours.The dam crest elevation of the river blocking dam is 171m, the dam crest length is 506m, and the maximum dam height is 162m, which is the highest dam in East China.
Jinshuitan Reservoir, located at the upstream of Oujiang RiverYunhe CountyIn the north of the city, with a catchment area of 2761 square kilometers, it is the first project for the development of water resources in the main stream of the Oujiang River. It is a water conservancy project focusing on power generation, with comprehensive benefits such as flood control, irrigation, shipping and the development of freshwater fisheries.The construction started in October 1981 and the dam was completed in June 1986.The dam reservoir has a total storage capacity of 1.393 billion cubic meters and an installed capacity of 300000 kilowatts.In 1988, all six units were put into operation, providing 250000 kilowatts of peak shaving capacity and 50000 kilowatts of load reserve and emergency reserve capacity for East China Power Grid, with an average power generation of 490 million kilowatt hours for many years.The reservoir area is 34.2 square kilometers, which can increase the fish farming area by 40000 mu.After the impoundment of the reservoir, the flow of downstream streams will be regulated, and the peak flow can be reduced by 57% in the event of a 20-year flood, which plays an important role in improving the flood control capacity of Lishui urban area and Bihu Town, and protecting 70000 mu of farmland in Lishui and Bihu basins.[25]
Shitang Hydropower Station is the largest river bed type medium-sized hydropower station in Oujiang River basin.It is the secondary power station of the Jinshuitan Hydropower Station, with a distance of 22km between the two stations.Shitang Hydropower Station is located in Yunhe County, with a drainage area of 3234 square kilometers above the dam site and a catchment area of 473 square kilometers to the tight water beach;The reservoir is a river type with a total storage capacity of 83 million cubic meters for daily regulation.The total installed capacity of the power station is 78000 kilowatts, and the average annual power generation for many years is 189 million kilowatt hours.The power station hub is composed of river dam, power house, switch station, booster station and navigation raft crossing facilities.The dam is a concrete gravity dam with a crest elevation of 104.9m and a maximum dam height of 38.9m;The total length of dam crest is 255m.[26]
Pollution
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The water quality of Oujiang River is good, and most river sections meet the surface water environmental quality standards. However, based on the extreme value assessment, the polluted river length accounts for 26.6% of the assessed river length. The main polluted river sections include Qingtian, Wenzhou and Songyin Stream of Oujiang River.The main pollutants are volatile phenol, mercury, chemical oxygen consumption and chloride ion.[27]
Origins of Oujiang RiverLongquan , upstreamYunhe County、Qingtian CountyAll inLishui City。Lishui City is located at the junction of Zhejiang and Fujian in the southwest of Zhejiang Province. It is dominated by middle mountains and hills. The terrain inclines from southwest to northeast. The southwest is dominated by middle mountains, with low mountains, hills and valleys between mountains;The northeast is dominated by low mountains, with middle mountains and valley basins between them.The land area of the whole city is 17298 square kilometers, of which the mountainous area accounts for 88.42%, the cultivated land accounts for 5.52%, and the streams, roads and villages account for 6.06%. It is an area of "nine mountains, half water and half farmland".The mountain range in this city belongs to Wuyi Mountain system, mainly including Xianxia Mountain, Donggong Mountain and Kuocang Mountain, which are trending from southwest to northeast, extending to northwest, southwest and northeast respectively.There are 3573 peaks with an altitude of more than 1000 meters, including 244 peaks with an altitude of more than 1500 meters, Huangmaojian of Fengyang Mountain in Longquan City with an altitude of 1929 meters, and Baishanzu of Qingyuan County with an altitude of 1856.7 meters, which are the first and second peaks in Zhejiang Province respectively.There are Oujiang River, Qiantang River, Feiyun River, Lingjiang River, Minjiang River and Jiaoxi River systems in the territory, which are parallel to the mountain trend. Xianxia Mountain is the watershed between Oujiang River system and Qiantang River system, Donggong Mountain is the watershed between Oujiang River system and Minjiang River, Feiyun River and Jiaoxi River, including Cangshan Mountain is the watershed between Oujiang River system and Lingjiang River system.The terrain on both banks of each river is steep, the source of rivers and streams is short and fast, the riverbed is deeply cut, and the water level rises and falls sharply. It is a mountain stream river. Due to the large drop, it has rich water resources.Oujiang River is the largest river in the city. It originates from the northwest foot of Guomaojian, Donggong Mountain, at the junction of Qingyuan County and Longquan City. It meanders from west to east. The main stream is 388 kilometers long, the territory is 316 kilometers long, and the drainage area is 12985.47 square kilometers, accounting for 78% of the total area of the city.Located in Longquanxi upstream of Oujiang River, the Jinshuitan Hydropower Station Reservoir, namely Xiangong Lake, covers an area of 43.6 square kilometers and is the largest artificial lake in the region.[28]It belongs to the subtropical monsoon climate zone with mild climate, warm winter and early spring, long frost free period and abundant rainfall.[29-30]
Lishui has a long history. According to archaeological discoveries, human activities began more than 4000 years ago.In the ninth year of the reign of Emperor Kaihuang of the Sui Dynasty (AD 589), the prefecture was established. After liberation in May 1949, Lishui District was set up in October. In 1952, the district was revoked, and each county was divided into Wenzhou, Jinhua, and Quzhou districts.In May 1963, Lishui District was restored, with jurisdiction over Lishui, Qingtian, Jinyun, Suichang, Yunhe and Longquan counties.It was renamed Lishui District in 1968 and Lishui District Administrative Office was established in 1978.Among them, Qingyuan County was restored in 1973, Songyang County was restored in 1982, Jingning She Autonomous County was established in 1984, Lishui County was revoked in 1986, Lishui City was established at the county level, Longquan County was revoked in 1990, Longquan City at the county level was established, Lishui City at the county level was revoked in 2000, and Liandu District was established.On July 19, 2000, the administrative office system was revoked and Lishui City was established, which governs Liandu District, Longquan City and 7 counties of Qingtian, Jinyun, Yunhe, Qingyuan, Suichang, Songyang and Jingning.[31]
Lishui is known as "Zhejiang Green Valley" for its rich natural resources and superior ecological environment.The ecological environment quality ranks first in the province and the country, and the public satisfaction of ecological environment quality continues to rank first in the province.Lishui is rich in hydropower resources, with 3.278 million kilowatts of conventional hydropower resources available for development in the city, accounting for about 40% of the exploitable amount in Zhejiang Province.In 2004, Jingning County was awarded the title of "Rural Hydropower Town of China" by the Ministry of Water Resources.In November 2006, Lishui was awarded the title of "No.1 City of Hydropower in China" by the Ministry of Water Resources.By the end of 2007, the total installed capacity of small hydropower (below 50000 kilowatts) was 1225900 kilowatts, making it the first prefecture level city in the province and even the country to achieve more than one million small hydropower installations.All counties (cities and districts) in the city have realized rural hydropower electrification.
There are many tourist attractions in the city. There are 68 tourist spots open to the outside world, including 12 national AAAA level tourist attractions, including Liandu Dongxiyan Scenic Spot, Longquan Mountain Scenic Spot, China Qingtian Stone Carving Cultural Tourist Spot, Qingtian Shimen Cave, Jinyun Xiandu Scenic Spot, Jinyun Huanglong Scenic Spot, Suichang Nanjianyan Scenic Spot, Suichang Gold Mine National Mine Park, Suichang County Shenlong Waterfall Scenic SpotQianfo Mountain in Suichang, Window of She Township in China, and Yunzhong Waterfall in Jingning;7 AAA scenic spots.Jinyun Xiandu, a national scenic spot, is famous for its mountain peak rock landscape. The provincial scenic spots include Lishui Nanming Mountain Dongxiyan, Jingning Waterfall, Qingtian Shimen Cave, Songyang "Ruoliao Andaihou" and Qingyuan "Shuangmiaojian Yueshan". The city and county (city and district) level scenic spots include Suichang Nanjian Rock, Songyang Shuangtong Snow.There are not only strange peaks, different caves, deep valleys and flowing springs, but also numerous cliff inscriptions, ancient buildings, religious temples and other cultural landscapes in the scenic spot.There are 83 nature reserves at all levels (including nature reserves) in the city, of which the forest ecosystem types include Longquan Fengyang Mountain - Qingyuan Baishanzu, Suichang Jiulong Mountain, the provincial nature reserve Jingning Wangdongyang Mountain Wetland, and the county level nature reserve Songyang Ruoliaoxian.There are 11 forest parks at or above the provincial level, including 8 provincial forest parks, including Baiyun Mountain in Liandu, Dashan Peak, Yunhe Xiangong Lake, Longquan Longyuan, Jingning Grass Fish Pond, Dayang Mountain in Jinyun, Kuocang Mountain, and Qingyuan Jinzi Peak;There are three national forest parks, Suichang, Qingtian Shimen Cave and Songyang Maoshan.There are many artificial lakes in Oujiang River basin, and the landscape is as natural as nature.Xiangong Lake is surrounded by "Summer Cave", "Eight Immortals Cave", "Nine Ponds and Eighteen Bays" and other landscapes;Tankeng Reservoir (Qianxia Lake) is another picturesque, leisure and tourist place in Lishui, with the magnificent scene of Qianxia Lake surrounding the lake, which gives people infinite reverie.[1]
Middle and downstreamWenzhou CityDomestic, includingYongjia County、Ouhai District、Lucheng District、Longwan DistrictIt is located in the southeast of Zhejiang Province, bordering the East China Sea to the east, Fujian to the south, Lishui to the west and northwest, and Taizhou to the north and northeast.The urban area (Lucheng, Longwan and Ouhai) covers 1187 square kilometers.The terrain within the territory is trapezoidal from southwest to northeast.The mountain ranges of Donggong, Kuocang, Yandang, and the Baiyun Peak in Taishun, 1611 meters above sea level, are the highest peak in the city.In the eastern plain area, artificial rivers crisscross.The main water systems are Oujiang River, Feiyun River and Chea River, and there are more than 150 rivers in the territory.Wenzhou has a land coastline of 355 kilometers and 436 islands.The coastline twists and turns, forming a natural harbor such as rock.It is in the middle subtropical monsoon climate zone. The winter and summer monsoon alternate significantly, the temperature is moderate, the four seasons are distinct, and the rainfall is abundant.Wenzhou Port now has 55 productive berths, including 7 deep-water berths above 10000 tons. Dongtou, Yueqing Bay and other natural deep-water ports have good prospects for development, and 10 200000 ton wharf berths can be built.[32]Wenzhou, a famous town in East Ou with splendid culture, was the capital of King Zou of East Ou in 192 BC.In AD 323, the county was built as Yongjia County. It is said that when the county was built, there were white deer carrying flowers around the city, so it was called Lucheng.It was called Wenzhou in 675 AD.Historically, it is famous for its developed handicraft industry and is one of the birthplaces of celadon. Papermaking, shipbuilding, silk, embroidery, lacquerware, shoe leather, etc. have a certain position in China's history.In the Southern Song Dynasty, it was opened as a foreign trade port, and was known as "the head of a prosperous sea, and has always been called Little Hangzhou".Wenzhou is the hometown of Southern Opera. In the middle of the 14th century, the famous Wenzhou playwright Gao Ming's "The Story of Pipa" was translated into many languages and widely spread in the world.Wenzhou is famous for its outstanding people and outstanding places. In the Southern Song Dynasty, the Yongjia School represented by Ye Shi and the Jianghu Poetry School represented by the "Yongjia Four Spirits", as well as Sun Yirang, Xia Nai, Xia Chengtao and Su Buqing in modern times, had a significant impact on the history of ideology, literature and science in China.Wenzhou has a long history and rich cultural relics.Ouyue culture, landscape culture and national culture have a long history.[33]The annual output value of six major industries, including electrical machinery and equipment manufacturing industry, leather, fur, feather (down) and its products industry, power and heat production and supply industry, general equipment manufacturing industry, textile and clothing industry, rubber and plastic products industry, exceeds 20 billion yuan.[2]Wenzhou, known as the "Southeast Mountains and Rivers Top the World", has many famous mountains and waters, and beautiful scenery.National key scenic spots include Yandang Mountain, Nanxi River, Baizhang Waterfall Feiyun Lake;National nature reserves include Wuyanling and Nanji Island;There are nine provincial scenic spots, including Xianyan, Yaoxi, Zeya, Binhai Yucang Mountain, Dongtou, Zhailiao Stream, Baizhangji Waterfall, 12 municipal scenic spots and 11 county-level scenic spots, including Chashan, Mingang, Tianzhu Temple.The total land area of the scenic spot is 2279 square kilometers, accounting for 20% of the city's land area.There are also five national forest parks and eight provincial forest parks in the city.It is one of the most livable areas on the west coast of the Pacific Ocean.[3]
Honors won
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On December 24, 2021, Oujiang River (Daxi) in Qingtian County was selected into the list of beautiful rivers and lakes to be announced in 2021 by Zhejiang Provincial Water Resources Department。[34]
