Gucheng Lake

Gucheng Lake is a typical grassy lake with rich natural food. It is the best natural lake in Jiangsu Province for drinking water quality, especially suitable for the culture of Eriocheir sinensis. Now crab purse seine culture has become the pillar industry of Gaochun agriculture. In 2005, the county's culture area reached 200000 mu, and the output is expected to exceed 6.5 million kg. There are also shrimps, Monopterus albus, soft shelled turtle, perch and rare fish in the lake More than 20 special aquatic products, such as pearl. Gucheng Lake is named after the ancient "Gucheng" lakeside, commonly known as Xiaonanhu. The predecessor of the lake was originally a lagoon on the seashore. Coral fossils of that time can be found and collected on the limestone in the east of the lake and Huashan Area, which is historically known as Danyang daze. After years of river sediment accretion, a lot of beaches appeared; after generations of reclamation, daze was divided into three lakes: Danyang, Shijiu and Gucheng. Only Gucheng Lake is owned by Gaochun County, with an existing area of more than 30 square kilometers. The water quality is pure and rich in fish, shrimp and water chestnut. Gucheng Lake is a natural regulating lake for detention of mountain torrents in the lower reaches of Shuiyang river. However, since 1971, the outlets of the three rivers, namely, the Waigang River, the Shishu River and the zhilonggang River, have been blocked by dams, and the flood of the Shuiyang River can not be discharged into the lake, which has increased the pressure of the main stream and the flood and waterlogging problem in the polder area along the lake in Xuanzhou City. It was originally a lake depression. Due to long-term flood with sediment deposition and reclamation, it was divided into Danyang Lake, Shijiu lake, Gucheng Lake, Jinqian lake, Luxi lake and other small lakes, and the rest formed a river network polder area. Gucheng Lake is located in Gaochun County. The shape of the lake is approximately a triangle, wide in the north and narrow in the south. The original area of the lake is 65KM2, the length is 10.4km, the maximum width is 8.2km, the average width is 5km, the maximum water depth is 3.6m, the general bottom elevation is 5.0m, the minimum is 3.5m. Due to reclamation, the area of Gucheng Lake is only 39km2, the normal water level is 7.8m, the storage volume is 65 million m3, the design flood level is 13.0m, and the corresponding volume is 265 million m3. Gucheng Lake is a natural lake with the best drinking water quality in Jiangsu Province. The main inflow river is Xu River.

Gucheng Lake

Gucheng Lake is the branch water of Yangjiang River. Located at the junction of Gaochun District in Nanjing city and Xuanzhou District in Xuancheng City, Anhui Province, Xiaonanhu lake is named after the ancient "Gucheng" on the lakeside. It is a natural regulating lake for storing mountain torrents in the lower reaches of Shuiyang river. Gucheng Lake and Danyang Lake, Shijiu lake and Nanyi Lake are the forerunners of ancient Danyang Lake, which were later formed by sediment deposition and successive reclamation.

Gucheng Lake has many functions such as navigation, irrigation, flood storage and breeding. It is a natural lake with the best drinking water quality in Jiangsu Province. The main inflow river is Xuhe River, which is rich in natural food and suitable for breeding Chinese mitten crab. It has become a pillar industry of Gaochun agriculture. Gucheng Lake crab has become a geographical indication product of Gaochun district.

The origin of the name

Gucheng Lake, named after the ancient "Gucheng" by the lakeside, is commonly known as Xiaonanhu. In the spring and Autumn period, in the fourth year of King Jingwang of Zhou Dynasty (541 BC), King Yu Ji of Wu built "ziluo city" 15 kilometers east of Gaochun district. Because the city was high and solid, it was named "Gucheng", which was later Gucheng street, and based on this, LaiZhu town was established. " The name of "Xiaonanhu" should be used to distinguish Nanyi Lake in its south.

Location context

Gucheng Lake is located between 31.14-31.18 N and 118.53-118.57 E. On the right bank of the Yangtze River and at the junction of Nanjing City in Jiangsu Province and Xuancheng City in Anhui Province, the lake district belongs to Gaochun District in Nanjing city and Xuanzhou District in Xuancheng City in Anhui Province. Chunxi town of Gaochun district is located in the northwest corner of the lake, with Gucheng town in Hubei, Liqiao town in Xuanzhou District in Hunan, zhuanqiang town and Yangjiang town in Gaochun district on the West Bank of the lake. Gaochun District accounts for most of the area.

The lake is triangular, wide in the north and narrow in the south. The lake area, according to the 1992 edition of natural geography of Nanjing, was 10.4 km long from north to South and 8.2 km wide from east to west before 1949. The lake area is 76 square kilometers, 35.7 square kilometers in the 1990s. According to the 1999 edition of Jiangsu Provincial Records, the lake is 9.5km long, 4.9km wide and 24.3km2 (corresponding to the water level of 7.37m)

According to Xuancheng county annals in the 1980s, the lake covers an area of 81 square kilometers, of which the southern part is under the jurisdiction of Xuanzhou District, covering an area of 15 square kilometers, which should be the data before liberation

.

The reduction of the lake area is mainly due to reclamation. In 1978, Gaochun district built yongshengwei in guchenghu District, covering an area of 41400 mu. Once reclaimed, the lake area will be reduced by 27.4 square kilometers. With the reclamation of Gucheng Lake in Anhui Province, the area of Gucheng Lake decreased by about 50% from 1949 to 1990.

Lake genesis

Gucheng Lake and Shijiu lake are located at the edge of Nanjing sag. Due to the faulting in the late Mesozoic Yanshanian movement, the northwest limb of Ligao anticline was faulted and subsided, resulting in a large number of depressions including Gucheng Lake, Shijiu lake, Danyang Lake and their Western polder area, thus laying the basic prototype of the lake basin. In the early Holocene, the Tongjiang gap in the western part of the depression was blocked, and the drainage was not smooth. * then the lake was built into the ancient Danyang lake. The ancient Danyang Lake covers a large area, including not only Gucheng Lake, Shijiu lake and Danyang Lake, but also the Western polder area. Since then, the Western Delta of the depression has gradually developed, and the lake has become shallower and narrower, which can be divided into Gucheng Lake, Shijiu lake and Danyang Lake. Due to the continuous deposition of sediment and large-scale reclamation of the lake, the lake has changed even more. Danyang Lake has disappeared, Gucheng Lake has only two tenths of its original surface, and Shijiu Lake's surface has shrunk greatly.

hydrographic features

The average water depth of Gucheng Lake is 1.6m, and the maximum water depth is 3.67M. When the normal water level is 7.27m, the volume is 7-95 million cubic meters.

However, according to the geographic records of Jiangsu Province, the average water depth is 1.6 meters and the water storage capacity is 39 million cubic meters.

The low-lying area is also a natural flood detention area and flood passage corridor.

In 1954, the mountainous area of Southern Anhui was flooded, and the Yangtze River was irrigated backward. The highest water level of Gucheng Lake was 12.45 meters, 1.26 meters higher than that of Dongba dam crest. During the flood season of 1983, from June 23 to July 24, there were torrential rain in the whole basin of Shuiyangjiang river. During the same period, the rainfall in Gaochun district was 527mm. The mountain torrents were discharged and the river water was propped up, forming a huge flood. The highest flood level of Gucheng Lake after the founding of the people's Republic of China was 12.57 meters, which was 0.12 meters higher than that of 1954. There were 81 polders in Gaochun District, 43 polders were broken, 59000 mu of farmland was submerged, and more than 14000 houses were collapsed.

Main tributaries

The rivers entering the lake are niuergang, Xuhe and Qiqiao, the tributaries of Shuiyang River, and the rivers leaving the lake are Guanxi river.

Xuhe River, also known as Wushen canal and XuXi River, was excavated in 506 BC (spring and Autumn period). It has been excavated for 2500 years. As the earliest canal recorded in China, it is also the earliest canal excavated in the world. At the junction of Gaochun district and Liyang City, it starts from Gucheng Lake in Gaochun District in the west, passes Dongba, goes to Xiaba and dingbu, and ends at Yaxi estuary of Zhujiaqiao in Liyang City, connecting with Nanhe river. Also known as Chunxi River, ancient name XuXi River, XuXi river. In the spring and Autumn period, King Helu of Wu conquered Chu and used Wu Zixu's plan to transport grain to Taihu Lake in the East and Yangtze River in the West. And then it was annihilated. In the second year of Tang Jingfu (893), Yang xingmi built five weirs to transport grain. In the Northern Song Dynasty, the five weirs were gradually abandoned, and the East and West dams were built to prevent the lake water from invading into the East in Gaochun. In 1392, Xuhe river was dredged again, and the stone gate was built to open and close, so as to connect Jiangsu and Zhejiang grain. At the beginning of the Ming Dynasty, Yongle abandoned yundao and built Dongba again. In the 35th year of the Jiajing reign of the Ming Dynasty (1556), the lower dam was built, and the water of the Gaochun lakes was no longer eastward. In 1958, Xuhe river was dredged, Dongba water diversion project was demolished, sealing dam and Maodong sluice project were built. With a total length of 30.6 km and a width of 20-160 m, the river is a channel for water diversion, irrigation and navigation between Gaochun and Liyang.

Qiqiao River, located in the north central part of Gaochun District, Nanjing City, belongs to the Shuiyang River Basin in the lower reaches of the Yangtze River. The whole river course runs from northeast to southwest. The upstream originates from the longdunhe reservoir, and the downstream flows into the northeast corner of Gucheng Lake. Under the longdunhe reservoir, the river course has a total length of 16 kilometers and a total catchment area of 109.4 square kilometers. It undertakes the tasks of flood control and drainage, water supply and irrigation, shipping, water environment, etc.

Shuibiqiao River, also known as Gangkou River, has a total length of 8.5 km, connecting Shuiyangjiang River and Gucheng Lake from shuibiqiao to Gangkou.

Guanxi River starts from the northwest Bank of Gucheng Lake in the South and flows to Huyang Township in the north, connecting with Yunliang River and Shijiu lake. The length of the river is 8.7 km and the bed height is 3.5-4.5 M.

Yunliang River, on the Bank of Danyang Lake, used to be a water transport channel, so it is named. It flows from south to north, connects Shuiyangjiang River in the south, passes through the northwest of Gaochun District in Nanjing, and reaches xiaohuajin in the north, with a total length of 22.5 km. The river bed is about 50m wide and the highest water level is 12.41m (July 14, 1983) at Dalong station.

Niuergang, located in the northeast of Xuanzhou District, Xuancheng City, is one of the rivers where Shuiyang River naturally divides flood into Gucheng Lake. From Xiaohekou of Dongxiang, it enters Gucheng Lake at taibaowei via Liqiao Town, with a total length of 11 km.

Aquatic resources

Chinese PinYin : Gu Cheng Hu