Jianhu Lake

Jianhu Lake

Jianhu Lake is one of the important plateau wetlands in Yunnan Province. It is located in the middle and south section of Hengduan Mountains in Northwest Yunnan Province, in Jianchuan County of Dali Prefecture, close to the county seat.

Location context

Jianhu, close to the county seat, is located between 99 ° 55 ′ - 99 ° 59.5 ′ E and 26 ° 25 ′ - 26 ° 31.5 ′ n. Jianhu Wetland Natural Reserve is composed of Jianhu reservoir, Yuhua reservoir, Huishui area and Mianshan forest in the surrounding mountain basin. It is 12.3km long from north to south, 6.2km wide from east to west, and 2186m in elevation. It is a typical wetland in Yunnan Plateau Wetland and one of the most representative wetland types in Northwest Yunnan Plateau.

hydrographic features

Jianhu Lake is a faulted lake formed by accumulating water in the subsidence area during the rising and falling process of neotectonic movement. It is a hilly and mountainous faulted basin with little fluctuation around the lake. The terrace is developed and the basin is multi lacustrine sedimentary. Up to now, Jianhu Lake, West Lake and many ponds still occupy or remain. The main tributary of Lancang River, the Heihui River in the upper reaches of Yangbi River, passes through the lake. The inflow river is called Jinlong River, which is an important source of water for Jianhu Lake. In addition to the Jinlong River, there are dozens of inflow streams such as Yongfeng River and Shihe River, with a catchment area of 918 km. The average water depth of Jianhu Lake is 2.7 m, the maximum water depth is 6 m, the total storage capacity is 206000 m, and the lake elevation is 2186 M.

Due to the destruction of vegetation in the upper reaches of Jianhu Lake and around the lake, a large amount of sediment has been washed into the lake. The water area of Jianhu Lake has been reduced year by year, and the lake water has become shallow. The water area of Jianhu Lake decreased from 9.36 km to 6.23 km in the early days of the people's Republic of China, with a net decrease of 3.13 km, a decrease of 33.4%; the water storage decreased from 45.32 million m to 16.8 million M, a net decrease of 28.53 million M, a decrease of 62.9%.

General situation of River Basin

Geology and geomorphology

As far as Jianhu wetland itself is concerned, its geomorphic structure and geomorphic types are very simple. However, when it is extended to Jianhu basin and nature reserve as a whole, it reflects the characteristics of diverse geological and geomorphic types, complex structure and prominent features

(1) There are various types of landforms;

(2) The geomorphic combination of North-South mountains and rivers;

(3) The landform is mainly of the original upper type and the original edge type;

(4) The development of special geomorphic types.

The main landform types are mountain landform and valley and Bazi (basin) landform. The highest elevation is 2833 m and the lowest is 2186 m. The Valley and Bazi (basin) landform can be divided into Valley, Bazi, karst landform, glacier and permafrost landform.

climate

Jianchuan is located in Hengduan Mountain area. In summer, it is mainly a subtropical weather system. With the northward withdrawal of the westerly jet, the Indian low pressure develops strongly. The whole area is controlled by the warm and humid air flow from the bay of Bengal, with abundant water vapor and concentrated precipitation. The convergence area between the Western Pacific subtropical high and the Qinghai Tibet high is formed in the upper air, which is the main weather process of heavy rain in Hengduan Mountain Area in summer. In the winter half year, it is mainly the westerly weather system. The lower layer is the dry and warm air flow from the western dry area. The wind speed is high, the rainfall is less, and the sunshine is sufficient. When the South Branch jet flows eastward along the south side of the Qinghai Tibet Plateau, it is disturbed by the landform and produces ridge line or trough, which strengthens the southwest air flow northward and brings part of the water vapor from the bay of Bengal into the area. The activity of the South Branch trough is small in winter and spring Small and medium scale weather process of large-scale precipitation. This circulation pattern constitutes the climatic characteristics of Jianchuan County with distinct dry and rainy seasons.

soil

The vertical height difference of Jianhu basin is large, and the soil types are complex and diverse. However, the soil types that have a great impact on Jianhu wetland are only the soil types that are collected below 2500 m above sea level around the lake. There are four soil types: red soil, alluvial soil, paddy soil and swamp soil, and six sub types: red soil, mountain red soil, dark red soil, dark alluvial soil, gley paddy soil and swamp soil, which are mainly distributed in the lake basin and lakeside at an altitude of 2186 m, and on the hillside up to 2500 m.

Culture

Every year, June 15 of the lunar calendar is the time for the village around Jianhu to go around the sea. At that time, the villagers of all villages were like a festival, and they took their own villages as the starting point to go around Jianhu Lake. In this way, the villagers in each village along the lake are both hosts and guests - hosts when they entertain people from other villages in their own village, and guests when they leave their own village and enter other villages.

Along the way, young people sing and dance, and old people talk about the past and the present. When they pass through the village, they give each other tea and candy. Through the meeting, villagers can not only increase contact with each other, increase understanding, enhance friendship, but also cultivate temperament and entertain themselves. Therefore, it can be followed year by year and has continued to this day.

scenic spot

Manxian forest at the northern foot of Jinhua mountain covers an area of 2097 hectares. The skyscrapers built hundreds of years ago and the spring water that never dries up all the year round have become a summer resort. The biggest advantage of Jianhu Lake is that it does not suffer from pollution and damage, and maintains its natural scenery. The lake is clear, with a distant view of the "sky mirror" side, and a close-up view of the fish. Around Jianhu, there are villages inhabited by Bai people, with beautiful scenery, different landscapes in the four seasons, and picturesque villages in Tianchou. In the past, on June 15 of the lunar calendar, the local Bai people took their village as the starting point and destination, dressed in costumes, and walked around Jianhu Lake in groups. It was called "sea going meeting", which became an ancient custom.

Among the "eight sceneries of Jianhu Lake" praised by predecessors, Jianhu Lake holds two Titles: one is "autumn moon at Haimen", the other is "fishing lights on the sea". According to the records of Jianchuan Prefecture compiled in the 52nd year of Emperor Kangxi of the Qing Dynasty, the wonder of "Autumn Moon in Haimen" is that "the moon is reflected in Haimen water before the Mid Autumn Festival is over.". The wonder of "sea fishing lantern" is "fishermen fishing in the lake at night, and the fire is as bright as a star". Unfortunately, due to the narrowing of the water surface, the wonder of "Haimen Autumn Moon" is no longer seen. However, we can still see the beautiful scenery of "fishing lights on the sea", just as a poem of predecessors described: "a boat on the sea is light, and the fishing fire is as bright as a star when you come late. Jianchuan is 129 kilometers away from Dali, Yunnan Province. It is an ideal place to stay and play on the way to Lijiang and Diqing, Yunnan Province.

Biological resources

Animal resources

There are 15 species of fishes in Jianhu Lake, which belong to 3 orders, 4 families and 14 genera. After eliminating the alien species, there are only 8 species of indigenous fishes, which belong to 2 orders, 3 families and 7 genera. Among them, Cyprinidae has the largest number of species, 4 genera and 5 species, followed by 2 genera and 2 species of loach family, and 1 genus and 1 species of branchiidae. Compared with the large lakes in Yunnan Province, the fish fauna of Jianhu Lake showed more class elements and less radiation differentiation of genera and species, except for Carassius auratus and Misgurnus The common genera of Jianhu Lake are carp and Schizothorax, while there are only eight indigenous fish species in Jianhu Lake, but loach is endemic to Jianhu Lake, and four species are unique to Yunnan lake.

A total of 94 bird species belonging to 62 genera and 32 families were recorded in Jianhu wetland reserve, accounting for 11.6% of the total bird species (810 species) in Yunnan Province. About 7.5% of the total birds in China. Among the 94 species of birds identified, there are 42 species of resident birds, accounting for 44.7%; 7 species of summer migratory birds, accounting for 7.4%; 45 species of winter migratory birds, accounting for 47.9%. It shows that the species of migratory birds is slightly dominant compared with the species of migratory birds in Jianhu wetland reserve, and the population of ducks is absolutely dominant. According to the life form and habitat type of birds, there are 12 species of waterfowl on the surface of the lake, accounting for 12.8% of the bird fauna composition of the reserve; 42 species of wading birds on the lakeside wetland, accounting for 44.7% of the bird fauna composition of the reserve; 40 species of forest birds, accounting for 42.6% of the bird fauna composition of the reserve.

plant resources

The vegetation types of Jianhu wetland include 4 formations of swamp type group, grass swamp type group, 10 formations of shallow water plant wetland type group, floating plant type, floating leaf plant type and submerged plant type.

Submerged vegetation is the most widely distributed, the most abundant and the most diverse type of wetland vegetation in the nature reserve. Among them, there is a rare submerged plant - cauliflower, which is unique to Yunnan plateau lakes and is the key national protection. There are 443 species of vascular plants in Jianhu nature reserve, belonging to 281 genera of 112 families. Among them, 20 species belong to 14 genera of 10 families, 423 species belong to 267 genera of 102 families. Among 102 families, there are 4 species of gymnosperms in 3 families and 3 genera, and 419 species of angiosperms in 99 families and 264 genera. The flora of seed plants in the nature reserve is relatively poor. The quantitative structure of "a few families" reflects the ancient and conservative nature of the flora in this area to a certain extent.

Jianhu wetland vegetation is divided into swamp vegetation type group and shallow water vegetation type group

(1) Swamp vegetation type group

The swamp vegetation in Jianhu Lake is mainly composed of grasses, Polygonaceae, Compositae and other herbs, with coverage of more than 90%. It belongs to grass swamp wetland, distributed in the lakeshore zone around the lake and the transitional zone between lakeshore and lakeshore, including bermudagrass formation (< iform Cynodon dactylon < / I), Polygonum hydropiper formation (< iform Polygonum hydropiper < / I) and Polygonum hydropiper formation (< iform Polygonum hydropiper < / I)

Chinese PinYin : Jian Hu