Location of Qiandao Lake

Qiandao Lake (Xin 'anjiang Reservoir) is located in Chun 'an County, Hangzhou City, Zhejiang Province, with a small part connected with the northwest of jiande city. The artificial lake for Xin 'anjiang Hydropower Station was built in 1955 and completed in 1960. The dam is105m high and 462m long. The length of the reservoir is about 150km, and the widest part exceeds 10km. The deepest part exceeds 100 m, with an average water depth of 30.44 m. Under normal water level, the area is about 580 square kilometers, and the storage capacity178 billion cubic meters. At the highest water level, there are more than 0.25 square kilometers of land bridge islands 1078, mainly islands below 2 square kilometers, with an island area of * * 409 square kilometers.

Qiandao Lake is the first water body in China, and it is a national first-class water body. It can meet the drinking water standard without any treatment, and is known as "the best water in the world". 1984 12 15 The Zhejiang Geographical Names Committee officially named Xin 'anjiang Reservoir "Qiandao Lake".

200 1, Qiandao Lake Scenic Area was awarded the first batch of AAAAA tourist areas in China. On April 20108/KLOC-0, the National Tourism Administration awarded Qiandao Lake Scenic Area the honor of national 5A-level tourist attraction.

General situation of lakes

Location context

Qiandao Lake is located between 2911'and 30 02' north latitude and1115' east longitude, and is located in Chun 'an County, which borders on the south of Anhui Province in the west of Zhejiang Province.

geologic structure

Before the construction of the reservoir, Xin 'anjiang entered the Chun 'an Basin from Tunxi, Anhui Province, connected to Dongxi Port and Jinxianxi Port in the east, connected to Sui 'an Port in the south, arrived at the port and left Tongguan Gorge. In the upper reaches of Tongguan Canyon, Xin 'an River winds among the mountains. Due to the steep slope of the river bed, the river drop is getting bigger and bigger. From Tunxi to Tongguan Gorge, the natural drop is 100 meter. The structural line in the reservoir area is northeast, with faults such as the axis of Majinfu anticline and Yinzhubu-Hua Kai passing through, and the ridge line is in the same direction as the regional structural line. Most of the landforms in the reservoir area are eroded hills and karst hills, and a few are valley plains. Most of the reservoir bottom and bed are Paleozoic dense impermeable rocks, a few are semi-dense or cemented impermeable and slightly permeable rocks, and some are impermeable magmatic intrusions, whose exposed elevation is greater than the designed backwater elevation. The soil and water conservation in the reservoir area is good, and the average sediment concentration for many years is only 0.248 kg/m3, so the erosion and siltation are not serious. Tongguanxia dam site of reservoir dam. Tongguan Canyon is 800 meters long, with its banks at an altitude of 300 meters. Its riverbed is 20-22 meters above sea level, and its lower part is steep, with a slope angle of 30-40. The width of the canyon in dry season is about 180 meters. The lithology on the left bank is Tangjiawu timely sandstone (S3t), and the lithology on the right bank is Xihu Formation timely sandstone (D3x). Most of the riverbed is Tangjiawu sandstone, with compressive strength of150x65,438+006 Newton/m2 and friction coefficient of 0.60. There is no weathered layer at the bottom of the river and no large broken zone in the riverbed.

Qiandao Lake area belongs to the hilly area of western Zhejiang, which consists of middle and low mountains, hills, small basins and river valleys. The terrain is high around, low in the middle, and inclined from west to east, forming a landform form in which the middle and low mountains around gradually transition to the central hilly area. Before Paleozoic, Qiandao Lake area was in the ancient ocean. The late Mesozoic Indosinian orogeny gradually rose, which laid the foundation for the landform outline of the whole area. After Yanshan movement and Himalayan orogeny, it was eroded by long-term external forces and uplifted to varying degrees, and weathered, denuded and leveled by volcanic eruption, magma intrusion, fault activity and external forces, forming a landform dominated by low mountains and hills in this area. Mountainous areas and basins are distributed in cascade multi-layer topography. In the low hilly basin downstream of the valley, erosion and terrace develop, river alluvial, diluvial and lacustrine deposits are widely accumulated in the valley and basin, and residual slope deposits and diluvial deposits are developed on both sides of the valley slope. After the formation of Xin 'anjiang Reservoir, the valleys and low mountains below 108 meters above sea level became water surfaces, and the landform of low mountains became more prominent. The landform types are mainly denuded mountain landforms, followed by accumulated landforms and artificial lakes.

River basin survey

The basin area above the dam site of the reservoir is 10442 square kilometers, of which 60% of the basin area (catchment area) is in Anhui Province. It mainly includes Chun 'an County, Zhejiang Province, Shexian County, huangshan district City, Anhui Province and Xiuning County. There are 33 rivers in the reservoir. Design water level108m (elevation of the Yellow Sea), water surface area of 573km2, storage capacity178.4×108m3, and longitudinal length of reservoir area150km. The average water depth is 3 1. 13m, the coastline length is 1.406km, and there are 1.078 islands. Xin 'anjiang Reservoir belongs to subtropical humid monsoon climate, with average temperature 17.8℃, average precipitation 1.489.0 mm and average evaporation of 65438+. The annual net inflow is 94. 1× 108 cubic meters, and the outflow is 90.0× 108 cubic meters. The water exchange cycle is 2 years. Xin 'anjiang River in the upper reaches is the main inflow river, and the rainwater collection area above the street section is 6000 square kilometers, and the inflow runoff accounts for 60.2% of the total runoff.

The main water source of Qiandao Lake is Xin 'anjiang River in Anhui Province and its tributaries, and the catchment comes from Shexian, Xiuning, Tunxi, Jixi, Qimen and southern huangshan district in Huizhou, Anhui Province.

Many ancient cultural sites and ancient tombs have been discovered in Qiandao Lake, including the Neolithic cultural site in Wulong Island, the cultural site from the Western Zhou Dynasty to the Spring and Autumn Period in Xiaotangwu, and the cultural site from the Spring and Autumn Period to the Jin Dynasty in Shuidui. There are also ancient temple buildings such as the Bone Pagoda, Mishan Temple and Yinshan Temple on Mishan Island, as well as ancient tombs such as Ye Lingyuan and Zheng Yunzhong Tomb.

1959, due to the construction of Xin 'anjiang Hydropower Station, he cheng, Shicheng, Weiping Town, Chayuan Town and Port in Chun 'an County were flooded, accounting for 49 townships 1377 natural villages, including 307,838 mu of cultivated land and 255 urban industrial and commercial enterprises. Chun 'an and Sui 'an counties merged into Chun 'an County. Under the jurisdiction of Hangzhou, it governs 30 townships and 899 administrative villages with a total area of 4,427 square kilometers. It is the largest county in Zhejiang Province, bordering Shexian and Xiuning counties in Anhui Province, and six counties and cities in Zhejiang Province, including Lin 'an, Tonglu, Jiande, Quxian, Changshan and Hua Kai, with a total population of 450,000, mostly Han nationality. Chun 'an is mountainous, with plenty of water and little arable land. There are more than 80 peaks with an altitude of 1000 meters in the county. The highest peak is1523m above sea level. Mountain hills account for 80% of the county's total area. In 20 12 years, Chun 'an County achieved a regional GDP of1592.28 million yuan, an increase of 10.6% over the previous year at comparable prices.

Climatic characteristics

The annual average temperature of Qiandao Lake is 65438 07℃. The rainy season in Qiandao Lake is from early June to early July, and mid-July to late August is the summer drought season. The weather is sultry, and the highest temperature rises to 36℃ in the afternoon.

Hydrological characteristics

Hydrological water quality

Qiandao Lake is a thermocline from the water surface to below 10 meter, and the water temperature changes back and forth between 10℃ and 30℃. The water temperature changes with depth, with the most significant change in July and August, and the water temperature changes from 26℃ to 10℃ every time the water depth drops. 10℃ from the water surface to 25 meters, and the stagnant water layer from the water depth of 25 meters to the bottom of the lake. The water temperature remains stable all the year round, the stagnant layer is below 25m in the first half of the year and below 35m in the second half, and the water temperature remains around 10℃ all the year round.

According to the national report on ambient air quality of key cities and water environment quality of key river basins in the first half of 20 1 1 issued by the Ministry of Environmental Protection, Qiandao Lake Reservoir has the highest first-class water quality among the monitored 10 major reservoirs, and it is also the only one with first-class water quality among 10 reservoirs. The visibility of the lake is as high as12m in clear weather.

The annual water temperature stratification time in Qiandaohu Lake area is long (April ~ 65438+February) and the mixing period is short (1~ March). It is a typical subtropical single mixed water body, and the DO concentration in the thermocline of the lake area is low.

water level

201On July 27th, 5, the measured water level of Xin 'anjiang Reservoir 105.02m was the highest water level in that year, which was lower than that of the previous year1.51m. On February 20th, the measured water level was 98.06m, which was the lowest water level in the whole year and 3.03m higher than the lowest water level in the previous year. The annual variation of water level is 6.96m, and the annual average water level is101.96m. ..

Ecological characteristics

The trend of Qiandao Lake from eutrophication to eutrophication, the pollution elements are heavy metals, nitrogen, phosphorus and organic matter, cages and cruise ships in turn; The water temperature is stratified, and the annual average temperature is 19.6℃. From June to September, the temperature of the surface layer (from water surface to underwater10m) varies greatly, with an average of 28.2℃-24.4℃, which is called warm water layer and is greatly affected by floods. The middle layer (10-30m) is a constant temperature layer. There are 83 species of fish in the lake, such as bighead carp, silver carp, grass carp, etc. 13 family, as well as valuable fish such as mandarin fish, mandarin fish and eel, with an annual output of more than 3,000 tons. Artificial aquaculture is developed, with a commercial fish farm of 666 square meters, mainly carp, bighead carp and tilapia, with an annual output of nearly 90%.

morphological character

Qiandao Lake is tree-shaped, with an area of 567.40 square kilometers and more than a thousand islands. The dam is108m high and 462m long, with a drainage area of10480km2, a total storage capacity of17.84 billion cubic meters, a length of150km from north to south and a width of10km. The water area is 580 square kilometers, and the coastline length is 1406 kilometers. The water depth in front of Gandao Lake dam can reach 90 meters, with an average water depth of 34 meters. The bottom of the lake is mainly yellow clay. It flows into the lake through 25 streams and rivers around the lake, among which Xin 'anjiang is the largest, longest and richest in water, as well as Wuqianghui, Zhongzhou, Jinxianxi and Mubaifan.

natural resource

Qiandao Lake has 1786 species of plants and more than 2,000 species of animals and insects. The forest coverage rate of the islands in the lake reaches 82.5%, and the annual catch of 87 species of freshwater fish exceeds 4000 tons. There are 94 species of fish resources in Qiandao Lake, belonging to 13 family. There are 90 species of birds, including 6 1 species of mammals, 90 species of birds, 50 species of reptiles, 16 orders, 320 families and 0/800 species of insects.

Qiandao Lake Scenic Area is rich in plant species, including vascular plants 1824 species, of which 20 species are under state protection.

A total of 456 species of vascular plants were recorded in 54 islands of Qiandao Lake, including arbor 120 species, shrub 6/kloc-0 species, herb 232 species and vine 43 species. Trees are mainly Pinus massoniana and FAGACEAE plants; Shrubs are common in Ericaceae, Rosaceae, Hamamelidaceae, Ilex and Quercus. Herbs are mainly compositae and Gramineae.

Governance and development

Tourism development

Main entrance: Qiandao Lake Scenic Area

1986165438+10 In October, Qiandao Lake Scenic Area was approved as a national forest park by the Ministry of Forestry.

200 1, Qiandao Lake Scenic Area was awarded the first batch of AAAAA tourist areas in China.

On April 20108/KLOC-0, the National Tourism Administration awarded Qiandao Lake Scenic Area the honor of national 5A-level tourist attraction.

Environmental governance

65438-0999 Chun 'an County established the "Qiandao Lake Protection Special Fund" for the environmental protection of Qiandao Lake.

In 2009, the local government of Qiandao Lake launched "Five Remedial Measures", focusing on banning "sand mining, cage culture, fishing, domestic sewage from ships, illegal buildings, etc." By June 20 12, the cage culture rectification in Qiandao Lake, which lasted more than two years, was basically completed, and about 50,000 cages landed.

water conservancy project

In 20 14, the water distribution project of Qiandao Lake, the second water source in Hangzhou, started from the Zhu Jin brand water intake of Qiandao Lake in Chun 'an, all the way eastward11km, and reached the Xianlin Reservoir in Yuhang, which was divided into three roads, covering the main city, Xiaoshan and Yuhang respectively.