Xuancheng geographical environment

Xuancheng City is located in the southeast of Anhui Province. The ground span is 29 57' ~ 310/9' north latitude and 0/7 58' ~19 40' east longitude. It borders Changxing County, Anji County and Lin 'an City in Zhejiang Province in the east, Huangshan City in the south, Chizhou City and Wuhu City in the west and northwest, and Maanshan City, Gaochun County, liyang city City and Yixing City in Jiangsu Province in the north and northeast.

The easternmost point is at the junction of taoyuan village and Changxing County, Xinhang Town, Guangde County, the westernmost point is at the junction of Daidi Village, Taohuatan Town, Jingxian County, Qingyang County and huangshan district County, the southernmost point is at the junction of Lianjinshan and Shexian County, and the northernmost point is at the junction of Licun, Dangtu and Gaochun, Shuiyang Town, Xuanzhou District.

The territory is 1.6 1.5km long from east to west and 1.50km wide from north to south, with a total area of 1.23km, accounting for 8.9% of the total area of the province, ranking fifth in all cities in the province, among which, the mountainous area1.967. The hilly area is 8202.33 square kilometers, accounting for 66.5%; Plain 19 12.29 square kilometers, accounting for15.5%; The lake is 257.6 1 km2, accounting for 2. 1%.

Among the counties and cities under its jurisdiction, Xuanzhou District covers an area of 2,620.75 square kilometers, Langxi County covers an area of 1 104.75 square kilometers, Guangde County covers an area of 21/5.95 square kilometers, Ningguo City covers an area of 2,437.5 square kilometers, and Jingxian County covers an area of 2,023.75 square kilometers.

The urban area is 90km away from Hefei 190km, 230km away from Shanghai, 50km away from Nanjing 150km away from Lukou Airport10km away from Hangzhou. Xuancheng city is located in Yangtze paraplatform area in geological division. Strata belongs to the lower Yangtze sub-region of the Yangtze stratigraphic region, and the strata in each era are relatively complete. Controlled by geological structure, the topography is high in the south and low in the north, and the landforms are complex and diverse, which can be roughly divided into five types: mountains, hills, basins, valleys, hills and plains. Mountains, hills and valleys crisscross in the south, and the altitude is generally above 200- 1000 meters. The central hills are undulating, and the elevation is generally 15 ~ 100 meters; Except for some broken mountains in the north, most of them are vast plains, dotted with rivers, lakes and ports. The overall elevation of the polder area is 7-12m. The mountains in the south and southeast belong to Tianmu Mountain, the mountains in the southwest belong to Huangshan Mountain and the mountains in the west belong to Jiuhua Mountain. There are more than 60 peaks above 1000 meters above sea level, and the highest one is 1787.4 meters, which is located at the junction of Jixi County, Shexian County and Zhejiang Lin 'an County.

Xuancheng city is located in the transitional zone between the southeast hills and the middle and lower reaches of the Yangtze River, with high terrain in the southeast and low terrain in the northwest. The altitude is generally 800 ~ 1800 meters in the southern part of Zhongshan, 500 ~ 800 meters in the low mountain area, 50 ~ 500 meters in the central hilly area and below 50 meters in the northern plain area. There are three mountains in the territory: Huangshan Mountain, Tianmu Mountain and Jiuhua Mountain.

Tianmu Mountain extends from southwest to northeast, from the east of Jixi County to Guangde and Langxi County through the south of Ningguo City. Huangshan Mountain enters Xuanzhou District and the south of Langxi County from south to north from the border of Jixi and Jingde through the west of Ningguo City and the east of Jingxian County.

Jiuhua Mountain Range is only distributed in some low mountain areas in the west of Jingxian County and the southwest of Xuanzhou District. The landform is complex and diverse, which can be roughly divided into five types: mountains, hills, basins (valleys), hills and plains. Mountains, hills, basins and valleys in the south crisscross; The central hills are undulating; Except for some hills in the north, most of them are vast plains, with rivers, lakes and ports dotted around.

The mountainous area is 20 17.66 square kilometers, the hilly area is 7948.36 square kilometers and the plain area is 2389.64 square kilometers. The highest peak in China is located in Liangqingfeng, Fuling Town, Jixi County, with an altitude of1787.4m.. The lowest point is located in the center of Jinbaowei, Shuiyang Town, Xuanzhou District, only 5 meters above sea level. The climate in Xuancheng area belongs to subtropical humid monsoon climate type, which has the following remarkable characteristics: obvious monsoon and distinct four seasons. Xuancheng, located in the mid-latitude zone, is one of the areas with the most obvious monsoon climate. Due to the difference of thermal properties between land and ocean, the south wind from the ocean prevails in summer and the north wind from the inland prevails in winter. In summer, it is controlled by tropical ocean air mass, which is hot and rainy, and in winter, it is controlled by Eurasian air mass, which is cold and rainy, and the rainfall distribution is uneven during the year.

Summer is the longest in a year, about 12 1 day, from May 2 1 day to September 18 day, and the average temperature is >: 22℃; Winter comes next, about 102 days,1October 27th to March 8th of the following year 165438+, and the average temperature is <1o℃; Spring is short, about 73 days. From March 9th to May 20th, the average temperature was between10 and 22℃. Autumn is the shortest, about 69 days, from September 19 to June165438+1October 26th, and the average temperature is between 10 ~ 22℃. Warm spring, hot summer, cool autumn and cold winter have four distinct seasons. With the synchronization of light and temperature, the annual changes of sunshine and temperature tend to be consistent in the same season of rain and heat, and precipitation is concentrated in warm and hot seasons.

The climate is humid and the rainfall is abundant. The annual average temperature in Xuancheng is 15.6℃, the average temperature in the hottest month is 28. 1℃, the average temperature in Leng Yue is 2.7℃, and the annual average temperature is 25.4℃, with mild climate change. The dryness is between 0.68 and 0.90, that is, the possible evaporation is less than the actual precipitation, which belongs to the humid climate zone. There is abundant rainfall, with annual precipitation ranging from1200mm to1500mm. The climate is humid and mild, and the frost-free period is as long as 8 months.

Plum rain is obvious, and it is an important weather phenomenon in Xuancheng that summer rain concentrates on plum rain. Every year, plum blossoms enter in mid-June and blossom in early July, with rainy days of about 25 days. The average amount of plum rains is 200 ~ 350 mm, which generally accounts for about a quarter of the annual rainfall. Summer rainfall concentration is one of the characteristics of monsoon climate. Generally, the summer precipitation is 500 ~ 600 mm, accounting for about 40% of the annual precipitation.

Xuancheng has four distinct seasons, mild climate, large annual temperature difference, moderate rainfall, abundant sunshine, long frost-free period and many easterly winds, and belongs to subtropical monsoon climate. The annual average temperature 16.0℃, the monthly average temperature 1 3.3℃ and the extreme minimum temperature-16.0℃. The average temperature in July is 28.0℃, and the extreme maximum temperature is 465,438 0.5℃. The annual average temperature is 24.7℃, and the maximum daily range is 26.9℃. According to the average temperature, the four seasons in Xuancheng are as follows: March16-May 25th, summer May 26th-September 20th, autumn September 2nd1-165438+1October 20th, winter165438. The average annual growth period is 234 days, and the average annual frost-free period is 228 days, with the longest 242 days and the shortest 224 days. The annual average sunshine hours are 1784. 1 hour. The duration above 0℃ is 355 days. The annual average precipitation is 1, 429.6 mm, and the geographical distribution is characterized by more in the south and less in the north, more in the mountains and less in the plains.

The annual average rainy days are 146 days, with the maximum 179 days and the minimum 104 days. The maximum rainfall in extreme years is 2308.2mm, and the minimum rainfall in extreme years is 695.0mm. Rainfall is concentrated from May to 10 every year, with the maximum in June. The larger lakes in China are Nanyi Lake, Qinglong Lake, Taiping Lake and Gucheng Lake, with a total area of about 239 square kilometers.

Nanyi Lake is located at the junction of Xuanzhou and langxi, also known as "South Lake", with an area of about 189 square kilometers. It is the largest natural freshwater lake in southern Anhui and an important aquatic product supply base in southeastern Anhui.

Qinglong Lake, located in Ningguo City, is a harbor bay reservoir in the upper reaches of Shuiyangjiang River, with an area of 32.8 square kilometers.

Taiping Lake is located in the east of Taohuatan Town, Jingxian County, with Huangshan Mountain in the south and Jiuhua Mountain in the north. It is Chencun Reservoir in the upper reaches of Qingyi River, with a water area of 88 square kilometers. It is the largest artificial lake in Anhui Province, with 2 square kilometers in Jingxian County.

Gucheng Lake is a natural lake between Gaochun County of Jiangsu Province and Xuanzhou District of this city, with a water area of 8 1 square kilometer and Xuanzhou territory of 15 square kilometer.

There are two major rivers in China: Qingyi River and Shuiyangjiang River, both of which belong to the Yangtze River basin. 36% of the basin area of Jixi County belongs to the Yangtze River basin, and 64% belongs to the Qiantang River basin. Natural lakes are part of Nanyi Lake and Gucheng Lake, with a total area of more than 200 square kilometers.

Surface water: Xuancheng has abundant rainfall and abundant surface water resources. The average annual runoff in Xuancheng City is 9.203 billion cubic meters, and the per capita water resources and cultivated land per mu are higher than the average level in Anhui Province. But the distribution is uneven, and there are more in the south than in the north.

The average annual runoff of Jixi and Jingde counties is 65.438+003 million cubic meters and 908 million cubic meters respectively. Due to the high terrain and insufficient water conservancy facilities, runoff resources are not fully utilized and most of them are lost, resulting in water shortage in winter and summer. In dry years, mountainous areas are more vulnerable to disasters.

Groundwater: The groundwater in Xuancheng City is mainly controlled by regional structure, aquifer rock properties and other factors, mainly falling water springs. Most of the groundwater is distributed along the fault zone, which is deeply buried and less developed and utilized. There are 65,438+02 known groundwater distribution areas.

The total groundwater in Jixi County is about 245 million cubic meters, of which Qiantang River basin accounts for more than 2/3, and the annual recharge is10-150,000 cubic meters/square kilometer. There are about 100 surface springs, which are mostly exposed in deep mountains, narrow valleys and ridge paths. Although the amount of water is small, it is inexhaustible.

The groundwater in Jingde County is mainly bedrock fissure water, pore fissure water and carbonate fissure water, and the resources are relatively poor.

Hydropower: Xuancheng has abundant rainfall, criss-crossing rivers and streams, large river bed gradient and abundant hydropower resources. Xuancheng's hydropower reserves exceed 530,000 kilowatts.

Jixi county has a reserve of 75,000 kilowatts and an exploitable capacity of 22,600 kilowatts, mainly in the Xin 'anjiang river system.

Jingde County has a reserve of 60,300 kilowatts, and the exploitable capacity is1.500 kilowatts, mainly in Qingyijiang River system. The developed and utilized hydraulic resources in the two counties are less than 20% of the exploitable amount.