Geographical environment of Lishui district

Lishui District belongs to Ningzhenyang hilly area, with high terrain in the southeast and low terrain in the northwest. The hilly area accounts for 72.5% of the total area, with the highest elevation of 368.5 meters. Fushan, Donglu Mountain, Huifeng Mountain, Fangshan Mountain, Qiuhu Mountain and Wuxiang Mountain in the area are arched in the east and south, and Xiheng Mountain is abrupt at the west end.

Lishui District is located in the prominent and continuous area of Maoshan Mountains. The hills in the territory are low and scattered, and the terrain is high in the east and low in the west. It is bounded by the watershed between Shijiu Lake and Qinhuai River. Qinhuai River in the north is high in the southeast and low in the northwest, and Shijiu Lake in the south slopes from high to low in the northeast, connecting with the lake area. The overall terrain is hills, hills and soil, criss-crossing, and the gentle hills and hills continue to extend, showing an obvious stepped distribution. The highest level consists of low mountains above 100 meters above sea level, the second level consists of low hills above 50 meters above sea level, and the third level consists of river valleys and lakeside polder areas. The first and second steps are the forestry production bases in this region, and the third step is the main base of agricultural production and economic fruit in this region.

The strata and geological structure in Lishui area belong to the structural unit of the fold belt of the Yangtze platform under the Yangtze ancient land. Quaternary sediments are widely distributed in this area and are the main soil-forming materials. Except for steep slopes, mountains and river (ditch) slopes, acidic yellow loam developed by weathered residual rocks and slope deposits covers low mountains and their foothills and river (ditch) valleys, and the soil thickness varies. The estuary delta is widely distributed in alluvial soil and alluvial soil, and lacustrine soil is only found in Shijiu Lake.

Lishui area mainly belongs to Shijiu Lake water system and Qinhuai River water system, and only 2.73 square kilometers of mountain area in the southeast corner belongs to the west of Taihu Lake water system. The watershed between the two major water systems runs through the central part of the area from east to west. Direction: Starting from Jiuligang, jurong city, upstream of Dongfang Reservoir, passing through Wangjiapeng to Zhujiabian in this area, along Bai Yuan Highway (Gaogangdi) to Chachang, Qiligang, Hejiashan, Guantang, Zhizigang, Luzishan, the main peak of Qiuhu Mountain, Shuangjian Mountain, Maanshan and Heiyakou, passing through Wangxi to Yan Zhigang, crossing Tianshengqiao River at Tianshengqiao Gate and entering Yanzikou. The river basin divides the river flow potential in the region into two directions: the north water flows to Qinhuai River and the south water flows to Shijiu Lake.

Shijiuhu water system

Shijiu Lake covers an area of 207.65 square kilometers and belongs to Lishui District, covering an area of 90.4 square kilometers. The catchment area is 582.54 square kilometers and the total length of the main canal of the water system is 53.57 kilometers. Among them, Xinqiao River has a total length of 26.28 kilometers and a catchment area of 204.36 square kilometers. The total length of canal tributaries is 1 1.99 km, and the catchment area is 103. 17 km2. In addition, there is a river valley south of Longtou Reservoir in Hefeng Town, with an area of 16.85 square kilometers, which flows into Gucheng Lake and is an independent branch of Shijiu Lake water system.

Qinhuai river system

Lishui District is the south source of the upper reaches of Qinhuai River and one of the main tributaries of Qinhuai River. Among them, the total length of the main stream is 28.3 kilometers, and the catchment area is 172.98 square kilometers; Article 2 The length of the main river is 25.60 kilometers, and the catchment area is 227. 10 square kilometers. The total length of Sangan River is 1 1. 19 km, with a catchment area of 64.74 square kilometers. Lishui has a subtropical monsoon climate, with an average annual temperature of 15.5 degrees, an average annual sunshine of 2 146 hours, and an average annual precipitation of 1037 mm, with four distinct seasons, intact original vegetation and excellent natural environment. The air quality has reached the national secondary standard all the year round.

20 1 1 year, the annual average temperature 16.3 degrees, 0.7 degrees higher than normal; The annual precipitation is 958. 1mm, which is less than normal 10%. The annual sunshine is 2025. 1 hour, which is the same as normal. The number of days of snow in the whole year is 14. Among them, the snowfall weather with great scope and influence is mainly concentrated in 65438+ 10. Affected by the continuous convergence of cold air in the north and warm and humid air in the southwest, it snowed for four consecutive days from June 65438 to1October 18 to June 2 1 day, and the ground temperature in the early stage was low, resulting in serious snow and road icing. In the first half of the year, the drought in Lishui was serious, and the drought level once reached a severe drought. During1~ May, the precipitation was 60% less than normal, which was the lowest value in the same period in history. Except for medium-sized reservoirs, other reservoirs and ponds in Lishui District are seriously short of water storage. The water level of nine small reservoirs is lower than that of the dead reservoir, and some ponds and dams in Shijiu Lake have dried up. There is a serious shortage of water in Shijiu Lake area. 36,700 hectares of crops in Lishui District are affected by drought. Among them, 654.38 million hectares were seriously affected by drought, more than 3,300 hectares were affected by aquaculture, and the agricultural economic loss was 383 million yuan. /kloc-I entered Mei in June of 0/4, which is too early. On July 2 1, plum rose, which was later. Meiyu period is long, which is 37 days (average 22 days in the whole year). The precipitation after entering Mei is local, process, short-term precipitation intensity and rainy days. Due to rainy weather, low temperature and serious lack of illumination, some agricultural facilities were damaged and farmland was flooded. From August 22 to 3 1 day, continuous precipitation, rainy weather, low temperature and lack of sunshine have great influence on the growth and development of rice, resulting in weak overall growth of rice and widespread occurrence of pests and diseases. From September 17 to September 19, the temperature in Lishui area plummeted due to the influence of strong cold air, and rice was affected by cold dew wind, which was not good for filling. The main meteorological disasters in the whole year are cold wave, freezing, drought, rainstorm, typhoon and fog. Compared with previous years, meteorological disasters occurred less in 20 1 1 year, but drought and rainstorm were more serious.