The geographical environment of yugan county

Yugan is located in the subtropical zone, with mild and humid climate, abundant sunshine, abundant rain, long frost-free period, obvious monsoon and distinct seasons, which is beneficial to the growth of crops. The average temperature for many years 17.8℃, 1 year, the average temperature in Leng Yue is 5.2℃, the extreme minimum temperature is-14.3℃, the average temperature in the hottest month is 29.7℃, and the extreme maximum temperature is 40℃. In recent 10 years, the winter temperature has gradually warmed, and heavy frost, heavy snow and freezing weather are rare.

(1) Temperature: The local climate belongs to subtropical humid monsoon climate, characterized by warm spring and inflammation in summer, cool autumn and cold winter, mild climate, obvious four seasons, abundant water, abundant sunshine and long frost-free period, which is beneficial to the growth of crops. The average temperature for many years 17.8℃, 1 year, the average temperature in Leng Yue is 5.2℃, the extreme minimum temperature is-14.3℃, the average temperature in the hottest month is 29.7℃, and the extreme maximum temperature is 40℃. In recent ten years, the temperature in winter has gradually warmed up, and heavy frost, heavy snow and freezing weather are rare.

(2) Illumination: annual average sunshine hours 1872 hours, sunshine rate of 42%, total solar radiation 100.29 kcal/cm2, and average frost-free period over the years of 256 days.

(3) Precipitation and evaporation: the annual average precipitation is 1, 586.4 mm, and April, May and June are rainy seasons, accounting for 40-50% of the annual precipitation. The monthly average rainfall is over 200 mm, and the annual average evaporation is 1, 557.7 mm, 7- 1, 654, 38+0.

(4) Wind: The dominant wind direction in the urban area is the north wind all year round and the southerly wind in summer, with an average annual wind speed of 3.5m/s, which belongs to the windy area in northeast Jiangxi, and 57% of the strong winds occur in April, July and August. The maximum wind speed in 1964 exceeded 40m/s (above12), which caused serious damage to the county seat. Xinjiang is the largest river flowing through Yugan. Originated in Pingjiayuan, the northern foot of Huai Yu at the junction of Zhejiang and Jiangxi, it passes through Yushan, Shangrao, Guixi, yingtan, yujiang county and other counties and cities, then enters from Tanbu in the southeast of the county, and reaches Tongjiangtan in two ways. From east to north, one enters Zhuhu Lake through the mouth of the county horse, which is called Dongdahe, and the other enters Poyang Lake through Ruihong to the west, which is called Xidahe. In addition, there are Tangsanhe River and Huhuihe River on the edge of the county seat, which were blocked during the Daxing water conservancy project and have become passive rivers. The average annual discharge of Xinhe River is 888 m3/s, the highest Meigang water level is 29.84 m (Wusong water level) in198, the lowest water level in 70 years is 60 m3/s, the lowest water level is 18.04 m, the lowest water level is 50.8 m3/s in 8 1 year, and the lowest water level is/kloc. The flood frequency is 5% (the above data comes from 1993 yugan county master plan).

The county seat is rich in groundwater resources. The middle part of the loose rock pore water area in Xinjiang Valley of yugan county, namely Fenggang-County-Bao 'anshan coal mine area, is covered with karst water, and the catchment area of the aquifer in County-Yang Gang area is 68* 106 square meter, covering 310.4 million tons/day of fissure water exploitation resources, and the groundwater level is 3-6 meters. Surface water is considered to be a big river east of the Yangtze River, which flows through the county seat, with an average annual runoff of 65.438+0.756 billion cubic meters, and the reaches around the county seat are Grade II water quality. Yugan county has experienced many tectonic movements, and its structural features can be divided into Shegeng-Wulei anticline, Yuganzhen-Fenggang syncline, Ruihong-Kangshan depression belt and other structural zones.

There are no adverse geological phenomena such as collapse, slump, landslide and weathering in yugan county City. According to the Fujian-Jiangxi earthquake sequence map, the Yugan earthquake sequence is 6 degrees. The county belongs to the secondary terrace alluvial plain area, and the surface soil layer is thick. Shihu urban area is unstable in structure, belonging to piedmont alluvial fan, with vertical and horizontal gullies and ponds, and short sedimentation time. The soil layer is roughly divided into: filled soil layer, light loam layer containing silt, loam layer and fine sand layer, and there is no obvious boundary between the layers, which is pointed out. Filling layer, silt-containing light loam layer and loam layer have low bearing capacity (5- 10t/m2), so they cannot be used as natural foundation bearing layers. The soil layer structure around Ganyue Avenue in the periphery of the county is relatively stable, which is generally filled soil layer, silty clay layer and gravel layer of medium sand layer. Silty clay has good bearing capacity and is a good natural foundation soil.