The Geographical Environment of Shihe District

Shihe District is a gentle slope with high southwest and low northeast, Tongbai Mountain and Dabie Mountain in the west and south, and Huaihe River alluvial plain in the east and north, with the highest elevation of 906 meters and the lowest elevation of 54 meters.

The western and southern parts of the area are surrounded by Tongbai Mountain and Dabie Mountain, and the terrain slopes from southwest to northeast in turn. The highest point of Wangsishan is 906.2 meters above sea level, and the lowest point of Shuangjinghe Village is less than 70 meters above sea level. The territory has complex terrain, including mountains, hills and plains.

The mountainous areas are mainly distributed in the south, west and southwest of the area, covering an area of about 654.38+0.05 million mu, with an altitude of 500-654.38+0.000 m, a relative height of more than 300 meters, and a slope of more than 35 degrees. Most of them are steep mountains and steep slopes, with bare cornerstones, deep valleys and continuous mountains. There are more than 20 peaks over 500 meters. Because of the strong weathering in mountainous areas, there are quite thick residues, which is an ideal environment for developing forestry, animal husbandry and agriculture.

The hills are mainly distributed in the north of Shandong and the south of Huaihe River, covering an area of 620,000 mu, with an altitude of 200-350 meters, a relative height of 100 meters and a slope of generally below 30 degrees. Shihe District is distributed in a discontinuous zone along the periphery of the mountain. It is the main producing area of cash crops, rice, wheat and other food crops.

The plain along the Yangtze River is mainly distributed on the floodplain on both sides of Huaihe River and Shihe River. In this area, Huaihe Plain is mainly distributed in Wujiadian, Youhe and Shuangjing. Shihe plain area is mainly in urban areas. The surface material is diluvial alluvium, with open and flat terrain, deep stratum, fertile soil and abundant groundwater resources, which is suitable for planting a variety of crops. Shihe District, located in the south of Huaihe River, belongs to the continental monsoon climate of transition from subtropical zone to warm temperate zone. It has the climatic characteristics of moderate temperature, mild climate, sufficient light and heat, abundant rainfall, the same season of rain and heat, distinct seasons and changeable weather. The average temperature in China is 15. 1℃. In spring (March, April and May), the temperature fluctuates greatly and there are more rainy days. The seasonal average temperature is 14.8℃, and the seasonal average precipitation is 292.2mm: in summer (June, July and August), the weather is hot, the precipitation is concentrated, and droughts, rainstorms and floods occur from time to time. The average temperature in summer is 26.6℃, and the average seasonal precipitation is 598.4 mm, which is the season with the most concentrated precipitation in the whole year. In summer, if the summer monsoon is too strong, the local area may be dry and lack of rain, resulting in summer drought; If the summer monsoon is weak, the precipitation belt will stay in the Jianghuai area, resulting in excessive local precipitation and heavy rain.

The annual average temperature in China is 15. 1℃, the annual average surface temperature is 16.9℃, and the surface temperature below 10 cm is 16.6℃. The annual average precipitation 1 109. 1 mm, and the annual average evaporation 1352.3 mm, which is 243.3 mm more than the precipitation. The annual average relative humidity is 76%, and the annual average frost-free period is 22 1 day.

The average solar radiation in Shihe District is 1 17.72 kcal/cm2; The average annual sunshine is 2 172.9 hours, and the average sunshine rate is 49%. The annual average accumulated temperature is 5490.4℃.

The law of wind direction change is generally south in summer and north or north in winter.

The climate disasters in the whole region mainly include rain and waterlogging, drought, continuous rain, hail and dry hot wind, among which rain and waterlogging are slightly heavier, with an average of 3-4 years. The geological structures in this area are mainly folds and faults. The fold is mainly Nanwan compound syncline, which is located in the area of Wan Wan Reservoir. The area is about 20 kilometers long and 2-3 kilometers wide. Faults Guishan and Meishan (Anhui) faults are distributed from the north side of Nanwan Reservoir Dam to Guishan, with a strike of 290-295 degrees. The dip angle is 55-65 degrees, and the width of the area ranges from tens of meters to hundreds of meters.

Yijiawan fault, which is about 5 kilometers long, is distributed from Tiefo Temple to Yijiawan of Shiliqiao. Parallel to the guishan fault.

Shiyan fault and Qiujiawan fault are distributed in the west of this area.

Tongbai-Shangcheng fault is distributed from the west of Nanwan Reservoir to Liulin.

Qilipeng fault, distributed in Qilipeng-Dongshuanghe-Wushengguan line, is about 100 m wide.

The Xiershan fault is located in the line from Shuangjing Xiershan to Jinniu Mountain in He Shili, about12km long, and it is the dividing line between the plain and the mountainous area. Shihe District is located in the eastern extension of Kunlun Mountain and Qinling fold belt, and belongs to Kunlun Qinling geosyncline, also known as Qinling fold system. The exposed strata are mostly ancient metamorphic rocks and magmatic rocks are widely distributed.

In the history of this area, there are frequent magmatic activities, including intrusive rocks and extrusive rocks. The intrusive rocks mainly include metamorphic bedrock (distributed in Shihegang), basic neutral intrusive rocks (distributed in Liulin area), ultrabasic rocks (distributed in Nanwan and Wohu areas) and granite (distributed in Liulin, Lijiazhai and Jigongshan areas). The ejected rocks are equiaxed and dispersed. The eruptive rocks in this area are mostly found in Pipa Mountain and Tanshanbao area, mainly volcanic rocks.