The geographical environment of Liuzhi Special Zone
Liuzhi Special Economic Zone is located in the connection zone between Wumeng Mountain and Miaoling Mountains on the eastern slope of the Yunnan-Guizhou Plateau. The middle section of Wuzhi Mountain traverses the central part of the special zone and divides the whole zone into the Yangtze River Basin and the Pearl River Basin. In the long-term geological evolution, due to the comprehensive influence of internal and external geological forces, the north of the watershed belongs to the Yangtze River system and the south to the Pearl River system. The basic shape is high in the northwest and low in the southeast, with deep valleys, broken surface, and large terrain changes. Laowang Mountain, the highest in the area, is 2126.9 meters above sea level. The outlet of Beipanjiang River is 609.5 meters above sea level. The relative height difference is 1517.4 meters. The average altitude in the area is between 1200 meters and 1400 meters. Various types of karst landforms, peaks and depressions , caves, etc. are widely developed. Due to the continuous weathering of rocks and sedimentation of sediment, many mountain basins, hills and dams are distributed.
(Note: Album picture source) Liuzhi Special Zone has a mid-subtropical monsoon climate. Rainfall is mainly affected by water vapor in the Bay of Bengal in the Western Pacific and the activity of its subtropical high ridge. The climate is relatively mild. According to the special zone According to weather station data and Liupanshui City Hydrology and Water Resources Bureau data, the average rainfall has been 1519.1 mm (1957-2006), and the total annual average precipitation is 2.53 billion cubic meters. However, the spatial and temporal distribution of rainfall is uneven, and the regional distribution is characterized by northern It is smaller than the south, and the distribution of rainfall within the year is also extremely uneven. Most of it is concentrated from May to September. Its multi-year average rainfall is 1198.6 mm, accounting for 77.6% of the annual average rainfall. The highest year (Liuzhi Station in 1983 ) rainfall reached 1924.4 mm, accounting for 85% of the annual rainfall. January is the smallest month of the year, with an average of 25.5 mm, and June has the highest rainfall of 317.7 mm. The inter-annual rainfall variability is also large, with the highest being 2341.7 mm (June 1983). Zhi Station), the minimum is 1021.1 mm (Langdai Station in 1953).
The annual average temperature in the territory is around 14.5℃. The hottest month, July, has an average monthly temperature of 22℃ and an extreme maximum temperature of 34.1℃. January is the coldest month, with a monthly average temperature of 5.2℃ and an extreme minimum temperature of -5.5℃. , the total solar radiation has an average multi-year average of 86.93 kcal/cm2, with the highest in July being 10.53 kcal/cm2, and the lowest in January being 4.7 kcal/cm2. The average number of sunshine hours over the years is 1144.2 hours, and the average frost-free period over the years is 291 days. According to satellite remote sensing survey statistics in 2000, the total area of Liuzhi Special Economic Zone is 1,792.1 square kilometers, including 687 square kilometers in the Yangtze River Basin and 1,105.1 square kilometers in the Pearl River Basin. The total area of soil erosion is 538.48 square kilometers (excluding traces), accounting for 30.05℅ of the total land area. , including 288.87 square kilometers of mild, 235.30 square kilometers of moderate, 13.55 square kilometers of intense, and 0.76 square kilometers of extremely strong. The area of water and soil loss in the Yangtze River Basin is 198.59 square kilometers, accounting for 28.96℅ of the total loss area, of which 101.74 square kilometers are mild, 90.34 square kilometers are moderate, and 6.87 square kilometers are severe; the area of water and soil loss in the Pearl River Basin is 339.53 square kilometers, accounting for 10% of the total water and soil loss area. 30.72℅, of which 187.13 square kilometers were mild, 144.96 square kilometers moderate, 6.68 square kilometers intense, and 0.76 square kilometers extremely strong. The rocky desertification area is 30,719 square hectares, the average erosion modulus is 3,768 tons/year square kilometers, and the annual soil erosion amount is 6.7526 million tons.
The main form of erosion is hydraulic erosion, among which surface erosion is the main one. The main factors causing water and soil erosion are the fragmented terrain, high mountains and steep slopes, a large proportion of sandstone and argillaceous sandstone, sparse vegetation, low forest coverage, and frequent and high-intensity rainstorms in the region, making water and soil erosion more serious. , the comprehensive evaluation of ecological environment quality is poor. Soil erosion causes landslides, debris flows, etc., which deposits large amounts of sediment in rivers, weakens the river's ability to carry out floods, and causes serious flood disasters.