The geographical environment of Xinchang County

Xinchang has a subtropical climate and is located in the transition zone between the mid- and northern subtropics. It is mild and humid with four distinct seasons. Rain and heat are synchronized in early spring and summer, while midsummer is mostly sunny and hot. Light and temperature complement each other in autumn and winter, and there are more disastrous weathers. There are about 1,900 hours of sunshine all year round, the annual average temperature is 16.6°C, the annual precipitation is 1,500 mm, and the frost-free period is 240 days. At the same time, it has typical mountain climate characteristics, with obvious differences in horizontal and vertical directions.

The four seasons are long in winter and summer and short in spring and autumn. In spring, warm and cold air masses advance and retreat across the county, resulting in sudden cold and sudden heat, changeable weather, and continuous rain. There is a lot of precipitation, accounting for 26% to 35% of the year. "Late spring cold" occurred in March and April. In early summer, there is often "Meiyu" with heavy rainfall. Sometimes "Meiyu" occurs early in late May. In midsummer, from July to August, the Pacific subtropical high pressure enters the country and the weather is sunny and hot, forming a "latent drought". Typhoons, violent storms and rains often cause disasters, and precipitation is also associated with drought relief. There are often local thundershowers in the afternoon, with occasional hail, strong winds, and heavy rain causing disasters. Precipitation accounts for about 37% of the year. In early autumn, warm and cold air masses clash, with many low temperatures and cloudy and rainy days. After mid-autumn, affected by small high pressure in the lower reaches of the Yangtze River, autumn is high and crisp, "autumn drought" is common, and "Little Indian Spring" appears in October. Precipitation accounts for 14%. In winter, the high tide enters the Sanjiang River Valley through the northwest valley plain (basin), the temperature drops sharply, and the precipitation accounts for 23% of the year. Landform

Xinchang is located in the upper reaches of the Cao'e River. The landform features "eight mountains, half water and half fields".

The main peaks in Xinchang County are all above 600 meters above sea level. The highest peak is Xiaojiang Bodhi Peak, with an altitude of 996 meters. The Siming Mountains enter from the northeast and reach the Shaxi Mountains in a short distance. Two branches of the Tiantai Mountains enter from the central and southern parts. The Tianmu Mountain Area, known as "Yiyi Main Mountain" in ancient times, meanders to Anding Mountain and forms the eastern mountainous area from Ru'ao to Huishan. The Kuaiji and Dapan Mountains enter from the southwest and lie between Anshan in Jingping Township and Xikeng in Jingling Town, forming the southern mountainous area of ​​Jingling. The central part is hilly platform, generally basalt platform with an altitude of 250 meters to 500 meters. The larger ones include Huishan, Dashiju, Mengjiatang, Dunshan, etc., and the edges are steep slopes and mountains.

Xinchang County is part of the low mountains and hills of Zhejiang and Fujian. The eastern part is dominated by low mountains and hills, with the main peaks above 800 meters above sea level. The central part is mostly hilly and plateaus below 300 meters, descending in steps from south to north. The northwest is alternately distributed with valleys and low hills, with altitudes below 150 meters. , the lowest altitude is only 28 meters. According to statistics, the mountainous area of ​​the county is 382.49 square kilometers, accounting for 31.7% of the total area, the hilly platform area is 765.48 square meters, accounting for 62.25% of the total area, and the basin area is 73.56 square kilometers, accounting for 6.58% of the total area. According to the land resources survey from 1989 to 1992, the total land area of ​​the county is 1.8208 million acres, including 501,700 acres of cultivated land (including field ridges and ridges), accounting for 27.56%; 178,000 acres of garden land, accounting for 7.03%; and 904,100 acres of forest land, accounting for 27.56%. 1.08%; water areas are 81,100 acres, accounting for 4.45%; unused land is 117,200 acres, accounting for 6.44%.

Rivers

Xinchang County has three main rivers, Chengtan, Xinchang and Huangze. The county drainage area is 1,209 square kilometers, with 73 large and small tributaries, with a length of 455.6 kilometers and a river network density of 0.38. km/km². It is a typical mountainous river with many tributaries, large drop and rich water resources. Chengtan River, Xinchang River and Huangze River flow into the Cao'e River to the northwest in a folded fan shape.

Chengtan River

Chengtan River is the main stream of Cao'e River. It originates from Jianggongling (870 meters above sea level) in Pan'an County. It was originally called Teng (Teng) River and passed through Wuzhangyan Reservoir. It is called Jiaxi. It enters 1 km northwest of Shiniankeng, Huishan Town, this county. It flows from south to north through Jingling, Chengtan, Meizhu and other townships. It flows into Shengzhou City at Baidu River in the east of Tiandong, with a total length of 91 kilometer. Xinchang has a territory of 44.1 kilometers and a drainage area of ​​388.63 square kilometers, accounting for 31.8% of the county's total area. The upper and lower river widths are about 80 to 140 meters respectively. More than 60% of the county's cultivated land and more than 70% of its population are concentrated on both sides of the Taiwan Strait. After liberation, the county built Shimen Reservoir and Menxi Reservoir in the upper reaches, providing guarantee for controlling and mitigating flood disasters in areas along the river.

Xinchang River

Xinchang River is a tributary of Cao'e River. It originates from Huading Mountain in Tiantai, passes through Shiliang Waterfall and Cisheng of Shiqiao Township, and enters Dazhuyuan. It passes through Xiaojiang Town, Shanghai Village, which is called Maoyang River and Huangtan River, and runs diagonally northwest through the middle of the county, passing through the big city of Juzhen, From Yulin Street, Nanming Street, Qixing Street to half a kilometer northwest of Houxi Village, it enters Shengzhou City, with a total length of 67.3 kilometers. Xinchang has a territory of 48.9 kilometers and a drainage area of ​​433 square kilometers. It accounts for 36.3% of the total area of ​​the county. The average river width is about 60 meters, and the natural drop is 173 meters. In the middle reaches is Changzhao Changku, also known as Wozhou Lake, which is a provincial-level scenic spot.

Huangzejiang

Huangzejiang, formerly known as Wangzexi, originated from Naifanling, Qiaoying Township (3 kilometers southeast of Zhongxi Village), and was originally called Jugenxi. It passes through Juzhen, Dashi, to Zhu'an, Xinlin Township, and is called Guangxi. After passing through Qin Village, Yulin Street, it is called Hengxi. After passing through Changshan Village, it is called Huangzejiang. It enters Shengzhou and ends at Huangzepukou, where it enters the Cao'e River. The total length is 70.6 kilometers. 50.6 kilometers within Xinchang. The basin area is 378 square kilometers, accounting for 30.9% of the county's total area. The average river width is about 70 meters, with a natural drop of 257 meters. There is Qiaoying Reservoir in its upper reaches.