Physical Geography

2015-09-28 09:08:35

[Profile] Situated in the hilly and mountainous area in Western Zhejiang, Chun’an County is composed of middle and lower mountain, hills, small size basins, valleys and reservoirs. The soil falls into four groups, 9 subgroups, 29 genus and 40 species and mainly include red soil, yellow soil, lithology soil and paddy soil, of which, red soil is the most extensively distributed soil genus in the county and covers an area of 274,700 hectares (4,121,100 mu); yellow soil covers an area of 36,800 hectares (552600 mu), lithology soil covers an area of 61,400 hectares (921,400 mu) and paddy soil covers an area of 18,200 hectares (272,500 mu). The clayey makes up 22.56%, chiltern accounts for 28.41% and gravelly takes up 20.77% of soil. The soil fertility is medium and is suitable for growing rice, wheat, corn, June beans and other crops as well as various kinds trees of economic value. 

The mineral resource is featured by numerous points, extensive distribution and small size. Fuel mine mainly include stone coal and bituminous coal; non-metallic ore mainly include pyrite, phosphorite, fluorite ore, fire-resistant clay, pegmatite, marble and quartz (vein). Metal ore mainly include magnetite, hematite, Tin-iron ore, limonite, iron-copper-tin ore, copper-zinc ore, lead-zinc ore, cooper ore, antimony ore, tungsten ore, mercury ore, vanadium ore, molybdenum ore, beryllium ore and arsenopyrite ore. Based on mineral classification, the county has 15 fuel minerals, 53 non-metallic minerals and 84 metal minerals. 

The vegetation of the county belongs to subtropical evergreen broad-leave forest in northern forest sub-zone and falls into glauca and sclerophylla cultural vegetation zone in hilly areas in Zhejiang and Anhui province. The forest coverage of the county is 65.00%, of which, the forest coverage within Thousand-islet  Lake is as high as 82.50%. The county has diversified biological species and rich resources. There are 1824 identified vascular plant species, including ferns of 35 families, 69 genus and 126 species and seed plants of 159 families, 761 genus and 1698 species. 18 species of plants are under national protection. The wild animals include 51 species of beasts, 224 species of birds, 50 species of reptiles, insecta of 16 orders, 320 families and 1800 species; amphibians of 2 orders, 4 families and 12 species and fishes of 13 families and 94 species. Five species of wild animals are under national first grade key protection, including clouded leopard, leopard, tufted deer, Chinese merganser and white-neck long-tail pheasant. 41 species are under national second grade protections, including macaque, black bear, pangolins, otter, zibet, golden cat, river deer, serow, Hainan geese, mandarin duck, black-winged kite, black kite, crested Serpent-eagle, Northern Harrier, goshawk, sparrow hawk, gray face buzzard eagle, common buzzard, buteo, forest eagle, kestrel, merlin, Eurasian hobby, peregrine falcon, pukras, white crane, coucal, :collared scops owl, Asian barred owlet, hawk owl, long-eared owl, fairy pitta, sparrow hawk, goshawk, silver pheasant, grass owl, short-eared owl, turtle and giant salamander. 

[Lakes and Rivers] All rivers within the territory of the county belongs to Qiantang River Water System. The rivers crisscrossed the territory with complicated flow directions and water system assumes feathered distribution. The main rivers include Xin’an River and its tributaries Dongyuan Port and Sui’an Port. Xin’an River is also named Hui Port. In 1985, Zhejiang Province Qiantang River Source and Estuary investigation and survey confirmed that Xin’an River was 373  in total length and stretched 82.69km in territory of Chun’an. The main tributaries of Xin’an River include Tongxi River, Liudu Source, Jiukeng Source, Zhitong Source, Yunyuan Port, Qingping Source and Shangjia Source. Tongyuan port is also named Jinxian River and Fuqiang River with flow length of 40.90 km, with main tributaries including Shibadu Source, Tantou Source, Langtong Source; The main tributaries Shui’an Port with total length of over 80km include Wuqiang River, Fenglin Port, Langchuan River, Shangwu Wudu Source, Shangfang River, Fengjia River, Longquan River and Longchuan River.  

[Hydrology] In 2014, Chun’an County Hydrometric Station has 19 subordinated rainfall monitoring stations, including Zhongzhou, Guanjia, Qiandaohu, Xiahong, Xiaomaoling, Xiling, Helinghou, Shuangxikou, Xianrentan, Jinzhulin, Bailuofan, Yaoshan, Dashu, Baima, Zhang Village, Chenjia Village, Jiangjia, Dujing and Tashan. Zhongzhou hydrometric station is responsible for the observation of data of rainfall and water level. Since Sept. 1st, 2010, the station stopped observation of water level due to change of fracture surface of the station as a result of the construction of the flood control dam. The observation will be resumed after completion of the renovation of Zhongzhou hydrometric Station in 2015. Chun’an County Hydrological Station is responsible for collection, analysis and compiling of the rain condition and water regimen of the whole county and has an accumulation of annual hydrological data of the county to provide service for flood prevention and drought control, water resources and hydropower engineering construction and other economic construction. The automatic collection system for rain condition and water regimen of key small watersheds, reservoirs of small-scale (I) and above and part of small scale (II) reservoirs is in sound condition. Mountain torrent disasters monitoring and early warning system, which started construction in 2011, completed test run in the end of 2012 and passed completion acceptance in 2013, provides accurate basis for timely delivery of rainfall and water regimen information for the county’s flood prevention commanding and decision-making as well as for scientific scheduling of the reservoir. 

[Rain condition] In 2014, precipitation of Chun’an was less than normal, with mean annual precipitation of 1953mm, 12.90% more than normal value of multi-year mean precipitation. Due to extensive territory and complicate terrain of the county, space-time rainfall distribution in the county was uneven. The precipitation at Chenjia Village Rainfall Station in Langchun Township was 2524mm, while that in Bailuofan Rainfall Station in northwest of the county was only 1771.80mm. The difference of precipitation observed from the both stations was as high as 752.20mm. The maximum daily precipitation of the county was 140.50mm, which was observed in Baima Rainfall Station in Fengshuling Town . 

[Water Regimen] On July 18th, 2014, the actual measured water level of Xin’an River Reservoir was 106.53m, the highest level of the year, 2.04m higher than the highest level in 2013. On December 17th, the actually measured water level of the reservoir was 95.03m, the lowest of the year, 1.01m lower than the lowest water level in 2013. The annual amplitude of water level variation was 11.50m and mean annual water level was 100.87m.  

[Survey of Weather] In 2014, the air temperature was relative higher, the rainfall was relative higher and the sunshine was less than normal. The annual average temperature was 17.60℃, the annual extreme lowest temperature was -2.20℃ (occurred on Feb. 11th). There were 12 low temperature days with minimum air temperature of ≤0℃. The annual extreme highest temperature was 37.20℃(occurred on July 21st) and there were 15 high temperature days with maximum air temperature of ≥35.00℃. The annual total precipitation was 1768.80mm with 154 annual rainy days including 5 snowfall days. The annual total sunshine duration was 1741.20 hours.  

The winter was mainly sunny and warm in 2014. It had been sunny without rainfall for consecutive 25 days from Jan. 12th to Feb.5th. Forest fire danger class remained high with frequent outbreaks of fire accidents in the county. The early spring was mainly overcast and rainy. Crops were subjected to waterlog harm due to long-term water logging in farmland and soil. From March 9th to 10th, it snowed with average snow cover of 2.00~125px throughout the county. The snow cover in mountain area exceeded 125px. Some bamboo and agricultural greenhouse facilities were broken and damaged by the weight of snow. Plum rain period lasted for 20 years, from June 17th to July 7th , which was almost equal to ordinary years, and the average rainfall during the period was 406.10mm, 22.40% more than previous year. The maximum rainfall during plum rain period was measured 627.10mm in Yanwo Village of Lishang Township. On June 21st and June 27th ,there were intense fall and downpour with precipitation of 92.60mm and 100.70mm respectively. From July 23 to 25, due to impact of “Matmo” typhoon, the accumulated rainfall of the whole county was 77.30mm and 11 sites measured force-7 wind. The three heavy rainfalls had caused intense fall, flood, inundation of farmland, landslide and other disaster in most regions of the county. In the year, the temperature in midsummer was not so high. In August and September, low temperature with little sunshine was the obvious weather characteristics of the county with average temperature of 25.90℃, 0.50℃ lower than the same period of the previous year. The precipitation in this period was 368.30mm, 160.40mm more than the same period of the previous year, increased by 77.10% year on year. Continuous low temperature and rainy effected negative impact on agricultural production in summer and resulted in severe crop diseases and pests. 

[Meteorological Monitoring and Service] In 2014, Chun’an County Meteorological Bureau continued to improve the regional automatic meteorological monitoring station network of the county, and newly built 12 regional automatic meteorological monitoring stations, three live monitoring stations and 3 atmospheric electric field instruments. The total number of automatic meteorological monitoring stations of the county was increased to 95. The county newly established 50 weather information electronic display screens in 50 central villages and characteristic villages to release weather forecast and warning information in time. The Meteorological Bureau and Environmental Protection Bureau jointly announced air quality index (AQI) forecast and opened microblog and WeChat channel for Chun’an weather forecast service. Straight-through type meteorological service was provided for 300 big specialized households of crops and animal production, including tea, sericulture, fruits, edible mushrooms and aquatics.