Chinese Geography: In which month did the drought occur in the Pearl River Basin? Thanks

The dry season of the Pearl River Basin is generally from October to March of the next year

Detailed knowledge of the Pearl River Basin

Pearl River Basin

Physical Geography

The Pearl River is a large river in southern my country, flowing through Yunnan, Guizhou, Guangxi, Guangdong, Hunan, Jiangxi and other provinces (regions) and the northeastern part of the Socialist Republic of Vietnam, with a drainage area of ??453,690 square kilometers, of which my country's territory covers an area of ??442,100 square kilometers.

The Pearl River Basin is bordered by Wuling to the north, the South China Sea to the south, the Yunnan-Guizhou Plateau to the west, hills and basins in the middle, and delta alluvial plains in the southeast. The terrain is high in the northwest and low in the southeast. The land resources of the whole basin are 663 million acres, including 72 million acres of cultivated land and 189 million acres of forest land. The cultivated land rate is lower than the national average. The per capita land in the basin is only 9.31 acres, which is about three-fifths of the per capita land in the country. .

Meteorology and Hydrology

The Pearl River Basin is located in the subtropical zone, with the Tropic of Cancer running through the middle of the basin. The climate is mild and rainy, with the annual average temperature ranging from 14 to 22°C and the annual average rainfall of 1,200 to 1,200 degrees Fahrenheit. 2200mm, the rainfall distribution obviously decreases gradually from east to west, the rainfall is unevenly distributed within the year, and the regional distribution differences and inter-annual changes are large.

The average annual river runoff of the Pearl River is 336 billion cubic meters, including 238 billion cubic meters in the West River, 39.4 billion cubic meters in the Beijiang River, 23.8 billion cubic meters in the East River, and 34.8 billion cubic meters in the delta. Runoff is extremely unevenly distributed throughout the year. The flood season from April to September accounts for about 80% of the total annual runoff, and the three months of June, July and August account for more than 50% of the annual runoff. The Pearl River is rich in water resources. The per capita water resource in the entire basin is 4,700 cubic meters, which is equivalent to 1.7 times the national average. However, large interannual changes and uneven spatial and temporal distribution result in frequent natural disasters such as floods, waterlogging, droughts, and saltwater in the basin.

Floods in the Pearl River Basin are characterized by peak height, large volume, and long duration. The main weather systems causing floods in the basin are mainly peaks or stationary peaks and southwest troughs, followed by tropical depressions and typhoons. Annual heavy rains and floods mostly occur in June, July and August.

The dry season in the Pearl River Basin generally lasts from October to March of the following year. The multi-year average low water runoff is 80.3 billion cubic meters, accounting for only about 24% of the annual runoff in the entire basin. The minimum flow rate during the dry season at Xijiang Wuzhou Station is 720 cubic meters per second, Beijiang Jiaoshi is 130 cubic meters per second, and Dongjiang Boluo Station is 31.4 cubic meters per second.

The Pearl River is a river with little sediment, with a multi-year average sand content of 0.249 kilograms per cubic meter and an annual average sand content of 88.72 million tons. According to statistical analysis, about 20% of the sediment is deposited in the Pearl River Delta river area every year, and the remaining 80% of the sediment is exported to the South China Sea through Badakoumen.

The tides at the Pearl River Estuary are irregular semi-diurnal tides. The Pearl River Estuary is a weak tidal estuary with a small tidal range, with an average tidal range of 0.86 to 1.6 meters and a maximum tidal range of 2.29 to 3.36 meters. The multi-year average of the total high tide in Badakoumen is 376.2 billion cubic meters, and the multi-year average of ebb tide is 702.2 billion cubic meters, with a net reduction of 326 billion cubic meters.

River system

The Pearl River Basin is a complex river basin, consisting of four river systems: the Xijiang River, the Beijiang River, the Dongjiang River and the Pearl River Delta rivers. The west and north rivers merge into the Pearl River Delta at Sixianjiao, Sanshui City, Guangdong Province, and the Dongjiang River merges into the Pearl River Delta at Shilong Town, Dongguan City, Guangdong Province, passing through Humen, Jiaomen, Hongqimen, Hengmen, Modaomen, Jiximen, Humen Eight major entrance gates, including Tiaomen and Yamen, flow into the South China Sea.

The mainstream Xijiang River originates from Ma Xiong Mountain in Qujing City, Yunnan Province, and flows into the South China Sea at Modaomenqirenshi in Zhuhai City, Guangdong Province, with a total length of 2214KM. The Xijiang River is composed of the Nanpan River, Hongshui River, Qianjiang River, Xunjiang River and Xijiang River. Its main tributaries include Beipanjiang River, Liujiang River, Yujiang River, Guijiang River and Hejiang River. The river above Sixianjiao is 2,075km long, with a basin area of ??353,120 square kilometers, accounting for 77.8% of the Pearl River basin area.

Beijiang originates from Damao Plateau, Xinfeng County, Jiangxi Province. The river length above Sixianjiao is 468KM, with a basin area of ??46,710 square kilometers, accounting for 10.3% of the Pearl River basin area. The main tributaries include Wu River, Dengjiang River, Lianjiang River, Suijiang River, etc.

The Dongjiang River originates from Yaji, Xunwu County, Jiangxi Province. The length of the river above Shilong is 520KM, with a basin area of ??27,040 square kilometers, accounting for 5.96% of the Pearl River basin area. The main tributaries include Xinfengjiang River, Xizhijiang River, etc.

The Pearl River Delta covers an area of ??26,820 square kilometers, with a dense network of rivers and crisscrossing waterways. There are more than ten main rivers that flow into the Pearl River Delta, including Liuxi River, Tanjiang River, and Shenzhen River.

Social and Economic

The Pearl River Basin includes six provinces (regions) including Yunnan, Guizhou, Guangxi, Guangdong, Hunan, and Jiangxi, as well as 63 prefectures (states) in Hong Kong and Macao. city. According to statistics in 1993, the total population of the Pearl River Basin was 87.66 million (excluding Hong Kong and Macau), and the average population density was 191 people per square kilometer. In the population structure, the rural population accounts for about 69%, and the urban population accounts for 31%. The population distribution is extremely uneven, with the Pearl River Delta accounting for approximately 22.6%.

There are many ethnic groups in the basin, with more than 50 ethnic groups in the country.

The main ethnic groups include Han, Zhuang, Miao, Buyi, Maonan, etc. Among them, Han people are the largest, followed by Zhuang.

The Pearl River Basin has superior natural conditions and rich resources. According to statistics in 1993, the total industrial and agricultural output value of the basin was 536.556 billion yuan, of which the total industrial output value was 455.667 billion yuan and the total agricultural output value was 80.889 billion yuan. The Pearl River Basin area has a large gap between rich and poor, and underdeveloped areas account for more than 90% of the area.

Physical resources

The Pearl River has abundant runoff and abundant water resources. The developable hydropower installed capacity in the entire basin is about 25.12 million kilowatts, and the annual power generation can reach 116.8 billion kWh. Among them, the Hongshui River in Xijiang has a concentrated drop, large flow, and excellent development conditions. It is known as the "rich ore" of hydropower resources. At present, few have been developed and utilized, and development urgently needs to be accelerated.

The Pearl River Basin is rich in mineral resources. There are 58 proven mineral species and 25 species with reserves of more than 100 million tons, mainly including coal, tin, manganese, tungsten, aluminum, phosphorus, etc. In addition, the South China Sea outside the Pearl River Estuary is rich in oil and natural gas, and exploration and development is currently underway.

The Pearl River is one of the seven major rivers in my country. The rivers in the basin have abundant water, stable river channels, and good shipping conditions. There are currently 1,088 navigable rivers with a total navigable mileage of 14,156 km, accounting for approximately 13% of the national navigable mileage. The annual freight volume ranks second after the Yangtze River.