Sishui County Tuoh River Provincial Nature Reserve

Sishui County Tuoh River Provincial Nature Reserve

I. General Overview

The scope of the Anhui Sishui County Tuoh River Wetland Provincial Nature Reserve includes the North Tuoh River and South Tuoh River within Sishui County and their adjacent river basins. The North Tuoh River enters Sishui County from Xuxuizi, flows southeast to Cao’gou where it meets the Tang River, then turns south to Fanji where it joins the South Tuoh River and flows into Tuoh Lake, with a total length of 19 km. The South Tuoh River is the boundary river between Sishui County and Wuhe County, flowing southeast from Shen Zhuang to Fanji where it meets the North Tuoh River and flows into Tuoh Lake, spanning 17 km in length. The reserve is located between 117°37' to 118°10' east longitude and 33°16′ to 33°46′ north latitude, encompassing nine natural villages in Caogou Town—Wanglou Street, Jexi, Caogou, Qiudong, Jianan, Wangshang, Daliang, Liwei, and Da’an—as well as three natural villages in Dinghu Town—Suotan, Xiangyang, and Fanji. The total area of the reserve is 2,463 hectares.

The wetlands in the reserve belong to the Tang and Tuoh river systems, mainly consisting of the South Tuoh River, North Tuoh River, and Tang River. These rivers drain internal waters from the southwestern part of the county into Tuoh Lake, covering a catchment area of 384 km² with cultivated land spanning 17,220 hectares. The river system traverses the western part of the Changgou District and most areas of the Caogou and Dinghu Districts.

The Sishui County Tuoh River is one of the important wetlands in the Anhui section of the Huai River Basin. It lies to the east of China’s third-largest freshwater lake—Hongze Lake—and borders the Anhui Tuoh Lake Provincial Nature Reserve to the south. With a total length of 83.2 km and a drainage area of 556 km², it forms a regionally significant wetland ecosystem. Protecting the Tuoh River wetlands is not only crucial for the regional ecosystem of Sishui County but also vital to the implementation of China’s water resource conservation strategy.

The Anhui Sishui County Tuoh River Wetland Provincial Nature Reserve is comprehensively planned based on the wetlands of the North and South Tuoh Rivers. The Tuoh River runs from northwest to southeast through Sishui County. The reserve features diverse vegetation, dense reed beds, vast expanses of blue water blending seamlessly with the sky, and a rich abundance of migratory birds such as wild geese, ducks, and herons. In 2009, the People’s Government of Suzhou City, Anhui Province, approved the establishment of the Anhui Sishui County Tuoh River Nature Reserve, and in February 2012, the People’s Government of Anhui Province officially designated it as the Anhui Sishui County Tuoh River Provincial Nature Reserve.

II. Flora and Fauna Resources

The Tuoh River wetland lies in the transitional zone from the warm temperate region to the subtropical region, boasting abundant biological resources. It is one of the areas in Sishui County with the highest concentration of vertebrate species and serves as an essential stopover for migratory birds.

According to scientific survey reports, the wetland vegetation includes 419 species from 95 families, among which two species—the lotus and wild water caltrop—are classified as Class II nationally protected plants. Key economic plants consist of lotus, water caltrop, cattail, reed, wild rice stem, and hornwort. Wetland fauna includes: 32 fish species from 13 families under 7 orders; 15 species from 9 families of amphibians and reptiles; and 96 bird species from 36 families under 15 orders. Among the birds, two species are Class I nationally protected—the Oriental white stork and the great bustard—while seven species are Class II nationally protected, including the little egret, kite, common buzzard, hen harrier, red falcon, short-eared owl, and long-eared owl. There are also 30 species under Anhui provincial protection. Mammals total 11 species from 7 families under 5 orders.

III. Hydrology and Climate

The reserve is situated in the mid-latitude zone and falls within the warm temperate, semi-humid monsoon climate region. It experiences distinct monsoon seasons, clearly defined four seasons, mild temperatures, moderate rainfall, ample sunlight, and a long frost-free period. The annual average temperature is 15.5°C, with an average annual precipitation of 1,097.1 mm, average annual sunshine duration of 2,085.9 hours, and total solar radiation ranging from 110 to 120 kJ/cm², amounting to a total radiation of 489,060 J/cm². The average frost-free period lasts 207 days. The rainy season generally begins in mid-to-late July, often in the form of heavy rainstorms, with an annual evaporation rate of 904.7 mm. River water transparency ranges from 2.5 to 2.6 meters. Relative humidity typically stays between 70–80%, remaining relatively stable, with an annual average of 73%. The mean annual evaporation is 1,921.2 mm.