The average annual runoff of Tanghe River is 17.44 cubic meters, with the maximum value at 1975, and the runoff is 3910 million cubic meters. The average measured river flow for many years is 48.78 m3/s, with the maximum value appearing in July and August, and the maximum flow reaches13400m3/s (1975 August 10 Guotan Station). The Tanghe River stores water quickly, floods are fierce, and the flood peaks fluctuate greatly, which often leads to catastrophic floods. Generally, the flood with a speed of more than 2,500 m3/s occurs once every 3 to 8 years, and the flood with a speed of more than 6,000 m3/s occurs once every 0 years, mostly in July and August. The river erosion modulus ranks first in the whole region, with an annual average of 709.74 tons /km2, and the maximum value can reach 1975 1830 tons /km2. The sediment concentration of river water is second only to that of Danjiang River, with an average of 3.2 1 kg/m3 and 8.94 kg/m3 (1965).

The water quality of Tanghe River is good, the salinity is less than 130mg/L, the total hardness is less than 2.25mg/L, the annual average temperature of the river is 14.6 ~ 15.8℃, the initial glacial period is 65438+February 65438+February 3rd, and the final glacial period is 65443.