Holocene Extreme Floods and Environmental Change of Qishuihe River in Western Guanzhong Basin
关中西部漆水河全新世特大洪水与环境演变

Palaeoflood hydrologic study was a leading subject in the global change study. Using sediment physiognomy, archaeology and OSL chronology, the palaeoflood slacking deposits were found and analyzed on T2 terrace between the Qishuihe and Weihe rivers. The results showed that 20 palaeoflood events happened in the 4 periods of 4650-4600 a BP, 4400-4300 a BP, 4200-4100 a BP and 3100-3010 a BP since 11500 a BP, respectively. Then their peak discharges were calculated according to the hydrology principle, which greatly prolonged the flood data sequence in the Qishuihe river valley. And the flood frequency curve was established to enhance the reliability to control and reduce flood disasters in this valley. This research result is not only practical to the flood control, water resources exploitation and eco-environmental construction for Yangling, a well-known agricultural and high-tech city in Northwest China, but also fills in the blank of the palaeoflood hydrologic study in the Weihe River Basin, which is of great scientific significance to the comprehensive improvement of the eco-environment of the river basin.