关中西部漆水河全新世特大洪水与环境演变

古洪水水文学研究是全球变化研究的前沿课题。本文通过对漆水河流域深入调查研究, 在漆水河与湋河交汇的二级阶地全新世黄土-土壤剖面中发现古洪水沉积夹层, 利用沉积地貌学、沉积学、考古学和释光年代学方法, 确定了在全新世时期的11500 年内, 漆水河曾经在4650~4600a BP、4600~4300a BP、4300~4100a BP 和3100~3000a BP 发生了4 期20 次洪水事件。通过利用水位-流量关系模型, 计算出这4 期20 次特大洪水的洪峰流量, 大大延长了洪水水文数据序列, 并建立了漆水河全新世洪水频率曲线, 科学、系统地提高了漆水河洪水水文学计算精度, 增强了渭河流域防洪减灾和水资源开发当中洪水频率分析的可靠性。这项研究成果对于我国著名的农业科技城-杨凌的防洪减灾、水资源开发和生态环境建设具有重要的应用价值, 同时填补了渭河流域古洪水水文学研究的空白, 对于渭河流域生态环境综合治理具有重要的科学意义。

Holocene Extreme Floods and Environmental Change of Qishuihe River in Western Guanzhong Basin

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.