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通过对马莲河中下游的深入考察,在甘肃省合水县河段发现全新世古洪水滞流沉积剖面,对采集的沉积物样品进行粒度成分、石英砂表面结构等分析,证明为典型的古洪水滞流沉积物。通过地层学年代对比分析,确定马莲河在全新世中晚期发生特大洪水,年代大致为4200~4000a B.P.之间。根据该组古洪水滞流沉积物所指示的洪峰水位,采用比降法恢复洪峰流量在16400~16900 m3/s之间。同时对该断面2003年和2005年洪水的洪痕进行了流量恢复计算,计算结果与实测洪水误差小于5%,证明古洪水水文学计算结果合理可靠,从而为马莲河水利工程建设及沿岸城镇的防洪减灾提供了科学依据。
Through the in-depth investigation of the middle and lower reaches of the Malian River, the sediment profile of the Holocene pale flood was found in the Heishui section of Gansu Province. The sediment samples collected were analyzed for the grain size composition and quartz sand surface structure, which proved to be typical paleo-floods Stagnant sediment. Through the stratigraphic age comparative analysis to determine the Malianhe in the late Holocene catastrophic floods, age roughly between 4200 ~ 4000a B.P. According to the crest water level indicated by the sediment of the flood flood in the ancient flood control group, the flood peak discharge is reduced to 16400 ~ 16900 m3 / s by using the slope reduction method. At the same time, the flow recovery calculation of flood traces in 2003 and 2005 in this section was carried out. The calculated error is less than 5% of the actual measured flood, which proves that the calculation results of paleo-flood hydrology are reasonable and reliable. Disaster relief provides a scientific basis.