【摘要】 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。更多还原

【Abstract】 Through investigations in the middle and lower reaches of Malian River,Holocene palaeoflood slack-water deposition profile were identified in Heshui County.Samples of the palaeoflood slackwater deposits were collected,and the grain-size distribution and the quartz grain surface texture were examined.All of these index-es showed that the slackwater deposits were typical in the study area.Stratigraphic correlations showed that the slackwater deposits recorded the largest floods occurred between 4200-4000 a B.P.on the river.The flood peak discharges were estimated to be 16780-17200 m3/s by using the slope-area method.Reconstruction of the peak discharge of the 2003 and 2005 floods with the same method and indicators showed that the palaeoflood recon-struction was reliable.These results are important for hydraulic engineering and flood control along the Malian River.更多还原