淮河上游卢庄段全新世古洪水水文恢复研究

通过沿淮河上游野外考察，在毛集河口卢庄找到了一典型全新世古洪水滞流沉积物剖面，进行了系统采样和沉积学粒度分析及水文学恢复的研究工作。粒度分析表明，古洪水滞流沉积物（SWD）与上下层黄土-古土壤区别明显，粒度参数Q型聚类层次分明，其粒级组分以砂质为主，而黄土古土壤粒度以粗粉砂为主，SWD其粒度分形维数明显偏低，各沉积单元粒级组分端元特征明显，通过粒度特征能够很好地鉴别古洪水滞流沉积物层。水文学研究结果表明，自8 500 a以来，在淮和上游至少发生了6次特大洪水，根据各层SWD的厚度和产状关系推求出了其最大可能的洪峰水位，高于水平位10.03~14.36 m之间，据滞流回水环境状态下淮河河道相应的洪峰水位，采用恒定均匀流比降-面积法求得各期洪峰流量介于7 062.18~16 040.94 m³·s^-1之间。研究结果对古洪水滞流沉积物鉴别和古洪水洪峰水位的恢复提供新的思路和方法，同时有效地延长了淮河上游洪水数据序列，可为淮河上游卢庄段全新世时间尺度上洪水流量-频率关系的建立提供参考数据。这对于淮河上游水利水电工程洪水设计和洪水资源化开发管理具有重要的现实意义。

Palaeoflood sedimentological and hydrological study of the Luzhuang section in the upper reaches of Huaihe River

Precipitation changes in Huaihe River basin have been notable in the history.Because it is located in a transitional climate zone between the north and the south in China and also in a transitional zone in the mid-latitude of the Northern Hemisphere,the heavy rainfall events and floods had frequently occurred which resulted in extremely serious loss of life and property in the region.The palaeoflood research about the Huaihe River Basin is almost blank.It is extremely necessary to consider the flood frequency in a longer time scale In this study,through detailed field investigation,the paleoflood slackwater deposits (SWDs) were identified from Holocene loess-paleosol profiles in the upper reaches of Huaihe River and analyzed at the laboratory.Using methods such as the particle size parameters Q-type clustering,the fractal dimensions and end member analysis,the study on the particle size revealed that the difference between the SWDs and loess-paleosols was obvious which was in accordance with the macro characteristics observed in the field.On top of this analysis,the flood peak stage and peak flow of the palaeoflood were simulated based on the bedrock canyon river channel and the characteristic of the stratigraphic sediments.This hydrologic reconstruction indicated that there were at least six extraordinary flood events with their flood peak stages about 10 meters high above the normal water level in the upper reaches of Huaihe River since the Holocene.The flood peak water levels were 111.28 m (SWD₁),110.03 m (SWD₂),111.78 m (SWD₃),112.03 m (SWD₄),113.67 m (SWD₅) and 114.36 m (SWD₆) respectively and the corresponding peak flows were 9 361.52 m³·s^-1 (SWD₁),7 062.18 m³·s^-1 (SWD₂),10 247.65 m³·s^-1 (SWD₃),10 732.87 m³·s^-1 (SWD₄),14 326.04 m³·s^-1 (SWD₅) and 16 040.94 m³·s^-1 (SWD₆) respectively.The methods and the results presented in this study have important significance for the construction of water conservancy and hydropower project in the upper reaches of Huaihe River.