GU Jiawei

(School of Tourism Management, Henan Finance University, Zhengzhou 450046, China)

Abstract: This paper calculates the sedimentation rate of the alluvial wetlands in the lower Yellow River based on the 210Pb and 137Cs dating techniques and analyzes the relationship between the evolution of sedimentation rate and the change of water and sand in the upstream river. Results showed an exponential decrease trend of 210Pb and the occurrence of two spikes of 137Cs prove the feasibility of this radionuclide method. Sedimentation rates of 1.68 cm/a and 0.67-2.76 cm/a are calculated based on the CIC model and CRS model of 210Pb, respectively; meanwhile, sedimentation rates of 2.67cm/a, 1.08cm/a and 1.21cm/a are found for bottom, middle and upper sediments based on two spikes of 137Cs fallout in 1963 and 1986. Furthermore, the sedimentation rate in the alluvial wetlands of the lower Yellow River decreased gradually in the past decades, this is closely correlated with the climate change, damming in the upstream, water and soil conservation project, and the downstream water utilization. In addition, the reservoir operation also affects the sedimentation rate to a certain degree. The dying flood make it harder for the sediment to deposit in the wetland.

Key words: the Yellow River; sedimentation rate; 210Pb; 137Cs

EARTH AND ENVIRONMENT Vol.48, No.6, Tot No.338, 2020, Page 698-703