The Study Of Waves And Currents Contributing To Sediment Resuspension By In-situ Observation

Waves and currents, the two main dynamic factors of sediment resuspension,have been studied less about their contributions to the resuspension. Supported by theNational Nature Science Foundation Project “Investigation of sources and governingfactors of seabed erosion and resuspension in Yellow River estuary”(Contract No.41072215; Awarded:2013-2015) and the marine geological survey project of Chinageological survey “Study on Land-Ocean Interaction and Coast Geologic Disaster”(Contract No.41072215; Awarded:2012-2015), based on in-situ observation, thispaper reveals the contributions of waves and currents to resuspension in Jiaozhou Bay,Baisha Bay and Yellow River Delta. A bottom tripod in-situ observing method is usedin Jiaozhou Bay and Baisha Bay; By shielding waves or currents, we compare theconcentrations of suspended solid with only one factor and two factors simultaneouslyexisting in Yellow River Delta. Through laying plastic film, collecting the surfacefine-grained soil samples under the membrane, this article studies the waves“pumping” effect to sediment resuspension in Yellow River Delta.1. Currents is the main motivating factor of sediment resuspension in Jiaozhou Bay.At state1sea conditions, the seabed sediment resuspension is almost all caused bycurrents, with its contribution rate close to100%; at state2sea conditions, thecontribution rate of sediment resuspension caused by waves is about21.9%to58.3%,and the contribution rate caused by currents is about41.7%to78.9%.2. Sea currents less affects seafloor sediment resuspension in Baisha Bay, and largerwave action is the main dynamic factor causing sediment resuspension. When thesignificant wave height is below50cm, the contribution rate of sediment resuspensioncaused by currents is about50%to100%, with waves’contribution rate less than50%.When the significant wave height is above50cm, the currents’ contribution rate isless than50%, and the waves’contribution rate is more than50%.3. Among the resuspension events in Yellow River delta, the waves’ contributing rate to sediment resuspension is14%to73%, and that of currents is27%to86%；Inthe process of wave-induced sediment resuspension, the contributing rate to sedimentresuspension of waves “pumping” is11.5%to42.8%, and that of wave shearingaction is57.2%to88.5%.4. It takes a longer time to complete the settlement process after sedimentresuspension. So, the method of studying the contribution of currents to sedimentresuspension by shielding waves on the scene is not feasible.