黄河三角洲地貌演变的动力机制与环境效应

The morphological evolution of the Yellow River delta can be characterized with significantly spatial heterogeneity and highly temporal dynamics owing to its river course avulsion, quantities of water discharge and sediment load, influence of marine dynamics, as well as increasing human intervention. Its environmental impacts also present complex multiplicity. Over the past few decades, the runoff and sediment load in the Yellow River underwent dramatic changes due to the climate change and human activities in its basin, which inevitable resulted in a new pattern of its delta morphological evolution. This research will consider the Yellow River delta-front estuary, coastline and littoral zone as an integrated object, and use a novel conceptual framework of “collecting morphological and environmental data”-“understanding of processes and mechanism”-“modelling and quantifying of system evolution” to fully comprehend the long-term and insightful mechanism of morphological evolution of the Yellow River delta. The project will combine field observation and data collection, remote sensing monitoring and interpretation, numerical modelling, as wells as the integrated analysis of hydrodynamics, sediment, deposition, morphology and environment in the study site, to further advance on two key areas: 1) the coupling mechanism of water and sediment discharge into the sea, marine dynamics and delta evolution; and 2) reliable and accurate quantification using the advanced modelling techniques for the long-term evolution of the delta under the interaction between land and sea. The project will yield a significant advancement and enrichment from the existing knowledge and understanding on the morphological evolution and environmental effects of mega-river deltas for sustainable development and management of the Yellow River delta.

受河口流路变迁、入海水沙变异，以及海洋动力和人为干预作用，黄河三角洲地貌演变表现为显著的空间异质性和时间动态性，其环境效应也呈多重性。近年来，受流域气候变化和强烈的人类活动影响，黄河入海水沙情势产生了剧烈的变化，三角洲演变出现了新的格局。本项目拟以黄河河口流路、三角洲海岸和近岸海床为重点研究对象，基于“地貌与环境-过程与机理-模拟与量化”的总体思路，采用资料收集、遥感解译、野外观测、数值模拟等手段，以及动力-泥沙-沉积-地貌-环境综合分析方法，阐明三角洲地貌演变的过程和规律及其动力机制；重点解决“河流入海水沙、海洋动力与三角洲地貌演变的耦合机制”和“陆海相互作用下三角洲演变的定量模拟技术”两大关键科学技术问题；利用国际先进的数值模型，深入研究入海泥沙输运和三角洲地貌演变；在此基础上，综合评估三角洲地貌演变的环境效应。项目研究将丰富大河三角洲地貌动力学理论，推进黄河三角洲环境的可持续发展。

项目针对新入海水沙情势下黄河三角洲地貌演变新的格局，以黄河河口流路、三角洲海岸和水下三角洲为重点研究对象，围绕“河流入海水沙、海洋动力与三角洲地貌演变的耦合机制”和“陆海相互作用下三角洲演变的定量模拟技术”两个关键科学与技术问题，较系统开展了黄河三角洲地貌演变的动力机制与环境效应研究，取得了系列重要成果：量化了流域气候变化和人类活动对黄河三角洲地貌演变的影响；阐明了调水调沙以来黄河尾闾河道冲淤演变及其影响因素；发现了现行黄河口演变主要受调水调沙和口门出汊的控制；提出了维持现行黄河河口海岸冲淤平衡的水沙阈值；监测和揭示了黄河三角洲北部潮滩动态和变窄的原因；探讨了转型中的黄河三角洲演变过程及其动力机制；发现了波流联合作用是造成孤东近岸强烈侵蚀的主要原因；揭示了风暴对黄河三角洲近岸水沙动力和地貌演变的显著影响；定量模拟了入海水沙变化对河口滨海区沉积动力过程；发现了现行黄河口冲淡水主体向莱州湾扩展的规律等。在此基础上，提出了黄河三角洲流路稳定治理与海岸防护、生态保护相结合的途径。项目发表学术论文32篇，其中SCI论文12篇。结合项目研究培养毕业博士3名，毕业硕士6名。项目研究成果可为黄河三角洲流路稳定综合治理、海岸侵蚀防护以及可持续发展提供科学依据。