Collaborative Research: Investigating Human and Climate Influences on Delta Evolution Using Fluvial Discharge and Coastal Evolution Models

受陆地和海洋作用的影响，三角洲是陆地-海洋界面上的重要沉积地貌，提供了过去环境变化的记录。全世界的三角洲目前正受到人类活动的严重影响，特别是河流筑坝，减少了到达海岸的沉积物数量。虽然大型水坝是相对较新的现象，但自农业出现和发展以来，人类对景观的改变一直在进行。结合现场数据收集，河流建模，海岸演变建模，本研究将探讨人类活动是否有显着影响的现代埃布罗三角洲的形成，在地中海沿岸的西班牙。具体来说，它是hypothersized的增长，埃布罗三角洲可以归因于大规模的森林砍伐，农业目的开始在罗马时代。实地研究将通过收集和分析三角洲平原沿着的沉积物岩心，记录埃布罗三角洲在过去大约3,000年的演变。气候驱动的水文模型HydroTrend将用于计算这段时间内河流向海岸的沉积物排放量，其中包括可能归因于气候变化的沉积物输送变化以及人类改变埃布罗河流域可能造成的沉积物输送变化。一个能够纳入长时间尺度的海岸线演变的数值模型将被应用于研究三角洲形状的原因，并评估河流流量的变化将如何影响海岸后，被海浪改造。耦合的河流和海岸数值模式的一个重要目标，作为社区表面动力学模拟系统（CSDMS）的概念验证，了解历史和未来的形态变化的三角洲已变得越来越重要，海平面上升和泥沙负荷喂养三角洲继续被隔离在后面的大坝在内地。三角洲通常人口稠密，为社会提供许多重要的自然资源，特别是沿着多岩石的西班牙地中海海岸，靠近海平面的土地很少。在受到人类文明影响的地区，三角洲可以作为大流域气候和土地利用变化的记录。西班牙的埃布罗三角洲具有独特的平面形状，在过去的两千年里经历了重大的形态变化;这些变化可能归因于埃布罗流域的人类活动。这项研究的结果将具有广泛的适用性，以解开世界各地的三角洲的历史（例如，尼罗河、波河、多瑙河、印度河、密西西比河）。 如果人类活动在很大程度上对世界三角洲的形状负责，这将为理解人类在未来几个世纪将如何管理这些资源提供一个重要的背景，特别是随着气候变化和人类继续改变这些地貌。

Influenced by both terrestrial and marine processes, deltas are critical sedimentary landforms at the land-sea interface that provide records of past environmental changes. Deltas worldwide are currently being severely altered by human activities, in particular river damming, which has reduced the amount of sediment reaching the coast. Although large dams are relatively recent phenomena, human alteration of landscapes has been ongoing since the advent and expansion of agriculture. Combining field data collection, fluvial modeling, and coastal evolution modeling, this research will examine whether human activities have significantly influenced the formation of the modern Ebro Delta, on the Mediterranean coast of Spain. Specifically, it is hypothersized that the growth of the Ebro Delta can be attributed to massive deforestation for agricultural purposes initiated in Roman times. Field research will document the evolution of the Ebro Delta over approximately the last 3,000 years by collecting and analyzing sediment cores from along the delta plain. The climate-driven hydrological model HydroTrend will be used to compute riverine sediment discharge to the coast over this time period, incorporating changes to sediment delivery that could be attributable to climatic changes and those that could be caused by human alterations to the Ebro River watershed. A numerical model of shoreline evolution capable of incorporating long timescales will be applied to examine the causes of the delta's shape and to evaluate how changes to riverine discharge would affect the coast after being reworked by waves. Coupling of the fluvial and coastal numerical models serves an important goal as proof-of-concept of the Community Surface Dynamics Modeling System (CSDMS).Understanding the historic and future morphologic change of deltas has become increasingly important as sea levels rise and sediment loads feeding deltas continue to be sequestered behind dams in the hinterland. Deltas are often densely populated and provide many importantt natural resources to society, particularly along the rocky Spanish Mediterranean coast with scant land near sea level. In regions that have been affected by human civilization, deltas can serve as a record of climate and land-use changes across large watersheds. The Ebro Delta, Spain, with its distinctive plan-view shape, has experienced significant morphologic changes over the last two millennia; changes that may be attributable to human activities in the Ebro watershed. The results of this research will have wide applicability to unraveling the history of deltas worldwide (e.g., Nile, Po, Danube, Indus, Mississippi). If human activities are largely responsible for the shape of the world's deltas, this would provide an important context for understanding how humankind will manage these resources over the coming centuries, particularly as climate changes and humans continue to alter these landforms.