Quantitative Meso-Scale Mass-Flux Routing Across a Large Tropical Foreland Basin

9903157大卫河蒙哥马利 我们将研究和模拟前陆盆地在调节从山脉到低地河流和河口的泥沙运输中的作用，开发一个定量的、基于过程的泥沙运输和储存模型，包括细颗粒的“冲刷负荷”，通过蜿蜒的、移动的河流。我们将通过研究亚马逊河的安第斯支流穿越玻利维亚东部前陆盆地，从早期对亚马逊河沿着洪泛区沉积过程的调查中获得见解。 我们已经开始对这些玻利维亚河流进行实地观测和卫星图像解释，这是我们先前对从安第斯山脉流入前陆盆地的沉积物通量进行研究的结果。 实地研究将包括沿河流沿着的纵向断面，以测量水流和沉积物沿河道沿着进入洪泛区所需的河道特征，以及横跨洪泛区的断面，以收集210 Pb和137 Cs的沉积物芯，这将有助于测试计算结果和其他假设，这些假设涉及洪泛区和河道之间交换沉积物的过程。 实地取样将在一组穿越广阔洪泛区的蜿蜒河道中，在泥沙输运和储存的数学模型（空间“到达尺度”为1-10公里，时间尺度为1年）的背景下进行。 本文的研究成果将有助于进一步完善盆地和沿着构造运动、河流地貌与沉积作用之间的关系理论。 这项研究还将探讨沉积物迁移与河道和洪泛区特征之间的河流地貌关系，并将制定通过移动的河道和动态洪泛区的山前河段的沉积物路线的方法，这对科学家、工程师和关心大型冲积河谷可居住性的资源规划者是有意义的。

9903157David R. Montgomery We will study and model the role of foreland basins in modulating the transport of sediment from mountain ranges to lowland rivers and estuaries, developing a quantitative, process-based model of sediment transport and storage, including fine-grained 'washload', by sinuous, mobile rivers. We will develop insights from earlier investigations of floodplain sedimentation processes along the Amazon River by studyingAndean tributaries of the Amazon as they cross the foreland basin of eastern Bolivia. We have initiated field observations and satellite-image interpretation of these Bolivian rivers as an outgrowth of our prior study of the flux of sediment out of the Andes into the foreland basin. The field study will include longitudinal transects along the river to measure channel characteristics required for flow and sediment routing along thechannel and into the floodplain, as well as transects across floodplains to collect sediment cores for 210Pb and 137Cs that will facilitate the testing of calculations and other hypotheses concerning processes that exchange sediment between floodplain and channel. The field sampling will be conducted in the context of a mathematical model of sediment transport and storage (of spatial 'reach-scale' 1-10 km and temporal scale 1 year) in a set of sinuous river channels crossing a broad floodplain. The results ofour study will contribute to theories of the relationship between tectonism, fluvial geomorphology, and sedimentation in basins and along rivers. The study will also address the fluvial geomorphic relationships between sediment transport and channel and floodplain characteristics, and will develop methods for sediment routing through mountain-front reaches of mobile channels and dynamic floodplains which are of interest to scientists, engineers, and resource planners concerned with the habitability of large alluvial valleys.