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

9903157大卫·R·蒙哥马利我们将研究和模拟前陆盆地在调节泥沙从山脉向低地河流和河口输送方面的作用，开发一个基于过程的定量泥沙输送和储存模型，包括由蜿蜒流动的河流进行的细粒“冲刷负荷”。我们将通过研究亚马逊的安第斯支流穿过玻利维亚东部的前陆盆地，来发展对亚马逊河沿岸泛滥平原沉积过程的早期调查的见解。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，这是我们先前研究从安第斯山脉进入前陆盆地的沉积物流量的结果。实地研究将包括沿河的纵向横断面，以测量沿河道和进入泛滥平原的水流和泥沙输送所需的河道特征，以及跨泛滥平原的横断面，以收集210Pb和137Cs的沉积物岩心，这将有助于测试有关泛滥平原和河道之间交换沉积物的过程的计算和其他假设。现场采样将在跨越广阔泛滥平原的一组蜿蜒河道中的泥沙传输和储存的数学模型(空间“范围尺度”1-10公里和时间尺度1年)的背景下进行。我们的研究成果将有助于研究构造作用、河流地貌和流域及沿江沉积作用之间的关系。这项研究还将探讨泥沙输送与河道和洪泛平原特征之间的河流地貌关系，并将开发通过流动河道和动态洪泛平原的山前段的泥沙路线方法，这是科学家、工程师和资源规划者关心的大冲积山谷宜居性的问题。

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.