Geovisualization geoscience of large river floodplains

Alluvial river landscapes of the lower Mississippi and Atchafalaya rivers in the south-central USA are flood prone and have shifted historically in position and form, resulting in interventions for flood reduction, navigation, and water supply. Fisk mapped these landscapes in the middle of the twentieth century as a series of artistic colourful map plates. Selected areas are revisited with modern data sets (LiDAR from 2003, hydrographic surveys from 2006 and 2007) including two sites along the Mississippi River (near the Old River juncture and near Morganza Floodway) and one in the middle Atchafalaya River. By using 2D and 3D geovisualization, we find that the extent, variety, and dimensions of anthropogenic landforms have grown in prominence since Fisk’s mapping. The volumes of the highest positive landforms are quantified to provide some indication of direct and indirect anthropogenic activity in these landscapes.

美国中南部密西西比河下游与阿查法拉亚河的冲积河川地貌属于洪水频发区域，历史上其位置与形态持续发生变迁，由此催生了防洪、航运与供水相关的工程干预措施。菲斯克（Fisk）于20世纪中期将这类地貌绘制成一系列色彩丰富的艺术化地图图版。本研究借助2003年的激光雷达（LiDAR）、2006年及2007年的水文测量等现代数据集，对部分选定区域开展重访调研，调研点位包括密西西比河沿岸两处（老河汇流处附近与摩根扎泄洪道附近）以及阿查法拉亚河中游的一处点位。通过二维与三维地理可视化技术，研究团队发现，自菲斯克完成地图绘制以来，人为地貌的分布范围、类型多样性与规模维度均愈发凸显。本研究对规模最大的正地形体积进行量化分析，以此为这类河川地貌中直接与间接的人类活动强度提供量化参考依据。