Analysis of reach-scale sediment process domains in glacially-conditioned catchments using self-organizing maps
Analysis of reach-scale sediment process domains in glacially-conditioned catchments using self-organizing maps
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DOI：
10.1016/j.geomorph.2021.107684
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发表时间：
2021-06
期刊：
影响因子：
3.9
通讯作者：
Kristen L. Underwood;D. Rizzo;M. Dewoolkar;Michael S. Kline
中科院分区：
文献类型：
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作者：
Kristen L. Underwood;D. Rizzo;M. Dewoolkar;Michael S. Kline
鉴于可用于管理侵蚀危害和处理河流沿着水质损害问题的资源有限，参与水资源管理的利益攸关方将受益于确定最容易调整的河流河段以及向受纳沃茨输送不成比例的沉积物的河段。响应自然和人为干扰的垂直和横向河道调整的程度和速率在空间和时间上变化很大;这种复杂性和非线性给使用传统统计技术的河段分类或建模带来了挑战。自组织映射（SOM）是一种数据驱动的计算工具，具有对多变量观测进行聚类或分类以及探索性数据分析和复杂非线性系统可视化的优势。我们应用SOM聚类多变量流地貌评估数据到达到规模的沉积物过程域的193条河流到达美国东北部的冰川条件集水区使用现场和GIS派生的水力和地貌参数。该河段包括一系列的渠道类型，从封闭到开放，陡到浅梯度，中到高阶，基岩冲积河道。15个变量被确定为有意义的分离达到七个沉积物制度，两个阶段的SOM应用程序。一个粗调SOM确定的沉积物制度类在供应有限和运输有限的极端的连续性，包括基岩渠道和封闭，陡梯度达到以及编织，沉积渠道在冲积扇或三角洲设置。第二阶段，微调SOM细微差别的泥沙生产和运输的无压河段与不同程度的洪泛区断开导致自然或人为的压力。这种分类框架是转移到其他水文气候区域，考虑额外的或替代的独立变量，这些地区独特的，并可以提供宝贵的见解，河流管理，以促进洪水恢复能力，恢复水质，改善河流和河岸栖息地。
Given the limited resources available for managing erosion hazards and addressing water quality impairment along rivers, stakeholders engaged in water resource management would benefit from tools to identify those river reaches most prone to adjustment and which disproportionately load sediment to receiving waters. The extent and rate of vertical and lateral channel adjustments in response to natural and human disturbances vary considerably across space and time; and this complexity and nonlinearity introduce challenges for classification or modeling of river reaches using conventional statistical techniques. The Self-Organizing Map (SOM) is a data-driven computational tool with advantages for clustering or classifying multivariate observations and for exploratory data analysis and visualization of complex, nonlinear systems. We applied a SOM to cluster multivariate stream geomorphic assessment data into reach-scale sediment process domains for 193 river reaches in glacially-conditioned catchments of northeastern US using field- and GIS-derived hydraulic and geomorphic parameters. The reaches comprised a range of channel types from confined to unconfined, steep- to shallow-gradient, mid-to-high order, and bedrock to alluvial channels. Fifteen variables were identified that meaningfully separated reaches into seven sediment regimes, following a two-stage application of the SOM. A coarse-tune SOM identified sediment regime classes at the supply-limited and transport-limited extremes of a continuum, including bedrock channels and confined, steep-gradient reaches as well as braided, depositional channels at alluvial fan or delta settings. A second-stage, fine-tune SOM nuanced differences in sediment production and transport for unconfined reaches with varying degrees of floodplain disconnection resulting from natural or human stressors. This classification framework is transferable to other hydroclimatic regions, with consideration of additional or alternate independent variables unique to those regions, and can provide valuable insights for river management to promote flood resiliency, restore water quality and improve instream and riparian habitats.