Longitudinal streambed profiles along the sides of piers at selected bridge sites in Montana

The U.S. Geological Survey (USGS), in cooperation with the Montana Department of Transportation (MDT), collected longitudinal streambed profile data along the sides of piers at selected bridges in Montana. The streambed profile data extends upstream and downstream of piers so that local pier scour effects might be distinguished from more general geomorphic scour processes. Two or more streambed profiles were obtained on each side of piers at each bridge site. Contraction scour was not considered a factor mainly because none of the bridges reflect a substantial contraction of flow, given the spring runoff conditions that were experienced. The purpose of the data collection is to determine if scour and channel instability occur in the vicinity of the bridge structures. Data were processed, analyzed, and compiled for bridge scour monitoring, facilitating better understanding, documentation, and prediction of scour processes.

美国地质调查局（U.S. Geological Survey, USGS）与蒙大拿州交通运输部（Montana Department of Transportation, MDT）合作，在蒙大拿州选定桥梁的桥墩两侧采集河床纵向剖面数据。本次采集的河床剖面数据覆盖桥墩上下游区域，以便将桥墩局部冲刷效应与更广泛的地貌冲刷过程区分开。每个桥址的桥墩两侧均获取了两条及以上的河床剖面数据。收缩冲刷（contraction scour）未被纳入考量因素，原因在于本次观测处于春季径流时段，所有桥梁均未出现显著的过流断面收缩。本次数据采集的核心目标是研判桥梁结构周边是否存在冲刷现象及河道失稳问题。相关数据已完成处理、分析与整编，用于桥梁冲刷监测工作，以推动对冲刷过程的深入理解、规范记录与精准预测。