Passive Acoustic Measurement of Bedload Transport in Natural Bedrock Channels

0126131 SlingerlandThe本提案的目的是设计和校准一个非侵入性的，被动声学系统测量空间集成推移质输运率在一个天然基岩通道。 本文提出测量推移质碎屑在运输过程中的自生噪声。 我们的实验设计包括8个水听器和8个地震检波器部署在沿着100米的范围内，数据记录到磁盘后，通过一个16通道的模拟到数字转换板上的笔记本电脑。 这些手机将被环氧树脂固定在靠近河岸的基岩上，以及溪流中心的大石头上。 将比较水听器阵列和地震检波器阵列，以确定哪一个（如果有的话）是优选的，并消除来自流体湍流、空化和气泡破裂的信号。 将分析宽带和窄带振幅对推移质输运的预测能力。 流向阵列的目的是利用下游传播的推移质输运波的存在，并确定最佳的采样设计。 该系统将被校准使用推移质输运率在低流量下观察到的常规技术，如铁丝网陷阱和Helley-Smith采样器，并在高流量下的三角洲的多个调查流清空到一个常设机构的水三角洲调查将使用浅水回声测深仪完成。 在研究河段还将测量关键水力变量，以便将这些变量与实测推移质通量联系起来。 其结果将是一个非侵入性的方法，测量横截面集成推移质输沙率在基岩达到在很短的时间间隔。

0126131SlingerlandThe objective of this proposal is to design and calibrate a non-invasive, passive acoustic system for measuring spatially-integrated bedload transport rates in a natural bedrock channel. We pro-pose to measure the self-generated noise of bedload clasts in transport. Our experimental design consists of eight hydrophones and eight geophone deployed along a 100m reach, with data recorded to disk after passing through a sixteen-channel analog-to-digital conversion board on a laptop computer. The phones will be epoxied onto bedrock, near the banks, and onto large boulders in the center of the stream. The hydrophone array and the geophone array will be compared to determine which, if either, is preferable and to eliminate signals from fluid turbulence, cavitation, and bubble collapse. Both broadband and narrowband amplitudes will be analyzed for predictive power of bedload transport. The purpose of the streamwise array is to exploit the presence of downstream propagating waves of bedload transport and to determine an optimal sampling design. The system will be calibrated using bedload transport rates observed at low flows by conventional techniques such as chickenwire traps and Helley-Smith samplers, and at high flows by multiple surveys of a delta where the stream empties into a standing body of water The delta surveys will be accomplished using a shallow-water echosounder. Key hydraulic variables also will be measured in the study reach in order to relate these variables to measured bedload fluxes. The result will be a non-invasive method for measuring cross-sectionally-integrated bedload transport rates in bedrock reaches at very short time intervals.