Continued Development of Signal Processing Methods for Surrogate Bedload Measurement on the Elwha River

Project ID: 9562
Principal Investigator: Robert Hilldale
Research Topic: Water Resource Data Analysis
Funded Fiscal Years: 2010
Keywords: None

This is the start of the wiring job, routing two wires each from 72 sensors into signal conditioners, analog to digital converters, and then one of three computers that operate the system. May 2011.<br>[<a href='imagepop.cfm?id=9562|184' target='_blank' style='color:#bbb'>view information</a>] These are three analog to digital converters, routing the wiring from sensors to computer.<br>[<a href='imagepop.cfm?id=9562|186' target='_blank' style='color:#bbb'>view information</a>] This is the back of the computer cabinet showing the bus boards on the back door and signal conditioners at the top of the cabinet. Two of the three PCs are visible at the bottom of the cabinet.<br>[<a href='imagepop.cfm?id=9562|188' target='_blank' style='color:#bbb'>view information</a>] This photograph shows the front of the computer cabinet. Visible is one of the PCs that operate the system, a KVM switch, power strips on the right wall, and the signal conditioners at the top of the cabinet.<br>[<a href='imagepop.cfm?id=9562|190' target='_blank' style='color:#bbb'>view information</a>]

Research Question

Downstream of the Glines Canyon and Elwha Dams on the Elwha River, a series of bedload impact sensors are being installed across the river. Previous research shed light on what type of sensor best fits this application and how to infer bedload from the sensors. This research was carried out in a lab setting using a prototype using three plates, each with a sensor attached. Our primary research question is:

* How do we sample, process, and store the tremendous volume of continuous data being captured by the bedload impact sensors?

This is a complex process, involving the determination of sample frequency and duration from 73 total sensors, 46 geophones, and 27 accelerometers. This research seeks to build on previous findings at the St. Anthony Falls Laboratory.

Need and Benefit

In the short term (2 to 4 years following dam deconstruction) the bedload impact sensors will provide valuable information regarding the transport of coarse sediment from Lake Mills and Lake Aldwell to downstream reaches of the Elwha River. Coarse sediment will make the greatest contribution to changes in bed topography and channel morphology, which has implications for safe channel capacity regarding the levee height and future channel alignment. An adaptive management program will be utilized during dam deconstruction, which is scheduled to take place over a 2 to 3 year period. Measured bedload data will provide valuable feedback as to how to proceed with the deconstruction schedule. Additionally, measured bedload transport will be compared to that predicted with sediment modeling.

In the longer term, bedload data will provide useful information for continued sediment research. This is particularly significant for those developing surrogate methods for bedload measurement. Other Federal agencies and universities have been encouraged to take advantage of the conditions at this site, which will be measured bedload and dependable transport of coarse sediment that is decoupled from the hydrograph during the first few years following dam deconstruction. One National Science Foundation (NSF) proposal has already been submitted for sediment research at this site.

Contributing Partners

Contact the Principal Investigator for information about partners.

Research Products

Bureau of Reclamation Review

The following documents were reviewed by experts in fields relating to this project's study and findings. The results were determined to be achieved using valid means.

Continuous Surrogate Bedload Measurement on the Elwha River Following Dam Removal (final, PDF, 373KB)
By Robert Hilldale
Publication completed on June 10, 2011

The Bureau of Reclamation, in cooperation with the National Park
Service, is currently installing a series of bedload impact sensors to continuously monitor the bedload movement following dam removal. The use of a surrogate method of sediment transport measurement is an attempt to supplement classic physical sampling of bedload. The surrogate methods to be used on the Elwha River are a result of research performed jointly by Reclamation and the National Center for Earth-Surface Dynamics.

Laboratory Research and Development of Bedload Impact-Plate Sensors (final, PDF, 459KB)
By Robert Hilldale
Publication completed on June 10, 2011

Here we report on an effort to develop a technology for continuous monitoring of bedload transport in rivers that utilizes advanced technologies for measuring sound and vibrations generated by impacts of moving gravel on a steel plate mounted in the bed of a river. The premise of the technology assumes that the frequency of vibration or sound is correlated with the mean size of particles in transport and the intensity of the sound (volume) is correlated with flux rate.

The following documents were not reviewed. Statements made in these documents are those of the authors. The findings have not been verified.

Registering Bed Load Impacts on the Riverbed for Surrogate Bed Load Measurement (final, PDF, 427KB)
By Robert C. Hilldale (PI)
Publication completed on September 30, 2016

This bulletin summarizes the research results and potential application to Reclamation's mission.

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Last Updated: 6/22/20