Geology topics

Jonathan AuBuchon

Publications and source records attributed to Jonathan AuBuchon.

4 recordsLinked to original sources

USGS2023

Acoustic measurements on a shallow, sand-bed river: A case study from the Rio Grande

The Middle Rio Grande (MRG) is a dynamic and complex fluvial system where flow and sediment transported from the Upper Rio Grande and MRG tributaries influence the form of the river. How sediment is transported through the MRG is an important planning question as it addresses a wide range of concerns including flood control and river rehabilitation, thus continuous sediment measurements are needed to develop accurate sediment budgets. Sediment measurement techniques have continued to improve and the advent of sediment surrogates, such as acoustic technology, have proven to be effective options at obtaining more complete spatial and temporal sediment data in larger fluvial systems. Measurements of sediment in shallow, sand bed rivers, like the Rio Grande, are more difficult because of the changing channel morphology and often limited water depth in which to install instrumentation. During the 2019 spring snow-melt runoff season two acoustic techniques were employed on the Rio Grande to evaluate sediment movement. Sediment movement near the bed was calculated by the Integrated Section Surface Difference Over Time version 2 (ISSDOTv2) using swath data collected from a multi-beam sonar. Measurements were made adjacent to U.S. Geological Survey (USGS) gaging stations where near simultaneous measurements were made by the USGS for streamflow, suspended-sediment concentration and gradation, and bed-material gradations. These measurements were conducted at two locations on the Rio Grande, one of the locations was co-located with two side-profiling suspended-sediment acoustic Doppler profilers that had been installed in the fall of 2016. Both a 1 MegaHertz (MHz) and 2 MHz side-profiling suspended-sediment acoustic Doppler instrument were installed on a fixed platform that was co-located with a USGS sediment gage. The ISSDOTv2 method using multi-beam sonar and the side-profiling acoustic Doppler profilers proved successful in collecting sediment information and compared well with the more traditional sediment measurements, while providing insight into the sediment transport on the MRG because of the increase in spatial and temporal resolution. Overall, there are some limitations of these acoustical techniques, but the additional information gleaned is beneficial in understanding sediment transport in a shallow, sand-bed river, such as the Rio Grande.

New Mexico↗

USGS2022

Field testing a high-frequency acoustic attenuation system for measuring fine suspended sediments and algal movements

Acoustic measurements of suspended sediment have the potential to allow remote, autonomous monitoring of sediment movements at much higher temporal resolution than traditional manual sampling methods. Although suspended sands present a challenging measurement problem due to their logarithmic distribution with depth, fine clay sediments are distributed evenly throughout a stream cross section, making them amenable to point measurements. In order to improve measurement capabilities for fine sediments in stream channels, The National Center for Physical Acoustics at The University of Mississippi has developed a remote, autonomous acoustic system to monitor fine sediments transported in streams. The system was tested on the Middle Rio Grande near San Acacia, New Mexico, and in Goodwin Creek in Panola County, Mississippi. The acoustic instruments were compared to sediment concentrations from physical samples in both deployments. Diurnal patterns were found in the acoustic signals from the Middle Rio Grande, and a follow up experiment at The University of Mississippi Biological Field Station was used to investigate the potential effects of algal biomass on acoustic attenuation measurements. The results showed diurnal patterns in attenuation were associated with patterns in light, temperature, and dissolved oxygen. These results combined with information from the literature indicate diel movement of algal colonies in the water column of some water bodies may interfere with high-frequency acoustic measurements in natural environments and that acoustic methods have the potential to allow ecological researchers to evaluate mass algal movements in the field. Results from Goodwin Creek demonstrate that the acoustic system is able to provide measurements of sediment concentration with high temporal resolution that track well with expected sediment transport patterns in response to discharge hydrographs.

Applied Acoustics↗

USGS2021

Risk-informed levee erosion countermeasure site selection and design in the Sacramento area part 1: Soil sampling, testing, and data processing

USACE partnered with the United States Department of Agriculture, Agricultural Research Service, United States Geological Survey, and Texas A&M University to evaluate the erodibility of the river banks and levees to inform probabilistic numerical simulations using the Bank Stability and Toe Erosion Model (BSTEM). This paper discusses the measurement of the intrinsic erosion and geotechnical properties of the soil for improved BSTEM results and is the first of two parts. Sampling and testing were conducted at select sites to obtain the soil stratigraphy and collect samples for estimation of engineering properties. Soil erodibility was measured using the Erosion Function Apparatus test, the Borehole Erosion Test, the Pocket Erodometer Test, and the mini-Jet Erosion Test. Critical evaluation of previously existing datasets and the collection of these new datasets helped to provide better definition of the range in erosion parameters for improved probabilistic erosion estimates using BSTEM for risk-informed levee erosion countermeasure site selection and design.

California↗

USGS2021

Risk-informed levee erosion countermeasure site selection and design in the Sacramento area part 2: Probabilistic numerical simulation of bank erosion

USACE partnered with the United States Department of Agriculture, Agricultural Research Service, United States Geological Survey, and Texas A&M University to evaluate the erodibility of the river banks and levees to inform probabilistic numerical simulations using the Bank Stability and Toe Erosion Model (BSTEM). This paper, the second of two parts, addresses processing the collected data to inform inputs for probabilistic bank erosion estimates in BSTEM. Measuring the intrinsic soil properties for BSTEM is discussed in part one. Soil critical shear stress and soil erodibility coefficients were calibrated by Unified Soil Classification soil type to observed erosion on the American River. Adjustments were made in the probability density functions for these parameters to reflect field-measured variability and carry forward the reduction in error achieved during calibration. The resulting calibrated values were tested at additional sites, validating the resulting critical shear stress and soil erodibility coefficient values and probability density functions for more robust probabilistic bank erosion estimates using BSTEM.

California↗