HR: 0800h
AN: H51I-0892    [Abstracts]
TI: Measurement of Large-Scale Sediment Transport Dynamics Using Multibeam Sonar
AU: * Simmons, S M
EM: s.m.simmons@leeds.ac.uk
AF: Institute of Geological Sciences, School of Earth and Environment, University of Leeds, Woodhouse Lane, Leeds, LS29JT, United Kingdom
AU: Parsons, D R
EM: parsons@earth.leeds.ac.uk
AF: Institute of Geological Sciences, School of Earth and Environment, University of Leeds, Woodhouse Lane, Leeds, LS29JT, United Kingdom
AU: Best, J L
EM: jimbest@uiuc.edu
AF: Departments of Geology and Geography and Ven Te Chow Hydrosystems Laboratory, University of Illinois at Urbana-Champaign, 1301 W. Green St., Urbana, IL 61801, United States
AU: Malzone, C
EM: cmalzone@reson.com
AF: Research Applications Manager, RESON Inc., 100 Lopez Rd, Goleta, CA 93117, United States
AU: Keevil, G
EM: g.keevil@see.leeds.ac.uk
AF: Institute of Geological Sciences, School of Earth and Environment, University of Leeds, Woodhouse Lane, Leeds, LS29JT, United Kingdom
AB: Multibeam Echo-Sounder (MBES) sonar systems have developed rapidly over recent decades and are now routinely deployed to provide high-resolution object detection and bathymetric surveying in a range of aquatic environments, from the deep-sea to lakes and rivers. MBES systems were developed for bottom-detection and measurement of bed morphology, and have previously discarded the received acoustic back-scatter from the water column after the bottom-detection algorithms have been performed. However, modern data handling and storage technologies have facilitated the logging of this large quantity of acoustic intensity and phase information, and commercial MBES systems are now available that provide this capability. This paper develops a novel methodology to exploit this logging capability to quantify the concentration and dynamics of suspended sediment within the water column. This development provides a multi-purpose tool for the holistic surveying of sediment transport by imaging suspended sediment concentration, associated coherent flow structures and providing concurrent high-resolution bathymetry. This paper presents methods of data analysis and results obtained from deployment of the RESON SeaBat 8125 and 7125 MBES systems in the field and during testing in a controlled environment. The field results were obtained from sites on the Paraná river, Argentina, with the aim of examining the dynamics of suspended sediment transport over dune bedforms and in the region of flow mixing between large rivers of significantly different suspended sediment concentration. Controlled testing was performed in a former ship dry-dock by creating flows density currents of known suspended sediment concentration with different types and mixes of sediment. The results demonstrate the capability of the RESON MBES systems to successfully resolve the contrast in suspended sediment concentration, and hence the spatio-temporal monitoring of the associated coherent flow structures. The results demonstrate the ability of MBES systems to obtain large sets of data across a two-dimensional swath: this enables the real-time monitoring of suspended sediment transport and related flow processes on a scale previously unrealisable with single-beam acoustic back-scatter systems.
DE: 1862 Sediment transport (4558)
DE: 4558 Sediment transport (1862)
SC: Hydrology [H]
MN: 2007 Fall Meeting