Wave Glider Monitoring of Sediment Transport and Dredge Plumes in a Shallow Marine Sandbank Environment

Abstract

As human pressure on the marine environment increases, safeguarding healthy and productive seas increasingly necessitates integrated, time- and cost-effective environmental monitoring. Employment of a Wave Glider proved very useful for the study of sediment transport in a shallow sandbank area in the Belgian part of the North Sea. During 22 days, data on surface and water-column currents and turbidity were recorded along 39 loops around an aggregate-extraction site. Correlation with wave and tidal-amplitude data allowed the quantification of current- and wave-induced advection and resuspension, important background information to assess dredging impacts. Important anomalies in suspended particulate matter concentrations in the water column suggested dredging-induced overflow of sediments in the near field (i.e., dynamic plume), and settling of finer-grained material in the far field (i.e., passive plume). Capturing the latter is a successful outcome to this experiment, since the location of dispersion and settling of a passive plume is highly dependent on the ruling hydro-meteorological conditions and thus difficult to predict. Deposition of the observed sediment plumes may cause habitat changes in the long-term.

Seafloor change detection using multibeam echosounder backscatter: case study on the Belgian part of the North Sea

“…To assess environmental impacts, a monitoring programme was setup combining multibeam recordings with seabed sampling, visual observations and water column measurements as well as hydrodynamic and sediment transport modelling . Sediment plumes arising from the marine aggregate extraction activities, and their deposition, were depicted in acoustic imagery (Van Lancker and Baeye 2015), and numerical modelling results showed that their deposits reach the gravel beds in the Habitat Directive Area up to the study site . The cumulative volume of marine aggregates extracted throughout the duration of the data time series is shown in Fig.…”

Current status and prospects of marine renewable energy applied in ocean robots

“…It was a great success for wave glider in the PacX game (from California to Australia), which has created a new world record for the longest distance traveled by an autonomous vehicle (12 872 km) and attracted the attention of experts around the world . By equipping with different sensors on wave glider, considerable research work has been carried out in the ocean biological monitoring, water measurement, marine ecological environment research, marine meteorology, etc. At present, the wave glider has been commercialized to serve a variety of scientific research, based on its reliability performance.…”

The Potential of Multibeam Sonars as 3D Turbidity and SPM Monitoring Tool in the North Sea

“…However, these datasets are restricted to the surface layer of the water column, whereby the penetration depth depends on the wavelength of the signal and the amount of sediment in suspension [29]. Within the water column, optical (LISST, OBS) and acoustic (ADCP) sensors are used to measure SPM in the BPNS in both stations [9,24,30,31] and transects [32,33]. However, coastal and near-shore areas, such as the BPNS, are dynamic environments where SPM patterns can exhibit fluctuations across all four dimensions of spacetime [9,10].…”