Characterizing the Composition of Sand and Mud Suspensions in Coastal and Estuarine Environments Using Combined Optical and Acoustic Measurements

Abstract

Quantifying and characterizing suspended sediment is essential to successful monitoring and management of estuaries and coastal environments. To quantify suspended sediment, optical and acoustic backscatter instruments are often used. Optical backscatter systems are more sensitive to mud particles (< 63µm) and flocs, whereas acoustic Accepted ArticleThis article is protected by copyright. All rights reserved.Confidential manuscript submitted to JGR-Oceans allows us to estimate whether there are more sand or mud particles floating through the water. The relationship between "seeing" and "hearing" can be described in a single number, the sediment composition index (SCI). We successfully tested this approach in laboratory experiments and then applied it to a site on the coast of the Netherlands. This approach gives us a new way to understand environments that are both sandy and muddy.

The Existence and Origin of Multiple Equilibria in Sand‐Mud Sediment Beds

“…We can simplify this to an overall constant mud concentration, regardless of the local mud content in the bed, whereas sand concentrations in the water column would decrease with increasing mud content in the bed. This is supported by the findings of Colosimo et al ( 2020) and Pearson et al (2021), combined with the fact that muddy beds mainly prevail in calm environments. In the next section we test this simplification of the deposition fluxes, for the Wadden Sea and for tidal basins in general, and we explore its relevance for the observed bimodality of p mud in the sediment bed.…”

“…(2020) and Pearson et al. (2021), combined with the fact that muddy beds mainly prevail in calm environments. In the next section we test this simplification of the deposition fluxes, for the Wadden Sea and for tidal basins in general, and we explore its relevance for the observed bimodality of p mud in the sediment bed.…”

“…In general, the settling velocity of sand is at least an order of magnitude larger than that of mud. Local sand concentrations mostly depend on the local hydrodynamic conditions, whereas local mud concentrations are often supply limited and (because of the small settling velocity) determined by conditions elsewhere or by the hydrodynamic history (Colosimo et al., 2020; Pearson et al., 2021). This typically results in high sand concentrations in the channels and low sand concentrations over the flats, while the suspended mud concentration is more uniformly distributed over the channels and the flats.…”

Understanding meso-scale processes at a mixed-energy tidal inlet: Ameland Inlet, the Netherlands – Implications for coastal maintenance

“…Conversely, mud in the distal samples was likely freshly deposited after Storm Sebastian, several days prior to their collection. Pearson et al (2021a) demonstrated that mud is regularly found in suspension over the sandy bed of the delta, even if it does not There is no trend in sorting with either ρ or θ, but 80% of samples are well sorted (0.35 < σ < 0.5 based on the Logarithmic Folk and Ward graphical measure (Blott and Pye, 2001). Moderately sorted samples (0.5 < σ < 1) tend to be located on the distal edge of the delta, while the most poorly sorted samples (σ > 1) are mainly found in the channels (Fig.…”

FlocARAZI: An In‐Situ, Image‐Based Profiling Instrument for Sizing Solid and Flocculated Suspended Sediment

“…The work of Fall et al (2021) is a helpful example for considering how to combine data from multiple instruments to better constrained poorly measured components of the floc fractal model. Additionally, Pearson et al (2021) recently developed a method to differentiate between components of the suspended mass associated with the sand and mud fraction by using a combination of sound and light scattering instruments. Comparison of data from such a system could help to better test and constrain the differentiated suspended mass from images making use of the sand and floc SVM segregation.…”