Optimizing measurements of sediment transport in the intertidal zone

Abstract

The intertidal beach is very dynamic and is characterized by high sediment transport rates which may result in large topographic changes. Measuring techniques are well developed for both sediment transport and beach topography but the quantification of transport remains difficult. This paper provides an in-depth review of studies that cross-checked sediment transport measured underwater to transport derived from topographic change and/or predictive formulas to optimize future measuring campaigns in the intertidal zone. Based on these studies it is strongly recommended to measure sediment transport at multiple locations in the intertidal zone, although it is recognized that this is costly. When the suspended sediment is mixed and vertically stratified, it should be gauged over the entire water column. Acoustic backscatter intensity can be used for this purpose but needs to be corrected for grain size and turbulence. When cross-checking measured sediment transport rates with beach volume changes topographic profiles may not be sufficient. Instead, laser scanning of the beach is recommended. Additionally, valuable insights can be obtained from continuously measuring the beach topography. When beach topography is only measured during low tide, wind-driven transport should be taken into account during energetic conditions. It is deemed necessary to improve sensors to measure bed load transport and suspended sediment transport close to the bed and to further improve formulas to predict sediment transport. With the suggestions given in this paper it is encouraged to perform field investigations of sediment transport in the intertidal zone to improve our knowledge of the intertidal beach morphodynamics.

PREFERENSI TIPE SUBSTRAT DAN KEPADATAN POPULASI Ophiomastix annulosa (Muller & Troschel, 1842) DI EKOSISTEM INTERTIDAL PANTAI BILIK TAMAN NASIONAL BALURAN

“…Ekosistem ini memiliki luas wilayah yang terbatas, namun faktor lingkungan pada ekosistem intertidal bervariasi dibandingkan ekosistem lainnya. Hal tersebut yang menyebabkan keanekaragaman organisme di daerah intertidal sangat tinggi (Brand et al, 2020). Spesies O. annulosa umumnya dapat ditemukan di ekosistem intertidal pada daerah yang tergenang air, dengan populasi spesies yang rendah (Setiawan et al, 2018).…”

Statistical characterization of erosion and sediment transport mechanics in shallow tidal environments. Part 2: suspended sediment dynamics

“…Owing to the complexity of the underlying processes and the interplay between physical and biological drivers, sediment dynamics in shallow tidal systems are rather entangled. Therefore, observation-based approaches have been widely adopted to investigate the suspended sediment concentration (hereafter SSC), using either in situ point measurements (e.g., Wren et al, 2000;Gartner, 2004;Brand et al, 2020) or remote sensing and satellite image analysis (Miller & McKee, 2004;Ruhl et al, 2001;Volpe et al, 2011). However, both these techniques have some drawbacks.…”

Data-Driven Interpolation of Sea Surface Suspended Concentrations Derived from Ocean Colour Remote Sensing Data

“…The main source of sediment load comes from land, and the resuspension of sediments occurs under the effect of tidal currents and waves but also from fish trawling and maritime development, such as harbor sediment dredging and dumping, aggregate extraction, submarine cable installation, offshore wind farm exploitation, oil and gas activities, etc. Due to to those complex natural and anthropogenic interconnected forcings, sediment process characterization has to be improved [3][4][5]. In this context, numerical models lead to high uncertainty levels in assessing sediment fluxes from their continental source to the shelf edge [6][7][8].…”