Optimizing measurements of sediment transport in the intertidal zone
In: Earth-Science Reviews. Elsevier: Amsterdam; Lausanne; London; New York; Oxford; Shannon. ISSN 0012-8252; e-ISSN 1872-6828, more
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| Author keywords |
In-situ measurements; Field investigations; Sediment transport; Morphodynamics; Beach topography |
| 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. |
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