Salt marsh surface survives true‐to‐scale simulated storm surges

Abstract

A full-scale controlled experiment was conducted on an excavated and re-assembled coastal wetland surface, typical of floristically diverse northwest European saltmarsh. The experiment was undertaken with true-to-scale water depths and waves in a large wave flume, in order to assess the impact of storm surge conditions on marsh surface soils, initially with three different plant species and then when this marsh canopy had been mowed. The data presented suggests a high bio-geomorphological resilience of salt marshes to vertical sediment removal, with less than 0.6 cm average vertical lowering in response to a sequence of simulated storm surge conditions. Both organic matter content and plant species exerted an important influence on both the variability and degree of soil surface stability, with surfaces covered by a flattened canopy of the salt marsh grass Puccinellia experiencing a lower and less variable elevation loss than those characterized by Elymus or Atriplex that exhibited considerable physical damage through stem folding and breakage.

Quantifying Bed Level Change at the Transition of Tidal Flat and Salt Marsh: Can We Understand the Lateral Location of the Marsh Edge?

“…In contrast to the highly variable bed levels on the tidal flats, the bed levels remained much more constant on the marshes (Figure ). Experimental results by Spencer et al () also showed highly stable bed levels on a marsh during high hydrodynamic energy conditions. Location 2E.…”

Role of eelgrass on bed‐load transport and sediment resuspension under oscillatory flow

“…Several studies indicate that coastal vegetation may reduce erosion both on bed load form and resuspension (Ward et al ; Christianen et al ; Spencer et al ), which is normally attributed to a reduction of the hydrodynamics within the canopy (Bos et al ; Infantes et al ; Möller et al ). The reduction of the sediment erosion is important to maintain the water clarity, necessary for seagrass development (Dennison ; Duarte ), and to retain the sediment in coastal areas (Christianen et al ; Ganthy et al ; Spencer et al ). Whereas a lot of work has focused on the aboveground plant‐flow interactions, the effect of belowground biomass (rhizomes and roots) on the sediment stabilization is still relatively poorly studied.…”

Biogeomorphology: diverse, integrative and useful

“…In their discussion of intertidal mangrove forests, Balke and Friess (2016) offer a compelling argument for the application of geomorphological knowledge for successful restoration and conservation, and for improving coastal resilience against extreme storms in the tropics. Similarly, Spencer et al (2016) demonstrate how European saltmarsh communities show high resilience with respect to sediment erosion under true-to-scale simulated storm surge conditions. Their study further demonstrates how species' morphological traits moderate the nature and efficacy of biogeomorphological processes.…”