Hydrodynamic feedbacks of salt-marsh loss in shallow microtidal back-barrier systems

Finotello, Alvise; Tognin, Davide; Carniello, Luca; Ghinassi, Massimiliano; Bertuzzo, Enrico; D’Alpaos, Andrea

doi:10.1002/essoar.10511787.2

Cited by 4 publications

(11 citation statements)

References 96 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…-5-manuscript submitted to Water Resources Research Finotello et al, 2022). From the beginning of the fifteenth century, the main rivers (Brenta, Piave, and Sile) were gradually diverted in order to flow directly into the sea and prevent the lagoon from silting up, but this triggered a sediment starvation condition.…”

Section: Methodsmentioning

confidence: 99%

“…Later, during the last century, the inlets were provided with jetties and deep navigation channels were excavated to connect the inner harbour with the sea (L. D 'Alpaos, 2010;Sarretta et al, 2010). The jetties deeply changed the hydrodynamics at the inlets establishing an asymmetric hydrodynamic behaviour responsible for a net export of sediment toward the sea (Martini et al, 2004;Finotello et al, 2022), especially during severe storm events, which are responsible for the resuspension of large sediment volumes (Carniello et al, 2012). In general, these modifications heavily influenced sediment transport triggering strong erosion processes that were further aggravated by sea-level rise.…”

Section: Methodsmentioning

confidence: 99%

“…Moreover, repeated closures of storm-surge barriers designed to protect the city of Venice from flooding and known as Mo.S.E. system are expected to further exacerbate this morphological degradation by cutting off significant supplies of inorganic sediments brought in by intense storm-surge events (Tognin et al, 2022).…”

Section: Methodsmentioning

confidence: 99%

“…The three most ancient configurations (i.e. 1611, 1810, and 1901) were modeled by relying on historical maps, whereas the topographic surveys carried out by the Venice Water Authority (Magistrato alle Acque di Venezia) in 1932, 1970, and 2003 were used for the more recent ones (L. D 'Alpaos, 2010;Finotello et al, 2022). Due to some morphological modifications at the three inlets associated with the Mo.S.E.…”

Section: Methodsmentioning

confidence: 99%

“…

…”

mentioning

confidence: 99%

See 4 more Smart Citations

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

Tognin

D’Alpaos

et al. 2022

Preprint

View full text Add to dashboard Cite

A proper understanding of sediment transport dynamics, critically including resuspension and deposition processes of suspended sediments, is key to the morphodynamics of shallow tidal environments. Aiming to account for deposition mechanics in a synthetic theoretical framework introduced to model erosion dynamics (D'Alpaos et al., 2022), here we investigated suspended sediment dynamics. A complete spatial and temporal coverage of suspended sediment concentration (SSC) required to effectively characterize resuspension events is hardly available through observation alone, even combining point measurements and satellite images, but it can be retrieved by properly calibrated and tested numerical models. We analyzed one-year-long time series of SSC computed by a bi-dimensional, finite-element model in six historical configurations of the Venice Lagoon in the last four centuries. Following the peak over threshold theory, we statistically characterized suspended sediment dynamics by analyzing interarrival times, intensities and durations of overthreshold SSC events.Our results confirm that, as for erosion events, SSC can be modeled as a marked Poisson process in the intertidal flats for all the considered historical configurations of the Venice Lagoon because exponentially distributed random variables well describe interarrival times, intensity and duration of overthreshold events. Moreover, interarrival times, intensity and duration describing local erosion and overthreshold SSC events are highly related, although not identical because of the non-local dynamics of suspended sediment transport related to advection and dispersion processes.Owing to this statistical characterization of SSC events, it is possible to generate synthetic, yet realistic, time series of SSC for the long-term modeling of shallow tidal environments.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

“…

…”

mentioning

confidence: 99%

See 3 more Smart Citations

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

Tognin

D’Alpaos

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

Statistical characterization of erosion and sediment transport mechanics in shallow tidal environments. Part 1: erosion dynamics

D’Alpaos

Tognin

Tommasini

et al. 2022

Preprint

View full text Add to dashboard Cite

Wave-induced bottom shear stress is one of the leading processes that control sediment erosion dynamics in shallow tidal environments, because it is responsible for sediment resuspension and, jointly with tidal currents, for sediment reworking on tidal flats. Reliable descriptions of erosion events are foundational to effective frameworks relevant to the fate of tidal landscape evolution. However, the absence of long-term, measured time series of bottom shear stress (BSS) prevents a direct analysis of erosion dynamics. Here we adopted a fully-coupled, bi-dimensional numerical model to compute BSS generated by both tidal currents and wind waves in six historical configurations of the Venice Lagoon in the last four centuries. e one-year-long time series of the total BSS were analysed based on the peak over threshold theory to statistically characterize events that exceed a given erosion threshold and investigate the effects of morphological modifications on spatial and temporal erosion patterns. Our analysis suggests that erosion events can be modeled as a marked Poisson process in the intertidal flats for all the considered configurations of the Venice Lagoon, because interarrival times, durations and intensities of the over-threshold exceedances are well described by exponentially distributed random variables. Moreover, while the intensity and duration of over-threshold events are temporally correlated, almost no correlation exists between them and interarrival times. The resulting statistical characterization allows for a straightforward computation of morphological indicators, such as erosion work, and paves the way to a novel synthetic, yet reliable, approach for long-term morphodynamic modeling of tidal environments.

show abstract

Blue Carbon Assessment in the Salt Marshes of the Venice Lagoon: Dimensions, Variability and Influence of Storm‐Surge Regulation

Puppin,

Tognin,

Paccagnella

et al. 2024

Earth's Future

View full text Add to dashboard Cite

Salt marshes are intertidal coastal ecosystems shaped by complex feedbacks between hydrodynamic, morphological, and biological processes. These crucial yet endangered environments provide a diverse range of ecosystem services but are globally subjected to high anthropogenic pressures, while being severely exposed to climate change impacts. The importance of salt marshes as “blue carbon” sinks, deriving from their primary production coupled with rapid surface accretion, has been increasingly recognized within the framework of climate mitigation strategies. However, large uncertainties remain in salt marsh carbon stock and sequestration estimation. In order to provide further knowledge in salt marsh carbon assessment and investigate marsh carbon pool response to management actions, we analyzed organic matter content in salt marsh soils of the Venice Lagoon (Italy) from 60 sediment cores to the depth of 1 m and estimated organic carbon stock and accumulation rates in different areas. Organic carbon stocks and accumulation rates were highly variable in different marshes, being affected by organic and inorganic inputs and preservation conditions. Our estimates suggest that the studied marshes store 17,108 ± 5,757 tons of carbon per square kilometer in top 1‐m of soil and can accumulate 85 ± 25 tons of carbon per square kilometer per year. However, flood regulation may reduce the annual marsh CO2 sequestration potential by more than 30%. Our results contribute valuable information for regional carbon assessments, reinforcing the need for integrated coastal management policies to preserve the ecosystem services of coastal environments, and underscore the importance of considering local variability and methodological variations.

show abstract

Hydrodynamic feedbacks of salt-marsh loss in shallow microtidal back-barrier systems

Cited by 4 publications

References 96 publications

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

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

Statistical characterization of erosion and sediment transport mechanics in shallow tidal environments. Part 1: erosion dynamics

Blue Carbon Assessment in the Salt Marshes of the Venice Lagoon: Dimensions, Variability and Influence of Storm‐Surge Regulation

Contact Info

Product

Resources

About