Wave attenuation potential, sediment properties and mangrove growth dynamics data over Guyana's intertidal mudflats: assessing the potential of mangrove restoration works

Abstract

Abstract. Coastal mangroves, thriving at the interface between land and sea, provide robust flood risk reduction. Projected increases in the frequency and magnitude of climate impact drivers such as sea level rise and wind and wave climatology reinforce the need to optimize the design and functionality of coastal protection works to increase resilience. Doing so effectively requires a sound understanding of the local coastal system. However, data availability particularly at muddy coasts remains a pronounced problem. As such, this paper captures a unique dataset for the Guyana coastline and focuses on relations between vegetation (mangrove) density, wave attenuation rates and sediment characteristics. These processes were studied along a cross-shore transect with mangroves fringing the coastline of Guyana. The data are publicly available at the 4TU Centre for Research Data (4TU.ResearchData) via https://doi.org/10.4121/c.5715269 (Best et al., 2022) where the collection Advancing Resilience Measures for Vegetated Coastline (ARM4VEG), Guyana, comprises of six key datasets. Suspended sediment concentrations typically exceeded 1 g L−1 with a maximum of 60 g L−1, implying that we measured merely fluid-mud conditions across a 1 m depth. Time series of wind waves and fluid-mud density variations, recorded simultaneously with tide elevation and suspended sediment data, indicate that wave–fluid-mud interactions in the nearshore may be largely responsible for the accumulation of fine, muddy sediment along the coast. Sediment properties reveal a consolidated underlying bed layer. Vegetation coverage densities in the Avicennia-dominated forest were determined across the vertical with maximum values over the first 20 cm from the bed due to the roots and pneumatophores. Generalized total wave attenuation rates in the forest and along the mudflat were between 0.002–0.0032 m−1 and 0.0003–0.0004 m−1 respectively. Both the mangroves and the mudflats have a high wave-damping capacity. The wave attenuation in the mangroves is presumably dominated by energy losses due to vegetation drag, since wave attenuation due to bottom friction and viscous dissipation on the bare mudflats is significantly lower than wave dissipation inside the mangrove vegetation. Data collected corroborate the coastal defence function of mangroves by quantifying their contribution to wave attenuation and sediment trapping. The explicit linking of these properties to vegetation structure facilitates modelling studies investigating the mechanisms determining the coastal defence capacities of mangroves.

Integrated drag coefficient formula for estimating the wave attenuation capacity of Rhizophora sp. mangrove forests

“…In addition, a depth attenuation correction was conducted for frequencies ranging between 0.05 Hz and 0.43 Hz with a maximum correction factor of 5 to avoid overamplification of high-frequency signals, as described by Hu et al (2021). Finally, following the methods employed in other studies (e.g., Horstman et al, 2014;Best et al, 2022), a spectral analysis was conducted to obtain parameters, such as the significant wave height (H m0 ) and peak period (T p ). To ensure an adequate characterization of the wave height evolution in the mangrove forest, bursts in which all the sensors were inundated and H m0 exceeded 0.05 m at S1 were selected following Quartel et al (2007).…”

“…and Sonneratia sp., continuing with inland zones covered by Rhizophora sp., where roots, trunks and canopies are clearly identifiable. Best et al (2022) characterized a mangrove forest in a restored area of Guyana; Avicennia germinans was determined to be the dominant species, and Laguncularia racemosa was identified as the secondary species, along with sparse young trees of the Rhizophora mangle. The work of Best et al (2022) is one of the few field campaigns conducted in the Atlantic East Pacific (AEP) hemisphere.…”

“…Best et al (2022) characterized a mangrove forest in a restored area of Guyana; Avicennia germinans was determined to be the dominant species, and Laguncularia racemosa was identified as the secondary species, along with sparse young trees of the Rhizophora mangle. The work of Best et al (2022) is one of the few field campaigns conducted in the Atlantic East Pacific (AEP) hemisphere. The AEP zone covers distinct mangrove species, such as those from the Indo West Pacific (IWP) hemisphere, where most of the studies related to the wave attenuation ability of mangrove forests have been conducted.…”

Integrating SAR, Optical, and Machine Learning for Enhanced Coastal Mangrove Monitoring in Guyana

“…The three primary species of mangroves in Guyana are black mangroves (Avicennia germinans), red mangroves (Rhizophora mangle), and white mangroves (Laguncularia racemosa). Significant portions of the coast are productive monoculture stands of black mangroves [13,14], with secondary establishments of red mangrove usually within riverine environments. White mangroves vary in density along the coast [14].…”

“…Significant portions of the coast are productive monoculture stands of black mangroves [13,14], with secondary establishments of red mangrove usually within riverine environments. White mangroves vary in density along the coast [14]. Conocarpus erectus, popularly known as buttonwood, is considered a mangrove associate and usually grows at higher elevations within the mangrove ecosystem [15].…”