Effect of river vegetation with timber piling on ship wave attenuation: Investigation by field survey and numerical modeling

Thuy, Nguyen Ba; Nandasena, N.A.K.; Dang, Vu Hai; Kim, Sooyoul; Hiền, Nguyễn Xuân; Hole, Lars Robert; Thai, Tran Hong

doi:10.1016/j.oceaneng.2016.11.004

Cited by 12 publications

(5 citation statements)

References 13 publications

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“…The quantification of C D , A t , α and related uncertainties for a mangrove forest are the focus of this investigation. Field studies have measured wave height attenuation through mangroves for wind waves, reporting wave height attenuation rates ranging 0.002-0.012 m −1 (Mazda et al, 1997a;Quartel et al, 2007;Bao, 2011;Horstman et al, 2014), boat wakes (La et al, 2015;Ismail et al, 2017;Thuy et al, 2017). Similar studies considering storm surge and tidal currents have shown that mangroves can build the substrate and mitigate inland flooding over larger spatial scales (Furukawa et al, 1997;Mazda et al, 1997b;Krauss et al, 2009;Montgomery et al, 2018).…”

Section: Previous Studies Of Wave Height Attenuation Through Emergent Vegetationmentioning

confidence: 99%

Prototype-Scale Physical Model of Wave Attenuation Through a Mangrove Forest of Moderate Cross-Shore Thickness: LiDAR-Based Characterization and Reynolds Scaling for Engineering With Nature

et al. 2022

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This study investigates the potential of a Rhizophora mangrove forest of moderate cross-shore thickness to attenuate wave heights using an idealized prototype-scale physical model constructed in a 104 m long wave flume. An 18 m long cross-shore transect of an idealized red mangrove forest based on the trunk-prop root system was constructed in the flume. Two cases with forest densities of 0.75 and 0.375 stems/m2 and a third baseline case with no mangroves were considered. LiDAR was used to quantify the projected area per unit height and to estimate the effective diameter of the system. The methodology was accurate to within 2% of the known stem diameters and 10% of the known prop root diameters. Random and regular wave conditions seaward, throughout, and inland of the forest were measured to determine wave height decay rates and drag coefficients for relative water depths ranging 0.36 to 1.44. Wave height decay rates ranged 0.008–0.021 m–1 for the high-density cases and 0.004–0.010 m–1 for the low-density cases and were found to be a function of water depth. Doubling the forest density increased the decay rate by a factor two, consistent with previous studies for other types of emergent vegetation. Drag coefficients ranged 0.4–3.8, and were found to be dependent on the Reynolds number. Uncertainty in the estimates of the drag coefficient due to the measured projected area and measured wave attenuation was quantified and found to have average combined standard deviations of 0.58 and 0.56 for random and regular waves, respectively. Two previous reduced-scale studies of wave attenuation by mangroves compared well with the present study when their Reynolds numbers were re-scaled by λ3/2 where λ is the prototype-to-model geometric scale ratio. Using the combined data sets, an equation is proposed to estimate the drag coefficient for a Rhizophora mangrove forest: CD = 0.6 + 3e04/ReDBH with an uncertainty of 0.69 over the range 5e03 < ReDBH < 1.9e05, where ReDBH is based on the tree diameter at breast height. These results may improve engineering guidance for the use of mangroves and other emergent vegetation in coastal wave attenuation.

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Section: Previous Studies Of Wave Height Attenuation Through Emergent Vegetationmentioning

confidence: 99%

Prototype-Scale Physical Model of Wave Attenuation Through a Mangrove Forest of Moderate Cross-Shore Thickness: LiDAR-Based Characterization and Reynolds Scaling for Engineering With Nature

et al. 2022

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“…Emergent vegetation can provide protection to inland areas by affecting nearshore hydrodynamics and attenuating wave heights (e.g., NAS, 1977;McIvor et al, 2012), nearshore currents (e.g., Guannel et al, 2015), and storm surge heights (e.g., Zhang et al, 2012). As a result, emergent vegetation may reduce the risk of erosion (Coops et al, 1996) and flooding (e.g., Narayan et al, 2017Narayan et al, , 2019Dong et al, 2020), as well as wave forces and resulting damage to coastal structures (Kyprioti et al, 2021;Mitchell, 2021) and ecosystems, both in response to chronic (La et al, 2015;Thuy et al, 2017;Tomiczek et al, 2022) and acute hazards (Narayan et al, 2019;Tomiczek et al, 2020a;Menéndez et al, 2020). Additionally, emergent vegetation can dynamically respond to increases in sea level by trapping sediment and moving landward, unless it is squeezed by development or rapid rates of submergence (Borchert et al, 2018;Saintilan et al, 2020).…”

Section: Nnbf In the Context Of Traditional Structuresmentioning

confidence: 99%

State of the practice and engineering framework for using emergent vegetation in coastal infrastructure

Ostrow

Guannel

Biondi

et al. 2022

Front. Built Environ.

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Natural and Nature-Based Features (NNBF) are promoted as alternatives to structural flood protection measures. Progress has been made in understanding the physics and engineering of these systems; however, engineering, ecological, and social barriers to implementation remain. This paper identifies these barriers using the results of a literature review and summary of expert opinion; contrasts the state of the practice of NNBF with traditional structures; and details the main engineering challenges to NNBF implementation, including the uncertainty in current calculation techniques and lack of engineering design guidelines. We suggest that, emergent vegetation systems can be designed with the current body of information, and an example framework is proposed for assessing these systems for their wave attenuation performance. The framework is discussed in the context of risk, and future research priorities are presented.

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“…Ship induced wave analysis review shows that the waves are affected both by the ship characteristics including hull form, speed, load condition and draft and by environmental factors such as water depth, distance to banks, currents, tidal movement [9] and Civil Engineering Research Journal even vegetation [10]. In 1972 [11] applied a wave pattern analysis in order to suggest form improvement of the ship.…”

Section: Previous Studiesmentioning

confidence: 99%

Experimental Study of the Impact of Drift, Depth, and Lateral Restrictions on Inland Ship-Induced Waves under Small and Moderate Ship Speeds

2021

CERJ

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The study of ship-induced waves is essential to prevent bank erosion and optimize the ship's maneuverability. Inland ship-induced waves are in general affected by many factors divided into ship related parameters (form, draft, speed, drift, and navigation environment parameters (depth, distance to banks, and offset of the sailing line from the channel middle). Based on a set of towing tank experiments, this article depicts the effects of a number of these parameters on inland ship generated waves. To account for real navigation conditions, the ship speed is chosen so as to comply with the regular range of inland navigation speed which is close enough from the maximum allowable speed supported by the experimental setup. To study the effect of ship form, the experiment was carried out on a containership, a pusher-barge and a pusher-two barges. The study is achieved for two different ship's draft (T =0.1 m and T=0.04 m) and repeated for different configurations of water depth (h between 0.24 m and 0.12 m). The lateral confinement is studied by varying the channel width (W=2.88 m, 1.44 m and 0.72 m). Special attention is paid to the study of a restricted waterway combining both depth and lateral confinement. Besides, to identify the influence of drift, three drift angles were imposed (between 0 and 5°). Finally, the influence of the eccentricity is identified through varying the offset distance (offset = 0.44 m and 0.55 m). The ship wave maximum amplitude is validated by comparison to literature.

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Effect of river vegetation with timber piling on ship wave attenuation: Investigation by field survey and numerical modeling

Cited by 12 publications

References 13 publications

Prototype-Scale Physical Model of Wave Attenuation Through a Mangrove Forest of Moderate Cross-Shore Thickness: LiDAR-Based Characterization and Reynolds Scaling for Engineering With Nature

Prototype-Scale Physical Model of Wave Attenuation Through a Mangrove Forest of Moderate Cross-Shore Thickness: LiDAR-Based Characterization and Reynolds Scaling for Engineering With Nature

State of the practice and engineering framework for using emergent vegetation in coastal infrastructure

Experimental Study of the Impact of Drift, Depth, and Lateral Restrictions on Inland Ship-Induced Waves under Small and Moderate Ship Speeds

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