The measurement of sand transport in two inlets of Venice lagoon, Italy

Autor: Amos, C.L. (1), Villatoro, M. (1), Helsby, R. (1), Thompson, C.E.L. (1), Zaggia, L. (2), Umgiesser, G. (2), Venturini, V. (1), Are, D. (3), Sutherland, T.F., Mazzoldi, A. (2), Rizzetto, F. (2)
Rok vydání: 2010
Předmět:
Zdroj: Estuarine, coastal and shelf science
87 (2010): 225–236. doi:10.1016/j.ecss.2009.05.016
info:cnr-pdr/source/autori:Amos, C.L. (1), Villatoro, M. (1), Helsby, R. (1), Thompson, C.E.L. (1), Zaggia, L. (2), Umgiesser, G. (2), Venturini, V. (1), Are, D. (3), Sutherland, T.F., Mazzoldi, A. (2), Rizzetto, F. (2)/titolo:The measurement of sand transport in two inlets of Venice lagoon, Italy/doi:10.1016%2Fj.ecss.2009.05.016/rivista:Estuarine, coastal and shelf science (Print)/anno:2010/pagina_da:225/pagina_a:236/intervallo_pagine:225–236/volume:87
ISSN: 0272-7714
DOI: 10.1016/j.ecss.2009.05.016
Popis: Sand transport in Lido and Chioggia inlets was measured using modified Helley-Smith sand traps equipped with 60-micron nets. The traps had an efficiency of about 4% only but provided enough material for analysis. Very fine sand (0.07 < d < 0.11 mm) only was collected in the traps. Transport of sand was greatest in the bottom 10% of the water column and followed a Rouse profile. Sand extended to a height of about 4 m above the bed during peak flows corresponding to the estimated thickness of the boundary layer; and observed in synoptic ADCP profiles. The sand in the benthic boundary layer was largely inorganic (>95%); above this layer, organic content varied widely and was greatest near the surface. The movability number Ws=U* showed a linear relationship to dimensionless grain diameter (D*): (Ws/U*) = (D*/10); D*< 10. Sand concentration in suspension was simulated by a mean Rouse parameter of -2.01 +/- 0.66 (Lido inlet) and -0.82 +/- 0.27 (Chioggia inlet). The b parameter (Hill et al., 1988) was correlated with D* and movability number in the form: b = 2:07 - 2:03D* + 59(Ws=U*)^2 (r^2 = 0.42). Von Karman's constant was back-calculated from a Law of the Wall relationship as a test on the accuracy of U* estimates; a mean value of 0.37 +/- 0.1 (compared to the accepted value of 0.41) suggest U* was accurate to within 10%. The constant of proportionality (g = 3.54 x 10^-4) between reference concentration (Ca) and normalized excess bed shear stress was in line with the published literature.
Databáze: OpenAIRE
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