Sediment supply to beaches: cross-shore sand transport on the lower shoreface
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Sediment supply to beaches : cross-shore sand transport on the lower shoreface. / Aagaard, Troels.
I: Journal of Geophysical Research, Part F: Earth Surface, Bind 119, Nr. 4, 04.2014, s. 913-926.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Sediment supply to beaches
T2 - cross-shore sand transport on the lower shoreface
AU - Aagaard, Troels
PY - 2014/4
Y1 - 2014/4
N2 - Many beaches have been built by an onshore supply of sand from the shoreface, and future long-term coastal evolution critically depends on cross-shore sediment exchange between the upper and the lower shorefaces. Even so, cross-shore sediment supply remains poorly known in quantitative terms and this reduces confidence in predictions of long-term shoreline change. In this paper, field measurements of suspended sediment load and cross-shore transport on the lower shoreface are used to derive a model for sediment supply from the lower to the upper shoreface at large spatial and temporal scales. Data collection took place at five different field sites that exhibit a wide range of wave conditions and sediment characteristics. Data analysis shows that both suspended sediment load and cross-shore sediment transport scale with the grain-related mobility number which ranged up to ψ ≈ 1000 in the measurements while the effect of orbital velocity skewness is more limited. A 1 year long simulation of sediment transfers between the lower and the upper shorefaces on a natural beach compares well with transport rates estimated from long-term bar migration patterns and aeolian accretion on the same beach.
AB - Many beaches have been built by an onshore supply of sand from the shoreface, and future long-term coastal evolution critically depends on cross-shore sediment exchange between the upper and the lower shorefaces. Even so, cross-shore sediment supply remains poorly known in quantitative terms and this reduces confidence in predictions of long-term shoreline change. In this paper, field measurements of suspended sediment load and cross-shore transport on the lower shoreface are used to derive a model for sediment supply from the lower to the upper shoreface at large spatial and temporal scales. Data collection took place at five different field sites that exhibit a wide range of wave conditions and sediment characteristics. Data analysis shows that both suspended sediment load and cross-shore sediment transport scale with the grain-related mobility number which ranged up to ψ ≈ 1000 in the measurements while the effect of orbital velocity skewness is more limited. A 1 year long simulation of sediment transfers between the lower and the upper shorefaces on a natural beach compares well with transport rates estimated from long-term bar migration patterns and aeolian accretion on the same beach.
U2 - 10.1002/2013JF003041
DO - 10.1002/2013JF003041
M3 - Journal article
VL - 119
SP - 913
EP - 926
JO - Journal of Geophysical Research: Solid Earth
JF - Journal of Geophysical Research: Solid Earth
SN - 0148-0227
IS - 4
ER -
ID: 113179870