ERDC/CHL CETN II-43
June 2000
measured at a particular data-collection station is spatially representative of transport at that
cross-shore position plus and minus some distance (approximately 17 m for the STORM
experiment). Additionally, the integrated estimate assumes that longshore transport at a
particular station is representative of transport over a particular period (approximately 4 hr for
the STORM experiments).
The form of spatial integration of the measured data is represented in the diagram in Figure 6.
From the notation in Figure 6, the integrated longshore sand transport, Q, can be represented as
N
∑ qi bi
Q=
(3)
i=1
where,
qi = vertically integrated unit transport rate, units of mass/unit width/time
bi = width of representative bin associated with qi
b3
b5
b1
b2
b4
q5
q3
q4
q1
q2
Figure 6. Schematic for integrated longshore transport calculation
SUMMARY: Longshore sand transport can be estimated with reasonable accuracy if
measurements are made on the appropriate spatial and temporal scales and data are properly
processed to eliminate spurious signals and background concentration. In addition, the user must
have a reasonable understanding of the limitations of the instruments under the conditions where
they are employed. The methods outlined in this CETN offer one tested approach to measuring
longshore sand transport. The instruments and data collection system proved to be robust and
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