Pathways and rates of near-bed sediment transport near Popponesset Beach,
MA ., were calculated using several distinct techniques. For the nearshore
platform, sand transport in the form of sand waves was determined from
vertical aerial photography spanning periods of four decades. In addition,
calculations based on theoretical and empirical equations for near-bed
sediment transport were made using field measurements of wind waves and tidal
currents. Net sediment transport to the southwest inferred from these two
techniques differed by about a factor of five. The higher net transport rate
predicted in the aerial photographic method is a result of lack of wave
measurements during storm conditions. Storm waves increase the net transport
through a local increase in bed shear stress. Net transport to the southwest
across the platform is between 700 and 3300 m3/yr.
Littoral sand transport along Popponesset Beach was calculated from one
month of directional wave measurements, extrapolated to a yearly value using
long-term meteorological observations. Littoral transport from these
calculations is 10,000 m3/yr to the northeast, opposite the sense of
alongshore transport in the shallow nearshore.
Patterns of shoreline change are discussed from a historical perspective,
and using the transport calculations discussed above. Several management
alternatives for coping with predicted shoreline change are presented for
consideration by the Town of Mashpee.Funding was provided by the Town of Mashpee, a Community Assistance
Grant was provided through the Coastal Zone Management Program, a
Sea Grant Program Grant NA80AA-D-00077(RB-40) and support from
ALCOA Foundation
