This raster layer set contains the maximum bottom shear stress based on maximum tidal current speed in the Massachusetts Ocean Partnership (MOP) planning area (and extended rectangular region ~ 6 nautical miles from the southern planning border) which was calculated as the sum of the M2 and S2 tidal components in the ADCIRC VDatum model. The maximum spring tide velocity is estimated from the M2 and the S2 tidal frequencies which are the two largest components of the tidal variability. The data product is therefore the estimated fortnightly (spring tide) maximum velocity. The maximum spring tide depth-averaged velocity was, then, utilized to estimate maximum bottom shear stress following the method described in Wilcock (1996, Water Resource Research). The grain size data from USGS USseabed program (http://coastalmap.marine.usgs.gov/regional/contusa/eastcoast/gome/capecod/data.html) were used for the bottom roughness data. The ocean currents, and thus bottom shear stress, at any instant, will never appear as they do in the figure. This is an estimate of the maximum that each location will experience over 14 days. The estimated maximum is exported from Matlab and read into ArcGIS as a point file with location and bottom shear stress data. The value at each point in the 250 meter grid is taken from the nearest point in the triangular ADCIRC model grid nodes. Data were produced for the Massachusetts Ocean Partnership planning grid and does not extend to the entire northeast. This data set was developed to aid in coastal development and navigation. The data provides the maximum bottom shear stress based on maximum tidal currents experienced during a tidal cycle. This layer is presented in the WGS84 coordinate system for web display purposes. Downloadable data are provided in native coordinate system or projection.
