Jb. Erdmann et al., ANALYSIS OF WIND-INDUCED AND SHIP-INDUCED SEDIMENT RESUSPENSION IN DULUTH-SUPERIOR HARBOR, Water resources bulletin, 30(6), 1994, pp. 1043-1053
Suspended solids and ammonium concentration profiles measured at five
locations in Duluth-Superior Harbor during July-October 1985 were anal
yzed to quantify wind and ship effects on sediment resuspension and re
sulting harbor water quality. Wind components from the SE quadrant cor
related strongly with depth-averaged suspended solids concentrations t
hat were unaffected by ship passage or thermal stratification. Winds f
rom that quadrant have the largest fetch in the harbor. The highest co
rrelation (r2 = 0.93) was with the 6-hour average of the ESE wind velo
city component. Multiple linear regression analysis of data from post-
ship passage concentration profiles yielded numerical estimates of set
tling velocities of 0.08 to 0.25 cm s-1, typical of ship-resuspended s
ediments, and vertical eddy diffusivities of 4 to 13 cm2 s-1. The resu
lts suggest that ambient vertical eddy diffusivities in the harbor are
less than 4 cm2 s-1 in the absence of ship passages and with winds le
ss than 5 m s-1 (10 knots).