The 1973 disposal operation had several obvious effects on the bottom within the disposal area. The disposal of approximately 1.5 million cubic yards of spoil produced a 2-12-foot average increase in bottom elevation. In the eastern portion of the disposal area a mound of spoil extended to approximately -28 feet. This mound contained a relatively high 30 concentration of coarse sand and because of the relatively shallow depths, it was exposed to relatively strong currents and wave turbulence. The grain sizes of spoil around the mound decreased and concentrations of fine and very fine sand increased from 50 to over 90 as water depths increased away from the center of the mound. Biologic activity, as indicated from cores, was directly related to grain size and water depth. Bioturbation biologic mixing of sediment increased from the coarse, shallow-water sediments towards the fine-grained, deep-water sediments. The stability of the sediment in the disposal area is closely related to water depth and physical energy.