Mobile Bay Model Study. Report 2. Effects of Enlarged Navigation Channel on Tides,Currents, Salinities,and Dye Dispersion,Mobile Bay,Alabama;Hydraulic Model Investigation.

摘要

This report is the second in a series of reports on the resutls of model tests on the Mobile Bay model. Report 1 covers the verification and effects of porposed Theodore Ship Channel and Disposal Areas on Tides, currents, salinities, and dye dispersion. Model tests in this report (Report 2) were chiefly designed to determine the impact of widening and deepening of the navigation channels and the accompanying dredged material disposal islands on tides, currents, salinities, and dye-dispersion patterns in Mobile Bay. The test results consist of comparable measurements of tide heights, current velocities, salinities, and dye-dispersion patterns for existing and proposed conditions. There was very little change in the tide heights in the bay for any plan. In general, for all plans an increase in maximum velocity occurred at stations in the low-velocity regions (the central region of the channel) and essentially, no change or a slight reduction in maximum velocity occurred at stations in the high-velocity regions (the upper and lower reaches). Enlargement of the channel seemed to be the dominant cause of salinity changes in the bay. All the plans generally raised the average salinity of the upper (north) bay and lowered the average salinity in the lower (south) bay. No plan maintained status quo (change at 0.5 ppt or less) in all four critical oyster-bed areas for area-average salinity or average bottom salinity. (Author)