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PATTERSON-SIMMONS. MODEL STUDIES 



[Ch. 17 



velocity in Front River was effected by the tide gate in Back River 

 and the Hutchinson Island cut. (Fig. 8). 



Operation of this plan was such that the tide gate opened during 

 the flood-tide period and the flood tide entered Back River normally; 

 the gate closed at high-water slack; and, during the ebb-tide period, 



Fig. 8. Savannah Harbor model study; effect of tide gate in Back River. 



the Back River tidal prism above the gate emptied through the Hutch- 

 inson Island cut and thence through lower Front River, thereby in- 

 creasing ebb velocities in lower Front River to a large extent. Tests 

 of replacing the tide gate with a solid dam indicated that this method 

 would also effect large increases in velocity in lower Front River; how- 

 ever, with the solid dam instead of the tide gate, both flood and ebb 

 velocities in Front River were increased. By varying the location of 

 the tide gate or the solid dam in Back River, thus varying the portion 

 of the Back River tidal prism that would be added to Front River by 

 either of these plans, it was found that velocities in lower Front River 

 could be increased up to a maximum of 4 to 5 feet per second. It was 

 also found, however, from a study of the effects of the tide-gate and 



