5.73 SITING 



The proper siting and spacing of jetties for the improvement of a 

 coastal inlet are important. Careful study, including model studies in 

 some cases, must be given to the following hydraulic, navigation, control 

 structure, sedimentation, and maintenance considerations: 



a. Hydraulic Factors of Existing Inlet . 



(1) The tidal prism and cross-section of the gorge in the 

 natural state; 



(2) Historical changes in inlet position and dimensions (i.e., 

 length, width, and cross-section area of the inlet throat); 



(3) Range and time relationship (lag) of tide inside and out- 

 side the inlet; 



(4) Influence of storm surge or wind setup on the inlet; 



(5) Influences of the inlet on tidal prism of the estuary and 

 effects of fresh water inflow on estuary; 



(6) Influence of other inlets on the estuary; and 



(7) Tidal and wind-induced currents in the inlet. 



b. Hydraulic Factors of Proposed Improved Inlet . 



(1) Dimensions of inlet (length, width and cross-section area); 



(2) Effects of inlet improvements on currents in the inlet, 

 and on the tidal prism, salinity in the estuary, and on other inlets into 

 the estuary; 



(3) Effects of waves passing through the inlet; and 



(4) Interaction of the Hydraulic Factors (item b.) on Naviga- 

 tion and Control Structure Factors, (item c. and d.)- 



c. Navigation Factors of the Proposed Improved Inlet . 



(1) Effects of wind, waves, tides and currents on navigation 

 channel; 



(2) Alignment of channel with respect to predominant wave 

 direction and natural channel of unimproved inlet; 



(3) Effects of channel on tide, tidal prism and storm surge 

 of the estuary; 



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