3 . Siting. 



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

 coastal inlet are important. Careful study, which may include model studies 

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

 structure, sedimentation, and maintenance considerations: 



a. Hy draulic 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-sectional area of the inlet throat). 



(3) Range and time relationship (lag) of the tide inside and outside 

 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 freshwater inflow on estuary. 



(6) Influence of other inlets on the estuary. 



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



b. Hydr aulic Fac tors of Prop osed Improved Inlet ; 



(1) Dimensions of inlet (length, width, and cross-sectional 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. 



c . Navigation Factors of t he Proposed Imp ro ved Inlet ; 



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

 channel. 



(2) Alinement 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. 



(4) Determination of channel dimensions based on design vessel data 

 and number of traffic lanes. 



(5) Other navigation factors such as (a) relocation of navigation 

 channel to alternative site, (b) provision for future expansion of channel 

 dimensions, and (c) effects of harbor facilities and layout on channel 

 alinement. 



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