STABILITY OF COASTAL INLETS

1. Introduction 1.1 Historical background 1.2 Origin of tidal inlets 2. Natural inlet regimen 2.1 General 2.2 How and why inlets shoal 3. Consideration of tidal hydraulics and stability of channels and inlets 3.1 Tidal hydraulics 3.2 Results of stability theories of empirical nature 3.2.1 Rivers and canals 3.2.2 Tidal inlets 3.3 Rational theories and results 3.3.1 Lane's theory on limiting tractive forces for stable channel design 3.3.2 Bretting's stable channel theory 3.3.3 Ning Chien's river studies 3.3.4 Straub's investigations on the effect of channel contraction works 3.3.5 Van Bendgedom's studies on the regime of tidal channels 3.3.6 "Nedeco" - Studies of the rivers niger and benue of Africa 3.3.7 Comparison between Bretting's and Van Bengedom's theories and actual conditions 3.4 Mathematical description of inlet stability 3.4.1 Stability of inlet gorge 3.4.2 Stability of inlet channels 4. Pertinent factors involved in inlet stability 4.1 The influence of the maximum flow Qm 4.2 The influence of the shape factor "beta" 4.3 The influence of the shear stress "tetra' 4.4 The influence of soil condition of the bottom or bed "B" 4.5 The influence of suspended sediment load , "c" 4.6 The influence of wave action. "Wa" 4.7 The influence of littoral drift, "M" 4.8 The influence of river discharge , "Qo" 4.9 The time history of the inlet , "t" 5. Analysis of actual inlet data 5.1 General 5.2 Presentation 5.2.1 Results based on shear stress analysis 5.2.2 Results of theoretical nature based on considerations of material transport and littoral drift 5.2.3 The influence of fresh-water flow 5.3 Comparison of determining stability shear stresses for tidal inlets 5.4 Comparison with Bretting's stable channel theory 5.5 Comparison with data from an estuary: The River Eems in Holland 5.5.1 Available information 5.5.2 Comparison between theoretical and observed values 5.6 Remarks on some results by Leopold and Maddock 5.7 The relative stability of a tidal inlet 5.7.1 Material transfer stability 5.7.2 Cross-section stabiltity 6. Design of tidal inlets 6.1 General 6.2 Definition of "Ideal Cross-section" of a tidal inlet in granular material 6.3 Design procedure for tidal inlet 6.3.1 Inlet gorge A, Tidal prism "ohm" and maximum discharge Qm 6.3.2 Geometrical shape of inlet channel 6.3.3 Design Shear stress 6.3.4 Practical approach 6.4 The Importance of model study 6.5 The non-scouring channel 6.6 Evaluation of "effeciency" of cross-section

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