distinctions, four inlet studies have been selected as examples which 

 conform to the requirements of the unique situation associated with each 

 inlet. Frequently, the inlet to be investigated is a component of a much 

 larger bay or estuary model and therefore is probably distorted in scale. 

 In other situations, the inlet may not presently exist as a prototype or 

 may not be allied with an existing model; the opportunity then occurs for 

 construction of an undistorted-scale model. The scales of movable-bed 

 models are, in general, distorted. 



The Shrewsbury Inlet model was selected as typical of fixed-bed, 

 undistorted-scale models. This model study required an investigation 

 of hydraulic phenomena in the vicinity of a proposed new inlet; there- 

 fore, the fixed-bed criterion prevailed. The size of the area to be 

 reproduced permitted model construction to an undistorted scale. 



A representative example of a fixed-bed, distorted-scale inlet model 

 was the study of the Galveston Bay entrance. Hydraulic characteristics 

 were required in this study to determine discharge coefficients to verify 

 the results of surge routings by analytical means. Steady-state flows 

 were established in the existing, comprehensive model of the Houston Ship 

 Channel. 



The Fire Island Inlet model study is a typical case where the primary 

 problem was littoral drift trapped in the inlet; thus, sand movement along 

 the beaches had to be simulated in the model. A distorted-scale, fixed- 

 bed model was first constructed and all proposed alternatives were tested 

 to determine their effects on hydraulic conditions in the inlet. After 

 completion of the hydraulic tests, the problem area of the model was con- 

 verted to a movable bed molded of sand. 



Other problems occurred at Galveston Bay and it became necessary to 

 study shoaling of the entrance channel. A movable-bed, distorted-scale 

 model was appropriate for this study, but an analysis of the forces avail- 

 able to transport sediment indicated the movable bed should be molded of 

 crushed coal. This study demonstrated the practicality of using material 

 other than sand as the transport medium when the scaled forces involved 

 dictated a size and density relationship as one which had to be of a manu- 

 factured variety. In this case, coal crushed to a desired size was 

 appropriate. 



a. New Inlet Construction and the Effects on Shoaling, Navigation 

 and Water Quality — Shrewsbury Inlet, New Jersey . 



(1) Project . Construction of a small boat channel across Sandy 

 Hook Peninsula to connect the Atlantic Ocean with Sandy Hook Bay. 



report. 



(2) References . McNair and Hill (1972); Section lll,6,h of this 



(3) Laboratory . WES. 



(4) Test Period. January to December 1969. 



48 



