I. SUMMARY - INTRODUCTION 



In late December 1948, the Freeport Sulphur Company requested 

 the writer to undertake construction of an hydraulic model of the 

 Barataria Bay area in which their Lake Grande Ecaille, Louisiana, 

 mine is located (see frontispiece adapted from Chart 1273 U.S.C.iSc 

 G.S.)' In this area, roughly 25 miles square, the characteristic 

 depth of water is about three feet, necessitating either a very 

 large model or a highly distorted smaller model. It was decided 

 to make the model eight feet square, and employ a horizontal scale 

 of 1/20,000 and a vertical scale of l/l92j that is, employ a ver- 

 tical exaggeration of 1/104. The model was built and operated on 

 the property of the Woods Hole Oceanographic Institution in Woods 

 Hole, Massachusetts, 



The model was constructed on a strong bed of 2 x 12-inch fir 

 timbers (fig. 1) arranged to form a tight network of triangular 

 voids. The framework was then covered with 3/4 inch marine ply- 

 wood in steps (fig. 2) so cut that the treads had the shape of the 

 intervals between successive 12-foot contours on the bottom topog- 

 raphy in the prototype (fig, 3). This "staircase" was boxed in by 

 a heavy combing, caulked, (fig, 4) and covered with a lath of hard- 

 ware cloth (fig, 5). Over this a 4- inch thickness (3/4 ton) of 



Hydrocal B-11 (precision pattern-maker's CaSO, plaster) was cut as 



4 



a monolith in which the intricate modeling of the bays and islands 

 could be cut with rotary tools. The layout of the land and islands 



