west of Cleveland, Ohio, and 21 miles east o£ Sandusky, Ohio (Fig. 4-20). 

 The harbor includes the lower 3,600 feet of the Vermilion River, numerous 

 artificial lagoons, and a channel of approach from the lake. Local inter- 

 ests requested improvements to Vermilion Harbor that included (a) con- 

 struction of protective structures to provide a safe entrance to the har- 

 bor under moderate to fresh gale conditions, and (b) dredging of the river 

 channel above the existing Federal project limit to provide adequate depths 

 for navigation. The entrance to Vermilion Harbor is exposed in varying 

 degrees to storms generating waves from directions ranging clockwise from 

 west to northeast. The storm waves break in the relatively shallow water 

 inside and immediately outside the entrance piers, making navigation diffi- 

 cult and dangerous during moderate storms and preventing use of the harbor 

 as a harbor of refuge. 



(f) Purpose of Model Study . The model study was conducted 

 to (a) determine the extent of wave action in the harbor for existing con- 

 ditions and after installation of the proposed revisions, (b) test and 

 develop other remedial plans for alleviation of undesirable wave action 



at the harbor entrance and in the channel approaching the lagoons, and 

 (c) determine whether modifications could be made to the proposed plans 

 that would result in significant reduction in construction costs and 

 still provide adequate protection from wave action in the problem area. 



(g) The Model . The Vermilion Harbor model was designed in 

 accordance with Froude's law and was constructed geometrically similar 

 to the prototype at a linear scale of 1:75. The model, molded in cement 

 mortar, reproduced approximately 1 mile of the Lake Erie shoreline, the 

 harbor and lagoons to a point about 3,000 feet upstream in the Vermilion 

 River, and sufficient underwater contoured area to permit generation of 

 waves and wave-front patterns from all significant directions of wave 

 approach to the harbor. Vertical control in model construction and 

 operation was based on the low water datum for Lake Erie, which is 568.6 

 feet above mean water level at Father Point, Quebec (International Great 

 Lakes Datum, 1955). Horizontal control was referenced to coordinates of 

 the State of Ohio Lambert Projection, North Zone, U.S. Geological Survey. 

 Lake bottom contours were reproduced to an approximate prototype depth of 

 22 feet. A sloped transition extended downward from the contoured area 

 to the wave generator pit, which was at an elevation of -60 feet. The 

 entire area of the model was about 8,800 square feet, representing nearly 

 1.8 square miles in the prototype (Fig. 4-20). Model waves were generated 

 to scale by a bulkhead-type wave generator 52 feet in length. The waves 

 were produced by the displacement of water incident to the horizontal 

 periodic motion of the vertical bulkhead. The bulkhead speed and dis- 

 placement were infinitely variable within sufficient ranges to generate 

 waves of the periods and heights foimd in Lake Erie when reduced by the 

 length and time scales of the model. The wave generator was also mounted 

 on retractable casters that enabled the generator to be positioned to 

 propagate waves from the required directions. Wave heights in the model 

 were measured by electrical, printed-circuit staff gages and were recorded 

 electrically with a multichannel oscillograph. Photography was also used 

 to record comparative wave patterns that were obtained for individual test 

 conditions. 



254 



