Figure 56. Molded concrete bank simulating natural conditions 

 (Courtesy of Mr. Harlan Glenn). 



In rivers, natural lakes and manmade reservoirs, bottom depths must often be accepted as 

 they are, sometimes well below a higher level indicated to be adequate by navigation 

 criteria. Then, less conventional anchorages must be devised for floating systems, and 

 floating wave baffles may be needed. In rivers and off-river basins where sediment 

 deposition becomes troublesome, initial project depths may have to be increased to allow 

 for bottom buildup between periodic maintenance dredging activities. Also, during initial 

 planning, consideration must be given to the interference problems of later dredging. Fixed 

 structures must be kept to a minimum in areas where accretion is anticipated. Where 

 possible, provision should be made for periodic removal of shoals by means of land-based 

 equipment operating from strategically placed moles or platforms. 



c. Interior Wave Barriers. Within a small-craft harbor, troublesome waves are often 

 generated by boat wakes (Sorensen, 1973) from a busy fairway or strong winds blowing 

 from a long interior watercourse. The best way to keep these waves out of a berthing area is 

 to place a solid sheet barrier between the source and the berths (Fig. 57). Where a solid 

 barrier may prevent the necessary water circulation needed for water quality control, a 

 baffle made of alternating panels on either side of a pier framework, may be a better barrier 

 (Fig. 58). A single diaphragm with windows will seldom give satisfactory results; too much 



106 



