SHOFffl PROTECTION 



PLA1#IIKG Al^ID DESIGN 



PART I 

 FUNCTIONAl PLANI>IING 



INTRODUGTIOM 



lo Shore protection can be provided by thr-ee general methods: (a) off- 

 shore breakwaters, (b) protective beaches, axid (c) seawalls, revetments or 

 bulkheads c Offshore bre aktfjaters provide protection by intercepting waves 

 before they reach the shore. Protective beaches dissipate wave energy before 

 the waves reach an erodible upland and may be eirployed either alone or in con- 

 junction -tidth groinso Seawalls, revetnants and bulkheads are used to prevent 

 dajTi£i.ge to upland areas by inteiposing a wave resisting structur-e approx- 

 imately parallel to the shore line at a location landward of tlie low water 

 line. Sand dunes are a natural form of shore protection batureen the beach 

 and the uplande As such they should be preserved* They also provide a 

 reservoir of beach ma.terial xirhich helps reduce beach recession at td.mes of 

 excessive loss of beach material. 



2» In selecting the best iiBthod for remedying an erosion problem or 

 inproving tlie beach in a specific area, all methods believed capable of pro- 

 ducing the desired end result should be considered and conpared economicaliys 

 The effect of each method upon shores beyond the limits of the problem area 

 must be evaluated, in terms of public interest if the work is planned by a 

 governmental agency -and with a view to possible liabilitjr if the xrorks are 

 to be privately owned, 



PHYSICAL FACTORS APPEGTING FUNCTIONAL PL.Ai\iIgNG ,. 



3. The basic physical factoar'S which establish tlie criteria for 

 fimctional planning, in addition to characteristics of the shore itself in 

 the problem area, are; wind and wave action^ changes in water level) aiid 

 littoral drift. Though ice may be a major factor, especially on the Gi*eat 

 Lakes, it should primarily be considered in its structural aspects* 

 Functionally only the fact that ice may reduce xjave action at certain 

 locations need be consideredo 



WAVE ACTION 



lis Wave s_ in Deep Water . - The vertical distance between a trough of a 

 wave and the follox-ri.ng crest, called the wave height (H)| the tijue taken for 

 identical points on two successive crests ~('or troughs) to pass a point j knox-m 

 as the period (T)', and the distance betxreen identical points on successive 

 crests, called the wave length (L) axe the parameters used to define a wave's 



