(c) Seasonal Variations on Beach Profile . Beach recession 

 in winter and growth in summer can be estimated by site inspec- 

 tion and seasonal beach profile variation. The extent of 

 winter beach profile lowering will be a contributing factor 



in determining the type and extent of toe protection needed. 



(d) Water Level Range . Changes in water level on the revet- 

 ment can be caused by tides, storm surge, or seasonal water level 

 changes due to runoff (lake levels). Predicted tidal ranges are 

 published by the National Oceanic and Atmospheric Administration; 

 storm surges can be estimated by methods described in the SPM, 

 chapter 3; seasonal level data may be available through State or 

 local government agencies. Maximum water levels establish the 

 Stillwater level for estimating wave runup. Toe-scour estimates 

 should be based on the minimum water level. 



(e) Beach Composition . The foreshore, berm, and backshore 

 beach material-size gradations are necessary to determine the 

 revetment filter requirements. 



(f) Beach Use . Beach use for recreation and other purposes 

 may dictate use of upper beach revetment to contain runup and 

 sandfill on the beach face seaward of the revetment. 



VI. REVETMENT DESIGN PROCEDURE 



The previously listed design considerations must be satisfied to 

 ensure an adequate revetment design. Generally the most desirable reve 

 ment would have to be stable under the design wave attack, have a rough 

 and permeable surface to reduce wave runup and reflection, and be flex- 

 ible for satisfactory adjustment to settlement and scour. Detailed 

 design procedures as described in the SPM are summarized as follows: 



(a) Armor Unit Size . Determine armor unit size for sta- 

 bility under design wave for specified slope (App.; SPM, ch. 7). 



(b) Runup Elevation . Determine runup elevation of design 

 wave height and period for specific revetment slope and rough- 

 ness (App.; SPM, ch. 7). 



(c) Toe -Scour Depth . Determine toe-scour depth for design 

 wave for specific revetment slope and revetment wave reflection 

 (App.; SPM, ch. 5). 



(d) Toe Protection Type . Determine toe protection type 

 based on amount of allowable scour (Fig. 4) . 



(e) Revetment Slope Length . Determine revetment slope 

 length, based on runup, water level changes, and toe scour 

 (SPM, ch. 7) . 



(f) Filter Type . Determine filter type, based on embank- 

 ment gradation and revetment armor characteristics (Fig. 3) . 



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