Use of the forraala derived hj Irribarren and Mogales should he limited 

 to smooth surfaces not overtopped by the waves and gives the slope i-iith a 

 reflecting pox^rer of about 50 percent. If used >jith the rougher reflecting 

 sui'faces it is greatly over-conservative. 



As the recoiiiBfinded values of the coefficient p are presently supported 

 by a limited nuBiber of observations, additional testing is desirable to 

 corrr^lete e-xisting data and evaluate tte various factors involved. Some 

 exanples are gj.ven as: 



1, InJT'luence of pronounced obliquity in direction of -wave 

 attack; 



2, Influence of roughness of surface in contact T>ri.th Faves 

 in relation to diiregnsions of the wavesj 



3« Influence of permeabilitjr of structures, or tlieir capacity 

 for absorption diu-'ing upmsh of tke wavesj 



if.. Influence of overtopping of the structure by vravesi 



5e Cases of beaches or ver'y flat slopes for which the 

 validitjr of equation 2 is problematical. 



Additional investigation is also desirable to determine the character 

 and magnj-tude of forces^ shocks and general pressm^es to wliieh the structures 

 are siibinitted diiring wave a,tts.cke 



Lication of the itethods described in this paper for determning 

 reflecting power of the structures bounding an ejs^anse of water does not 

 of course give the irLa5djTn.i3n wave aiiplitude that can be e^rpected at any 

 point -s-rithin the boujided expanse of water, but does define one necessary 

 stage in such a couples probleiii. 



