that the roughness increased the set-up over smooth bottom conditions 

 by as much as two times when the water depth was slightly above the 

 roughness top, though decreasing it to a negligible amount when the 

 water depth was about half way up on the roughness strips. Wave heights 

 were not appreciably affected for large depths over the roughness tops* 

 but were reduced for small depths; generally wave heights could be pre- 

 dicted adequately by using an "effective" depth equal to the depth over 

 the roughness. A report was published as Technical Memorandum No. 95 

 of the Board, Funds for this study were provided by the District Engineer, 

 Jacksonville, Florida, 



V. University of California. Contract DA-49-055-eng-44. Laboratory 

 Study of Wave Refraction. 



Refracted wave characteristics were measured in the model tank 

 for a series of wave, slope, and depth conditions. Measurements show 

 that these conditions are being isolated. Data also shows that in 

 general Snell*s law applies (even for a vertical discontinuity in slope), 

 although for certain conditions the waves considerably over-refract. 



VI, Agricultural and Mechanical College of Texas, Contract DA-49-055- 

 eng-45. Wave Statistics in ^he Gulf of Mexico, 



Wave hindcast data were comple ed for five locations on the Gulf 

 Coast for deep water and four shallo\ water depths (12,24,48, 96 feet) 

 and were published as Technical Memoranda Nos. 85-89 of the Board. Also 

 published (Technical Memorandum No. 8') was a description of the methods 

 used in obtaining the data for the shallow water locations. A detailed 

 analysis of a number of the more severe hurricanes in the Gulf was also 

 prepared, and by using an energy coefficient, the relative severities 

 of most of the hurricanes of this half century were obtained and compared 

 (Technical Memorandum No. 98). 



VII. University of Florida, Contract DA-49-055-eng-55. Analysis of 

 Existing Data on Tidal Inlets . 



Available data on certain tidal inlets in the United States and 

 a few foreign localities have been reviewed. A detailed analysis of 

 this data has been made for the inlets where sufficiently detailed data 

 were found to exist. The purpose of the analysis is to derive, if 

 possible, a mathematical expression interrelating the variables which 

 govern the cross-sectional area and controlling depth of an inlet. An 

 interim report has been submitted and a report is being prepared for 

 publication. This study is administered by the Beach Erosion Board for 

 the Corps of Engineers' Tidal Hydraulics Committee, 



VIII, Agricultural and Mechanical College of Texas, Contract DA-49-055- 

 Civ-eng-56-4, Estimation of Hurricane Surges. 



A method was devised for taking into account the effect of bottom 

 roughness and the resultant bottom shear stress on the flow of water 



35 



