The output of the program is shown on pages 54 and 55 in the 

 Appendix. Page 53 shows a printout of the basic information of the open- 

 coast storm-surge problem. For example purposes, the values indicated 

 below the series of stars on page 53 are the wind stress, astronomical 

 tide, and pressure setup data generated internally in the program for 

 all reaches along the traverse line for two time levels. These data 

 provide the basic information for the storm-surge problem, and is input 

 by card when IDATA =1. In case that lOMITD = 1, this information is 

 not printed. 



Page 54 in the Appendix shows an example of a detailed printout of 

 the storm-surge results for a single time level. If lOMIT = 1, this 

 information will not be printed. 



Page 55 in the Appendix gives a summary of the problem, together 

 with the various components contributing to the total setup at the 

 mouth. Thus, it is seen that the peak surge for this storm for the 

 Chesapeake Bay Entrance is 13.4 feet. The estimate of the peak surge, 

 tabulated in the column of total water level, is assumed to be correct, 

 but other values for the total water level would require correction for 

 the tidal oscillation. Such an adjustment will not be shown here since 

 it is only a matter of trigonometry and arithmetic. 



Because the surge is not being evaluated at the shore for this 

 particular problem, wave setup is not a factor in the total setup. Other 

 factors such as effects of the inlet, local bed configurations, may affect 

 the total water level at the mouth, but since we don't know how to esti- 

 mate them, we will consider these effects negligible. Thus, the peak 

 design water level would be taken 13.4 feet for the given storm at the 

 mouth of Chesapeake Bay. 



Bretschneider (1959) used a one- dimensional numerical scheme for 

 computing the open-coast storm surge for the Chesapeake Bay Entrance. 

 Although he used slightly different hurricane characteristics than the 

 ones used here, it appears that for this particular case that both 

 schemes would, for all practical purposes, give a wind surge on the 

 same order of magnitude. 



We will now consider determining the storm surge in the Chesapeake 

 Bay Entrance by manual calculation. For such problems, a bookkeeping 

 system is needed, so that all the values to be calculated can be carried 

 out in a systematic manner. One method is to construct tables similar to 

 the one shown on Table 1 for each time level. Such tables allow stepping 

 through all discrete points in space as well as time. For example pur- 

 poses only. Table 1 shows the necessary computations at a time level 

 centered between t = 16.5 hours and t + t = 17.0 hours. This corresponds 

 to the time of peak surge found previously from the results of the com- 

 puter program. The table not only shows the basic data for the present 

 time level, but the necessary values evaluated at the previous time level. 

 Many of the columns give a breakdown of the pertinent equations presented 



35 



